Indian Boiler Regulations, 1950.

REGISTERED No. D-481 The Gazette of India EXTRAORDINARY PART II—Section 3 PUBLISHED BY AUTHORITY No. 43 ] NEW DELHI, FRIDAY, SEPTEMBER 15, 1950 GOVERNMENT OF INDIA MINISTRY OF WORKS, MINES AND POWER CENTRAL BOILERS BOARD NOTIFICATION BOILERS New Delhi, the 15th September 1950 S.R.O. 600.—In exercise of the powers conferred by section 28 of the Indian Boilers, Act, 1923 (V of 1923), and in supersession of the Government of India Notification No. A. 470, dated Simla, the 27th October 1923, the Central Boilers Board is pleased to make the following Regulations, the same having been previously published as required by sub-section (1) of section 31 of the said Act, namely :— REGULATIONS PRELIMINARY 1. Short Title, Extent and Commencement;.—(1) These Regulations may be called the Indian Boiler Regulations, 1950. (2) They extend to the whole of India, except Part B States. (3) They shall come into force at once. 2. Definitions.—In these Regulations, unless the context otherwise requires,— (a) the "Act" means the Indian Boilers Act, 1923 ; (6) "accident" means an explosion of a boiler or steam-pipe or any damage io a boiler or steam-pipe which is calculated to weaken the strength thereof so as to render it liable to explode ; (c) "boiler" means any closed vessel exceeding five gallons in capacity which is •used expressly for generating steam under pressure, and includes any apparatus forming an integral part of a boiler, which is wholly or partly exposed to the action of the flue gases for purpose of recovery of waste heat, and also includes any mount- ings or other fittings attached to such vessel which is wholly or partly under pressure when steam is shut-off but not withstanding anything contained in section 2(b) of the Act doss not include an economiser as defined in clause (cc) of section 2 there- of- (d) "Chief Inspector" and "Inspector" mean, respectively, a person appointed to be a Chief Inspector and an Inspector under the Act; (e) ''economiser" means any part of a feed-pipe that is wholly or partly exposed to the action of flue gases for the purpose of recovery of waste heat ; (/) "feed-pipe" (i) moans any pipe or connected fitting wholly or part ly under pressure through which feed-water passes directly to a boiler. (ii) every reference to a steam pipe or steam pipes shall be deemed to include also a feed-pipe or foed-pjpes respectively ; (g) " Inspecting Authority " means an authority recognised by the Central Boilers Board as competent to grant n certificate in Form II* . (h) "Inspecting Officer" means— (i) in respect of material manufactured or boilers eonaUucled in any State an officer appointed by the Inspecting Authority in t ha t State. (ii) in respect of material manufactured or boilers constructed outside the States an officer acting on behalf of the Inspecting Authority ; (t) "owner" includes any person using a boiler as agent of the owner thereof and any person using a boilor ^ hich he has hired or obtained on loan from the owner thereof; (j) "prescribed" means prescribed by regulations or rules made under the Aot ; (k) "Steam-pipe" means any main pipe exceeding three inohes in internal dia- meter through which steam passos directly from a boiler to a prime-mover or other first user, and includes any connected fitting of a steam-pipe ; (1) "State"' or ' 'States" mean a State or the States to wMch these regulations extend ; and (m) " Structural alteration, addition or renewal" shall not T6»e deemed to include any lonowal or replacement of a petty nature when the part of fitting used for re- placement is not inferior in strength, efficiency or otherwise to the replaced part of fitting. *NOTM.—-Fot List of Inspecting Authorities reoogmsed by the Oontral Boilers Boardi see- Appendix U- CHAPTER I GENERAL REQUIREMENTS, APPLICATION OF STANDARD CONDITIONS AND EXCEPTIONS THERETO 3 (1) A boiler shall not bo registered undor sub-section (4-) of Section 7 of the Aot and n certificate shall not be issued under sub-section (5) of that section with reference lo a boilor, unless the sttmdnrd conditions in respect of material, design and unibtruction, 'which arc specified in. the subsequent Chapters of these Regu- lations me natiwnod in respect of such a boilor. (2) Notwithstanding anything contained in sub-regulation (1), the Chief Ins- pector may, Ruhjcrt to the provisions of Regulation 7, register a boiler and order tho issue of a certificate authorising the uso thereof, although the standard conditions are not fully satisfied in respect; of such boiler : Provided that the Chief Inspector shall not register such boiler or order the issue of such certificate, if a structural part of Hweh boilor which, is subject to piessure is made of Bessemer prpcees steel or( of cunt oi malleable cast iron. i STANDARD REQUIREMENTS ' 4. (aVM&tlWi&l.—All platwS, rivets and bars used in1 the construction of boilers shall bo tested and found to conform with the Regulations hereinafter contained, i tb) Coiistrutitibn.- Â l boilers during construction shall bo under the supervi^ eion of an Inspoctijijj Officer. (c) Inspecting Authority's certificate,—For boilers imported into the- States a. t, certificate from an Inspecting Authority in Form II certifying that the material was tested and the boiler built under their MI|><T\ Nimi >hfill be furnished to the Chief Inspector before or with the application J'oi ic^iMiiiiion. Together •with such in Form I prepared in the ]II;IMIUT pu MiMicd h.v UCJMII.U ion :>M> in respect of the ins- pection of the boiler during construction and the hydraulic test applied on comple- tion. In the case of steel made and tested by well-known makers in India or other countries the certificate of the makers in Form IV as prescribed in Regulation 26 may be accepted in. lieu of a certificate from an Inspecting Authority. The Central Boilers Board shall decide whether for the purpose of this Regula- tion a maker is " well-known" or not. (d) Certificates, etc. under section 14(1) (c) of the Act.—In advance of or along with an application for registration of a boiler, the following certificates and draw- ings or specifications should be furnished to the Chief Inspector, namely:— (i) A certificate in Form III of manufacture and test signed by the maker or by a responsible representative of the maker of the boiler containing a description of the boiler, its principal dimensions, particulars of the kind of material used in its construction, the thickness of all plates, the diameter of and method of forming the rivet holes in the shell platep, particulars of any departure from ordinary practice- in making the shell such as solid rolling or welding, the hydraulic test to •which the boiler was subjected, the intended -working pressure, the area of heating surface, the maximum continuous evaporative capacity, the year and place of make, and the works number of the boiler. There may be included in such certificate a further declaration that samples of the angle, stay or rivet bars and rivets used in the construction of the boiler have been certified by the makers to have been tested and found to comply with the re- quirements of Chapter II; in which declaration the kind of material used and the limits of tensile breaking strength with which the tests-comply shall be stated with sufficient precision to obviate the risk of confusion in making nllo-w imii-. Where such further declaration is included in such certificate, the cortiii<;)1-1.- v<i\ rrc <l to in clause (iii) of this sub-regulation shall not be required. (ii) A drawing or print to a scale, in the case of large boilers of not less than f inch to the foot and, in the case of small boilers, of not less than 1J inches to the foot, showing the principal dimensions and a longitudinal section and end -new of the boiler, and bearing the works number of the boiler and the maker's cffice stamp. The drawing shall show details of riveting of longitudinal and circumferential sean\<- with pitch of rivets, cross spacing of rivet rows and diameters of rivet holes : the radii of curvature of dished end plates, fillets of flangep and corners of bent plates, and where gusset stays are fitted, the number and diameter of rivet holes in each gusset In the case of water tube boilers, the foregoing scales phall apply to the main boiler drums only, but in addition a general arrangement drawing of the boiler to a scale of not less than "J" to the foot shall be provided. (iii) A certificate from the steel maker and a certificate from the maker of the plates, rivets or bars, of the nature referred to in Regulations 26 and 27 respectively. The certificate from the maker of the plates, rivets or bars, shall show the charge numbers, the plate or bar numbers and the number and dimensions of the various plates, etc., tested, their ultimate tensile breaking strength in tons per square inch of section, th" y "r"' • "" elongation and the length on which measured, the number, kind .,. •• . • ,. '•• or other tests made and the date of tests: Provided that whore an Inspecting Authority furnishes a certificate in Form I I together with a Memorandum of Inspection book in Form I in accordance with Bub-regulation (c), the certificates proscribed, under oluuses (i) and (iii) need not be furnished to the Chief Inspector when application is made for registiation of the boiler. But should any question arise in respect of the fitnoss of the boilers for the working pressure approved by the Inspecting Authority within a period of three years from the dato of their certificate, tho owner shall, if requested by the Chief Inspector, obtain and furnish the original documents specified in the said clauses. (p) Maker's stamp.—The boiler shall have stamped upon its front plate in a • oonapiouous position tho following particulars :— Mtiker's nmae Year at muke Work's nurabor Toated to lbn. on IiispiK'ting Officer's or Inspecting Authority's official tttamp. 6. Modification of formulae.—(i) Under the "Regulations for determining the working pressure to be allowed on various parts of boilers, the material to which the formulae apply shall in the absoncc of express provision to the contrary be steel complying with the requirements of Chapter II . (ii) Wheie no test certificates for shell plates and rivets are produced, the mate- rial may be treated as iron, if the Chief Inspector is satisfied that tho material is of suitable boiler quality. If in such cases the Chief Inspector is dearly satisfied that the material is of good quality, n, higher strength than that allowed for iron may be permitted but tho strength of the shell plates shall not, save for special reasons, bo assumed to be more than 20 tons. In such cases S and Sx in equations 1, 3 and 4 of Chapter IV may be respectively 20 and 21 for steel and 21 and 18 for iron. For iron across tho grain S may be 18. (iii) Where end plates, furnaces, flat plates, girders, gusset and other stays, etc. are made of stool or iron for which no test certificates are produced, the working pressure as found from the formulae in which S is to be taken at tho lowest limit proscribed for the pert, reduced by lfi per cent, shall, oxcept where such material is specifically provided for m nny founulH, be tho working pressure permitted. For flat plates of copper, the working pressure fts found from the formulae, reduced by 50 per cent, shall be the working pressure permitted. 6. Standard speoifloations for materials.—-The standard specifications for steel wrought iron and copper plates and barn, and for east steel shall be those prescribed iu Chapter II, but certificates of tests of material for wrought iron (exoept for special wrought iron for screw stays) copper and cast steel shall not be required unless special allowances are required. Suoh spocial allowances shall be in the discretion of the Chief Inspector. 7. Boiler Shells not in accordance with standard conditions.—When the standard conditions are not complied with, additions to the appropriate coefficient as defined in Regulation 176 shall be made as follows :— (a) When there are no proofs of testa of steel, 15 per cent, of the standard co- (b) When a boiler has not been inspected during construction by an Inspecting Officer and certified by him, 10 per cent, of the standard coefficient. (o) When the workmanship is in any way doubtful and the Inspector is not /satisfied that any of the foregoing additions to the coefficient would be sufficient. SEC. 3] THE GAZETTE OF INDIA EXTBAOEDINAEY 611 to meet the circumstances, such percentage of the standard co-efficient as the Chief Inspector deems fit. Provided that nothing in this regulation shall apply to a hollow forged or a fusion welded drum if it is constructed under the supervision of an Inspecting Authority. 8. Welding-—The use of welding in the construction of boilers shall be 1 permitted only where specifically provided for in the standard conditions. CHAPTER II MATERIALS OF CONSTRUCTION STEEL PLATES, RIVETS AND BARS 9. Process of manufacture.—Structural stool for boilers shall be mad" by the - Open Hearth or an electric process, acid or basic. 10. Chemical Analysis.—(a) The steel shall contain not more than 0-06 per cent, of sulphur or of phosphorus. (b) A sulphur print test shall be taken from the material of each charge used for rivet bars for the purpose of ensuring that sulphur segregates are not concentrated in the core. The stage in manufacture at which this test is made shall be at the option of the Steel Maker. 11. Freedom from Defects, etc.—The finished material shall be sound and free from cracks, surface flaws and laminations. Hammer dressing, patching or welding is prohibited but this does not prevent the removal of slight scale or shell by the use of chisel, file or buff, providing the material is not reduced to under the specified thickness. 12. Rolling Margin—No plate or rolled section shall be under the specified thickness at any part, nor more than 5 per cent, over the calculated weight, except that in the case of thin plates and wide plates the weight tolerances shall be as set out in the table below. Schtiule of pnrsenttjz Billinj anight tolerances for boiler plates. Thickness in. 1/4 to under 5/16 5/16 to under 3/8 3/8 to under 7/16 7/16 to under 1/2 1/2 to under 5/8 5'8 to under 3/4 3/4 to under 1 . 1 to under 2 . . Under to under o o Width m to under fro under la o o n i inches to under to under to under to under o/ /o and over /o All the above margins will be taken over nett theoretical weight. 18. Testing and Inspecting.—The following tests and inspections shall be made at the place of manufacture prior to despatch ; but, in the event of any of the material proving unsatisfactory in. t,lxe opqrfie of, being worker! into boilers, suoh material nh.aH be rejected, notwithstanding any previous certificate of satisfactory testing, «nd suoh further tests of the material from the same charge shall bo made as the Trtwpsiotitig1 Qffieef in- attendkhice1 may f-onsider desirable, 14. Selection oi test pieces.—All ttst pieces shall bo seleotod by tho Inspecting Offioor and tested in his presence, and he shfill satisfy himself that the conditions 'flWiii described are fulfilled. ' 16. (a) Tensile test pieces.—The tensile strength and ductility shall be deter- mined from standard test pieces (see App. "R) cut lengthwise or crosswise from tho rolled material. When material is annoaled or otherwise treated before despatch, tho test pieces shall be similarly and simultimeously tieatod with the material before testing. (b) (I) Plates, Angles and Tees.—Wherev^t practicable, the rolled surface shall be retained on two opposite sides of tho test piece. Tho tensile stress and elongation shall bo determined on standard test piece A (see App. B). (ii) Bound Ban.- -Round bars may be tested fall size tm rolled or they may be turned down to a convenient size If tested 1 inch djamettjr or under, test piece B (see App. B) shall be used. The sectional area of the tosi piece shall not be less than J squaro inch. Where fhe te,a,t piece is over 1 inch diameter, test piece Bx (see App. B) may b» usod. Any straightening of the test pieces which may be required shall be done oold. , J6r Tensile Testff.^-The ultimate tensile stress and elongation of the various ojasmos qf ,ma;terials phall be between tho limits shown in the table below but a range , of not mppo t h w 4 tons in'each olass of material shall be permitted. Should a tensile tost piece break outside the middle half of the test gauge length the test may be discarded and another test be made of tho same plate or bar. 1 i Pluten for shells butt utrrtp^, Flutes for fiii'iiacoH Rivot burn Ulhnidto toilflllo in 26—:t(l 2(1—Ifl Minimum elonKotion per oeut. Tre t̂ piono A 23 iur 2fl- 30 20 for 28 -32 20 for 3 2 - 36 23 for 2 4 ^ 3 0 20 for 28—32 23 for 2fi- 30 20 for 28—32 20 for 32—3fi 23 for 26—10 20 for 28—32 20 for 32 --30 25 for 24^-2.S 23 for 26—30 28 for 20- -30 24 for 28- - 32 24 for 32—38 30 for 2<1—2S 28 for 20- 30 17. Number of Tensile Tests.—(a) Plates.—For sholl platca, butt straps and gusset plates one tensile tost pieoo shall bo cut from oach end of every plato as roll- ed. (b) For other plates such as end plates, furnace and flanging plates etc., on« tensile tost pieco shall bo cut from one ond of every plate as rolled. (c) Angle, tee, rivet and stay bars.-—One tensile test shall be made from oaoh 15 or part of 15 bars rolled of oach seotion or diameter from tho same oharge, but not lesa than two tensile tests shall be made unloss the total number of bars rolled from tho ^arae charg-e is1 8 or less than 8 and the bars are of the same section or diameter, in J ^hfeh! odm brie tensile teat shall suffice. For round bars of 1} inches diameter and under, the numbers 50 and 20 shall be substituted for 15 and 8 respectively for determining the numbm of tests required. 18. Dump Testa.—Short lengths equal to twine, thoir diameter out from tho rivet bars shall, when rold, withstand -without fraoture being compressed to half their length. A dump test shall be made for eaoh Tensile Test. 19. Bend. Testa.—(a) Cold Bends.—Test pieces shall bo sheared lengthwise or crosswise from plates or bnrs, and shall not be less than 1 | inches wide, but for small bars the whole soetion may be used. For rivet bars bend tests aro Hot required, (b) In all cold bend tests, on samples 0" 5 inch in thickness and above., tho rough edge or arris caused by shearing may be removed by filing or grinding, and samples 1 inch in thiokness and above, may have the edges maohinod, but the test pieces shall receive no other preparation. The test pieoos shall not be annoaled unless the material from which they are out is similarly annealed in which case tho test piece shall be Similarly and simultaneously treated with tho material boforo testing. (o) For oold bend tests the test pieoe shall withstand, without fracture, being doubled over until tho internal radius is equal to 1£ times the thickness of the test pieoe and the sides are parallel. (d) For small sectional material these bond tests nmy be made from the flatten- ed bar. (e) Bond tests may be made either by pressure or by blows. 20. Number of Bend Teats.—(a) Plates.—A bend test shall bo taken from eaah plnio aw rolled. Vor plates exceedins; 2J- tons in weight one bend test shall bo taken from eacli end. The bend tests from shell plates, butt straps and other platen which have not to be flanged or •« ork<-d in the fire or Avhiob when in use are not to be exposed to flame shall be oold bend tests. (b) Angle Bars.—A oold bend lest shall be mado from eaoh angle bar rolled. (c) Stay Bali.—A cold bend (est shall be made from every i 5 stay bars a& rollod from eaoh oharge. 21. Manufactured Rivets.—(a) Quality of Material.—Rivets shall bo manufac- tured from steel complying with the aforementioned requirements of this Chapter in respect of iivot bais. (b) Tests. —(i) Tho rivet shanks shall bo bend cold, and hammered until two parts of the shank touch, without fractuie on Ibe outsirlo of the bend. (ii) Tho rivet heads shall be 6attenod while hot, without craoking at the edges, until their diameter is 2J times the diameter of the shank. (o) Number of Tests. —"Op to half per cont oi rivets of eaoh size shall bo selected by the Inspector or Inspecting Officer from bulk for the above tests. 22. Additional tests before rejection.—Should the test pieces first rjelootod by the Inspeotor or Inspecting Officer not fulfil the test requirements, two further tests of the sanio kind may bo made, but should either of these fail, the plates or bars from which test pieces wore out shall be Telected. In all such oases further tests shall be made before any material from tbo same charge can bo accepted. 28. Branding.—Every plate and bar shall be clearly and distinotly marked by the maker in two plaoes with .in approved quality hi and indicating that the material has complied with the lequired tests ; and alno with the number or identification marks by which they can be traced to tho charge from winch the material was made. 24. Defacing of rejected material.—In the event of the matorial failing in any case to withstand the prescribed tests, the Inbpectnr or Inspecting Officer shall see that the quality brand stamped on the matorin.1 has been defaced by punch marks xtending bevond the brand in the form of a cross, denoting that the material has e«ec rejected. 26. Facilities tor inspection.—The maker shall adopt a system of marking tHe' inpotH, billets, slabs, plates, bars, e tc , which will enable all finished material to bo traced to the original charge, and the Inspector or Inspecting Officer shall be given every facility for tracing all platen and bars to then* respective charges, and for witnessing the required testa. When ho is satisfied with the material and with the results of the tents, tie shall be furnished with two copies of the advice notes of the' material for his signature. 26. Steel not produced where rolled.—Where steel is not produced in the work* at which it is rolled, a certificate in Form IV shall be supplied to the Inspecting Officer deputed to witness the testing of the material, stating the Open Hearth or Electric Process by which it was made, the name'of the Steel Maker who supplied it, also the numbers of the charges for reference to the books of the Steel Maker. The number of the charge shall be marked on each plate or bar for the purpose of identi- fication, 27. Maker's certificate.- -Before tho mill sheets are signed, the maker shall furnish the Inspecting Officer with a certificate in Form IV guaranteeing that tha material ha.s been made by the Open Hearth or an Electric Process acid or basio and that it has been subjected to, and has withstood satisfactorily the test above described in the presence of the Inspecting Officer. WEOUOT IRON STAY AND HIVET BARS 28. Rivet Bars.--The tensile breaking strength shall bo between 21 nnd 2fl tor* with HU elongation of not less, than 25 per cent, measured on tho standard Tost Pieoe B (as rolled) or 30 per cont. measured on the Standard Test Pieoe Bx (as rolled). 29. Manufactured Rivets Tests.—To oomply with Regulation 21. 30. Stay Bars. —Tho tensile breaking strength Fhall be between 21 and 25 tonff with an elongation of not less than 22 per cent, measured on the Standard Tost Pieoa B or 27 per cent, measured on the Standard Test Piece B r 3X. Stay Bars—Bend Tests.—To comply with Regulation 19 32. Special Iron for Screw Stays for Fireboxes and Combustion Chambers.—I» order that iron screw wi ays may be approved of the same size an would be required for mild steel, the iron must withstand the following tebts:— (a) Tensile Tests.- -The tensile breaking strength.shall not bo less than 211 ton* per square inch, with an elongation of not less than 25 per cent, measured on the Standard Test Piece B or 30 por cent, measured on the Standard Test Piece Bx. (b) Bend Tests. —Tost pioces oither of tho bar as rolled, or turned down to 1 inch diameter, ^hall stand bending cold until the sides ate parallel and the space between the two sides is not greater than tho diameter of the test pieoe, (o) Number of Tensile Tests.—The bare us rollod shall bo placed in batohes of twenfcv, nnd one tensile test shall be t aken from each batoh, If this is unsatisfactory two other bars shall be selected for test, and should either of these fail tho batch shall be rejected. (d) Number of Bend Tests.—One ordinary bond tost shall bo taken from eaoh batch, and a similar test piece from each batch shall be lightly and evenly nicked on one side with a sharp cutting tool and bent back at this point through an anglo of 180 degrees by piossure or by a succession of light blows. The fraoture must be clean, fibrous, free fiom slag or dirt or any coarse crystalline structure, If cither of these is unsatisfactory, two other bars shall be selected for test, and should either of these fail the batoh shall be rejected. (e) In all cases the selection of tho test pieces shall be made by the Inspector or the Inspecting Officer. COPPER PLATEvS, STAY AND RTVET BARS AND TUBES 33. Plates—(a) Process.—Tho oox>por shall be nre-refinod or electrolytic, and hot-rolled from suitable nakes. (b) Chemical Composition.—The platan shall contain not loss than 99 per oent. of coppor, and between -3 % and -5 % of arsenic. (o) Freedom from defects.—Tho plates shall be cloan, smooth and froe from defects and shall have u workmanlike finish They shall be thoroughly annealed. (d) Boiling Margin.—No plat a shall bo under the specified thickness at any part, nor more than 5% over tho calculated weight. The scrap margin, partly sheared and left attached, shall be no1 lean than 3 inches tit the ends and 1J inches tiit each Hide. (e) Tensile Tests.—One tensile tusl shall bo taken from eaoh plato as rolled. The tensile breaking strength, fi oin Standard Test Piece A, shall not be leas than 14 tons per sq. in. "with an elongation of not loss than 35%. (f) Hot and Cold Bend teats. -Ono hot (temperature between 1200°T\ and 1400oI\) and ono cold bend test shall bo taken from each plate as rolled. Tor either hot or cold bend 1estH the test piece •ahall withstand being doubled. ovei without fraci uro uniil the sides are touching and parallel. 34. Stay and Rivet Bars—(a) Process.—To comply with Regulation 33 (a). (b) Chemical Composition—To comply wilh Regulation 33 (b). (c) Freedom from Detects.—To comply with Regulation 33(o) (d) Rolling Margin.—The bars in any part shall not be more than 1% over or more than 1/2 % under the specified diametci (e) Tensile Tests.—The tonsile broaking-sttength shall not ho less than 14 tona per sq. in. with an elongation of noi IOHH than 40% on the Standard Test Pieoe B. (f) Bend Teats. -To comply wilh Regulation 33(f). (g) Dump Tests. -Apiece of tod 1 in. long shall be placed on end and hammered or crushed down cold to a thick nebs of 3/8in. without showing either crack or flaw on tho circumference of the resulting dine. (h) Number of Tests.—One bar, from wliioh the required test specimens shall be taken, shall be solei ted at rnndom from each batch of 50 (or part thereof) bars of eaoh size from each melt. From each bar selected one tensile test, one cold bend test, ono hot bend test, and ono dump test shall bo made. 35. Tubes—(a) Process.—The copper shall bt fire-rofined or olootrolytio and shall bo made into tubes eithei by tho hot rolling or cold drawing piocess. The tubes shall be finished by cold drawing. (b) Chemical Composition.—To comply with Regulation 33(b). (c) Freedom from Detects.—The finished 1ubof», both externally and internally shall be sound, clean, smooth well finished and free from surface defects and longi- tudinal grooving, and the ends must bo clean and square. (d) Tolerance.—Tho actual weight of oaoh tube ahall not be more than 6% above the calculated weight. Unions, otherwise specified, they shall be straight cylindrical, of uniform tki<knoas and external diameter throughout. (e) Treatment o! Test Specimens.—All teat material, if not already hi an annealed condition, shall be annealed before testing and shall comply with the mechanical tests without further heat or mechanical treatment. OOLD DRAWN SEAMLESS STEEL BOILER AND SUPERHEATER TUBES— FOR DESIGNED STEAM TEMPERATURE NOT EXCEEDING 850°F (454°0) 36. (ft) Material.—The tubes shall be seamless and made of steel produoed by an Open Hoarth or Electric ProoesB, acid or basic, and shall be certified as such by the makers of the steel and tubes. The material of the tubes shall show on analysis not more than 0 • 045 por cent .of sulphur and 0 • 04 per oent. phosphorus and the manufacturer shall supply a certificate of the analysis when required to do so. Note.—Where the material i*» Uhed for designed stoam tern features above 750°F (399°0) and not exceeding 85O°P (454°0) the steel shall be of non-segregated of fully killed type. (b) Annealing.—The tubes shall be oarefaUy annealed throughout their length flfter the operation of drawing and the ends shall be carefully annealed after the process of swelling or reduoing the diameter. (o) Freedom from Defects.—The tubes both internally and externally shall be -sound, clean, smooth, well finished and free froni surface defects, rust, longitudinal Beaming and grooving. The ends shall bo clean and wquare. (d) Tolerances.—(i) ThlokneSB,—Tho tolerance in thickness shall be 5 por oent. toelow and 10 per oent. above the specified thickness. (ii) Swelled or Reduced Ends.—Where tho ends of tubes are swelled or reduced, the thickness at the ends may be reduced, or increased under or over, the actual thickness of the tubes by an amount strictly in proportion to the percentage of suoh swelling or reduoing and in addition to this allowance tho tolerances specified in paragraph (i) of this sub-regulation shall also apply. (iii) Diameter.—The external diamoter of the tubes, measured at any point shall be not greater than that specified, but may be loss by not more than 1 per oent, (iv) Length.—The length of the tubes shall be not loss than that epeoifiod and not more than 1/8 inch greater. 37. Selection of Tabes for Test.—Two per oont. of the tubes of oaoh thickness and diameter and only one for every 100 or part thereof above 400 tubes of suoh •similar size shall be made available to the Inspocting Officer for testing to the -extent of such numbers. 38. Tensile Test.—Test pieces out from the endft of the selected tubes shall comply with the following requirements :— .Strip out from tubes imd tested in thon' curved conditions. "Test lengths taken from finiahod tuboa (ends to be plugged for gripa). Ultimate tennde Not lesd than IS ot moro than Minimum i>loiigntion per cout. On i £ in. think and ovor i in. LOHO fclitin i" thick. On 2 in. £ in. thioli and over Letw than i" thiok. flue. 81 THE GAZETTE OF INDTA HXTBAORDINAEY ttlT 39. Flattening Test.—A ring not leas than 2 inohe* in length out from one end of each selected tube shall be flattened between two parallel flat surfaces, the width ofwhioh shall be not less than 1£ times tho diameter of the tube. When the pres- sure is released, the interior surfaces of tho lent piece (at the middle) shall remain at the following distances apart and the tent piece shall then show no sign of oraok or flaw. Tuboa over 10 3.W.G. in thieknrww TuboB up to and including 10 S.W.C1. in thickness. N't it THoro than twice the thicknem of the tube. Until the interior surfaces meet, at th» middle 40. Expanding Tests.—-The tubes shall withstand expanding by a drift expander having a total included angle of between 40° and 60° (20° to 30° per side) to the following increases in external diameter without showing crack or flaw. Thickness of tube 8 S.W.O. and thinner Increase in diameter per cent. 41. Additional test before rejection.—(a) Should a tube seleoted for testing purposes show definile signs of failure in any one or moro of the testa speoified in Regulations 38, 39 and 40, two further tests of the same kind may be made at the option of the manufacturer from two additional tubes selooted from tho same batch. (b) If the ropeat tests tire satisfactory the tubes shall be accepted provided that in all other respects they fulfil the conditions of this Standard. Should either of tho tubes fail in any test, the biitch of tubes represented may be re-heat-treated in accordance with. Rogulation 36(b) and then retested in accordance with Regulations 38,31) and 40 but employing twico the number of tost pieces. If these seoond repeat tests are satisfactory, the tubes shall be accepted provided that in all other respects they fulfil the conditions of this Standard; but if definite defects are again shown, the batch of tubes which tho test pieces represent shall be rejocted. 42. Hydraulic Test.—Each tube shall be tested at the makers works by hydrau- lic pressure in accordance with the following table governing the rolation between the test pressuro and tho design pressure to which tho tube will bo subjected in aei-vioe. Design pressure lb/nq. in. Up to and including 500 . Abovo COO upto tind including 1000 . Abovo 1000 minimum inoo Twice tho design pressure: 1000 ubove the design pressure. -#18 THE GAZETTE OF INDIA EXTRAORDINARY [PART U In all i-nses the tensile strews (S) on the material when under these tests shall DP not exceed 10 tons, per sq. in. as doterminod by the formula S «= -5— Where D =aoutsido diameter of tho tube in inches P a tea t pressure in tons per sq. in. t =inominal thickness of tube wall in inches. HOT FINISHED SEAMLESS STEEL BOILER AND SUPERHEATER. TUBES FOR DESIGNED TEMPERATURES NOT EXCEEDING 850nF (454°C) 43. (a) Material.—To comply with Regulation 36(a). (b) Annealing.—The ondt- of all tubon shall be carefully annoaled to a length not less than 0" if they have been submitted 1o a process of swelling or reducing the end dimensions. (c) Freedom from defects.—To comply with Regulation 36(c). (d) Tolerances.—The tubes shall be of the dimensions spooifiod, straight, cylin- drical, of uniform thickness and edema 1 diamol er i hroughout, subject to the working" margins piveti in the table below:— (i) Diameter.—The external diameter of the tubetj measured at any point shall be within the following tolerances of diameter specified :•—- Up to tirid including 2J in. H 1 % - (ii) Thickness.—Tho thickness of the tubes shall be within the following toleranoen •- — Outsido rlinintjter of tubes. Up to ami moluding 2J in. Tolerance J 17*% ^ io% Whero the ends of the tubes are swelled or reduced the thickness at the enda may be decreased below or increased above the nominal thiokness of the tubes by an amount in proportion to the percentage of aueh swelling or reduction and, in addition to this allowance, the tolerances relating to thickness shall also apply. (Jii) Length.—The tubos shall be not less than the nominal length but may «xcccrl it by the amount given below :— Up to and including 30 it. Over 30 ft 1/8 in. iH in. (e) Selection of tubes for test.—To comply with Regulation 37. 44. (a) Tensile Test Tost pieces out from the ends of tho annealed portions removed from tho ends of the selected tubes shall comply with tho folio-wing require- ments :•— Strips cut from tubes und tested in thoir curvod condition. Test lengths) tuken from tubtiH to be plugged from gripa). Ultimate tunsile HCJ. in. Not loss than Not more than Minimum nlongution ptir rent. on 8 1/4 in. thick and over in. Lena than 1 /4 in. thick on '2 in. 1/4 in. thick and over ,-JO Leni thn,ii 1/4 in. think (b) Flattening Test-—A ring not less than 2 inches in length cut from the anneal- ed portions removed from tin1 ends of the selected tuboH Hhn.ll be flattened between two parallel flat surfaces, (he width of which shall be not less than ] J times tho diameter of the tube. When the pressure is released, the interior surfaces of the test piec,c at the middle shall remain at a distance apart of not more than three times tho thickness of tho tube and 1 he test piece shall then show no sign of crack or flaw. (o) Expanding Tests.- -The annealed tube ends shall wilhstand expanding by a drift expander having a total included angle of between 40° and 60° (20° to 30° per side) to the following increase in external diameter without showing truck or flaw:— Thinner than 5 S.W.G. und up to and including 3 8.W.G. Increune in Diameter peT o«)it. IB 0-fi 45. (a) Additional tests before rejection.— Should tube suleettd for testing pur- poses show definite signs of failure in any one OJ more of 1he tests specified in Bogu- lations 44(a), 44(b) and 44(c) 1 wo further tests of the same kind may be made at the option of the manufacturer from tw o additional tubeH selected fi om the same batch. (b) If the repeat tests are satisfactory the tubes shall be aooepted provided that in all other respeots they fulfil the condition* of this Standard. Should eiiher of the tubes fail in any test, the batch of tubes represented may bo re-heat-treated in aooordanoe with Regulation 43(b) and then re-tested in aocordanoe with Regu- lations 44(a), 44(b) and44(c) but employing twice the number of test pieces. If these second repeat tests are satisfactory, the tubes shall bo aooepted provided that in all other respects they fulfil the conditions of this Standard; but if definite defeots are again shown, the batch of tubes which the tests pieoes represent shall be rejeoted. 46. Hydraulic Teit.—Each tube shall be tested at tho makers' works by hydraulic pressure in accordance with the following table governing the relation between the test pressure and the design pressure to which, the tube will be subjeoted in service. Up to and including 500 Above fiOO up to »nd including 1000 Above 1000 . - Hydrnuho test pressure Ib./sq. in. minimum Twice the danign pressure 1000 above the design preaauro. In all cases the tensile stress (S) on. the material when under these terti eh all not exceed 10 tons per sq. in. as determined by tho formula :— DP S ~ — 2t Whore D =* outside diameter of tubo in inches. P = test pressure in Ions per sq. in. t =• Nominal thk'knesN ot tube wall in inches. SEAMLESS HALF-PER CENT. MOLYBDENUM STEEL BOILER AND' SUPERHEATER TUBES EOR DESIGN STEAM TEMPERATURES NOT EXCEEDING 950cr (51()°O) 47. General.—Those Regulations (over both hot finishod and oold drawn seam- less boiler and superhoatei tubcR which Hhall conform in all respects with the require- ments herein specified. 48. (a) Material.—The 1ubos whaJl bo manufactured from steel produoed by the Open Hearth or Elootrio processes and shall conform to the following limits of chemieal compositions:— I'arbon . . . . . . . . 0 15% maximum Mmnganemi . . . . 0 4 0 to 0-70% Silioon . . . - 0 1 0 toO -38% Sulphur . • • • . 00.1% maximum Molyodouum 0-4"> to !• 63% The steelmaker shall supply a certificate of the normality of the steel. (b) Heat Treatment.—The tubes shall be normalised at a temperature bet-ween (o) Workmanship and toleranoe.—The tubes shall be well finished, 'olean and free from harmful defects. They shall bo reasonably straight, smooth, cylindrical, and subject to the following tolerances before bending :— (t) Diameter.—The external diameter of the tubes measured at any point shall be within the following tolerances of the diamoter specified :•— Type of Tube Hot finished . Cold drawn Ontsidn Diameter of Tube "Up to and including '2^ in. Over 21 in Tolerance -i 1/04 in. — 1/32 in. (ii) Thiokne«S.~The thickness of the tubes shall be within the following toler- anoea:— Hot . finished . U p to tincl inc lud ing 2J in. . . . Ovor 2-J in. Toleranue + Mt% - 7 i% H 115% H 10% Where the ends of the tubes are swelled or reduced the thicknopis at the ends may be decreased below or increased, nbove the nominal thickness of the tubes by an amount in proportion to the pereontage of such swelling or reduction and, in addition to thi'i allowimee. the 1oVrane.es relating to thickness shall also apply. Swelling or reduction sha.il \m carried out before the heat treatment specified in Regulation 48(b). (iii) Length.—The tubes shall bo no1 less than the nominal longth but raay exceed it by the amount given below :•— "Up to imd inclnrhng 30 it 1/8 in. 1/4 in. (d) Seleotion oi tubes for testing—After heat treatment, tho tubes shall bo presented foi1 mechanical teHting in accordance with Regulations 49(a), 49(b) ami 49(c) in batches of not more than 100 of the same nominal diameter and thickness. Tho manufacturer shall provide at his own expense extra tubes at, the rate of 2 per cent, of each diameter and thickness of tube specified and thi-> ]nsi~»oetiiig Offioer shall select for 1 est such of the tubes as he may think proper to the extent of the percentage mentioned. Should the number of tubes ouleied of any one nominal size exceed 400 then, for every 100 tubes or part thereof above that number, one additional tube shall be provided. The .samples for testing shall not bo heat-treated after selection. 49. (a) Tensile Test—Test pieces out from the ends of tho selected tubon shall comply with tho following requirements:— Strips flit from tubes tind timtod in their curvnd condition. Testi LoiigtliH tuknn from fniwhod tubes (en<ln oftnboH to be plugged for gripw). in tonn p«r sq. in Not lorn than 2r, Not more thtin Minimum elonfjution per oont. on M mches ami ovor LOHH than 1/4" thick (b) Flattening Test.—A ring not less than 2 inches in length out from one ond of each selected tube shall be flattened between two parallel flat surfaces, the width of which shall be not less than 1J times the diameter of the tubo. When the pTessure is released, tho interior surfaces of the test piece (at the middle) shall remain at a distance apart of not more than three timos the specified thickness of the tube and the test piece ahaII then show no sign of crack or flaw. (e) Expanding Tests.—Tho tubes shall withniaml expanding by a drift expander having a total included angle of between 40" and 60° (20° to 30" each sido) to the following increases in external diameter without showing crack or flaw :—7 Thk'kiiHHH of tube Thinner than 9 S.W.G-. up to un<l mcluriiup: 0 S.W.U. . Inert a«iH in rlitimetor pur i-ent. 12J «i 60. Additional tests before rejection.—Should a tube selected for tost ing purposes show definite ei^ns of failure in any one or more of the tests specified in Regulations 49 (a), 49(b) and 49(c), two further tests of the same kind may be made at the option of the manufacturer from two additional tubes selected from the same batch. If the repeat tests are satisfactory the tubes shall be aooepted provided that in all other respects they fulfil the conditions of this Standard. Should either of the tubes fail in any teat, the batch of tubes represented may be ro-heat-treated in accordance with Regulation 4-8 (b) and thon retosted in accordance with Regulation*! 49 (a), 49(b) and 49(c) but employing twice the number of test pieces. If these second repeat teats are satisfactory, the tubes shall bo accepted provided that in all other respects they fulfil the conditions of this Standard ; but if dofinite defects are again shown, the batch of tubos which the test pieoes represent shall bo rejected. 51. Hydraulic Test.—Each tube shall bo to, ted at the maker's -works by hydraulio pressure in accordanco with the following table governing the rolation between the test pressure and the design pressure to whioh the tube will bo subjected in Design pressure lb 'aq. in. C p to and inoluding 600 . . . . . Above 500 up to and including 1000 . Above 1000 Hydraulio test pressure lb/sq. in. minimum Twioo the dosign pressure. 1000 above the doaign presaur*. In all cases the tensile stress (S) onjtho material when under these tests oball not oxoeed 10 tons por sq. in. as determined by the formula :— 2t Whoro D =• outside diameter of tube in inches. P —test pressure in tons per sq. in. t ^nominal thickness of tube wall in inohes. SEAMLESS CHROME-MOLYBDENUM STEEL BOILER AND SUPER- HEATER TUBES POR DESIGN STEAM TEMPEEATURES NOT EXCEEDING 1000°F (538°C) 52. General.—The se Regulations oovor both Hot finished and Cold Drawn Seamless Boiler and Superheater Tubos which shall conform in all respeots with the requirom nts heroin spocifWl. 53. (a) Material.—Th> tub^s hall be manufactured from stool produoed by the open Hearth o.' Electri proi-os ,es and shall conform to the following limits of chemi- cal composition- - Carbon , . . . . . . 0 -12% maximum, Silicon 0'10 to 0 •60'% Sulphur . . . . . . . 0 -05% mnjimum PhoBphorufi . . . . . . . 0-05% maximum Molybdonum O'fiOtoO'70% Chromium 0-75 to 1-25% The sL^olmakor shall supply a certificate of the normality of the steel. (b) Heat Treatment.—Tho tubos shall bo fully annealed, or normalised at a (o) Workmanship and tolerance.—The tubes shall bo well finished, olean and free from harmful defects. They RHU.11 bo reasonably straight, smooth, cylindrical and subject to the following tolerances before bending :•—• (») Diameter. -Tho external diameter of tlw tubes measured at any point shall b» within tho following tolerances of the diameter specified :•— Typo of Tubs Hot, finished Cold drawn Outside Diameter of Tube Up to and including 2J in. . Ovor 2 | in. Tolerance h 1/64* 1 or («) Thickness.- Tho thickness of tho tubes shall be within the following tolerances :— Typo of Tube Hot finished . Cold drawn Oulsido Diumoter of tube Up to mid including 2$ in. Over 2$ in . All sizes . . . . . . . Toloranoe + iH% — o% - fi% Where the ends of the tubes are swelled or reduced, the thickness at tho ends may bo deoieased below or increased itbovo the nominal thiekne-w of the tubes by an amount in proportion to tho percentage of such swelling or reduotion and, in addition to this allowance, tho tolerances relating to thickness shall aho apply. Swelling or reduotion shall be carried out befoie the heat treatment specified in Regulation 53(6). (Hi) Length.—Tho tubes bhall be not less than t KB nominal length but may be 1/8 in. greater. (d) Salection of tubes for testing.—Ait or he»t treatment, tho tubes shall be pre- sented for mechanical testing in accordance, with Regulations 54(a), *>4(b) wnd fi4(e) in batches of not more th in 100 of the same nominal diamelei and thickti"RH. The man'ifact mvr whall urovide at his own expense exirji luhfi nt the m,re of 2 per c-ent. of each diameter and thickness of tube apneifi'wl and Ihc Inspecting Officer shall select for. t o^ such ot the tnbo as he may think proper to the extent of the percentage mentioned. Should tho number of tubes specified of any one nomina1 size e\eeed 400 then, for every 100 tubes or part th >reof above that numbei, ono additional tube shall be provided. The samples for touting shall not be heat treated after 54. (a) Tensile Test.—Tost pieces cut from the ends of the seleoted .tubos shall comply with the following requirements :-- Stripe cut from tubes and tasted in their curved oonditjon . Tost IengthH taken from finiBher) tubim (ends of tubea to be plugged for gripe). ITU untile Tonsilo Hire™ in tonH per HCJ. in. Not lobM than Not moi'o Lhan Minimum Elongation per cunt, on S mobos j " thick & over Le«n tlian J" thick (b) Flattening Test,—A ring not less 1han 2 iiichos in length cut from ono end of each selected tube shall be flattened between two parallel fiat surfaces, the width «>f which shall be not lews thttn 1J times the diameter of the lube. When the pressuro in released, the interior surfaces of the test pieces (at the middle) shall remain at a distance apart of not moie than three times the specified thickness of the tube and tho test piece shall then shew no sign of crack oi flaw, (o) Expanding Tests. - The tubes shall withstand expanding by a drift expander having a total included angle of between 40" and 60° (20° and 30° per side) to the following increases in external diameter without showing ci ack or flaw :— Thickness of Tubo 10 H.W.G. and thinner . Tlurmor than t> S.W.G. up to and including fi 9 . W . G . Iucroaup m Diamoter per oont. 65. Additional tests before rejection-- -KUoukl a tubo selected for u sling purposes show defuiite signs of failure m any one or more of the tests specified in Regulations 54(u), 54(b) and 54(e), two further tests of the same kind may be made at the option of the manufacturer from two additional selected tubes. If the repeat tests arc satis- faotory the tubes shall bo accepted provided that in all other leapcuts they fulfil the conditions of this standard. (Should either of tho tubes fail in tmy teat, the liatoh of tubes represented may be re-hoat-lreated in aecordimee with Regulation 53(b) and thon retestedin accordance with Regulations 54(a), 54(b) and 54(o), but employing twice the number of test pieces. If these second repeat tests are satisfactory, the tubes shall be accepted provided that in all othor respects they fulfil the conditions of this standard ; but if definite defects are again shown, the batch of tubes which the test pieces represent shall be rejected. 56. Hydraulic Test.—Eaoh tube shall bo tested at the maker's works by hydraulic pressure in accordance with the following table governing the relation between the test pressure and the design pressure 1O which the tubes will be subjected in service. ltoaitfn pressure Ib./»q. in. 000 or 1P88 Above 800 but not exceeding 1000 Above 1000 . . . . Hydraulic test pressure lb/sq. in. minimum. Twioe the design preaauro. 1000 above the design pressure. In all oases the tensile stress (S) on the material when under these tests shall not exceed 10 tons per sq, in. as determined by the formula :— DP 2t Where D = outside diameter of tube in inches. P =tost pressure in tons per sq. in. t ^nominal thickness of tube wall in inob.es. ELECTRIC-RESISTANCE-WELDE!) STEEL BOILER TUBES FOR TEM- PERATURES UPTO 750" F, AND PRESSURES UPTO 840 Lba./SQ. IN. (FOR EXTERNAL PRESSURE). 57. General.—These Regulations cover eleotrio-resistanee-welded tuboa made of steel and intended for boiler tubes. 58. (a) Material -Process.-—The material shall bo made either or both of the following processes : Open-hearth or electric-furnace. (b) Manufacture.—Tubes shall be made by oleotrio-resistanc -welding and shall be normalised at a temperature above the upper critical temperature. (c) Chemical Composition.—Tho steel shall conform to the requirements as to chemical composition prescribed in Table below:— TABLE—Chemical requirements. Carbon, per cent Manganpue, per cent Phosphorus, max., yxir oont. Sulphur, mm., per oent. . Type A 0-08 to 0-18 0 30 to 0-60 Type O Medium Carbon Steel 0-36 max. 0-80 max. 0'04S 59. (a) Flattening Test.—(i) A section ot the tube not let« than 2^ in. in length shall be flattened cold between parallel plates until the opposite walls of the tube meet. No oracke or breaks in the metal shall occur until tho distance between the platea is less than the calculated value of 'H' by the following formula :— (l+e)t JJ __ c+t/1) Where H «•» distance befrwocn flattening }jluics in inches, t = nominal wall thickness of tube in inches, D = aotual outside diamotor of tube in inches, an<l c = deformation per unit length (constant for iv given grade of steel, 0-08 for types A, 0"07 for type C). Evidenoe of laminations or burnt material, or incomplete penotration of the weld, shall not develop during tho entire flattening process (ii) The weld shall be placed 90 deg. from the line of direction of the applied force. (Hi) Superficial ruptures as a result of minor surface imperfeotione shall not bo cause for rejection. " (b) Flange Test.— (i) A section of tho tubo not less than 4 in. in length shall be capable of having a flange turned over at a right angle to the body of the tubo without oracking or showing flaws This flange, as measured from the outside of the tube, shall not be less than 1/8 in, nor more than ^ in. Within these limitu, the width of the flange shall be not less than the following :— Outs ide D iame te r of Tubo , in. 1 5 % of outs ide d i a n i t e r 3/8 in . 1 0 % of outs ide d i ame te r w 75 per nont of that required for (type A. (ii) In making the flange test, it is recommended that tho flaring tool und die block shown in ~Ei«. bfTow be u°pd. A-OOOT TUBE LESS i" P-ARJNG TOOL . txe BUOCW. (c) Crush Test.—When inquired by tho Inipoctinii Autliority^orushingFtestB shall be made on sections of tubo 2^in. in length whioh Hhall stand crushing longi- tudinally, without oracking, splitting, or opening at tho weld, as follows :— Height of Crushed Section, in. 3/4, or until outside folds are in contact Ii Crush te»t» not required. Slight rarfftoe checks shall not be cause for rejection. 628 THE GAZETTE Of INDTA EXTRAORDINARY [PART I I (d) Reverse Band Test. A motion 4 in. in 1 jjgih shall be taken evory 1Q00 ft. of flnishoil welded tubing to bo split longitudinally 180 deg. from tho weld and the sample opened n,n<J flattened with tho weld lit tho point of max. bend. There shall be no evidence of cracks or lack of penetration or overlaps resulting from flaeh. removal in the weld. 60. Tensile Properties.—Type (1 tubei-' shall conform to the reqtiirnnents u& to tensile properties prescribed in Tablo below :— Tensile Requirements 37000 lbs. 61. Hydraulic Test- -(a) Each tube shall b^ tosti-d at the milker's works and shall withstand for a minimum of 10 seconds a hydraulic test pressure which shall imposo a minimum fibre stress of 16,000 lbs/aq. inch and not oxoeoding 24,000**" lbs/«q. inch, for type A arid not exceeding 26,000 lbs/sq. inch, for typo C as determined by the following for/nula:— 2tS P -= I) Whore P — Hydraulic test pressure in lbs/eq. in, 8 — fibre stress. I) — Outside diameter of tubo in inches, and T — thioknoss of tube wall in inches. (b) Tube shall bo struck near both ends whilo under tlje tost pressure with a 2-lb. stool hammer or its equivalent. 62. Test Specimons.- (a) 'IVt spiciinfiia roqnimi for tho flattening and flange tests spocified in Eegulitions 59(a) and »9(b) MII.HII bo tiiken from the ends of finish- ed tubes prior to ui^-setting, swaging, expanding, or other forming operations, or be- ing out to length. They ahull be smooth on the ends and free from burrs und flaws.o (b) If dosirable and praufcieable, tension tests may be made on full sections of the tubes up to tho capacity of the testing machine. For larger size tubes, tho tension test specimen shall consist of a striji cut longitudinally from the tube and not flattened between gauge marks. Tho sides of the specimen shall be parallels betwoon gauge marks ; the width, irrespective of the thickness, shall be 1 in., the gaugo length shall be 3 in. (o) All specimens shajl be tested at room temperatures. 83. Number of Teste.— (a) .For type A, one of- tho tests specified in Regulations 69(i»), 59(b) and 5()(c) sball be made from each lot of 250 tubes or fraction thereof and from eaoh 2,000 ft. or fraction thereof safe end material. For typo C, one of each of the tests specified in Regulations fi9(a), 59(b), 5!)(o) and 60 shall bo inado from eaoh lot of 250 tubes or fraction thereof. A reverse bend test specified in Regula- tion 69(d) shall be uia.de on each 1600 ft. of finished tubing. (b) ff any test specimen shows dofectivo machining or develops flaws, it may be discarded and another specimen substituted. j (o) If the percentage of elongation of any tension tost specimen is less than that specified in Regulation 60 and any part of the fracture is more than 3/4 in. from the oontre of tho gauge longth, as indicated by scribe scratohos marked on the specimen beforo testing, a re-test shall bo allowed. (d) Eaoh tube shall be subjected to tho hydraulic test speoifled in Regulation SEC. 3] THE GAZETTE OF INDIA EXTB AOEDINAEY 629 LAPWELDED STEEL BOILER TUBES (FOR EXTERNAL PRESSURE) 64. (a) Material.—The tubes shall bd ,nade from steel which shall show on ana lysis not more than O'()5 per cent, of ^ulphur or phosphorus. The manufacturer shall supply a certificate of the analysis AH hen required to do so. (b) Annealing.—The ends of all tubes shall be carefully annealed . (c) Freedom from defects.—To comply with Regulation 36(c). (cl) Tolerances. — The t ibes shall be of the dimensions specified, straight, cylin drical, of uniform thickness and external diameter throughout, subject to the work ing margines given in table below :— Outside diameter of lube Under 2 | inch . 2-| inch and over On diameter Plus Inch Per cent. Minus Inch Per cent. On thickness Plus Per cent. t 10 Minus Per cent. on length Plus Inch Minus Inch (e) Selection of tubes for test.—To comply with Regulation 37. 65. Tensile test.—(a) To comply with Reg. 44(a). (b) Flattening test.—To comply with Reg. 44(b), the weld being placed 45° from the horizontal. t,c) Expanding test.—r-The selected tubes shall, when cold, withstand being ex- panded by a drift or a roller expander to the following increases in diameter with- out showing crack or flaw :— Thickness of tube 8.W.G. Up to 10 Above 10 to 6 Above 6 . . . . . . . . . . . Increase in diameter per cent. 66. Additional Tects.—Shrukl a tub<. !-elected for testing purpose, in accordance with Regulation 37 fail to satisfy the requirements of any one or more of the tests (specified in Regulations 65(a) (b) (c), if so desired by the manufacturer, the tubes represented shall be re-annealed and then retested in accordance with these Regula- tions and if the repeat tests are satisfactory, the tubes shall be accepted provided that in other respects, they fulfil the conditions of these Regulations, but if the tube again fails to satisfy the requirements, the tubes which the test pieces represent shall, be rejected. 67. Hydraulic test.—Every tube shall be tested at the Maker's works by hydraulic pressure to not less than 1,000 lbs. per sq. in. Any tubes failing to withstand this test shall be rejected. WROUGHT IRON LAPWELDED BOILER TUBES (FOR EXTERNAL PRESSURE) 68. (a) Material.—The tubes shall b<? made from wrought iron which shall show on analysis not more than 0*10% manganese and 0"03% sulphur. (b) Annealing.—The end of all tubes shall bn carefully annealed. (c) Freedom from defects.—To comply Auth Regulation 36(c). (d) Tolerance.—Tho tubes shall be of tho dimensions specified subject to working margins given below. They shall be straight and cylindrical, of unifoim thickness, concentric and unless otherwise specified, of uniform external diameter through* out. The working margin shall be as follows :— On thickness—plus or minus 10%. On external dia. for tubes under 2\"—plus 1/64* and minus 1/32". „ ,, for tubes 2" and larger—plus or minus 1 per cent. (e) Selection of tufces for test.—To comply with Regulation 37. 69. (a) Tensile Test.—Lengths or strips cut from the selected tubes shall comply with the following requirements :— Strips cut from the tubes clear of the welds and tested in their curved condition Tested longths taken from finished tubes (ends of tubes to be plugged for grips) Ultimate Tensile Strength in tons/ sq. in. Not less than Not more than Elongation per cent, on 8 in. (b) Flattening Test.—To comply with Regulation 39. 70. Expanding Test.—The selected tubos shall, when cold, withstand being expanded by a drift or roller expander to the following increases in diameter without showing crack or flaw:— Thickness of Tube SWG Up to 6 Above 6 . . . . . . . . Increase in Diamoter per cent. 71. Crushing Test.—A ring 2 in. in length cut from one end of each selected tube shall withstand, without showing crack or flaw, being crushed on end by hammering or pressure when cold, until the length is reduced to 1-5/8 in. 72. Hydraulic Test.—Every tube shall be tested by internal hydraulic pressure to not less than 1,000 lbs./sq. in. Any tube failing to withstand this test shall be rejected. STEEEL CASTINGS 73. Scope.—Steel castings shall be of the following grades, according to the purpose for which they are to be used and as may be specified :— Grade I . . . . . . . 28 to 35 tons per sq. ia. 74. (ft) Process of manufacture.—Steel for oastings shall bo made by the Open Hearth or an Electric Process, acid or basic (b) Ohemlcal Analysis.—Sto;>l usod for gradoa I and I I castings shall not show <>u analysis more than 0.06 per cent, of sulphur or phosphorus as determined from the test samples, and tho manufacturer shall supply an analysis of each oast when requested. (c) Heat treatment.—All castings flhall be hoat treated to refine the crystalline structure throughout tho oasting by heating to a uniform temperature not loss than the normalising temperature and allowing to cool slowly from the maxirmun tempe- rature in a praetioally uniform manner: or alternatively normalised by heating in. a similar manner and allowing to cool in still air. (d) Freedom from defects.—All castings shall be free from twists, craoks. flaws and similar defects. 75. Repairs to defective castings.—Casting* shall not bo repaired or weldod with out the speoino sanction of the Inspecting Officer, If required the castings shall be suitably re-heattreatod to remove- internal stresses. Should a defect impair the strength of the castings, ropair by welding or otherwiao shall not bo permitted. 76. Number of tests.—At least one tensile- and one bend test shall be made from the oaating from each charge, and when more than one casting is made from one ohargo, at least one tensile and one bend tost stall be made from the castings run from ono oommon pouring head ; but separate tests shall be made from each oast- ing or set of castings run from each soparate pouring head. Test pieces shall riot be cut off until they have been stamped by the Inspecting Officer after the annealing has been completed. 77. Temile tests. -The ultimate tonsils stress, yield point and elongation for grades I and I I eastings shall bo not less than shown in table below:— Tensile Tests on Steel Castings Omde I . . . . II . . . . Minimum ultimate Tonsilo Hti'ongth Tons per aq. in. Minimum yiold point JJI tonnB of Tonailu strength por cent. SO Minimum Elongation on test piouo 'C (figure 5 to Appx, B) per oent. Should a tensile test pieoe break outside the middle half of its gauge length, the test may at the manufacturer's option be discarded and another test be made of the same oaating. 78. Bend teats.—Cold bend tests shall bo made upon test pieoos having a rect- angular seotion of one inch Wide by 3/4 inch thick. The test pieces shall be maohined and the odgea rounded to a radius of 1/16 inoh. The test pieces shall be bent over th» thinner section. 632 THE GAZETTE OF TNDTA EXTRAORDINARY [PART II Bond teats may be made by pj essnni 01 by blows, and tho tost piecesshall without fraituro withstand being bent lound R forjm r having ft radius of 1 inch through an angle not Jess thim that given m the following table .— Braiio orCtiHtuiK 4.ugle of Bund I . . . . . 00° 79. Additional teats before rejection. —Should a test pr>er- fir«t wlectod by Hie luspeotor not fulfil the test roquiremonts, two additional tests of the namo kind from the sumc easting or group of cawlingfi shall bo made. Should one of the additional teat pieces fail to fulfil the specified tost requirements, the castings .shall bo rejected. 80. Waiving of tests.—No tests shall be mado from unimportant steel casting or from Hteol ('listings which aie used lor articles usually made ot cast iron, if the scantlings are not materially reduced below what would be required if oast iron were used. OARRON STEEL TORGINGS (OTHER THAN 4WAIMLESS DRUMS) 81. (a) Process ot manufacture.—(Jarbon . 1eel for forgings shall be mado by the Open Hearth or an Electric Process, acid or basic. (b) Chemical analysis.—Tho steel shall <ontain not more than 0-05 par eeul. ot sulphur or of phosphorus. (c) Fresdom from detects. -Til** forpingH shall be froo from defects ot any kind and shall bo finished to the prescribed dimensions. Defects m forgings, shall not be repaired without the previous .sanction of tho Inspecting Officer, (d) Heat treatment.—Kadi forging shall bo efficiently h'vit-tioated unless during the last stage of mauiifactute it has been finished at such n temperature as to ensure that tho mateiial ot tho foigmg •will have satisfactory meehunical proper- ties. 82. Selection of teat pieces.—Hiiftu iont material shrill be left on oa< h forging for test pieces. In the case of a number of small forgings, not less (linn two per cent, of (he total or not lesR than 2 forgings from each cast. 83. (a) Tensile tests. —The ultimate tenmlo wtroHs and elongation shall bo between the limits of 26 and 32 Tons per sq. in and 28% and 22% respectively determined on. Butmh Standard Test Piece 0, or subsidiary Standard Round Test Piece (See Appendix B.) In no case shall the sum of the ultimate tensile Htrows and corresponding < longa- tion be loss than 54. (b) Should a tonailr) t'»st pieoe break outside tho middl i half of the test gauge length the test may, at the maufacturor's option, bo discarded and anothei test be made of tho name forging. 84. Bend tests.- (a) Bond test pieces shall ba rectangular section I in. wide by 3/4 in. thick. The edges shall be rounded to a radius of 1/16 in. The tost pieoos shall bf> bont over the thinner seotion. Sao. 3] THE GAZETTE OF INDIA EXTRAORDINARY 633 (b) The test pieces shall, \ 'Jnn t old, be capable of being bent, without fracture through >in angle of 1K01", the internal radius of the bend not greater than \" inch Bend tests may bo inudo by uiessure or by blows. 85. Additional teats before rejection.- Should cither a tensile or a bend te^t fail, two fnrtliei tests of the type which failed may be made on tost piectfl cut fiom the same foiging. If the results obtained Jfiom those retests aro satisfactory, the forgings shall bo accepted, provided that in other respects they fulfil the conditions laid down above for steel forgingh. If these letests do not give satisfactory results the forgings represented may Lc re-heat-treatcd together with the remainder of the tost blocks and presented for furthei testings. in all cases whore final retests do not give satisfactory results, the forgings represented by the test pieces which fail shall be rejected GRNERAL GREY TRON CASTINGS (GRADtt A) 86. (a) Process Oi manufacture.—Tho eastings shall be cast from metal melted or refmed in any metallurgical plant other than an iron ore smelting furnace, for the use of which furnace permission m writing must bo received from the Inspecting Authority. (b) Chemical composition. The composition of the iron as cast shall be left to tho discretion of the manufacturer but the maximum percentage of phosphorus may be specified by the Inspecting Authority if In- MO dosnes. (c) Moulding.—(i) The castings shall be ucourai-ely moulded in accordance with tho pattern oi working drawings supplied by the Inspecting Authority, with tho addition of such lettering as may bo specified. (ii) The casting shall be sound, clean, out of t \uu t and free fioin blow holes distortion and all siutac and other defects. They shall be well dressed or fettled and Mhu.ll bo machinable by normal methods PROVISION OF TEST BARS 87. The Inspecting Authority shall stato at the t̂ mo of enquiry whether ho requires tensile or transverse tests, or both, and ho may also specify cast-on bars where the design oi (he cas1 ing and method oi lunning permit. When tho teat bars aro ea.s1 separately tJif \ shall be pound at tho same time and from the same ladle ot metal as I he anting oi castings they reprosmt The number of tost bars spenned in Regulation 92 shall be applicable to all castings of oach melt. When the bais are last-on, the mould for tho casting and the mould foi the tost piece shall be joined together in such u. inannei that the liquid m'otul fills both moulds at the same operation All tost ba,is shall be east in green sand or dry sand moulds according as to whether the casting or castings they lepresent are moulded in groen sand, or in loam or dry sand respectively. The test bars shall not be subjected to any heat treatment after leaving the moulds. DIMENSIONS OP TEST BARS 88. (a) Transverse Test Bars.—Tho tmnsverae tost bars of the diametor specified by the Inspecting Authority according to the main cross sectional thickness of the casting represented, shall oonform to the following dimensions : Diiimoter of toat Bar in. 0-6-fc 0-87S± l-2± l-6± 2-l± Limits on in. 0 -06fl Overall length in. ie Main crosa-ueotional thickness of casting represented in. Not evcooillng 3/8 Over 3/8 and not exceeding 3/4 Over 3/1 Hiir] not exoeoding 1,1/8 Over, 1,1/H urui not exrooding 1, 5/8 Over 1,5/8 Bars east to iv si/.e in excess of the limits given above may be mar-hiuerl to a diameter within the specified limits. Bars cast within these limits of diameter may also be machined before the transverso test io made, providing tha t the finished diameter falls within thche limits. DIAGRAM L ,-J. JU L .A H iU t 1JN U 1A J A U i TABLE Diameter as cast B in. Gauge diameter D in. Area A sq. in. Miu. parallel length P in. Min. radius R in. u 3i Min. length of plain C in. H 3i Screwed ends Size E in. i B.S.P. 9/16B.S.F. 9/16 B.S.W. 3/4 B.S.F. 7/8 B.S.W. 1,1/8 B.S.F. 1,1/8 B.S.W. 11 B.S.W. 2 B.S.P. Min. length F in. i-i /a Approximate minimum ov^all length Plain ends L P in. Screwed ends LS in. Main cross-3e«tional thickness of casting represented in. Not exceeding 3/8 Over 3/8 and not exceeding 3/4 Over 3/4 and not exceeding 1-1/8 Over 1,1/8 and not exceeding 1-5/8 O-T-ST 1-5/8. Th» test bars shall be cut as paralfel bars of the diameter given in Column X and than maohin»d to th» dimension* D and P in the above tabW. | (b) Tensile Test Bars.—Tho tonsils ton! bturs of tho diameter specified by the Inspecting Authority, according to the main croSH-wectional thickness of the oasting" represented, shall conform to the dimensions shown in tho following table. Bars may bo tested with either plain or bercwod ends. (c) For castingn over 2 inches in lb.ieU.neHH a test bar of larger diameter than 2-1 inches mu.y be used by agreement bolween the manufacturer and the Inspecting Authority. For diagram and table- wee pp. 28 to 29 MECHANICAL TEST 89. The canting must comply with the transverse and tensile teats spooiflod in Regulations 90 and 91. All tent pieces shall be selected by the inspector and tested in hid presence and to hin satisfaction. TRANSVERSE TEST 90. A transverse test bar cast in accordance with Regulation 88(a) must, whon placed on supports wet at the distance shown in column 2 of the following table sustain a load applied at the centre of not loss than that shown in column 3 and must show before luptme a deflect ion not lent) than that shown in column 4. The suppoitH and the point of application of the load shall he rounded to iv radiuft of not less than 1/8 inch. Diamotor of tent bar m. Distance between i n . J2 Minimum breaking load—Grade A lb . 4.2H0 Minimum dufloc- tion—Grude A in. 0 lfl If the diameter of a trsinsvorne test bur in cuflt varies within the limits specified in Regulation 88 (a) I he equivalent bunking load for the 1 >ut bar of nhindurd dia- meter shall be calculated in uccord.iine with the factors given in Appendix F. TENSTLE TEST 91. A tensile tesh bin machinal to the1 dimensions shown in Regulation 88 (b) and tested with either plain or screwed endH must show a bieaking strength of not less than that shown m tho following ttible. Diamoter ot tost btu" i n . ] -fi TOIIB por sq, in. 10-fi NOTD.—Solf-aligning grips to onsure axial loading ai'o rucoraroeudod. NUMBER OF TRANSVERSE AND TENSTLE TESTS 92. The nurabi'i of U«nts rnquiicd for each batch of cufitiiijrs hhull ho in aicot- dance with the following table, the various clas-fccf-. oi' uislings being divided into four repiesonttitiv-' gioiipr. One test shall refer to one transverse and ono tensile test, whethei taken i'lom otic or two lest bain at c .">-!.. Group Up to 28 lb Over 1 owt. and upto orin Lou T«Ht roquiremontu Ono test for ouch 30 cwt. of pnutm^B or part rlioinof. Ono tent for oaL'li 2 toils of castings or Xiait thmoof. One tost lor 'Jacli 4 tons of OftstingB or part t Unroof. In (ho above (Jroups, I, 3 und 3, all castings represented by one test must ho poured from tho same ludle or same heut as the bur nr barn provided for the test. 4 OVOT 1 ton and important castings whoro mutiinlly agrcod upon. One tost for enoh 4 tonfl of oustingB or part thereof or for eooh caatinp; weighing 93. Additional Tests.—The additional tests to be carried out. before a e&Btini!; or butch of castings in rejected H1IH.11 be in. accordance with tho following tiT lo :— Tent pieoi) l n t 2 n d Evont If this fails . . . . If this paRHOn If this CHIIH . . . . Oonditions The noooiid toHt pinco nlitill be tented. Tho batoh or sop&rnto cutting ropre^ontod Thn bulch or stipareto casting represented rauy be rejootcd Provided tihvayn that in the cane of failure of both test pieces if either show obvious defoel* a thiul test piece may be taken from a broken easting or a piece may bo cut from a usable uasling for further testing aw followtt :— If thin failH . . . . The batoh or miparate oastiug r(«proHOnted shall bo accepted, The biitoh or Hfijjarato casting ''eyirewentod may be rejected. COVERED ELECTRODES FOR MKTAL ARC WEUMNG 94. Construction.— Tho motal olootioilcs shall be provided with a Mnx co^ring applied eKtcnuilly by painting, wpraying, dipping, wrapping or other method. 9^. Application.—The covered ol.inirodeR shall b> wuitable for motal are welding of mild wtoel having a tensile strength not exceedig 33 tons per sq inch. 96. Quality.—The electrodes shall bo uniform in quality and when used in ac- •oordanoe with the appropriate instructions of the Manufacturer shall be capable of flowing freely and smoothly without producing an undue amount of " under cutting " in the parent metal adjacent to the weld. 97. Covering— (a) Strength.—Tho c ovoring shall be mifficiently robust to with- stand without damage the normal conditions of transport, storage, handling and use to which the electrodes are to be subjected. (b) Uniformity.—The oovering shall be substantially unifojm in out ido diarnoter throughout its length and shall fuse evenly. (c) Stability.—The stability of the covering shall be such that if the electrodes are stored they shall, after a period of thrco months, be oapablc of giving results similar to those at the date of despatch from the supplier, (d) Storage.—The requirements of paragraph (c) abovo shall apply only if the electrodes have been kept in their original packages in an enclosed dry storeroom. 98. Mechanical properties of All-weld Metal test pieces.—The mechanical pro- perties shall be determined on all-weld-metal test specimens as follows :•— (a) Tensile Test.—The tensile test shall be made on a specimen having ft gauge length of 3-54 times the diameter of the test piece. The ultimate tensile stress, elongation and reduction of area of tho deposited metal shall be not less than the figures given in the table. (b) Impact Test.—Impaot tests shall be made on a three notoh specimen. At least two of the three values obtained shall be not less than that given in the tablo. Ultimate Tonsil* •tread (tone per sq. in-) ruin. IS Elongation on 3 • 54D (per cent.) Reduction of Area (per cent.) min. Impact Vftluo CHAPTER HI CONSTRUCTION AND WORKMANSHIP GENEBAL 99. Preparation of Plates.—With ihe exception of gusset plates, which may be sheared, tho edges of all plates and butt fltiaps shall bo planned or machine gafl out to an angle of approximately 80° with the surface of tho plate. 100. Annealing after working in fire.—All steel plates which are welded, dished, flanged or locally heatod shall be afterwards efficiently annealed. 101. Minimum thickness of Plates.—No boiler plate shall be lens thnn £ inch in thickness. SHELLS, ANGLE RINGS, BUTT STRAPS, ETC. 102. Cylindrical Shells.—Eaoh ring shall be bent while cold to cylindrical form to the extreme ends of tho plate. Tho bonding shall be done entirely by machine and "heating or hammering is prohibited. 108. Position ol Longlttiainal Seam* Each rin£ of plate fotming "the shell, barrel or drum shell, where practicable, be in one piooe and have its longitudinal seam well out of line with those of the adjoining rings. In Lancashire, Cornish, and other types of boilers, -where p;utn <>f tho HIVII aie exposed to flame, the longi- tudinal yearns* î hull, whoio practicable, be in the steam »paie, arranged alternately on each wide of the crown and clear of tho buck work. 104. CireumSeiential ana End Seams.—(a) The s-trcngih of the search joining the end platen of flat end Lancanhi]e and Cornish boilers with the eylindi ical shells shall be not lew than S8 per cent, of the strength of the calculated thickness of the plat" JR found by Equation (1), The str ength of the int ormediate ?w»mR of flat ended bmlet'H and all scam a of diRh ended boilers shall be 50 per cent of that of the longitudinal seams but in no rust less than 42 per tent of the strength of tho cal- culated thickness of the plate. (b) In boilers of other types the strength of the circumferential and transverse Beanie shall be not loss than 38 per cent, of that of calculated thickness of the plate as found bv Equation (1) and not less than fi() peT cent of that of the longitudinal seams whichever is the greater. (o) When tho shell plate thickness exceeds ]l/lfi inch the intermediate cir- cumferential seams shall be double riveted. (d) In tho ca^e of the electrode boileis where the diameter of the shell does not exceed 18", the end platen may be attached to the fiholl by means of Electric Arc fillet w« ldin.2 provided the welds are stress relieved and the cubical capacity and working pressure do not exceed 30 gallons and 120 lbs. respectively. 105. Angle Rings.—Angle rings for the attachment of end pint OR to shell plates and 'ii flue sections shall be rolled or machined HO that they fit closely to the flat and cylindrical surfaces to bo connected, and shall be machined or machine gas out on tin. caulking edges. 106. Thickness ot Shell Angle Rings.—Where shell plukb find end plates are, connected by means of an external angle ring, the angle ringw s~.liall be not Ws in thii-ktiesq Ihnn as follows:— For nhnll phitoa up to and unlading S/H ineh in thirknom IWB^ nml upto and including 1 iiw-'h m thick- Fo\ HIH'II plutfp ov«r 1 inch in thiekiKmn 10 p« r cent in OXCRHB of the thickness of tha shell platxi. 00 por cent of the thieltiiesm but not lens thnii 11/16 inch. Miiriu from dnglo bar havnif; a sflction thiokneaa of 1 inch. 107. Welded Shell Plates.—(a) Except as provided for in Chapter V end in Regulation 112, where longitudinal seam1; arc welded the wold shall bo entirely co\oied by a butt strap or butt Htraps securely riveted to the shell. (b) Foi small steam domes when the welding is clone by hammer and the plates do not exceed £ inch in thickness butt straps may be omitted. (e) The strength of the weld covered by butt straps shall bo assumed to bo 50 pei mi t of that of the solid plate. The thickneHs of a single strap or combined thu knews- of double straps shall be not leas than tho thioknesr of the shell plate. , =a wil . 108. Longitadinal Seam*.—The longitudinal seams shall be butt-jointed with double straps when the diameter or Working Pressure exoeeds the limits stated below:— exceeds L b s . HO 109. Bntt Straps.—Butt straps shall bo out from the shtll plaUb or, alterna- tively, all the butt straps of each required thickness slip 11 be out from one plate. The lengths of the straps wherever practicable shall be transverse to the diicction of rolling of the plate. Straps shall be pressed or bent in rolls to the shell curvature. 110. Thinning ol Butt Straps.—Thinning of tho cnds of butt Rtisps which tuck under shell rings, shall be done oold by machine and not by heating or hammering. 'The shell plate shall be notched out to reoeivo the thinned end of the butt strap, -so that there shall be no undue thinning of the butt strap. 111. Alternative Construction.—(a) As an alternative lothe tucking of but1- *trap ends under the shell rings, tho ends may be terminated at the edge c f the shell rings or ends and electrically welded thereto. 112. Local Welding of Butt Seama.—(a) The ends of longitudinal butt soains of «hell rings may be welded for a lenjjth not exoeeding three times the overlap at the •circumferential seam, providod the butt straps are run as clorSely as practicable to the circumferential soam. (b) Only metal arc welding of the butt seams of shell rings shall be permitted. 113. Flat End Plates.—(a) The end plates of boilers shall preferably be in one piece made from one rolled plate. Alternatively, the end plates shall be built up by butt-welding two pieces. In the latter case the line of welding shall be parallel to the horizontal axis of the boiler and shall run through the centre line of furnace or furnaces of Lancashire boilers and between two rown of stays of marine type boilers. In tho ease of flat end plates the fusion welding, shall comply with stress relieving (requirements and in the ease of dished end plates the fusion welding shall be aub- jeotcd to both stress relieving and radiographio examination. (b) The peripheral flanging of end plates shall be done by machine. Such flanging shall preferably be dono in ono operation, but whore this is impracticable sectional or creep machine flanging may be permitted, pro\ ided that the plate in worked at a suitable temperature, and the plate is heated to an adequate distance beyond the portion under immediate treatment. (c) Care must be taken to see that the flanges arc circular and of good surface, free from local irregularities, and that they are parallel a ad square with the flat part of the plate. For the purpose of relieving internal stresses, all plates which have been Hanged or locally heated shall afterwards be efficiently annealed unless during the laat utage of manufacture they have been uniformly heated through- out. (d) Flat portions of end plates, on completion of all flanging and machining operations, shall be flat and free from set or distortion. 114. Strengthening of Flat End Plate at Manhole.—(a) In the End Plates of Lancashire Boiler type the raudhole in the lower part of the front end plate shall be fitted with a flanged rivetod strengthening ring, the thickness of the flat portion of which shall be not less than (1-5 T X1/8 in.) where T equals the thickness of the end plate in inches. (b) In boilers 7 ft. 6 in. diameter and above, the mudhole frame shall be fitted "with a peak to reinforce the portion of tho end plate between and below the furnaoeB, and this peak shall be .securely riveted thereto with rivets of similar pitch to the remainder of the frame. (c) In all cases the front end plate gussot stays below tho furnaoes shall be placod a,s closely as possible to tho mudhole frame. (d) Where flat end plates are flanged for connection to the shell, the inside Tadius of flanging shall bo not. less than ) -75 times the plate thickness, with a minimum of 1 | m. 115. End Plates in steam spaces.—When the end-plates of boilers situated in tho steam space are liable to contact with hot gasos the ond plates shall be effi- ciently shielded from such contact. 118. Hemispherical Crowns.—(a) All segments shall be pressed in one heat to 'correct curvature. The adjacent plates shall bed closely at the seams and wherever possible at the junction of two seams tho plates shall be maohined down to provide •a fair surface to tho joint, [f the thinning is dono by hoa+ing and hammoring the plate shall bo subsequently annealed. (b) The cylindrical portion of the crown shall be tangential to the hemispherical portion and fit truly to the shell. (c) Where hemispherical shell crowns are pressed from one plate they shall be pressed to form by machine in progressive stages without thinning and on com- •plction shall be annealed. 117. Dished End and Crown Plates.—(a) The inside radius to which a plate is dished shall not be greater than the external diameter of the shell to which it is attached, except in the case of Lancashire and Cornish boilers when the radius shall mot exceed 1^ timos the diameter of the sh 11. (b) Tho inside radius of curvature of the flanges tt the shell or firebox shall not be loss than four timos the thickness of the crown or end plato and in no case loss •than 2\ inches. (o) The inside radius of curvature to uptakes shall be not less than twice the thickness of the crown plate and in no case less than 1 inch. (d) Bunged mouth-pieces may be welded on to end plates in place of the ortho- •dox flanging for the attachment of furnace tubes. Such welding shall comply •with provisions of Regulation 125. (e) Manhole frames may be similarly welded on the front end plates, and will 'be subject to piovisionn of Regulation 125. 118. Tube Plates.—Smokebox tube plates ahull bo flanged for attachment to the 'barrel or shall be flat and connected thereto by an external riveted angle ring. 119. Parts ot the Smoke Tube Plates within the tube nests.—(a) Where the total urea of all tho 1 nbc no-.ts exceeds 7 sq. ft. stay tubes shall bo fitted within the nosts. "Whoi e Htay tubes Arc not fitted th» ends of tho tubes shall be beaded or boll mouthed. (b) The parts of tube plates which lio outside the nests of tubes shall bo stayed or supported wherever tho size of the area of plato subject to steam pre^u^e neces- sitates staying or support, either by marginal stay tubes or other means. 120. Flanging o4 End Plates.—All flanges shall bo a good fit to the shell and flues. Flogging and'or hammering in the fitting of these parts is prohibited. The. -caulking edges of all flanged plates shall be nmhined or machine gas cut. FURNACES 121. Furnaces in general.—(a) No furnaoo or firebox top, -whether plain or corrugated, shall exceed 7/8 inch in thickness, and all oircular sectioned furnaces •when new shall be as near the tiuJy circular foim as the type of joint •will permit. (b) The use of Z angle rings for furnace foundation seams shall be prohibited. 122. Furnaces of Horizontal Boilers.—(a) The &ection* of Hie, internal flues snail each be in one plate and Bhall be bent while cold to circular form and shall b» welded longitudinally. (b) The maximum permissible variation in diameter at any cross section shall not exceed the thickness of the plate. (c) The welds shall be placed at tho lower part of the flues, and shall break joint in successive sections by at least 12 inches. (d) Each flange for the circular seams shall be formed at one heat by suitable machinery. (e) The sections shall be allowed to cool gradually to avoid internal stresses. (f) The caulking edges of all fluo flanges shall be maohined or machine gas cut. (g) The circular seams shall be arranged so that they do not fall in line with those of the adjacent flue or with the circumferential seams of the shell and are at least 6 inches apart, (h) When flues ate flanged for attachment to both end plates tho total length of each completed flue thall not exceed the length of the shell measured from the inner surface ot tho back end plate to the inner surface of the front end plate, both ad- jacent to the shell. (i) Where the flues are flanged for attachment to tho end plates, tho end sec- tions sball be 1/16 inch thicker than the remaining sections, except in cases where the calculated thickness is over 13/16 inch, when the end-sections shall be 7/8 inch in thickness. (j) Tho flanged portion of furnace rings shall have a radius of curvative of not less than 1 inch on water side. (k) Seotions of corrugated flues may be fusion butt welded oiroumferontially and afterwards stress relieved by heat treatment. 123. Furnaces of Vertical Boilers.—(a) The vertical portion shall be in one plate and shall be bent to oircular form in a similar manner to the shell plates. (b) Circular furnaces shall preferably be tappered, a taper of 1J in. in diameter per 1 foot of height being recommended. The minimum water spaco at the bottom between the furnaces and the shell shall not be less than 2 in. for boilers up to 2 ft. 6 in. in diameter and shall be not less than 2J in. for boilers over 2 ft. 6in. in diameter. (o) Where hemispherical furnace crowns are pressed from one plate they shall be pressed to form by machine in progressive stages without thinning and on oom- pletion shall be annealed. (d) Ogee flanging where integral with the firebox or in a separate ring shall preferably be formed at one heat by suitable machinery and shall be allowed to cool gradually to avoid internal stresses, (e) Furnaces of vertical type boilers may be attached to the shell at the fire" hole by a solid rectangular section steel ring riveted together or by a circular ring of substantial section fusion welded to shell and firebox. Where the latter cons- truction is employed the opening in the shell for fireholc shall be substantially com- pensated by a i ing welded on the outside of the shell plate. (f) At the firehole the firebox plate and the shell plate may be flanged and fusion welded together. SEC. 8] THE GAZETTE OF INDIA EXTBAOBDINAIU 64» 184. Longitudinal Seams.—The longitudinal seams of furnaces may be either: (a) Forgo Lap Welded. (b) Fusion Butt Welded, (o) Riveted. Longitudinal seams of furnaces exoeeding 3/8* thickness shall uot be riveted. 125. Fusion Welded Longitudinal Seams.—Where the longihidinal Keam is fusion welded tho following precautions shall be observed :— (a) Plates over 5/8 in. in tliicknosH shall be bevolled from both sides of oaoh abutting edgo, but the bevel need not necessarily be the same on each side (HPO Figs. 1 and 2). Plates less than 5/8 in. in Lhicknesa may be bevelled from ono aide only of eaoh abutting edge (soe Figs. 3 and 4). The included angle of the bevel shall be not less than 60° ,nnd the bevelling may be any one of tho forms shown in Figs. 1—4. Fig. 6. Fusion Welding oJ Gross Tubes ol Vertical Cross Tube Boilers. (b) In ordor to obtain full penetration of the weld metal a gap shall be main- talned between the plates when they are being welded. Joints shall be welded from both aides, and the dag shall be removed after making eaoh run. Before the socond side of the joint is welded tuiy slag 01 defect at the bottom of the first) run shall be remoxed by grinding, chipping or machining. There shall be no appre- ciable undercutting of the plate. (c) Por the purpose of relieving internal stresses the plates adjacent to a fusion, •weld shall be efficiently annealed after welding, and when the firebox i« forge-welded! it should be allowed to cool gradually. 126. Furnace Crown.—(a) Tho furnace crown f.eum shall not fa 11 in line with any circumferential scam of the boiler shell. (b) the furau.ee crown nmy be riveted to tho vertical portion of tlic fijphox, or alternatively, the ioint nitty bo fusion hu1t welded by the electric are process, pro- vided the conditions, as to fusion welding in Regulation 125 are observed. Where the joint is to be welded the edges of tho furnace crown and the firebox body shall be bevelled in accordance with Tig. 3 or Fig. 4. The depth of tho flange of the furnace crown •plate from the commencement of tho curvature of the flanging radius shall be not lesi« than four times the plate thickness with a minimum of 1̂ inches. On completion of voiding the fiiebox nh&ll be effectively stress relieved by heat treatment (net JHO Ke^. 128.) 127. Cross Tubes.—(a) Cross tubes shall b< made from wckllesB .stoel tube or from plate or strip rolled and forgo water gas welded. Where welded tubes are used the longitudinal welds shall be so situated that they are not exposed to the direct impact of the flame. (b) The minimum thioknees shall be 5/16 in, (c) Where cross tubes are flanged and riveted to the furnaoe, the flanges shall bo set to the ourvature and taper of the furnace, and shall be a good fit before rivet- tog- (d) Where welded construction is employed the tubes shall be of sufficient length to enter the furnace plate and be flush with the water side all round or project not more than 6/8 in. into the water space at any part of the circumference. Where the tubes are fusion welded in position, the firebox plates shall be suitably ohamfored and the joints shall be welded externally and internally (see Fig. 5). 128. Uptakes.—(a) Tho uptakes shall be foimed from woldless., forge water gas welded or fusion butt welded steel tube and shall be securely riveted to the fur« nace crown plate and riveted to the shell crown plate. (b) As an alternative to riveting, the uptake may be fusion butt welded by the electric arc process to the upward flange of the opening in the fire box crown plate provided the conditions ajs to fusion welding in Regulation 125 are observed. The edges of the upward flange and the adjacent end of the uptake shall be bevelled in accordance with Fig. 3 or Fig. 4. The depth of the crown plate opening from the commencement of the ourvature of tho flanging radius shall be not less than twice the plate thickness with a minimum of 1 inch. On completion of welding the uptake and crown plate shall be effectively stress relieved by heat treatment. Where the firebox crown plate Is also fusion welded to the body of the fire- box, the firebox complete with uptake shall be effectively stress relieved by heat treatment on completion of the welding. (c) Welded uptakes shall be so arranged that tke weld is directly facing the longitudinal centre line of tbe manhole. 129. Loco Type Fireloxcs.—(n) The foundation M>sm whall be of rivetul con- atruction but all other seams may be welded subject to the depth of the flange being such that the welded seams fall between the 1st and 2nd rows of screwed «taye or between the flange and the adjacent row of sorewed stays. Sue. 8] THE GAZETTE OF INDIA EXTEAOBDINAEY 645 (b) The firohole mouthpiece may be similarly welded when the firebox and shell are flanged for the purpose. (o) The welding shall oomply with Regulation 125. STAYS 130. Bai Stays.—JSar staya shall not b<i w^Mod at any part. They Hhall pre. ferably have plus threads, the ends of the stays being upset or the middle portion being reduced for this purpose. Stay bars -which have been worked in the tire shall be subsequently annealed. 131. Longitudinal Stays.—(a) Longitudinal and nmnlai solid SUIVMI hta\s shall be efficiently secured with nuts at euch end and not merely riveted over. Where they are over 12 feet in length, they shall be supported at intervals of fl ft. along its length, (b) Where the stay is screwed through both platos, the stay and holes shall have a oontinnouB thread and fitted -with nuts and v, asheis on the outside. Whorn the stay passes through clearing holes tin internal nut and washer shall also be fitted. Where the stay is not normal to the surface of the plate the washers shall be shaped so as to form a true surface for the nuts or a knuckle joint may be fitted. (c) In vertical boilers the stays shall cither be screwed into both crown plates or screwed into the furnaco cro^vn plate and passed through clearing holes in the shell crown plate. 132. Nuts and Washers for Stays.- (a) The washers shall l>o at k-abi 2£ times the diameter of the threadod portion of the stay and not less than 1/4 in. in thick- ness, (b) The thickness of the external nuts Bhall be at least equal to the diameter of the threaded portion of the stay. Where bar stays pass through clearing holea in end plates, internal nuts of a thickness not less than two-thirds of the diameter of the threaded portion of the stay shall be fitted 133. Jointed Stays.—Wb^r« jonitod longitudinal sta^n .in hii(«i, 1 hoy shall, where practicable, be fitted with pins having an effective sectional area 25 per cent, in excess of that of the stay. If the pins are slack in the holes, the total slackness shall not be more than 1/10 inch. The pins shall be as close as possible to tho shoulder of the eye forging. The shoulder of the forging shall be at least 1/2 inch wide all round, i.e., the diameter at the shoulder shall be not less than the diameter of the hole plus I inch. 134. Diagonal bar or rod stays.—The sectional ar>>a of dia^om-l rod or bar stay shall boar the same proportion to that of a direct stay as the length of the dia- gonal stay bears to the length of the perpendicular line from the end of the diagonal stay to the surface supported. Tho ends of diagonal stays, shall not bo bent, but shall be attached to the plate -with bevelled washers and nuts or -with riveted tee, blocks or angles and shackle pins (see Regulation 133 for eyes and pins). SOBHWED STATS 136. Screwed Stays.-—(a) Screwed atayw and tho holes for these shall be sorewed with a continuous thread. (b) The screwed threads of the stay shall be clean, free from cheoks or imper- fections, of full depth, correot Whitworth form and a good fit in the holes. The middle portion shall preferably be turned down to the bottom of the thread. (o) The stays shall be screwed with fine threads of not less than 11 threads per inch. (d) The diameter of the stay over the threads shall not be less than 3/4 in. or twioe the thickness of the firebox plate whiohever is the greater. (e) The pitch of the stays at the furnaoe of vertioal boilers shall not exceed 14 times the thickness of the furnace plate. (f) Whero tho stays arc not fitted with nuts, the ends shall be riveted over to form substantial heads. (m) Crown stays of Looo Type boilers shall either be fitted with nuts or riveted over on the fire aide. 136. Axial drilling.- AH snowed .stays less than 14 in. long should pr̂ tVuably be drilled with a tell-tale holo 3/16 in. diameter to a depth of 1/2 in. beyond the innor face of tho plate. Stays whioh are obsouro on one side should preferably be made from hollow staybar. 137. Stay nuts.- (a) NuH IO W ' W stays in combustion chumlxis and lireboxos shall not bo less than 3/4 inch thick for stays up to 1^ inches diameter over threado, 7/8 inoh thiok for 1-5/8 inohes and If inches stays, 1 inch thick for 1-7/8 and 2 inohes stays, and 1-1/8 inches thiok for stays over 2 inohes in diameter. (b) The nuts shall be made of solid mild steel or of iron whioh shall be without weld if exposed to flame. 138. Spacing of end stays—Allowance lor curves, etc.—lYu tht> top* of fireboxes and combustion ohambors the distance between the rows of stays nearest to the tube plate or lirehol© plate or bade plate as the oase may bo, and the oommenoe- meafc of curvature of these plates at their flanges shall not be greater than the hori- zontal pitch of the stays. GIB DEB STAYS 139. (Jiider Stays for Firebox and combustion Chamber Crowns.—(.) FM H yrdf*1 when of the normal type, fitted with stay bolts and nuts, shall bo of the double plate interconnected type of sufficient strength to support its proportion of the load on the crown plate independently of tho crown plate. (b) Tho clear waterway between the crown plate and the underside of uhe girdor bars shall be as large as practicable but in no oase less than 1-1/2 inches aa in fig. 7. (c) The ends of the girders shall not rest on the landing of the flat crown plate but shall be oarefully fitted to bed direotly on the bends of the oorners of the vertical •end or sido plates. (d) The toes of the girders shall bo solid with the girder plates and not separate pieoes attached thereto. (e) Girders shall be properly attached to the crown plate by bolts or sorewe. NOTM.—Alternative methods of staying may be used, or unstayed firebox, crowns of special or patented design of equivalent strength may be fitted. See Regulations 230, 231 and 232. (f) Where an all welded firobox is fitted, the girder stays may be welded to the firebox prior to stress relieving. The girder stays shall be reoessed for waterways as in paragraph (h) (Figs. 6 and 7). Suoh girders shall be securely welded by an approved method to the firebox crown. The method of welding and the proportions of attachment shall be to the satisfaction of the Inspecting Authority. flWJ. 8] THE GAZETTE OF. INDIA EXTBAORl>INAft¥ 647 Pig. 6 Fig. 7 140. Gusset Stays.—(») Gusrot plates hhall bo flat and perpmidioular to the •end platoa. The gusset anglos shall be fitted to bed closely to the shell end and gussot plates. Cranking or setting of the plates is prohibited. (b) Gusset stays, where fitted, shall comprise flat plates seoured by double angle* to the shell and ond plato respectively, and shall be designed in accordance with the following conditions:— "breathing space around furnace connections and tube nests. (b) For Lancashire boilors the proportions shown in the table below are re- commended for the portion of the end plates above the furnaces and flues : TbickiiGBB of ond plates in. ft/16 11/18 "I 3/4 I 13/10 J Above 13/16 L=. U'ig- 3) in. L = (Pip. 0} hi. i i 648 THE GAZETTE OF INDIA EXTRAOEDINAHY [PABT I I Fig. 8 Fig 9 (c) Fig. 8 shows the breathing space recommended for the following condi- tions : Flat end, furnace or flues flanged for attachment to end plato, furnaces and? flues formed with Adaroson flanged seams, (d) Fig. 9 shows similar conditions to Fig. 8 except that the end plate is flanged outwards for tho furnace or flue ring connection, the breathing spaces allowed being 1 in. more than those for the same thickness of pl&te in Fig. 8. (e) Where a corrugated section not less than 6 feet long is included in eaoh internal flue of a Lancashire boiler, the dimensions given in the table above may- be reduced by approximately 1J in. throughout. (f) It is recommended that the breathing space below the furnaces and fluer shall be approximately one half the dimensions given in the table above. Where it is desired to use any other arrangement which gives a greater or less degree of exibility, the amount of breathing spaoc shall be specially considered and modified as the neoesaity of the case requires. (g) For gusset stays above tube nests, as fitted in waste heat boilers without internal furnaces, a breathing space of 8 inches from the centre lino of the top tubes to the centre of the too rivets of the gusset angles is recommended (see Fig. 9). 142. Gussets /ngles.—The gusset angle connecting the htajR to tho shell and end plates shall be at least 7/8ths of the thickness of the shell plate, but shall be not loss than 1/2 in. in thickness 143. Load on Gusset Stay.--Each guwet stay supporting the Mid plate of a boiler shall be designed to carry the whole load due to pressure on the area supported by it. 144. Gusset Riveting-(a) Hivel- securing gusset staj« shall be not Jess in diameter than the thickness of the cylindrical shell plate and the rivetmg shall be arranged so that the strength of the sheU plate where drilled for the gueaet rivet* shall not be less than the strength of the longitudinal seams, (b) Not less than three rivets shall be used to connect any gusset plate to any angle or any angle to the end plate or to the shell plate. BOILER TUBES SUBJECT TO EXTERNAL PRESSURE 14ft. Steel and Wrought Iron Tubes.— (a) Both plain and utaj smoke tubes may be made either of wrought iron or steel and may be either lapwelded or weldlesfl. (b) Tubes may also be fabricated by electric resistance welding from strip plate. This may be aooepted for temperatures up to 7TO0F and presmireB up to 840 lbs./sq. in. 146 Fitting Plain Ttltoes.—Wheie stay tubeN arc not fitted, the ends of the tubes shall be beaded over at the fire box end and beaded or bell-mouthed at the other end. If bell-mouthed the tubes shall protrude not less than £ inch beyond! the tube plate. SHO. 8] THE GAZETTE OF INDIA EXTRAORDINARY 649" 147. Screw Threads ot stay tubes.—St»y tub< N shall be screwed at both ends with continuous threads, and the holes in tho tubo plates shall be tapped with continuous threads. Tho pitch of the threads shall not be finer than 11 threads- per inch. The stay tubes Bhall bo expanded by roller expanders and not made tight by oaulking only. 148. Minimum thickness ot stay tubes.—The minimum thiekneSH of «tHy tubes in the body or at the ends under threads shall not be less than 5/32nds of an inch. 149. Thickened ends oistay tubes.—If ntay uibob are required to hav<> their thickness increased at the screwed ends so that the thickness at the bottom of the threads is approximately tho same as in tho body of the tube tho thickening shall be attained by upsetting and not am7 welding process, and the tubes shall be an- nealed after the upsetting. 150. Load on stay tubes, (a) Staj tub^s ^hall bo di-signwl to ctiny tho whole- load due to pressure on the area to be supported In eaoh case the areas to be cal- culated as follows :—• (b) For a stay tube within the tube nest the net area to be supported shall be the produot of the horizontal and vertical pitches of the stay tube less the area of the tubo holes embraced. Where the pitch of the stay tube is irregular tho area shall be taken as tho square of the mean pitch of the stay tubes (i.e., one-quarter the sum of four sides of any quadrilateral bounded by four adjacent stay tubes) leas tho area of the tube holes embraced, (o) For a stay tube in the boundary row, the net area to be supported shall b& the area enclosed* by lines passing midway between it and the adjacent points of support less the area of any tubes embraced. Tho adjacent points of support may be ofther stay tubes, or tho commencement of curvature of flanging of centre line- of the circle of rivets securing tho end plate to tho shell angle, BOILER AND SUPERHEATER TUBES SUBJECT TO INTERNAL PRESSURE 151. Steel Tubes.— (a) All tubi-ft which aib subject to inti ma] pressure of water or steam shall bo cold drawn or hot finished seamless in accordance with Regula- tions 30 to 56. Except as pro\ided for in sub-reg. (6) below they shall be without joint. (b) Tubes having an external diameter not exceeding 5 inches may be jointed and such joints may be flash welded, machine forge welded, aro or gas welded. (c) Flash welding shall be undertaken on a welding machine of a type approved) by the Inspecting Officer and the external fin caused by welding shall be completely removed. The internal fin caused by welding ahall also be removed subjeot to a maximum height of 20 per cent, of tho wall thickness of the tube. (d) Aro welded butt joints shall be made by the metallio shielded aro- process. (e) When gan welding is employed the technique followed shall be approved) by an Inspecting Officer and all welds shall be suitably heat treated. (f) For design steam temperatures over 850cF the material to bo used shall be in accordance with Regs. 48 & 63. 152. Attachment ot steel tubes.—(a) Tubtw nhall be connected to the tub©= plates by one of the following methods :— (1) Expanding. (2) Strength welding. (3) Mechanioal bolted ball joint. 680 THE GAZETTE OF INDIA EXTBAOEDINABY [PABT I I (b) Drift or roller expanded tubes shall projeot through the neok or bearing •port in the holes by at least a quarter of an inoh and shall be seoured from drawing •out by being bell mouthed to the extent of 1/32" for each inoh in diameter plus (o) Tubes may be seal welded into fittings or headers for both boilers and superheaters after they have been expanded and flared provided the material in the fittings or headers does not contain carbon in excess of 0 '35 per cent. (d) In the case of drifted or roller expanded tubes, the tube holes in tho tubes plates of drums, pockets, or headers shall be formed in such a way that the tubes oan be effectively tightened in them. Where the tube ends are not normal to •the tube plate, there shall be a neok or belt of parallel seating of at least 1/2" in depth measured in a piano normal to the axis of the tube at the holos. (e) Whore the tubes are strength welded direot to the tube plates, the technique followed shall be approved hy the Inspecting Authority and all welds shall be suitably heat treated. (f) Tube spacers, supporting olipM and lugs may bo welded to the tubes. Flash welding of studs for supporting refractories, etc., is also permissible. (g) The tubes shall be so arranged that they aro accessible for cleaning internally and externally. 153. Copper tubes.—Copp <r tub< s up to one inch in external diameter may bf> used for small boilers ; 'such tubes shall be not leas than 12 s.w.g. thiok. HEADERS, MUD BOXES, ETC., OF WATER TUBUS BOILERS 164. (<i) Hoadwb, mud boxot, i re., of water tube boilors may be of solid drawn or welded steel, or of cast steel complying with the requirements of Regulations 73 to 80. (!)) Each piece prior to being fitted in place shall be subjected to hydraulic teat to double the working pressure of the boiler into which it is to be fitted. For pressures over 1000 lbs. per sq. inoh, tho hydraulio teat pressure shall bo the permissible working pressure plus 1000 lbs. per sq. inoh. (c) (i) the sighting hole doors shall bo substantial and oapable of being removed and replaced from timo to time without loss of efficiency or safety. (ii) Tho bolts by which they are held in place shall be fitted to thorn in auoh a way as to satisfy the above conditions. (in) The doors shall be so designed that they will not blow out in the event •of breakage of the bolt. (iv) Circular holes also may be provided in addition to elliptical holes, if pro- vision is made to prevent the door boltw from turning, while securing tho joint. (d) All flanges shall have a fillet with a radius of curvature at least equal to the •thickness of the necks to which they are attached. STAND PIPES, PADS, ETC. 165. Stand Pipes and Pads.- -Stand pip«n and coatings for carrying mountings •shall be made of wrought, cast or fabrioatc-d steel. Where pipes are fabricated •by welding they shall be stress relieved. These shall tako the form of short ataud pipes, pressed steel plate saddles, forged pads or pads cut from round rolled l>ar as may be most convenient and seoured to the boiler by rivoting or welding. Where short stand pipes are used they shall bo of solid forged, fabricated or oast steel. They •«hall be carefully bedded to the shell before attachment and where riveted the rivets shall be so pitched as to ensure a tight joint. The jointing faces to whioh •mountings are to be bolted shall be machined. Pads shall have sufficient thiokneflB to allow the drilling of stud holes for mountings without the inner surface being pierced and the length of the screwed portion of the stud in the pad shall be not less than the diameter of the stud. 156. Design of Stand Pipes.—Whwo short Htand j>ipi-is are used, th« bolting flanges shall be forged solid with the bodios or attached by combined screwing and welding or by welding alone. The thickness of the stand pipes shall comply with table below:— Stand pipes In bore li . 2i . H . . . Pressed saddles Mtii-iinum pfrmjcmblfi working prosHurnB lbs. per eq. in. TJpto ISO adjoin- ing drum in 7/lfi 7/lfi 9/1 fi fl/18 5/S B/8 B/8 rhickiiosm oT B orly in 3/h 3/K 3/S 3/H 7/J0 B/8 upto 250 adjoin- ing drum in 5/K 3/S 5/S fi/S Thi. k- npea ol Body in 3/rt 3/ft .T)/^ r>'8 C'S o i S ff/8 Flnnge adjoin- ing drum i n 7/S 7/S 7/tt 7/S 7/S Thiok- nesa of Body in 3/S fi/S B/8 fi/8 5/S s/s upto 600 Flange adjoin- ing in of Body in. ] / a 5/S fi/8 shall be formed to bed olosely to the boiler, and be machined on the faoe jointing the mounting and on the edges. The studs for the attachment of mountings, if- Borewed through the saddle, shall eaoh be fitted with a nut on the inside having a. •thickness equal to the diameter of the stud. Where the stud holes do not penetrate 'through the saddle, the length of the screwed portion of the stud in the plate shall not ho less than the diameter of the stud. 168. Seatings tor Mountings.—For prcwRuros not njroef>ding 125 lbs. per nq, in. mountings with sorewed ends not exceeding 1 in. B.S.P.T. may be used; the sorewed portion of any such mounting being an integral part thereof and the thickness at rthe bottom of the thread being not less than 3/16". The mountings may be screwed :— (a) Directly into the boiler shell plate, nuts being fitted on the waterside, or (b) Into steel distance pieces the length of thread engaged being in no case less than the bore of the mounting plus 1/4 in. 'shell or end plate whero tho plate is of sufficient thickness to allow a suitable surface to be obtained for the attachment of the boiler mountings. (6) The minimum thickness at the hole in the shell or end plate shall bo not less than the thickness required for the maximum permissible working pressure considering the plate as being unpieroed. (c) Where the boiler mountings arc secured by studs, the studs shall have a full 'thread holding in the plate for at least one diameter. If the stud holes penetrate the whole thickness of the plate, the stud shall be screwed right through the plate and be fitted with a nut inside having a thickness equal to the diameter of the stud. Where bolts are used for securing mountings they shall be screwed right through 'the plate with their heads inside the shell or end plate. 160. Insufficient thickness of End Plates.—(u) In cases whero the thiokntF.i» of the end plate is insufficient for tills purpose the mountings shall be jointed to suitable steel soatings as provided in Regulation 155. (b) The following construction!* as to stand pipes attached to end plates shall be {permissible:-— (i) Where the internal diameter of the stand pipe does not exoecd 1 inch, the standpipe may be screwed into the plate and fitted with a nut on the waterside. (iiy Where the internal diameter of the standpipe exceeds 1 inoh but does not exoeod 2 incites, it may bo screwed in and seal-welded. ,(m) Where the diameter of the stundpipe exceeds 2 inches, it may bo welded to the end plate. The foregoing provisions as to the sfcandpipe shall be regulated by the following conditions. (iv) When standpipes are screwed, the screwing shall be British or American Standard Pipe Thread. i(v) Where standpipes, saddles or other forms of seatings are fabricated by fusion welding they shall bo stress relieved by heat treatment before attachment to the boiler. (vl) Where the boro of the standpipe or seating and the hole in the plate does not exceed 5 inches plus twice the thickness of the plate, the seating may be welded to the plate without subsequent heat troatment of the weld so made. Whero the hole in tho plate exceeds 5 inches plus twice the thickness of the plate, the plate to which the seating is attached shall be stress relieved by heat treatment. 161. Attachment oi Water and Pressure Gauges.—Water gauges and pressure ^gauge syphons may be attached direct to the front end plates without the inter- vention of a pad or standpipe, provided they are flanged and secured by studs If the studs are sorewed through the plate, nuts shall be fitted on the inside of the plate. 162. Mountings on Flat Plates.— -Where the flanged mountings are attached •direot to a flat plate, suoh mountings shall be provided •with a substantial spigot, the fall thickness of the boiler plate. 163. Bolts and Nuts.—Bolts and nuts shall b > machined where th°>y oorao in contact with the flanges, and all holes in saddles and pads shall be drilled. NOTE:—-In all oasos where the boiler 1a lagged, the joint of tho mountings shall be ulont of the lagging surfaoe or the lagging kept olear of the flangff so that tho joint oan be inipeuted and, when neoeaaary, remade. 164. Access.—(a) Sufficient sight and oleaning holos ahall bo provided to permit of efficient inspection and cleaning. Such holos shall normally be elliptical in forrt} «.nd not loss than 3$ in. x - J in.* (b) At least one manhole or sight hole shall be provided in the uppor part of the cylindrical shell or in the shell orown, or end plate and this shall not bo IPSB than:— Boilers not exceeding 2 ft. 6 in. . Boilora over 2 ft. 6 in. diameter and not exceeding 3 ft. Boilorei over 3 ft. diameter and not exoeeding 3ft. 8 in. Boilers over 3 ft. 8 in. diameter and not excoading 4 ft. m. 0X7 12X9 14x10 15x11 (o) Where the size or construction of the boiler does not pormit of entry for oleaning and inspection sufficient oleaning holes shall be provided in the shell for these purposes. (d) Where cross tubes arc fitted in Vertical boilers one cleaning hole shall be pro- vided opposite at least one end of each tube. At the bottom of tho narrow water •spuces at least three cleaning holes shall be provided. The oleaning holes shall be •so arranged that the circumferential distanoe hotwoon them does not exceed 3 ft. sunless tho foundation xing is sufficiently aoctwsible to permit of cleaning and ins- pection from the inside of the boiler. (e) Cleaning holes or mudholes in Loco Type boilers shall be providod at each 'bottom corner of the outer firebox casing, above the fire hole ting and on each side •of saddle plate in line with bottom of barrel. (f) In the case of small boilers or where the foregoing provisions are impraft.j- •oablo the cleaning holes or mudholoa shall bo as nearly as p>>-nibb in tho corner of the outer firebox casing and tho holos as largo as circumstances permit. 165. Compensating Rings and Frames lor Opanings in Shells .—(a) Compen- sating rings and frames for openings in shells shall ne of wiought ot cast steel. 'The compensation provided shall preferably be flan^vl frames which H1IH.II be fitted in all cases whore tho shell plate eiooeds 9/16in. thick. Flanged frames shall bo w^ldless and shall be flanged or pressod to provide a H ii ioin'i.is; finr.n'" for the NOTE.—Wherever practicable the frames Hhould bu secured to the maido of the shells so Ahat the shorter axia is parallel to the longitudinal oontro lino of the boiler. (b) All compenBating rings and frames shall be formed to bed closely to the Bur* faces to be connected. Where attached to cylindrical shells ana arc 12 in. x 9 in, or larger they shall be at least double riveted. AH caulking edges shall be maohined or machine gas cut. (c) The flat jointing surfaces of till flanged t r pressed frames and all doors or covers shall be machined. 166. Doors and Cross Bars.—(a) All internally fitted doois of manholes, mud- holes and sightholes shall be oi wrought steel built up or pi esscd to si wipe and anneal- ed or made from one thickness of plate with a machined recess for 1 he jointing material or may be a steel casting. Their spigot part or the reees,s shall not have u, groater olearance than 1/]ftlh inch all round, i.e., the axis .shall noi be le:,s than l/8th inch smaller than the holes in which they arc fitted. (b) The studs or bolt i of large doors shall be screwed through the plates and riveted over. (o) Internal doora for openings not larger than 9 in. x7 in. in size need only be fitted with one stud, which shall be piovided with an integral collar and screwed through the plate with a mil on the inside of the dooi. Internal doors for openings not largi i than 6 in. X 3-J in, may have the stud forged solid with the door or if screwed 'ie efficiently riveted to the doors. (d) Cross bars shall be of substantial proportions and either solid steel forging or of ci*st steel. 167. Raised Manhole frames and Cover plates.- (a) Raised circular manhole frames no1 < xcmling 10 inches in diameter shall be a1 l^ast 3/4 inches thick in, all parts. The ciroulai cover plates and joint flanges for such frames shall he not less than: 1 inch t'nck for pressures not exceeding 120 lb. sq. inch. 1-1/8 inch thick for pressures over 120 lb. but not exoeeding 200 lb. sq. inch. 1-1/4 inch thiok for pressures over 200 lb. but not exceeding 250 lb. sq. inch. For pressures 250 lb. sq. inch and over raised circular manhole frames shall not "be fitted. The cover plates shall be seemed by at least sixteen steel bolts not less than 1 inch diameter. (b) External raised ciroular mouthpieces shall be :-— (1) formed in one piece without welds, (2) formed fr om a suitable rolled section and forge welded, or (3) fabricated by fusion welding provided they are stress relieved by heat treatment after weldimr and before attaching to the boiler. Wolds should be positioned so that they are located on the transverse centre line of the boiler. The jointing flanges of mouthpieces and covers shall be machined on the face and edge and on the beat ing surface for the bolts. Bolts and nuts shall be mad lined where in contact with the flanges and tho joints should be formed inside and outside tho bolts to preclude tho possibility of flange distortion. Cover plates shaJl be dished outwards to a depth of approximately one-eight of the internal diameter ol the frame. All frames and mouthpieces shall bed olosely to the surfaces to which thoyjjare- to be connected, and where riveted to cylindrical shells shall be at least double riveted. All Caulking edges shall be machined or machine gas cut. €BO. 8] THE GAZETTE OF INDIA. EXTRAORDINARY 6K6 168. Position of Manhole in Shell.— Manholes in oylindrioal sholls rthall be placed is far as possible from any riveted seams, preferably towards the hack end of the boiler top. 169. Compensation Rings to Manholes, (a.) Compensation shall U- piovided" in every case for tho part ont out of a cylindrical shell for a manhole. The strength -of the net section of compensating rin<_' and of the rivets securing it to shell compared with that of tho part of shell cut out shall not bo loss than the st length of tho longi- tudinal scams. (b) The spacing of the rivets shall be such as not to reduce t,he -itretigth of the shell plate below that of the longitudinal seams. 170. Compensation lor cutting large holes in shell Type Boilers. - Where holes are cut in the cylindrical shell for the purpose of attaching a .seating, fritrno or door, compensation shall be provided such that tho added sectional area, including parts of the frame within 4 inches of fho shell and excluding rivet holes, shall be not. less than the sectional area of the plate removed whioh shall be the product of the dia- meter of the opening and the calculated thickness of the plate us found by Equa- tion I. Where holes are cut in tho cylindrical shell for the purpose of fixing seating for mountings and the diameter of the holes is greater than 2-1/2 times tlio thickness of the shell plate plus 2-3/4 inches, compensation shall be provided. Whore a large opening is cut in a cylindrical shell to receive another part of the structure, the sides where cut away shall be efficiently eross stayed or strengthened in some other 171. Rivets securing compensating Rings and Stand Pipes. For manholes or frames.-—Th"-1 total effective shear strenirtb of the nvnts on ,eh side of the longitud'iui.l centre line shn.ll be not loss than the 1 ensile strength of that portion of the shell plate, as found by .Regulation 170, which is removed and the rivets securing any cimpojuatiiig ring or frame shall bo so a-iangad that the joint •efficiency calculated on any line parallel to the axis of the boiler through any part of such ring or frame shall not be leas than 1 ho efficiency of the longitudinal noara of the boiler. For stand pipes.—-Where the hole in the shell to accommodate a, stttndpipe does not exceed 8 inche-- diameter, the total effective shear strength of I ho rivets on each side of t b j lo-ij;itudimil centre line shall not bo loss than 75 por cent, of Hi'- tensile stren/th of the portion of th/i plate, astound by Regulation 170, which h»s been removed The strength of rivets in double shear shall bo taken aa 1 • 875 times the strength of rivets in single shear. RIVETING 172. Rivet Holes.—(a) Kivot holes shall not be punched, but shall be drilled full aizo from the solid plate, and wherever possible, rivet holes shall be drilled in place with platen, straps and ends bolted in position. After drilling, the plates shall be separated, the burrs and the sharp edges of the holes shall be removed and the contact surfaces of the plates shall be cleaned. All taoking holes shall bo drilled to a si/,e which will allow tho holes to be enlarged to the required rivet size by drilling or reamoriiig. All rivet holes shall be slightly countersunk under each rivet head. (b) The diametei of the rivet hole shall be not more than 1/16 in. larger than 'the standard diameter of the cold rivet as manufactured. (o) Where sizes of rivets are mentioned the sizes refer to the diaraeters""of the rivet holes not to the diameters of the rivets used before closing. 173. Riveting.—(a) Rivets shall be closed by hydraulic, maohinery wherever the design of the boiler permits ; the rivets may bo closed by hand or pneumatic ihammer in position where hydraulic riveting is impracticable. 666 TEH GAZETTE OF INDIA EXTBAOEDINAEY [PAKT D (b) Rivets shall be of sufficient length to fill rivet holes and form sound and substantial heads. The headu shall be finished concentrically with the rivot shanks- . Rivets shall bo heated uniformly throughout thoir full length. (c) Drift pins shall not bo used with such force as to distort the rivet holes. If the rivet holes are found not to be fair when, the plates arc bolted up for riveting- the holes shall bo roamered fair before the riveting is commenced. (d) For hydraulic riveting the pressure shall be the loast neoessary to ensure a tight joint, and only sufficient pressure shall be used to close the rivets properly and seouroly without indenting, buckling or otherwise damaging the plate. The rivets shall be allowed to shrink while under pressure from the riveting machine. 174. Fullering and Caulking.—All seams shall be fullered or caulked inside and outside and this shall bo done in such a manner that the plates are not sprung or damaged. CHAPTER IV REGULATIONS FOR DETERMINING THE WORKING PRESSURE TO BE ALLOWED ON VARIOUS PARTS OF BOILERS OTHER THAN FUSION WELDED AND SEAMLESS FORGED DRUMS. 175. The maximum pressure u,t whioh a boiler may be used shall be deter- mined in accordance "with the provisions of this Chapter. The "Regulations in this- Chapter refer to material subjected to steam temperature not exceeding 500°F. SHELLS 176. Formula for working pressure oi shell.- (a) For cylindrical shells, barrels, steam and water drums, and dome-* of boilers the maximum working pressure per square inch to be allowed shall be calculated from the following formula :— [NOTE. Where parts of drums uf water tubo boilert are perforated for tubes, the work- ing pressure shall be calculated by equation (53) under 'Tube Plates*.] W.P. == • — Eqn. (1) C x P W.P. is the working pressure in lbs. per square inoh, t ifl the thickness of shell plates in 32nds of an inoh, S in the minimum tensile breaking strength of the shell plates in tons per square- iiHi or whatever strength ia allowed under Regulation 5, .1 is the percentage of strength of the longitudinal Beams of shell or of a line of hole1 in the shell for stays, or rivets, or of an opening in the shell not fully compen- sated, whichever is least calculated by the methods hereafter described, ( is n. co-efficient as follows :— 2'7--> -when the longitudinal seams are made with double butt straps and when small sh '11K are formed from solid rolled sections ; 2-H'J when the longitudinal Hoams aro made with lap joints and are treble riveted ; ;>•()-when 1 he longitudinal seams are made with lap joints and are double riveted ; :!•() when the longitudinal seams are welded and are filled with a single butt strap : !(-3 when the longitudinal seams are made with lap joints and are single riveted. D ib the inside diameter of the outer strake of plating of the cylindrical shell measured in inches. Sao. S] THE GAZETTE OF INDIA EXTBAOBtflNAE? (MPT (b) The Factor of Safety flhall in no oase be less than 4. The aot.ual Factor of Safety in each oase may be found from the equation :— t t-2 With the best form of joint and least co-efficient (C) the Factor of Safety for sholl plates, £inoh to If inohes in thiokness, varies from 5 13 to 3-99. (o) An addition of 10 per cent, whall be raado to the appropriate co-efficient for sheila of boilers in "which the longitudinal seams are lap jointed and aie not tiewsKible to close visual innpeotion and for shell plates of externally fired boilers exposed to the direct, impact of furnace flame ; provided that this addition nbaJl not apply to the steam and water drums of water tube boilers where tho drums aie not close to the fire-grate and there are tubes between the fire-grate and the drum. (d) The above co-efficient are standards and shall be used only for boiler open to inspection by an' Inspecting Officer during the whole period of construction And which arc oertified by Mm as having boen constructed in accordance with Lhe ataivl- ard conditions laid down in these Regulations. 177, Methods o£ calculating the strength ol riveted joints.--(a) The percentage of strength of a riveted joint (J) shall be found from the following forniiuse (i) (ii), (iii) : (i) and (ii) are applicable to any ordinary typo of joint ; (iii) is applicable only to that type of joint in which tho number of rivetP in the inner COM S is double that of the outer row. The lowest value given by the application of these formula? is to be taken as the percentage of strength of tho joint (.onipiiml with the solid plate. 100(P— D) (i) = Plate percentage . . . . . . Eqn. (2> P (iii) 1—• — — — —Combined plate and rivet jjorccnta^c. Eqn. (4\ F is the pitch of rivets ut outer row in inches, D is tho diameter of rivet holes in inches, A iB th^ sectional area of one rivet hole in square inchc-, N JB the number of rivets per pitch, (P), T is the thiokneuH of plate in inches, C >̂1 for rivets in single shear atj in lap joints, and 1-875 for rivets in double shear as in double butt strapped joints, Sj in the shearing strength of rivets, which shall be taken to be 23 tons per square inoh for steel and 18 tons per square inch for iron, S is the minimum tensile bieaking strength of shell plates in tons per squam inch, or whatever strength is allowed under .Regulation 5 of Chapter I. In the first formula (i) D is the diameter of the rivet holes in tho outer row s and in the third formulw J) is the diameter of the rivet holes in the next rows, [n the last formula A is the area of one ris ot hole in the outer row. (b) When the sectional area of the rivet holes is not the same in all rows, and when some of the rivets are in double shear and others in single shear the rivet aeotions per pitch of each size or shear Hhall bo gomputed separately mid added together to form tho total rivet section. «68 THE GAZETTE OF INDIA EXTRAORDINARY [PABT II 178. When Pitch exceeds maximum allowed.—Should the pitch of tho rivets exceed the maximum pitoh allowed, the permissible pitch shall he used in place of the aotual pitoh in determining the percentage of plate section. No greater percentage than 85 shall be allowed for any type of riveted joint. 179. Butt Straps and spacing of rivets below requirements.—Should the spacing of tho rows of rivets or the distance between edge of plate and rivet hole or the thick- ness of butt straps be lees than is specified in Regulations 182 and 184 the percen- tage representing the strength of joint shall be m idifled afl prescribed in those regulations. 180. Percentage of Welded and Strapped Seams.—In determining the percentage of strength of a welded seam covered by a strap or straps the formulas and allowances in Regulations 177, 178 and 179 shall be applied, but 50 per cent, shall he added to the rivet peroentago for the weld, 181. Percentage to be allowed lor Solid Rolled Shells.—When small shells are rolled from the solid, J. in equation (1) shall he taken as 100 per rent. 182. Thickness of Butt Straps.—The minimum thickness, of butt wtraps for tlie^ longitudinal seams of cylindrical shells shall be determined by the following formulae but all straps should be of sufficient thickness to permit of efficient caulking, and in any case shall not be less than 3/8 inch in thickness. Single butt straps having ordinary riveting :— Single butt straps having every alternate rivet in the outer rows omitted :— (P-D) (P-2D) Double butt straps of equal width having ordinary riveting :— Double butt straps of equal width having every alternate rivet in the outer rows omitted :— (P-D) (P-2D) Double butt straps of unequal width either having ordinary riveting, or having every alternate rivet in the outer rows omitted. Tx is the thickness of the butt straps in inches. The other symbols have tho same significance as in Regulation 177. Single and wide butt straps shall, wherever practicable, be on the inside of the shell. Should tho thickness of butt straps be less than that above described, the least percentage of joint as determined under Regulation 177 shall be reduced hi the pro- portion of the actual thickneBB to the proscribed thiokness, , 183. Maximum Pitch of Rivets in longitudinal joints.—The maximum pitoh of the rivets in the longitudinal joints of boiler shells shall be :— OxT+1 -625 =• maximum pitoh in inohes Eqn. (II) T is the thickness of the shell plate hi inches, 0 is a co-efflcient as given in the following table :— Number of Kiveta pfr pitch Co-effloiento for Lap joints Co-effloients for oinfile Butt-utrupped joints I B S 4>0rt Co-effloionts for double Rutt- atrapped joints 184. Spacing ot rows ol rivets. -(«) In joints, whothei lapped or fitted with butt straps, in which there are more than one row of rivets and in which there is an equal number of rivets in eaoh row, the distance between the ro^ s of rivets shall be not less than— ?jig-zag riveting. •33P+- 67D => distanoe between oentre lines of rows (R) . '. Bqn. (12) Chain riveting, 2D = distance between centre lines of rows (R) , . . Eqn, (13) (6) In joints in which the number of rivets in the outer rows is one half of the aumber in each of the inner rows, and in whioh the inner rowa are chain riveted the distance between the outer rows • nd tho next rows shall bo not less than as required by equations (12) and (13) whi lever is the greater, and tho distanco between the rows in which there are the full number of rivets shall bo not lesa than 20(1^). (o) In joints in •whioh the number of rivets in tho outer rows is ono half of the number in eaoh of the inner rows and in which the inner rows are zig-zag, tho dis- tance between the outer rows and the next rows shall bo not less than— •2P + 1-15D =• distance between centre lines of outer and next The distance between the rows in which there are the full number of rivets shall b« not leBS than— • 165P+ • 67D=dietanoe between oentre lines of inner rows (RjJ Eqn, (15) P is the pitch of the rivets in the outer rows, D is the diameter of the rivot holes in inches or the mean of the diameters of rivet holes when the distance to be determined is befrweon two rows of rivets of different diameters. (<2) Should the distance between rows of rivets be less than as prescribed above the plate percentage determined by equation (2) shall be modified thus— actual distanoe 100 [P—(2 - — -—-D)] prescribed distance ——-— —- =-> modified plate percentage, . Eqn. (16) P (e) In all oases the clear space between a rivet holo and the edge of a plate shall not be less than the diameter of the rivet holes, i.e., the centro of the rivet hole shall be at least \\ diameters distant from the edge of the plate (E)— Provided that, if thia condition be not observed, the strength value of the rivetB affeoted shall be reduoed in the proportion of the aotual distance between the outer •dge of the rlveta and the edge of the plate to the prescribed distanoe. 185. Circumferential and End Seams of Water Tube Boilers.—The suitability of eirournferential seams inducting the seams joining ends to shells shall be verified by the following formula :— ' is equal to or greater than WP . . . Eqn. (17) DxC K -= 160 for 26/30 tons tensile plates. K. = 157 for 28/32 tons tensile plates. Due to higher stresses, see Reg. 271 and 340. WP =• Tho working pressure in lbs. per sq. in. D = The diameter of shell in inches, measured inside the outer ring of plates. J Circumferential Joint effioienoy calculated by Eqns. 2 or 3. C — 8-24 where tho seams are made with lap joints and are treble riveted = 8 41 where the seams are made with lap jointu and are double riveted — 9-60 where the seams are made with lap joints and are single riveted. t — thickness of plate in 32nds of an inch. 186. Compensation ior Manholes and other openings.—Tho pmwjitHgn of com- pensating section shall be determined by the following formulae :— • — = percentage strength of compensating section . . . . . . . . . Eqn. (18) —— percentage strength of rivet section . . Eqn. (19) W is the width of compensation ring in inches measured in the direction of the longitudinal axis of the boiler, L is the lerigth of opening in shell in inches measured in the direction of the longitudinal axis of the boiler, D is the diameter of rivet holes in inches, Tr is the thickness of compensation ring in inohes, Ts is the thickness of shell plate in inobes, A is the area of one rivet hole in inches, N" is the number of rivets on one side of the longitudinal line. When the rivets .are in double shear 1 • 875 times tho single rivet section shall be allowed. Parts of raised manholo mouthpiooes within four niches of the shell shall, in addition to the ring, be included in the compensating seotion. 187. Uncompensated Holes in Water Tube Boilers.—The maximum dianiotor of any ancompensatcd opening in a shell shall be determined, subjeot to the condition that the minimum thioknoss at the hole in the shell or end plate shall be not less than the thickness reqnM-rrl fee thp maximum permissible working pressure, considering the plate as being unpierood, as follows :— Where d—Maximum mean efFective diameter of unoorapensated hole in inches. T = Thickness of drum shell in inohes, I) -- Internal diameter of drum in inohes, but not exoeeding 60. N — 3 where E does not exoeed 0-60. =-8x in other oases , Bqn. (21) The required thiokness of a seamless unpieroed shell] T DISHED END PLATES 188. Complete hemisphere without stays or other support made of one or more plates and subjeot to internal pressure.—The maximum working pressuw shall be determined by the following formula :— W.P. =- Eqn. (23) OxB W.P. ie the working pressure in lbs. per square inch, t le the thiokness of the end platea in 32nds of inoh, S is the minimum tensile breaking strength of the end plates in tons per square taoh, or whatever strength is allowed for them, J is the least percentage of strength of the riveted joints of the plates forming the hemisphere or seouring it to the cylindrical shell, R ia the inner radius of ourvature in inohes, C for single riveting is 3 -3, C for double riveting is 2-9, 0 for treble riveting is 2-83. 189. Dished ends subject to internal pressure.—(a) 3Tor unstayed ends of steam and water drums, tops of vertioal boilers, etc, when dished to partial spherical form the maximum working pressure shall be determined by the following formula :— R W.P. ia the working pressure in lbs. per square inoh, t is the thickness of end plates in 32nds of an inch, R is the inner radius of ourvature of the end in inohes, which shall not exceed the diameter of the shell to which it is attached, S is the minimum tensile breaking strength of plate in tons per square inoh, or whatever is allowed for it. (b) The inside radius of curvature at the flange shall be not less than 4 times the thickness of the end plate, and in no case less than 2 | inob.es, (c) When the end has a manhole in it (t—5), shall be substituted for (t—1) In the formula. (d) In the oaae of the eleotrode boilers where the attachment of ends is permitted %j fillet welding as per Regulation 104(d), for oo-effioient 15, the co-efficient 10 ehafl be substituted. (e) The total depth of flange of manhole from the outer surface in Inohei measured on the minor axis shall be at least equal to— •v/TxW=deptb of flange in inohea Eqn. (28) where T is the thickness of the plate in inohes and W is the minor axis of the hole |n inches. NOTB.—The foregoing provisions shall not precludo the u«e of diahed encta in compliance with Begs. 275 to 278 whore not fitted with an up-take. 190. Dished ends subject to external pressure.—In the casn of imstftyed dished ends, for the co-effloient 15 in equation (24) the co-efficient 12 ahall be substituted, and R ahall be the outer radius of curvature of plate. For plates exposed to furnace flame the co-efficient shall be 10-5. In no case shall — eiceed 2-76*. t 191. Dished ends oi Lancashire and Cornish type Boilers.—(a) For dished ends of Lancashire and Cornish boilers with external or internal flanges for furnace* formed in one piece, without stays and subject to internal pressure the maximum working pressure shall be determined by the following formula :— W.P. = Eqn. (26) R W.P. in the working pressure in lbs. per square inoh, t is the thickness of the end plate in 32nds of an inoh, R is the inner radius of curvature of the end in inches which shall not exceed one and a half times the internal diameter of the shell to whioh it is attaohed, 8 is the minimum tensile breaking strength of the plate in tons per square inch Or whatever is allowed for it. (b) The inside radius of curvature at the flange shall be not less than 4 times th» thickness of the plate and in no case less than 3J inohes. 192. Dished shell and firebox crowns.—(w) In determining the working pressure in accordance with Regulations 189 and 190 no account shall be taken of the In- fluence of the uptake tube in vertical boilers. If dished crown plates having up- takes are fit for higher pressures, when considered as flat plates, under Reg, 19T •uch higher pressure shall be allowed. (b) The radius R of the dished part may be found as follows :— Ca+H« R - Eqn. (27) 2H C and H are the lengths in inches of half the base line or chord on whioh H I* measured and the height of the dish or camber at the middle of the chord ro»* peotively. FLAT PLATES 193. Flat plates supported by solid screwed stays, marginal seams or flanges.— (a) For plain flat pkton supported by solid screwed stays or riveted marginal seams- or fiances the maximum workins pleasure shall be as follows :— 0(t- l )« W.P. - — ^ _ Eqn. (28) A*-]-Ba In this foimulft and in those following in the succeeding regulations relating to "Flat Plates" unless otherwise specified. W. P. is the working pressure in lbs. per square inoh, t IB the thickness of the flat plate in 32nds of an inch, tx is I he thickness of the washers, strips, or doublings omployed, m 32nds of an inoh, A is the hoiizontal pitoh of stays in inohes, B in the vertical pitch of the Htaye in inches, C is a co-efficient whioh varies in valuo with the method of fixing the stays and nature of the support. Where the plates are exposed to the direct impaot of the flame the following values of C shall be reduced 12J per cent.— C = 60 for stays screwed into the plate with their ends riveted over. Sao. 81 THE GAZETTE OF INDIA j^l.riAOitDJLNAJKrjL C =s 90 for stays screwed into the plate and fitted with nuts on the outside, C =• 100 for stays passed through tho plate and fitted with nuts inside and out- aide, C = 110 for a riveted seam or flange, in the flat plate securing it to the shell side plate, end plate, furnace or uptake. Whero portions of plate are supported by stays or riveted seams or flanges having various values of support, the value of C, shall be taken as the mean of the points of support concerned. The support of a rivetod seam shall bo assumed to be at the line through the centres of rivets in the nearest row and of a flange at the commencement of curvature. In tho latter oase, if the inner radius of curvature of the flango exceeds 2^ times the thiokness of the plate, the support shall be assumed to be at a distance of 2\ times the thickness of the plate from the inner wide of the flange. (6) For portions of plate where the stays are irregularly pitched D ' shall be used instead of A ' + B ' , D being the diameter in inches of the largest oircle which can be drawn passing through not less than throe points of support, viz., the centres of stays, or rivets or the commencement of the curvature of flanging, whiohever is applicable. (c) For the tops and sides of combustion chambers and fireboxes tho distance between the rows of stays nearest to tho back tube late, or the back or firohole plate respectively, and the commencement of curvature of those plates at their flanges, shall not be greater than the maximum 7)itoh of the stays. (d) For the tops of combustion chambers and fireboxes where they are joined to the sides by curved portions, if the outer radius of tho curved portion i'i less than, half the allowable distance between the girders, the distance between the first girder and tho inner surface of tho side plates shall not exceed the allowable dis- tance between the girders. If the radius of curvature is greater than half the allow- able distance between the girders, the width of the flat portion measured from tho centre of the girder shall not be more than half the allowable distance between the girders. (e) Where stay tubes are not fitted in neat of tubes, as in tube plates of loco- fcype boilers, and parts of plate outside the spaoe occupied by tubes are supported, in aooordance with Regulation 212 (b), by ftcrowed stays each stay in the row noareBt the tubes shall bo sufficient strength to support the plate up to the edges of the tube holes in addition to its share of the plate on the opposite side of the line of stays. The working pressure for the plate between 1 ubos and stays shall be determined by Eqn. (28), A bcin^; the horizontal pitch of 1 ho stays in the nearost row, B twice the distance between the centre line of stays and a lino touching the tubes opposite them and C the co-efficient appropriate to the kind of stay. 194. Flat plates supported by stays and nuts and large washers or strips or doublings.—(a) Whero the plates ari- supported by stays passing through tlvm and are fitted with nuts inside and washers and nuts outside, tho diameter of the wa- shers being at least 31 times that of the stay, and their thickness at least two-thirds that of tho plate, nut not greater than that of the plate, the maximum working pressure shall be ;— A'+B» (6) where the washers have a diameter of at least two-thirds of the pitch of the stays and a thickness of at least two-thirds of the thickness of the plate, but not greater than that of the plate, and are riveted to the piale in an ffloient manner, the maximum working pressure shall be :— A»+B" (o) Where the plate is stiffened by strips at least two-thirds of the pitch of the Htftye in breadth whioh have a thickness of at least two-thirds of that of the plate but not greater than that of the plate, and are riveted to the plate in an effloient manner, the maximum •working pressure shall be:— A«+B» (d) Where the plates are fitted with doubling plates having a thiokness of at least two-thirds of that of the plate but not greater than that of the plate, and are riveted to them in an effloient manner, the maximum working pressure shall be :•— A'+B* 198. Flat tube plates.—{a) For tho portions of tubo platow in the nests of tubes where stay tubes are required and where the minimum thickness and cross section of tube plate are not less than aw prescribed in Jiegulation 211 the maximum work- ing pressure shall be :— C(t-1)« P» P is the mean pitoh of the stay I ubes supporting any portion of the plate (being the sum of the four sides of tho quadrilateral divided by four). C => 70 for stay tubes sorowed and oxpanded into the plate and no nuts fitted. C ^ 85 for stay tubes screwed and expanded into the plate and fitted with nuts. (b) No ants shall be fitted to stay tubes at the combustion chamber or firebox end. (c) Where the platea are exposed to the direot impact of flame, the oo-efBoient O shall be reduced by 12J- per cent., and where the thickness or oross seotion Oi tube plate between tubes is leas than as piescribed in Regulation 2] 1 the appropriate oo-ofnoient shall bo reduced in proportion to the deficit. (d) For the wide water spaces of tube plates between the nests of tubes and between tho wing rows of tubes and the shell, tho maximum working prossure shall be:— C A«+B» A is the horizontal pitch of stay tubea in inohos measured across the wide water space from centre to centre, B is the vertical pitch of stay tubes in the bounding rows in inches measured from centre to centre, C •=• GO for stay tubea screwed and expanded into the tube plates and no nutn are fitted, 0 = 80 for stay tubes screwed and expanded into the tube platea and fitted with nuts, 0 •= 70 for stay tubes screwed and expanded into the tube platea ana nuts are fitted only to alternate stay tube, t is the thickness of tho flat pla*"o m 32nd1? of an inch, i1 is tho thickness of tho washci w, strips or doublings employed in 32nds of an iiwh. (e) Whore the plates aie exposed to the direct impact of flame, the co-efficient C shall be reduced 12J per cent. 196. Plates supported by gusset stays.—(a) For the end plates of Lancashire, Cornish, Vertical and Locotype boilers, and other flat surfaces supported by irregularly pitched gussot slays, the maximum working pressure shall he :-— C(t-1)» D« D IB the diameter in inches of the Lucent. oirele whioh can be drawn passing through not IBHK than throe points of Hiippf>rt, viz., the centre lines of rivets or the -commencement of the curvature of flanging, whichever is applicable. C = 100 for plates not exposed to flame. C a 88 for plates exposed to flame. (6) Where such plates are stiffened by suitable tee or angle bars securely riveted to tho plates within the circle D, tho appropriate co-efficient may be increased thirty per cent. Such stiffening bars shall be placed so as to transmit their load in a direct manner to the gusset stays or shell plate. (c) Foi the part of the end plate containing the manhole in Lancashire boilers "the maximum working pressure shall be :— D is the diameter in inohes of the largest circle which can be drawn enclosing the manhole and passing thiough the centres of the rivets in end plates connecting the shell and gusset angles and furnaces or to the commencement of curvature of flang- ing, whichever is applicable where the circle passes through only three of the possible five points of support mentioned the remaining two shall he embraced within the circle. t ife the thickness of thi end plates m 32nds of an inch, tx is the thickness of the base of the mouthpiece or flat ring in 32nds of an inoh, C c= 90 where the manhole mouthpiece is either of mild or cast steel, and has a turned-in flango of a depth, measured from inside of end plato, of not less than 4 times the thickness of the end plate, and thickness not less than tho thickness of the end plate, C =70 where only a fiat stcol < ompensatmg ling is fitted, C is to be taken aR tho moan of the points of support through whioh circle passes in accordant e with Regulation 19H where there iw no mouthpiece or flat ring and the end plate is flanged around the manhole to the depth required in Regulation 201. 197. Flat Crown plates ol vertical hollers.—(a) For the flat crown plates of vertical boilers either with or without bolt stays, Equation (35) shall be used in deter- mining the WOT king pressure wit h 0=80, when the plates are not exposed to flame, and 70 when thoy are exposed to flame. In this case T> ia the diaraetor of tho largest circle in inches that can be drawn passing through tho centres of tho rivets or bolt stays when fitted, or tho commencement of the ourvature of the flanging, whichever ig applicable. Where bolt stays are fitted with washers of tho same thickness as th« plate securely riveted thoreto, the cirole shall pass through the centres of the washer rivets but where the washors are not riveted or whore none are fitted the oirolo shall pass through the oontre of the stays. In the oasc of electrode boilers where the attach- ment of endfl is permitted by fillet welding as per Regulation 104(d), the working pressure shall be determined by Equation (35) with C=40. (b) Wliero the crown plate is flanged the inside radius of curvature at the flange shall not be less than 4 times the thickness of tho end plate, but in no case 198. Circular flat ends o! drums, etc., supported only at edges.—(a) 'For those ends C in Equation (35) shall be taken aa 140 whon the plates are not exposed to- flame, and 122-5 when they are exposed to flame. In this rase the circle D shall pass through the centres of rivets or bolts securing the end to the shell or, where- the end in flanged, through the commencement of ourvature. (b) Where flanged the inside radius of ourvature at the flange shall not be less than 4 times the thickness of the end plate but in no case less than 2|*. 199. Bar or bulb stiffened end plates and smokebox tube plates of locotype boilers.—Where suoh plates instead of being supported by stays aie stiffened in the steam space by substantial tec oi angle bar s securely riveted to the plate and ex- tending across the plate to within tbe margin allowed by Equation (37) or where suoh plates are formed with a deep bulb extending across the plate to well within the margin allowed, for the support thus given, 0 shall be taken as equal to 80 and 70 for plates not exposed, and exposed, to- flame respectively. The margin or pitch for suoh stiffening shall be measured from the centre line of rivets or commencement of ouivahiro of bulb provided it is not more than 2 inches from the oentre line of bulb. For the flat plate above the stiffenej or bulb, 0 shall be token as the mean of the values appropriate for the points of support. 200. Flat plate margins.—The amount of support in relief of stays which may- be credited to the sides of shells, furnanrcs, uptakes, fireholes and foundation rings to which flat plates are attached shall noi exceed that found by the following formula:— * VW.?. t •= Thiokness in 32nds of an inch W.P. ™= Working pressure in lb per sq inch C = 3 • 47 for plates exposed to flame C = 3-70 for plates not exposed to flame. Where the platos are flanged the margin shall be measured from the oommen- oement. of curvature or from a line 2$- times the tlj iokness of the plate distant from the side of the flange next to the inner radius of the corner whichever is tbe less. In othsr easeH, the margin shall be measured from the oentre line of rivets in th& nearest row of the seam by which the flat plato is attached. Doubling plates shall cover tho area supported between the stays and extend beyond the stays so that the oontre of tho rivets securing the doubling plate to the end plate shall be at least half tho distance from the outermost stays to the noareat substantial point of support. Where flat end plates are flanged for connection to the shell, the inside radius of flanging shall be not less than 1 • 75 times the plate thickness with a minimum of 1J inches. 8*0. 8] THE GAZETTE OF INDIA EXTBAOEDINA#T| " 667 201. Manholes and Mudholes in Flat Plates.—Where a flat plate is flanged to stiffen it at a manhole or sightholo, to permit same working pressure as would be allowed upon an unpierced piato, the depth of the flange measured from the outer surfaoe shall be at least equal to— •v/TxW=depth of flange in inches . . . . Bqn (38) Whore T is tho thickness of the plate in inches, and W is the minor axis of the hole in inches. STAYS 202. Solid screwed stays.—For sorew stays to oombustion chambers and fire boxes and for longitudinal and cross stays, the maximum working pressure for the stays is to be calculated from the appropriate one of tho following two formulae :— C / 1•28 \ " A \ N / W.P. = - - — Eqn (40) A W P. is the working pressure in lbs. per square inch, D is the diameter of stays over tljreads in inches, Da is the diameter of body of stay at its smallest part in inchest, N is the number of threads of stay per inch, A is the area in square inches supported by one stay [for area to be Hupported by stays near tubes in firebox tube plates of loootype boilers, see Regulation 193(0)], 0=7100 for steel or special wrought iron screw stays to combustion chamber or fireboxes C=8640 for stool longitudinal or cross stays fitted with nuts, C=4700 for i-oppor screw stays to fireboxes. Where stays are made with enlarged ends and the body of the stay IH smaller in diameter than at the bottom of the thread the working pressuro shall be calculated from tho second formula. 203. Stresses in steel jointed stays.—(a) The section of least strength whether of Htay, rivets, shankle or pin shall be used in calculating the working pressure for the stay. For parts in tension a stress of 9,000 Bbw. per squaro inch of net sootion shall be allowed, and for parts in shear a stress of 8,000 lbs. per squaro inch of net flection. (b) Parts in double shear shall be allowed a section of 1-875 times the single 204. Stay tubes.—For *tu\ tubon, wlwthor of wrought iron or steel, seamless 1) is the diameter of the 1 uhc ovoi threads in inches, J)1 is the internal diameter of the tube under the threads in iriches, N is the number of threads of stay per inch. A is the area in square inches supported by one stay tube, measured from centre to centre of stay tubes. When the area contains tubes or parts of tubes their aggre. ku c area, calculated from their smallest external diameter of body when in tension 668 THE GAZETTE OF INDIA RXTEAOBDINARY [PART j r and smallest internal diameter \Oien in compression, shall bo deducted from the area of the containing figure and the remainder used as A in the formula. 206. Stays in tension and compression.~ (n) The same stress shall be allowed' in compression as in tension. The strength of short stays in compression and not liable to lending shall bo calculated on tlie not section of the stay at hot torn of thread or in body, whichever in lew. (b) The stress to bo allotted on nn\ slay of part of a stay not provided for in foregoing shall he the same aw that allowed for stays of parts of stays of approxi- mately like kind in similar condition-. 206. Measurements of stayed areas in the end plates of locotype and vertical boilers.—When the areah supported b\ ->tays aro semi-circular as in the upper parts of the end plates and amokebox tube plates of loootype boilers, or annular as in the crown plates of vertical type boilers, the area to be supported by stays, A in Eqns. 39 and 40 shall, in the first case, bo the area of the plate contained within iihe margins orodited to oasing or barrel sides, screw stays, fire door ring or tube stays as the case may be, and in the seoond case be the area of the annulus between the margins credited to uptake and ah ell, When bolt staying is neoessary, the stays shall be properly distributed ; the aggregate stay seotion shall then be used, in the formula for calculating the working pressure. 207. Gusset stays.—The maabnimi working prcpmmi for gusset stays shall be calculated by the following formula :— • 9000 XC W.P. = — • . . . . Eqn. (42) A 0, the oo-effioient, is the number representing the least of the following ;- (4) N4XA«. diameters and sectional areas of the rivets in the joints of eaoh gusset stay, only- rivets in the supported area, to be < oimideml effective the order of the joints being (1), angles to end plate, (2) end plate unules to tjusset, (3) shell angles to gusset, ana (4) angles to shell, G is the depth in inches of gusset plate measured through the line of rivets attaching it to the end plate angles, Gx is the depth in inohes of gusset plate measured normal to the slant edge of plate through the rivet nearest to the end plate in the joint attaohing gusset plate to shell angles, t ia the thickness of the gusset plate in 32ndw of an inoh, A is the area in square inches of flat plate supported by the gusset stay which, in the case of Lancashire and Cornish boilers, shall be determined as follows : (a) The margins allowed under fiat plate regulations for shell and furnace shall be marked on end plates and the lengths of the centre lines of gussets between them measured, also the distance between eaoh pair of gusset lines from the middle of the smaller in a direction normal to the greater. TfLand l-^be the lengths of two adjaoen* Bso. 81 THB GAZETTE OF INDIA EXTBAOBtHflAjU 8#* gusset lines and if the distant* between them be W, th* area oontained by the gusset fines and the shell and furnace margin lines may be apportioned between the stays thus:— — . .. *• Portion of area in tqnare inches, apportioned to L line gusset Eqn. (43) = Portion of area in square inohea apportioned to LT line gusset . . . . . Eqn. (44) (b) The portion of the area on the other side of eaoh gusset line shall, except when of triangular form, be found in like manner and its amount added to that al- reedv found to form the total. """ fb) For the triangular portions in the wing spaces the area shall be taken an half the produot of the length of gusset line into the perpendicular distance between it and the intersecting point where the marginal ourves meet. BOLTS AND STUDS 308. (a) Bolts and studs connecting parts of boilers such as shell, end plates, tube plates, furnaces, uptakes, externally fitted manhole covers, mountings, eto., may be made either of steel or good quality wrought iron. (b) The maximum working pressure for the bolts or studs Bhall be oaloulated by the following formula :— A \ n / D is the diameter of bolt or stud over threads in incb.es, N ia the number of bolts or studs securing the part, n is the number of threads of sorew per inch, 0=4,700 for steel bolts or studs of 28 tons/sq. in. minimum ultimate tensile stress where the diameter over thread is less than 3/4 inch. C—5,100 for steel bolts or studs of 30 tons/sq. in. minimum ultimate tensile stress where the diameter over thread is less the 3/4 inoh. 0=5,600 for steel bolts or studs of 35 tons/sq. in. minimum ultimate tensile stress where the diameter over thread is less than 3/4 inoh. C=5,600 for steel bolts or stud a of 28 tons/sq. in. minimum ultimate tensile stress where thf diameter over thread ic not less than 3/4 inoh and not greater than 7/8 inch, C--7,000 for steel bolts for studs of 28 tons/sq. in. minimum ultimate tensile stress -«here the diameter over thread is greater than 7/8 inch. When the material is iron, a reduction of 15 per oent Bhall be made in the work- ing pressure as calculated by the formula. A the area in square inohes of the surface supported by the bolts or studs. For jointed flanges the area shall be taken to extend to midway between the pitoh line of tho bolts and the inner edge of the flange by whioh the part is secured, TUBE PLATES 209. Compression of tulbe plates.- (a) For fire-box or combustion chuinbu lube plates which are subject to compression due to the pressure on the roof plate, the maximum working pressure shall be :— W.P. =. Eqn. (46) LxP t is the thickness of the tube plate in 32nds of an inch, P is the pitch of the tubes in inches, rueasurod horizontally where the tubes are . ohain pitohod, arid diagonally where the 1 ubos are zigzag pitched and the diagonal pitch is less than the horizontal, D is the internal diameter of the plain tubes in inches, L is the internal length of the fire-box or combustion chamber in inohes measured at top between tube plate and firehole plate or baok plate, or between tube platea in doublo ended boilers with combustion chambers common to two opposite fur- naces, C = 875 for steel and 437-5 for copper. Provided that the above formula shall not apply in the case of fire-boxes where the girders do not rest on the tubo plate, or where the roof plate is stayed direct to * tho outer shell or to girders supported by the shell. (b) where girders rest on the side plutos or tlie roof plate is so formed that the load is» carried both by side and end platos, in no case shall tho compressive stress on the platos exoeed 14,000 Iba. per square inch for steel of 7,000 Tbs. per square inch for copper. 210. Parts to be stayed.—(a) Tho Htittm sh of tub" plates and pitch of stays within the nests of tubes where stay tubos nro required and where- marginal stay tubes are required in support of blank spurns adjacent to or between the nests shall be determined by flat plate rules under Regulation lOfi. (b) Tube plates within the nostn of tubes whether fitted with stay tubes or not shall comply with the requirements of Regulation 211 in regard to thickness and cross section between tubes. 211. Minimum thickness and cross section.—To provide a secure attachment for plain tubes in the tube plates the thickness .xud cross section, of tho plate between the tube holes shall not be less than • — Steei tube plate, •125D+ -2—minimum thickness in inches . . . . Eqn. (47) •17D+ 025 ̂ minimum cross section in square inches . . Eqn. (48) Copper tube plate, • 2D+-4—minimum thickness in inches Eqn. (49) •527D— -203=minimum cross section in square inohes . . Eqn. (50) D is the diameter in inches of the tube at tho part of attachment to tubo plate. Where the thickness and cross section of the tubo plates are less than the minimum the appropriate co-efficient jn Eqn. (51) shall bo reduced in proportion to the deficit. 218. Holding power of plain tubes.—(a) Whero tube plates are not specially stayod in nests of tubes, tho working pi ess ure, based on the holding power of the tubes shall not exceed that found by the following formula :— OXD W.P. = — Eqn. (51) A SEO. 8] THE GAZETTE OP INDIA EXTBAOEDINAEY 671 D is tho diani3ter of tube ab the part of attaohmont to tube plate in inches, A ia the area in square inehos of the tubo plate supported by each tube, which generally may be taken as tho product of the horizontal and vertical pitohos of tho tubs less the area of the tube itaolf, C t= 470 for tubes expanded into parallel holes in steel or irontubo plates, C = 530 for tubes expanded into taper holes in steel or irontubo plates. for copper tube plates or copper or brass tubes the appropriate co-efficient should be reduced 20 per cent. (b) In tho unstayed tubo plates of locotype boilers and in other tube platos in which ytay tubes aro not required the support afforded by the plain tubes shall not bo taken to extend beyond the lines enclosing the outer edges of the tubes. Parts of flat plato outaido this line uhall oither lie in the plate margin or be separately supported. No account need be taken of tho stiffness of tubo plate in the nests of tubes when tho above conditions are fulfilled. Ordinarily tho requirements of this clause are applicable only to expanded smoke and water tubes in flat continuous tube plates containing moro than one row of tubes. (See Beg. 152 for attachment of tubes in Water tube boiler.) 213. Tube plates, other than ends, of vertical toilers foimirg parts ot cuter shell.— (a) When, vortical boilers have a nest or nosts of horizontal tubes so that there is direct tension on the tube platos duo to tho vertical load on the boiler ends, or to their aoting as horizontal ties across the shell, the thickness of the tube plates and the spacing of the tubes shall be such that the section of metal taking the load is sufficient to keep the stress within that allowed on the shell plates. (&) Each alternate tube in the outer vertical rows of tubes shall be a stay tube. The tube plates botweon tho stay tubes shll be in accordance with the rules for tube plates and in addition, considered as part of shell, the maximum working pressure,— BXP t is the thickness of tho tube plate in 32nda of an inoh, V is tho vertical pitch of the tubes in niches, D is the diameter of the tube holes in inches, S is the minimum tensile breaking strength of the tube plates in tons per square inch, or whatever is allowed for them, R is tho radial distance of the contre of the outer row of tube hole from the axis of tho sholl in inches, 214. Curved Tube plates of water-tube boilers.—For tube phdos forming part of cylindrical drums the maximum working pressure shall be W.P. = ™ . . . . . . Eqn. (53) t = thickness of tube plato in 32nds of an inoh, E =Efficiency of the longitudinal joint or the ligament between the tube holes-, whiohevor is loss, S = Minimum Tensile Stress of the tube plato in tons per sq. in, or whatever is allowed for it, D =Inside diameter of tho drum in inches. 672 THE GAZETTE OF INDIA EXTBAOEDINABY [PAHT H 216. Efficiency of ligament.-—(a) When a shell or drum is drilled for lubes in n lino parallel to the ana of the shell or drum, tho efficiency of the ligament between the tube holos shall be determined as follows :— (a) When u pitoh of the tube holes on every row is equal (as in fig. 10). the for-" inula is :— p—d — = efficiency of ligamont. . . . . Eqn. (54)J] V Where p = pitch of tube holes, inches, d = diamoter of tube holes, inches. The pitoh of tube holes shall be measured either on the flat ulatc before rolling or on tho median lino after rolling. Example.—Pitch of tube holos in the drum as shown in Fig.r 10^= 5J in. Dia- meter of tube = 31". Diameter of tube holes = 3-9/32*. p^d 5 -25-3 '281 .—-=*- .—.—•—•—— =iO-376, efficiency of ligament. p 5-25 Fig. 10. Example of Tuba Spacing with Pitoh of Hoi a equal la every Bow. (6) When tho pitch of tube holes on any ono row is unequal (as in Figs. 11 & 12) the formula is :— p—nd P Where p = unit length of ligament, inches, n = number of tube holes in length p, d ~ diameter of tube holefl, inches. Example.—Spacing shown in Fig. 11. Diamoter of tube holes = 3-9/32*. — = • — — = 0-453, efficiency of ligament. v 12 Fig. 11. Example of Tube Spacing with Pitch of Holes Unequal in every Ssoond Row. Example.—Spacing shown in Fig. 12. Diameter of tube holes = "-9/32". = —• • = 0-4 '9, ^ffioienoy of ligament. p 29-25 SBO. 8] THE GAZETTE OP INDIA EXTRAORDINARY 6? 8 Fig. 12 Example ol Tuba Sparing with Pitch ol Holes varying in every Second and Third Row (c) The strength of I hose ligamonta botwoen tho tube holes whioh are subjected to a longitudinal stress shall be at least one half tho required strength of those ligaments whioh oorae between the tube holes whioh aro subjected to a circum- ferential stress. (d) When a shell or drum ia drilled for tube hole so as to form diagonal ligaments as shown in Fig. 13, the efficiency of these ligaments shall bo that given by the dia- gram in Fig, 14. p p' In this diagram the abscisses aro -and the ordinates d p Where p = longitudinal pitoh of tube holes, or distance between oentres of tubes in a longitudinal row, inches, p' = diagonal pitch of tube holos, inches, d = diameter of tube holes, inches. Fig. 13. Example ol Tube Spacing with Tuba Holes on Diagonal Lines V P To use the diagram in Fjg. 14. the values of——- and • d p are computed and the efficiency for the corresponding points is road off from"the diagram. Should the point fall above the curve of oqual officioncy for the diagonal and longitudinal ligaments, the longitudinal ligaments will be the weaker, in whioh oase the effioionoy is computed from the following formula :-— p- d V Example.- (1) Diagonal pitch of tube holes in drum as shown in Fi# 13 ™ 6 42 in. 674 THE GAZETTE OF INDIA EXTBAOEDINABY [PART II Diameter of holes = ijt in Longitudinal pitch of tube holes = 11J in. p 11-5 p' 6 4 2 d 4-031 p 11-5 The point, corresponding to these values is shown at A on the diagram in Kg. 14 and the corresponding efficiency is 35-3 per cent. As the point falls below the curve of equal efficiency for the diagonal and longitudinal ligaments, the diagonal ligament is the weaker. (2) Diagonal pitch of tube holes in drum = 6-35/64 in. Diameter of tube holes . . =4-1/64 in. Longitudinal pitch of tubd holes = 7 in. p i %>' 6'547 d 4-0166 p 7 The point corresponding to these values is shown at B on the diagram in Fig. 14 and it will bo seen that it falls above the line of equal efficiency for the diagonal and longitudinal ligaments, in which oase the efficiency is computed from formula (1)_ Applying formula (I), wo have : = 0-426, efficienoy of ligament, or 42'6 per cent. ffor holes plaoed longitudinally along a drum but which do not oome in a straight line, the above rulea for oaloulatin? efficiency shall hold, exoopt that the equivalent longitudinal width of a diagonal ligamjnt shall ba used. To obtain tho oquivalont width the lon^tudiDal pitoh of the two holes having a diagonal ligament shall be multipliod by tho efficiency of tho diagonal ligamont. The- effioienoy to be asod for tho diagonal ligaments ia given in Fig. 15. l;io IS DIAOIAM TOR DETERMINING EITICIEMCY OF DIAGONAL LIGAMEJ T^ IN OKDDR TO OBTAIN EQUIVALENT LONGITUDINAL ErnciENrv BOILER AND SUPERHEATER TUBES SUBJECT TO INTERNAL PRESSURE 216. The miximirm working pressure for tJio tubo shall be determined by Equation No. 87. (See Regulation 338). The minimum thickness of the tubes shall comply with the table given In Regulation 338(b). HEADERS AND SECTION BOXES OF WATER TUBE BOILERS 817. See Eqn. 88 Reg. (340) BOILER TUBES (SMOKE) SUBJECT TO EXTERNAL PRESSURE 218. Steel and Wrought Iron Tubes.— (a) The maximum working pressure for the tubes shall be .— W.P. = — Eqn. (56) D t is the thickness of the tubea in lOOths of an inch, D is the extornal diameter of the tubes in inohes, (6) No tube shall be less than 12 S. W. G. (-104") thiok. 219. Brass and Copper Tubes.—Th« thickness of tapered brass and copper smoke tubes for locomotive boilers shall, in the oase of tubes of an external dia- meter of 1J to If inches inclusive, bo not less than 12 S. W. G. (• 104 inch) at the emoke-box end and 10 S.W.G. (• 128 inch) at the other and in the oase of tubes of an external diameter of 2 to 2$ inohes inoluflive, the thickness at the smoke-box end shall not be less than 11 S. W. G. (116 inch) and at the other end not lee» FURNACES 220. Plain Furnaces of Horizontal Boilers.—For plain fumacos or furnaces •lengthened by Adamson or other joints or stiffeners of sufficient strength and for the semi-oylindrioal tops of fire-boxes and bottoms of combustion chambers where the sides are securely stayed, the working pressure shall not exceed the smaller of the values obtained from the following formulas— C (t—1)' D (L +24) Pi D I) is the external diameter of the furnace or chamber top or bottom in inches, t is the thickness of the furnace plate in 32nds of an inch, L is the length of the furnaoo or other part in inches measured between points of substantial support, i.°., centres of rows of rivets in end seams or commencement of curvature of flange, whiohever is applicable, C = 1450 where the longitudinal seams of steel furnaces are welded and 1300 where they are riveted, C = 725 where the longitudinal soams of oiroular copper fire-boxes or furnaoe are fitted with double butt straps and 050 where they are lapped, Cx =• 50 -where the longitudinal seams of steel furnaces are welded and where they aro riveted. G1 = 25 where the longitudinal seams of oiroular copper fire-boxes or furn&oes are fitted with double butt straps and 22 • 5 where thoy are lapped. pressure to be allowed on corrugated furnaces shall be determined by the following formula— D D is the least external diameter in inches measured at the bottom of the corrugations on the water side, t is the thiokness of the furnaoe plate in 32nds of an inch measured at the bottom of the corrugation or chamber, C = 480 for the Fox, Morrison, Deighton, Purves, and other similar furnaces and 510 for the Leeds Forge Bulb Suspension Furnace. 222. Plain Furnaces ot Vertical Boilers.—The same formula as for tho plain furnacea of horizontal boilers shall be used, but where the furnaces are tapered, the diameter to be taken for calculation purposes shall be the mean of that at the top and of that at the bottom where it meets the substantial support from flange or ring. The length for the same purpose shall be the distance from the oentre of the row of rivets connecting the crown and the body of the furnace to the substantial support at the bottom of the furnaoe, or to a row of screwed stays connecting the furnace to the shell, provided that the pitoh of stays at the furnace does not exoeed 14 times the thickness of the furnaoe plate when the stays are riveted at their ends, or 16 times when the stays are fitted with nuts. Suoh screwed stays shall be in diameter over the throads not less than twice the thickness of the furnaoe plate and in no case 223. Hemispherical Furnaces of Vertical Boilers.- When fume at. arc homi- flpV'Ioal in firm anl subject to praiaure on tho convex side and are without support from stays of any kind, the maximum working pressure shall be :— 275(t—1) B t is th© thifknoss of the top plate in 32ndB of an inoh, H is the outer radius of curvaturo of the furnaoe in inches. 224. Corrugated Fireboxes oi Vertical Boilers.—For tho somi-spirally corrugated fireboxes of "Sentinol" standard motor wagon boilers tho -working pressure shall be determined by tho following formula :— C(t-l) D t is the thioknesB of the firebox plate in 33nds of an inoh, T> is tho mean of the external diameters of firebox moasured over the plain part at each end at commencement of curvature of flange. C =• 390. 225. Foundations oi Vertical Boiler Furnaces.—Whore circular furnaces or fireboxes of vertical boilers are not connected to tho shell crown by uptake tube, smoke tubes or bolt stays and the whole load on the firebox vertically is borne by the bottom part of the firebox where it is connected to the shell the working preumire for the part, if firebox is joggled out to meet the shell or if an ogee ring is fitted, shall not exceed that found by the following formula :— 140(t—I)1 t is tho thioknoss of the joggled firebox plate or ogee ring in 32nds of an inch, D is tho inside diameter of the boiler shell in inchos. Di is the outside diameter of tho joggled firebox at the commencement of our- vaturo abovo joggled part or tho outside diameter of the firebox where it joins the ogeo ring. 228. Foundations ol Looo-type Boiler Fireboxes.—Whero tho firo-box roof in loco- type boilers it* not stayed direct to the external casing crown or to girders oarried by tho casing or is not connected to tho casing by slings in accordance with Regula- tion 229 (<;) and the whole load on the firebox vertically is borne by the bottom parts of the firobox where connected to tho external casing the working pressure for the parts, if plates are joggled out to meet tho casing or if an ogeo ring is fitted, shall not exceed that found by the following formula :—• W.P.=— — Eqn. (63) t is the thioknoss of the joggled firobox sido plates or fire hole plate (whiohever is leas), ogoo ring in 32nds of an inch, L is the length of firebox casing in inchos measured between tho water sides of front ond plate and saddle plate at the foundation seam, W is the width of firobox oasing in inohes measured betweon the water sides casing sido plates at the foundation seam, Wx is the width of firebox in inches measured botwoen the water sides of firo box sido plates at the commoncoment of curvature abovo jogglod part or where it joins the ogee ring, Whero only a comparatively narrow strip of tho firebox roof is stayod directly to the oasing crown the area so stayed shall be doduoted from the area roprosented by L X W in tho bottom line of tho formula thus, (L X W—A) (W—Wx) and so used in Equation (63) in determining the working pressure for the parts, "A" being the area in square inches of the part of roof supported by tho oasing crown. 227. Cross Tubes.—The working pressure of the tubes shall be determined by tho following formula :•—• 200(t—7) W. P . = Working pressure in lbs. por sq. inch, t = minimum thickness in 32nds of an inoh, D=J the internal diameter in inchos of tho cross tube. 228. Uptakes ol Vertical Boilers.—The working pressure for uptake tubes of vertical boilors shall bo determined by Eqns. 57 and 58 but only half the least pressure so found is to be allowed for uptake tubos. SUPPORTS FOR COMBUSTION CHAMBER AKX> FIREBOX CROWN 229. Girder stayB lor firebox crowns.—(a) For girders supporting crown plates of rectangular fireboxes, where the ends of the girders are supported by the vertical end or aideplates, their proportions shall he calculated from the following formula:— W.P. = — _ _ • Eqn. (65> Where WP = Woiking pressure in lb. per sq. inch, S = Minimum tensile stress of tho material in tons per sq. inch, T = Total thickness of the stay in thirty seconds of an inch, d = Depth of the girder si ay in inehei, L = Length of girder stay in inches measured between the inside of the tube plate and the firehole plate, or between the inside of the Bide plates, according to the method of support. Y = Pitch of girder stays in inches, C = 22 for steel plates or steel forgings 19 for steel castings. (b) Where girders are supported in any other way 1han by tho end or wide plates of the firebox or combustion chamber the calculations for (letcunining the working pressure shall be made in accordance with the actual conditions of support. In such cases the length of the strip of firebox or combustion chamber top plate to be supported by the girder shall, Hubjcot to the limit imposed on tho distanco of the nearest stay, bo taken as equal to the product of tho number of bolts carried by the girder into the pitch of the bolts. A maximum nominal stress of 14,000 lbs. per square inch on girder section shall be allowed for steel. (c) Slings, links, pins, rivets, and connections to shell of slung girders shall be sufficient to carry the whole load that would oLhorwise be carried by the girder, and each girder must be equally slung or supported. For wiresses allowed on tho sections,, see Regulation 203. (d) In the oase of girders supported at tho onds only by angle bars riveted to the casing crown, the length L may, when the girder extends over the full broadth' of the angle face, be taken as the distance between the centres of the angle faces. When this distanco does not oxceed that of L in the formula, the pressure shall be determined in the ordinary way. The supporting angles and rivets shall be of suffi- cient seoiion for the intended purpose. For stresses allowed on the sections, see Regulation 203. PATENT FIREBOX ROOFS OF LOCOTYPE BOILERS 830. Marshall Type.—For Messrs. Marshall Sons and Company's patent ataylcfis roof for firoboxes of loeotype boilers made of steol in which the centre lines of tho corrugations meet the centre lines cf the end riveted seams at points not farther distance from the side plates than ono half the inner radius of curvature of the oorncr formed by the roof and side plate, in order to ensure that tho thickness and height of tho pressed diagonal corrugations of the camber are satisfactory, the working pressure shall not exceed the smaller of the values obtained from the follow- ing formulae :•— W.P. = — . Eqn. (67) t is tke thickness of the roof plate in 32nds of an inch, H in the hoight of tho corrugation at its highest part measured perpendicularly on one side of the plate in inohos, W is the wicltfi of the roof plate between tho flat of side plates at top loss the inner radius of curvaturo of corner of roof and side plate in inohes, i.e., W+radius = internal width of firebox at top, L is the length of the roof plate botween oentre lines of rivets in inches. 231. Garrett Type. -For Messrs. Riohard Garrott and Son's corrugated stay- less roof for fireboxes of loootypo boilers made of steel in which the sido corruga- tions aro parts of true oirclcs and the radius of the middle corrugation is not inoro than about J',k of tho radius of the ouler corrugations and the corrugations are cam- bered longitudinally, the working pressure shall not exoeod the smaller of the values obtained from the following formulee :— C (t— 1)* II (L+24) Oi R t is the thickness of the corrugated plate in 32nds of an inoh, L is the length of tho roof plate between oentro linos of rivets in inches, H is tho external radius of the side corrugations at the middle of the length in inches, C = 303 where the roof and side plates aro in one piece and 325 wlion thpy are riveted, Cj = 12-5 where the roof and side plates are in one pieoo and 11 • 25 whore they are riveted. 232. Fowler Type.—(a) For M 'ssrs. John Fowlor and Company's (Leeds) oorruga- ted roof for fireboxes of lo 'otype boilers made of steel in which tho crown of the roof is transversely curved and corrugated in the style of Fox's corrugated furnace and the roof plate, if not soLd with tho side plates of the firebox, is securely riveted thereto and to the flanges of the tube plate and fireliole plate and there is a row of suitably sized and spaced screw stays b'elow the commencement of corrugations on each side attaching the roof plato to the external oasing, when the conditions hereundor are complied with, tho working pressure shall not exceed the smaller of the values obtain- ed from the following formulee :•— C(t-3) R W.P. = —• • • Eqn. (71) W t is tho thickness of roof plato before corrugations are formed, in 32nds of an inch, tj is the thickness of side plates of firebox to which roof plate is attached in 32nds of an inch, R is tho radius of transverse curvature or camber of middle part of corrugation measured fiom the bottom of corrugation on water side, in inches, W is the width of firebox in inohes measured over -water aidas of side plates at the seams attaching them to roof plate, C = 240, Cj = 875, (b) Thj corrugations measured from top to bottom on one aide, shall not bo less than throo timos the thickness of the finished plate in depth and not more than 12 James the thickness of the finished plate apart. (c) The inner radius of corner at aides where corrugations merge into the flat sides shall be not less than 4 times the thickness of the finished pinto. (d) Tho length of the plain parts at ends of roof bctweon tho centre lines of riveted scams and commonoonient of curvature of oomigations shall not exoeed that allowed for flat plato margins under Regulation 200. CHAPTER V FUSION WELDED AND SEAMLESS FORGED DRUMS FOR WATER TUBE BODLERS AND SUPERHEATERS GENERAL REQUIREMENTS 233. Where applicable tho genoral tormR of Chapter I relating to Certificates from Makers, Inspecting Authorities, e tc , and of Chapter I I I concerning construc- tion should bo followed. MATERIALS OF CONSTRUCTION 234. Material For Fusion Welded Boiler Drums.—(a) The requimnc-ntu of Re- gulations 9 to 20 so far as they relate to plates, shall apply to steel plates for fusion welded boiler drums exoopting that the ultimate tensile stress and elongation of the materials shall be between tho limits shown in table below and shall be speoified for •each component part of the boilers. Description, Platin for drum «h illi (»'."., w u jpur pl.it >H and tnbo platiw). Drum un'U, stand or brii-ich pipo, an 1 woatingH for mounting* TUtiimito tensile Toa^ pur HL|. in. f 26-30 j n T "i 28-32 ! L Minimum obligation per uont. Tejt pioce A or B 23 for 26-30 t ms por aq. in 20 for 28-32 tons p«r bq. in (b) Plates over 2 ' in thickness bofore being fabricated, shall be uniformly heat treatod to produce grain refinement. Heat treatment involving quenching in a liquid medium is not permitted. SEAMLESS FORGED DRUMS 235. Process of Manufacture.- -Carbon sleol for fioamli BB steol drums shall bo made by the open hearth or an electric prooess, aoid or basic 236. Chemical Analysis.—The steel shall contain not more than 0 06 p«r oent. of sulphur or of phosphorus. 237. Freedom from defects.-—Tho drum nhall be free from surface defects and shall be machined to the prescribed dimensions. Defeota in forgings shall not be repaired without the previous sanction of the Inspecting Officer. 238. Heat treatment.—Each drum shall bo efficiently hrat treated : (a) At various stages during manufacture, as required. (b) On completion of the forging process but prior to the hydraulic test. 239. Mechanical Tests.—Material shall comply with the mechanical tests heroin specified. Sufficient material shall bo left on the open end or ends of each forging to enable tangential test pieoes to be taken. These tests shall oonsist of not less than one tensile and one bend tost from each open end. In the case of drums with open ends the tost material shall not be partod off before heat treatment. If the drums are closed in at the ends the test rings shall be partod off immediately before this operation; subsequently tho test rings and the forging shall bo similarly, and simultaneously heat treated in the same furnace. 240. Selection of Test Pieces.—(a) All test pieces shall bo selecti d ly ihe autho- rised Tnspeotor and shall be tested in his presence and he shall satisfy himself that the conditions herein described are fulfilled. (b) Tensile Tests.—Tho ultimate tension stress find elongation ahull le between the limits shown below. A range of not more than 4 tons per sq. in. for any one forging shall apply, such rango to be speoified for each drum. (i) "Ultimate tensile stress 28 to 38 tons per sq. in. (ii) Elongation 29 per ocnt. to 19 per cent, determined on British Standard Test Piece 0, or a subsidiary standard round test piece (see Appendix B). In no case shall the sum of the ultimate tensile stress and corresponding elonga- tion be loss than 57. Should a tensilo test piece broak outside the middle half of tho test gauge length the test may be discarded and another test be made of the same drum. (o) Bend Test Pieces.--Bend test pieces shall bo of reotangular section 1 in wido by £ in. thick. The edges shall be rounded to a radius of 1/16-in. The test pieoes shall be bent over the thinnor section. (d) Bend Tests.-—Tho test pieces shall, when cold, bo capable of being bont without fracture, through an angle of 180°, the internal radius of the bend being not greater than that specified in table below. U l t i m a t a tmiHile atress, Toiia por ^q. in. 5/S Bend test may bo made by pressure or by blows, 241. Additional tests before rejection.—Should oil her a tensile or a bend test fail, two further tosts of the type which failed may be made on test pieces cut from the same test rings. If the results obtained from these re-tests are satisfactory, the drum shall be accepted, provided that in other respeots it fulfils tho conditions of this Chapter. If these re-tests do not give satisfactory results the drum represented SBO. 3] THE GAZETTE OP INDIA EXTRAORDINARY 688 may be re-heat-treated togother with tho roinaindor of the teat rings, and presented for further testings. In all case where final re-tests do not give satisfactory results, the drum re- presented by the test pieces which fail shall be rejected. 242. Discard.—Sufficient disotird shall b-> mado from the 1 op and hot lorn of each ingot to ensure soundness in the portion for forging. 243. Forging.—Tho forcing shall be uiado from a solid oast ingot, punohed, bored or trepanned, or alternatively, hollow cast ingots may be used. The resultant wall in the case of the solid oast ingot, or the wall of the hollow ingot as cast shall be reduced in thickness by at least one half in the process of forging. 344. Tubes.—(a) Tub̂ H shall b-> of oold drawn woldloss or hot finiNhod weldloss steol and shah1 comply with Regulations 36 to 56. Headers.—(b) Headers and similar pressure parts shell bo of forged steel, soam- less steel tube or of oast steol, to oomply with tho appropriate Regulations in Chapter n. 245. Pipes. - -Pipes forming an integral part of tho boiler unit shall oomply with the Regulations of Chapter VIII. 246. Steel Castings. -Sttel castings for pressure parts shall oomply with Rogu- lations 73 to 80 (28 to 35 tons per sq. in.). FUSION WELDED DRUMS 247. Definition of term 'Fusion Weld'.—Tho torm 'Fusion Wold' is, for tho purpose of this Chapter, applicable to all welded joints made by tho metal aro pro- cess with covered electrodes or other electric are proooss in which the aro stream and the doposited weld metal are shielded from atmospheric contamination. It is intended that this Chapter shall apply to the single run or heavy run welding process and that welded boiler drums manufactured by that process shall oonform with all Regulations of this Chapter, excepting those in which divergence is necessary solely because of special requirements essential for tho most officiont utilisation of that process. Thus all Regulations governing quality of material construction, workmanship and testing (both non-destructive and otherwiso) aro applicable. When welded drums ordorcd to this Chapter are made by the single run or heavy run process it will bo understood that Regulations 252 and 267 do not apply in their entirety. 248. Equipment o£ Workshop,—(a) The welding plant and c qnipment are to boot good quality and maintained in an efficient working condition, Tho welding appa- ratus is to bo installed undor cover and arranged so that the welding work may be carried out in positions freo from draughts and adverse weather conditions. The procedure is to be suoh that thoro is regular and systematic supervision of the weld- ing work, and the welding operators are to be subjected by the works officials to perio- dic tests for quality of workmanship, Rooords of these tests are to be kept and are to be available to the Inspecting Officers for scrutiny. (b) The Works should be equipped with an efficient testing laboratory which should include apparatus suitable for carrying out tensile, bend and impaot tests, mioro-cxamination of spooimons and X-ray examination of the actual jointe in pres- sure vessels. Tho Woiks should also be oquippod with a suitable heat treating fur- nace having satisfactory means for temperature oontrol, but as an alternative, arrangements may be made whereby the drums oan be heat treated elsewhere. 684 THE GAZETTE OF INDIA EXTBAOBDINABY [PART II 349. Constructional details and preparation for weldirg.—TLt> zrumifuciimr shall supply the Inspecting Authority with a fully dimensioned sectional drawing showing in full detail the construction of the drum (s) for approval before putting the work in hand. A full sized dimensioned sketch of the weld grooves for the longitudinal anrl oiroumferential seams shall bo shown on the drawing. Pull sized dimensioned sketches shall also be shown of the details of the joints for stand pipes, branoh pipes and seating and the position of those joints relative to> the longitudinal and circumferential scams and other openings shall be indicated. 250. Preparation of platep.- Tho edges of al] pltttts shall bo prrpun d and sur- faced by machining or ohipping. Before welding is ooramenced, the grooves shall be thoroughly oloaned of rust, oil or other foreign matter. Before welding of the joint is commenoed (apart from tack welding) the surfaces of the plates of tho longitudinal and circumferential seams shall at no part be out of alignment with one another by more than 10 per cent, of the plate thickness, but in no oase exceeding 1/8 in. for longitudinal joints or 3/16 in. for circumferential joints. 251. Cylindrical shells of drums.—Each drum shell plate shall bo of cylindrical form to the extreme edges of the plate. The bonding shall be done entirely by maohine and looal heating or hammering is prohibited. Where the plates are bent to a diameter less than 40 times the pltite thickness they shall be efficiently heat- treated after bending to relieve internal stressos unless during the last stage of bend- ing they have been uniformly heated throughout. 262. Method of making welded joints.—The seams shall be weldod from both side of the plate. Before tho sooond side of tho plate is welded, the metal at the bottom of the first side shall be removed by grinding, chipping or machining. Additional runs of metal shall bo deposited at both surfaces of the welded seams so that the weld metal at the level of the surfaces of the plate is refined as far as pos- sible. The surfaces of the wolds shall thereafter bo machined or ground so as to provide, smooth contours and to be flush with the respective surfaces of the plate. There shall be no undercutting at tho junctions. The positions of the welds shall be marked permanently to facilitate their loca- tion. Not less than two runs of metal shall be deposited at eaoh wold fixing stand pipes, branch pipes and seatings. Eaoh run of weld metal shall bo thoroughly oleaned and freed from slag before the next run is deposited. 253. Type of welded joints.—The longiiudina) and cim.mff initial f>< m H shall be made with but joints of the single or double U or Vee type. 254. Number of joints.—Where, having regard to the approved design, the dimensions are such that the shell cannot be made from a single plate, it shall be made with the minimum number of joints and the longitudinal seams in successive rings shall not fall in line. 255. Position of tube holes.—Tube hoW.s HhalJ not bo located in a welded joint. The distance botweon the edge of ,i hole and the odgo of a longitudinal or oiroum- ferential seam shall be not loss than 1 in. where the plate has a thickness less than 1 in. In plates 1 in. to 2 in. thickness tho minimum distance shall be not less than the thickness of the plate. For plates of thickness greater than 2 in. the minimum distance shall be 2 in. NOTH.—Tho oilge of the weld shall be i onsidori d as the rdge of the weld groove aa moohinud in the plato prior to welding. SEC. 3] THE GAZETTE OF INDIA EXTEAOBDINAEY 68& 256. CIroularity of drums.—Tlio difforonoe between 'the internal dirrrfitcr of the drum measured at any oross section and the nominal internal diameter of th» drum should not exceed 1 per oent. of the latter. Any departure of profile measured on the outside of the drum with a gauge of the designed form of the exterior of the drum and of length equal to a quarter of the internal diameter, shall not exoeed the percentage given in table below:— Flats at the wolded seams shall not be permitted and any local departure from oiroularity shall bo gradual. 257. Mechanical tests and test plates lor fusion welded seams.—(a) Fusion Weld- ed joints shall oomply with the mechanical tests herein specified. Not less than one set of test plates shall be provided to represent the welding of each longitudinal seam. The test plates may be attached at each end of the longitudinal seam or the set may be located at one end only. (b) Where the drum shell is formed in two or more ooursee, the staggered longi- tudinal soam shall be regarded as a continuous longitudinal seam, provided the welding be effected in one reasonably continuous operation and by the same operator or operators. (c) Where there arc circumferential seams only or where tho method of welding the circumferential seam differs from that employed for the longitudinal seams, the method of providing tho test plates shall be decided by the Inspecting Authority. (d) The test plates shall be of a size sufficient for the preparation of the test pieces specified in Regulation 258 (a) and for any repeat tost pieces that may be re- quired. The material for each set of test plates shall be out from the respective plate or plates forming tho appropriate seam, and before being out shall be stamped by the Inspecting Officer. (e) When the analysis of the plates is approved by tho Inspecting Authoiity and is considered sufficiently similar, tho teat plates may be out from one drum shell plato only. (f) In the case of insufficient material being available on the shell plate to permit the cutting of test picoes, these shall be aooeptablo if they aro made from another plate provided it is made from the same cast. (g) The weld groove in tho test plates shall bo similar to that adopted for the corresponding edges oC the longitudinal seam, and the respective fusion faces shall be in continuous alignment. The test plates shall be reinforced or supported during welding in order to prevent undue warping.