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REGISTERED No. D. 221

The Gazette of India

EXTRAORDINARY

PART II—Section 3—Sub-section (i)

PUBLISHED BY AUTHORITY

No. 80] NEW DELHI, SATURDAY, AUGUST 18, 1962/SRAVANA 27, 1884

MINISTRY OF WORKS, HOUSING AND SUPPLY

(Central Boilers Board)

NOTIFICATION

New Delhi, the 18th August 1962

G.S.R. 1093.—In exercise of the powers conferred by Section 28 of the Indian Boilers Act, 1923 (5 of 1923), the Central Boilers Board hereby makes the follow- ing Regulations further to amend the Indian Boiler Regulations, 1950, the same having been previously published as required by sub-section (1) of section 31 of the said Act, namely:—•

'

;

1. These Regulations may be called the Indian Boiler (Twentieth Amendment) Regulations, 1961.

2. In the Indian Boiler Regulations, 1960—

(1) In regulation 4(e), between the words "make" and "and" appearing in the last line the following words shall be inserted, namely: —

"tolerance within which they have been manufactured".

(2) For regulation 5(iv), the following shall be substituted, namely: —

"When the quality of material and the make of steel pipe have not been supported by certificates from, the manufacturers, the pipes shall be treated as roll lap welded steel pipes and the maximum permissible working stress will be reduced by 25 per cent, and they shall be presented for a hydraulic test before erection in situ",

(3) For regulation 298, the following shall be substituted, namely: —

"Discharge Passage.—The safety valve discharge pipes shall comply with the requirements of clauses (a) and (b) of this regulation. The discharge pipe shall be as short and straight as possible and be fitted with open drain to prevent accumulation of water in the pipe. Suit- able arrangement shall be provided in the discharge pipe system so that the discharge can readily be heard by the Boiler Attendant.

(425)

4 2 <5

T HE G A Z E T TE OF I N D IA E X T R A O R D I N A RY

[ P A UT •

(a) Steam safety valves.

(i) Ordinary and high lift valves. Where a waste steam pipe is fitted, the pipe and the passage leading to it shall have a cross-sectional area not leas than the minimum combined area of the safety valves required by regulation 293.

(il) Full lift valves. For full lift valves the area of waste steam-pipa and passages leading to it shall have a cross-sectional area not lesi than twice A, or such area above this minimum as may be requir- ed for valves having a higher approved constant, where A, E and P are as denned in regulation 293.

(b) Economiser safety valves. The area of the discharge pipe from an economlser safety vaJve shall be at least twice the area of the valve seating.

Where the discharge from several economiser safety valves is con- nected to the main discharge pipe, the diameter of the main dis- charge pipe shall be designed to prevent accumulation of pressure due to the formation of steam under the particular conditions of temperature and pressure which may be applicable."

(4) For regulation 317, the following shall be substituted, namely: —

"317. General.—The blow down cock or valve shall be of substantial con- struction. The waste pipe attached to the cock or valve shall not be bound fast in earth or brick work and shall discharge at a point where there is no danger of injury to any person. These pipes shall not be connected to a pipe common to another boiler. The contin- uous blow downs may, however, be connected to a common header discharging freely to an adequately vented tank or sump. The headers shall be of sufficiently large cross section and the blow-off tank shall be provided with a vent pipe free from valves and of sufficient size to prevent accumulation of pressure. If, however, the tank is intended for collecting flash steam, a safety valve of adequate capacity shall be provided. The tank shall be so located that all parts will be accessible for inspection."

(6) For regulation 343, the following shall be substituted, namely: —

"343. Pipes.—Steam pipes may be carbon steel, cast steel, alloy steel and in some cases of copper. Steel pipes may be solid drawn (cold or hot finished), lap welded, butt, welded or electric resistance welded. Copper pipes shall be solid drawn and no pipe made from electro- deposition of copper on a mandril shall be used for steam delivery."

(6) For regulation 344, the following shall be substituted, namely: —

"344. Steel Pipes.— (a) These pipes shall be made from steel made by the open hearth or an electric process acid or basic. Hot finished seam- less and roll lap welded pipes, may, however, be made of basic Bessemer steel. Basic Bessemer steel shall not be used for pres- sures exceeding 21 kg/cm³ (300 lbs. per sq, in.) or temperature exceeding 260°C (500°F). If the Bessemer process is used, the steel shall be made by a manufacturer approved by the Inspecting Authority.

When used for steam temperature exceeding 399°C (750°F), the steel shall be of the non-segregated or fully killed type.

(b) Carbon and alloy steel pipes shall not be used for design temperatures

exceeding those given in Table 2.

(c) For designed temperature over 427°C (800sF) special precaution shall be taken to ensure that the surface condition of the pipe is suitable for these requirements.

(d) The materials from which seamless and electric resistance welded pipes are made shall conform to the appropriate specification of tube" in Chapter II. The materials from which roll lap welded, hydraulic lap welded and butt welded pipes are to be made shall conform to the requirements of Table I under Regulation 347."

(7) For regulations 346 and 347, the following shall be substituted, namely: —

"346. Number of sets of tests.—The number of pipes on which mechanical tests shall be performed shall be as follows: —

Seamless pipes:

Upto and including 114 mm. As per requirements of Chapter II.

(4J In.) o.d.

Over 114 mm. o.d. . . 5 per cent of the lengths of pipe as made, or 2 per cent cent of the pipes from each cast where the cast (i.e., melt) can be identified.

Welded pipes . .. 2 per cent of the lengths of pipes

as made.

In the case of pipes for designed temperatures over 427"C (800"F) every pipe over 114 mm. (4J in.) outside diameter shall be tested.

347. (a) Flattening test [for pipes upto and Including 102 mm. (4 in.) nominal bore].—As per requirements of Chapter II.

(b) Cold bend test [for pipes over 102 mrn. (4 in.) nominal bore].—A strip not less than 38 mm. (1J in.) wide cut circumferentially from one end of each selected pipe shall when cold withstand, without showing either crack or flaw, being doubled over in the direction of original curvature round a bar, the diameter of the bar being: —

For pipes upto and including 10 mm.

(3/8 in.) thick. 3 times the thickness. For pipes over 10 mm, thick. 4 times the thickness.

(c) Bend test on the Weld.—A strip not less than 38 mm. (1J in.^) wide cut circumferentially from one end of each selected pipe with the weld near the middle of the strip, shall when cold withstand, with- out showing either crack or flaw, being doubled over in the direction of original curvature round a bar, the diameter of the bar being equal to eight times the thickness of the test piece, the weld being placed at the point of maximum bending.

(d) Additional test—Should a pipe selected for testing fail in any one or more of the tests specified above, two further tests of the same kind may be made from the same or another pipe from the same batch. Should either of these further tests fail, the pipes represented may be reheat treated and then retested. If the repeat tests are satis- factory, the pipes shall be accepted provided they comply with other requirements but if failure again occurs, the pipes which the test pieces represent shall be rejected.

,(e) Tensile t e s t ^ As per requirements of Chapter II.

TABLE I—CAEBON STEELS

t

00

Roll Lap welded and Butt welded pipes

Minimum elongation per cent.

Sulphur per cent

may

Phos- phorus per cent Ultimate tensile strength in Ke./Sq. mm.

(tons per

sq. in.)

H Kind of pipes

w

Not less than

Not more than

£

N

o

c

Strips cnt from the pipes dear of the welds and tested in their curved condition . . ..

1

44 (28)

w X

I .06

Test lengths taken from finished pipes (ends of pipes to be plug- ged for grips)

Q

44 (28)

35 (22)

J

g

I—I

!

T i BU I—CABSOH SflBtti

t

Hydraulic (water gas) Lap welded Sud Pipes.

•ensile stress

Phosphorus

03 mm,

Sulphur

Mia.E longalion per cent on 2

q. mm (TonW

(80

ma-rimffm

•ma-yirmmi

Ultimate 1 in Kg./*¹ sq. ii

%

%

(8) For regulation 348, the following shall be substituted, namely: —

"348. Method of manufacture, Heat treatment and Marking.— (a) The process of welding lap jointed seams shall be by hammering or rolling the Joint. The pipe shall be carefully annealed, thereafter.

(b) On completion of any work which involves heating, whether for hot, bending of the pipe or for any other similar purpose, the pipe shall be carefully annealed.

(c) Cold drawn carbon pipes shall be carefully annealed throughout their

lengths after the operation of drawing.

Cold drawn seamless alloy steel pipes shall be delivered in the norma- lised condition and hot finished pipes in the as rolled, or hot drawn, condition or in the normalised condition.

(d) Marking,—Inspection and identification marks shall be stamped on end faces of pipes plain at ends. These marks shall be machined or ground off before erection. When flanges are fitted Identification, marks shall be stamped on the rims of flanges.

(9) For regulation 349, the following shall be substituted, namely: —

"349. The pressure and temperature limits within which pipes, tees, branches, etc., shall be used, shall be in accordance with Table 2."

TABLE a

I

idaaummt pmmss&U working prttmre and Umptrature

3

Material

Maximum permissible temperature

Form

°C

°F

Carbon st"l

900

482

Straight!, bends or fittings.

o

482

900

Do.

482

900

Do.

o

260

500

Do.

900

482

Straights

9 00

4S2

Cast steel

w H

StraightS) bends or fit- tings.

Molybdenum steel o a

Do.

S24

975

1

621

Chromium molybdenum Steel

1150

Do.

Copper

Not allowed for superheated steam Straights and bends.

(10) For regulation 350, the following shall be substituted, namely: —

"350. Steel pipes.—The maximum working pressure allowed on steel pipes shall be determined by the following formula: —

2 Se (t—c)

W.P.= (Equation 91)

D

t~minimum thickness.

W.P.=Maximum working pressure.

Where the total relieving capacity of the safety valve on the superheater is not less than 20 per cent of the total evaporative capacity of the boiler, the steam pipes may be designed for a pressure at which any superheater safety valve Is to be set to lift provided that in no case shall these pressures be less than 91 per cent of the design pressure of boiler.

D—Outside diameter of pipes.

S>= Allowable stress as specified in Table 3.

c-= Efficiency factor.

— 1 for seamless and electric resistance welded steel pipes

— '9 for welded steel pipes for values of t up to and including 22 mm (7/8*) •.•85 for welded steel pipes for values of t over 22 mm (J*) and up to and including 29 mm (i|')

— -8 for welded steel pipes for values of t over 29 mm (ij*)

c—o*i cm ("04 in,)

TABLE 3

AfowmuM permissible working stress for straights, bends or fittings

Material and method of manufacture

Upto and including 26o°C (500°F)

Over26o°C

(5oo°F) up

to & including

Over 37i°C (700° F) up to and including 399°C (75O°F)

2S8°C (5SO°F)

 Over 288°C      Over  3i6°C    Over 343°C                   Over  399°C
   (55O°F)       (6oo°F)  up    (650° F)  up                (75O°F)  up  to
 np to &  in-     to  and       to  and                      and  including    H
   chiding        includhig    including                    427°C  (800°F)     a
3i6°C(6oo°F)    343=C (65O°F)                                                  w
                              37i°C(7OO°F)

Carbon steel

Na

Not used for these temoerarures

A Roll lap welded and butt welded, and Bessemer hot finished seamless.

o

B. Castings

(11,300 lbs. /sq.

654 kg/ cm¹ (9,300 lbs./

745 feg/cmE (10,600 lbs./sq.

I—< -li. UJ

'01) (i) For regulation 351, the following shall be substituted, namely: —

"351. (a) The material shall comply with regulations 73 to 80.

(b) The maximum working pressure allowed on cast steel pipes shall be- determined by the following formula: —

iS (t— oisD—C) W.P. = — • —— Eqn. (92)

D

Where, t — minimum thickness

W.P. — Working Pressure

D = External diameter of pipe

S — Allowable working stress as specified in table 4.

C — 0¹64 cm (0-25 in.)"

(11) For the table 4, the following table shall be aubstituted, namely: —

TABLE 4.

Maximum Permissible Working Stress for Carbon and Alloy Cast Steal Pipes (See Regulation 351)

Lowest value obtained in each case at the (specified temperature calculated en the following basis; —

T.S. Et.

For service temperature at or below 35°°C (662°F) . . or

35 *•"

Et Sr

Por service temperature above 35°°C (66a°F) . . . or — or Sc

16 1-6

T.S. — Minimum Tensile Strength of the material at room temperature,

Et — Warm yield point (0-2% proof stress) at temperature t. Sr =- The average stress at the service temperature to produce rupture in 100,000 hours and, in no case, more than 1 • 33 times the lowest stress to produce rupture at service temperature.

Sc — The average stress at service temperature to produce an elongation of 1% (creep) in 100,000 hours.

(12) For regulation 353, the following shall be substituted, namely: —

"353. Flanges of Steam Pipes.—(a) Flanges of steam pipes shall be made of cast steel or wrought steel made without a weld. They may be secured to the pipes by screwing, riveting or welding."

(13) For regulation 354, the following shall be substituted, namely: —

"354 Screwed on flanges.—Where flanges are secured by screwing the screw thread on the pipes and in the flanges shall be arranged to end at a point just inside the back of boss of the flange. After the flange has been screwed on, the pipe shall be expanded into the flange by a roller expander. Such screwed and expanded flanges may be used for steam for a maximum working pressure of 31-5 kg/cm³ (450 lbs./sq. in.) and a maximum temperature of 399 C (750°F) and for feed for a maximum pressure of 42 kg/cm² (600 lbs./sq. in.)."

(14) For regulation 357, the following shall be substituted, namely: —

"357 Welded on flanges.—(a.) Whore flanges are welded on, the welding shall be done by the oxy-acetylene or metal arc process the latter with covered electrodes which shall comply with regulations B4 to 98,

(b) The proportion of the weld shall be as indicated in the Figure Nos.' 28- to 34 of the following types: —

Type 1. 'Welding Neck' flange. Figure 28.

2. 'Face and Back' welded—on flange for metal arc welding.

Figure 29.

3. 'Bore and Back' welded—on flange for metal arc welding.

Figures 30 and 30A.

4. 'Face and Fillet' welded—on flange for metal arc welding.

Figure 31.

5. 'Bore and Fillet' welded—on flange for metal arc welding.

Figures 32 and 32-A.

6. 'Slip on' welded—on flange for metal arc welding. Figure 33.

7. 'Slip on' welded—on bossed flange for oxy-acetylene welding.

Figure 34.

The flange shall not be a tight fit on the pipe.

The maximum clearance between the bore of the flange and the outside diameter of the pipe shall be 3 mm. (1/8") at any point, and the sum of clearances diametrically opposite shall not exceed 5 mm. (3/16 in.).

NOTE.—All dimensions shown in the figures of types 1 to 7 relate to finished •tees.

The design conditions for each type are as follows: —

Types 1, 2 and 3 flanges for all design pressure and temperature condi- tions.

Types 4 and 5 flanges for all pressure conditions up to and including 42 kg/cm³ (600 lbs./sq. In.) and design temperature not exceeding 399°C. (750-F.).

Types 6 and 7 flanges for all pressure conditions up to and including 17-6 kg./cm² (250 lba./sq. in.) and temperature not exceeding 399°C (750°F.) except that Bossed flanges of type 6 shall not be used on pipes over 304 mm, (12") in nominal" bore, nor Bossed flanges of type 7 on pipes over 152 mm (6") in nominal bore.

(c) Heat treatment after welding*—Types 1, 2, 3, 4 and 5 carbon steel flanges welded on by the metal arc process shall have the welda stress relieved where the design depth of the weld recess is greater than 13 mm. ( i " ).

All welds joining flanges to alloy steel pipes shall be stress relieved.

(d) Where typo 1 flanges are attached by oxy-acetylene welding the welda shall be normalised.

(e) The procedure to be observed in the stress relieving and normalising of welds shaJl be in accordance with the following requirements: —

(i) Stress relieving.—The stress relieving temperature shall be;

for mild steel and carbon steel within the range G00/650°C. (1110/ 1200°F.).

for alloy steels within the range 630/660°C. (1170/1220°F.).

The stress relieving temperature shall be maintained for approximately one hour per 25 mm. (1 inch) of weld throat with a minimum of half an hour.

Stress relieving shall be carried out by one of the following methods: —

(a) Local heating using a portable muffle furnace, induction coils or other suitable heating appliance. Particular care shall be taken to apply heat uniformly over the area to be treated. The use of procedures

that do not provide adequate control for this purpose, such as manual operation gas torches, is not permissible. The temperature shall be measured by the thermo-couples' peened, welded or other- wise suitably attached to the surface of the pipe and, where neces- sary, protected from frame impingement.

(b) Heating in a stationary industrial furnace. The temperature of the joint shall be measured by thermocouples so disposed within the furnace as to give a true measure of the joint temperature.

(ii) Norpwlislng,—Welds in mild steel pipes shall be normalised by heating the metal to a temperature between 900 and 950°C. (1650—1740"F.), the tem- perature then being maintained for not less than two minutes for pipes up to and including 102 mm. (4") bore, and for not less than five minutes for pipes over 102 mm. (4") bore. Welds in pipes made from the alloy steel shall be normalised by heating the metal to a temperature between 92& and 975"C. (1700—1790°F.), the temperature then being maintained for not less than two minutes for pipes up to and including 102 mm. (4") bore, and for not less than five minutes for pipes over 102 mm. (4") bore. The higher temperatures of between 950 and 975°C. (1740—1790°F.) shall be used for alloy steels having a carbon con- tent upto and including 0 12 per cent, and the lower temperatures of between 926 and 950°C. (1700—1740°F.) shall be used for alloy steels having a carbon content of more than 0 12 per cent. After normalising the joint shall be cover- ed with a suitable muff or asbestos cloth to ensure slow and even cooling. The normalising of welds in pipes up to 102 mm. (4") bore may be carried out with welding names, the temperature being judged with the aid of a colour card or measured by means of one or more thermocouples or an optical pyrometer. The normalising'of welds in pipes over 102 mm. (4") bore shall preferably be carri- ed out in a portable pipe normalising furnace or muffle, the temperature being -measured by means of one or more thermocouples or an optical pyrometer. The width of the zone to be heat treated to the specified temperature shall extend at least 13 mm. (1") on either side of the weld reinforcement."

(15) For clauses (b) and (c) of regulation 360, the following shall be sub- stituted, namely: —

"(b) Where pipe having a wall thickness exceeding 13 mm. (J in.) are butt-welded together they shall be effectively stress relieved in accordance with the following: —

The stress relieving temperature shall be:

For mild steel and carbon steel within the range 600/650°C. (1110/ 1200T.). I

I

For alloy steels within the range 630/660°C. (1170/1220 F.).

The stress relieving temperature shall be maintained for approximately one hour per inch of pipe thickness with a minimum of half an hour.

Heat treatment shall be carried out by one of the following methods:

(1) Local heating using a portable muffle furnace induction coils, or other suitable heating appliance. Particular care shall be taken to apply heat uniformly over the area to be treated. The use of procedures that do not provide adequate control for this purpose such as manual operation of gas torches, is not permissible. The temperature shall be maintained symmetrically, over a peripheral band of metal of a minimum width of three times the width of the butt weld pre- paration. The temperature shall be measured by thermocouples peened, welded or otherwise suitably attached to the surface of the pipe and, where necessary, protected from flame impingement.

fii) Heating in a stationary industrial furnace. The temperature of the joint shall be measured by thermocouples so disposed within the furnace as to give a true measure of the joint temperature.

(c) Such Butt-welded joints conform to flg. 28.

(16) For clause (b) of regulation 361, the following clause shall be substi- tuted, namely: —

(b) The thickness of the pipes, from which bends are made shall be such that the minimum thickness required by equation (91) is maintain- ed throughout after the bending operation. The deviation from circularity in percentage at any cross-section of a bend shall be- calculated by the following formula: —

Dmax. —. Dmin,

C n

.—.—-—— X TOO

D

20D

This deviation shall not exceed

R

Where

C = The percentage deviation of circularity,

Dmax, = maximum external diameter of the pipe as gauged at the bend.

Dmin. = minimum external diameter of the pipe at gauged at the bend.

D "•" nominal external diameter of the pipe,

R — Radious of the bend on the central line of the bend.

(17) For regulation 382 the following shall be substituted, namely: —

"362. (a) Branches, Bosses and Drain pockets.—Branches, bosses and drain pockets welded to the pipes shall conform to the requirements of" regulations 249—253. Branches shall not be welded to any main at an angle of less than 60°,

(b) External reinforcement.—If the thickness of the main or branches of a single or multiple branch piece la less than that given by the equation &1-A external reinforcement shall be provided. -Such reinforcement may take the form as given in Figure 32-A or other reinforcement approved by the Chief Inspector applied to or around the junction between branch and main. Gusset plates attached longitudinally to the surfaces of either pipe, shall not be used.

(c) Thickness inhere no external reinforcement is provided.—Where more than one branch is attached to a pipe the opening of each branch shall be projected perpendicularly on the axis of the main and the distance between each pair of these projections measured. If the distance so measured between two branches is less than the sum of their bores, the two branches are deemed to affect each other; if this distance is equal to or greater than the sum of their bores, the two branches arc deemed not to affect each other.

In calculating the reinforcement required, each branch is to be considered in turn together with all the branches by which it is affected.

(i) A branch not affected by any other branch.—Where no external reinforcement is to be applied to a branch piece the thickness of the branch shall be determined from Equation 91-A.

PD

tm. •• —• 1- C Equation 9I-A.

2 Sex

where tm=>minlmum thickness of the branch.

P=Working pressure.

D—Outside diameter of branch.

S = Maximum permissible stress as specified in Table 3,

e™factor given in regulation 350,

x=l.—B (1— 0-7 sin y) Equation 91-B.

U—ratio of bore of branch to bore of main.

y= angle between braoch and main, in degrees. C=0-l cm (-04 in)

The value of tm derived from Equation 01-A is the minimum thickness and .•further provision shall be made for any minus tolerance.

No reinforcement is required If—

Y

B Is less than —— Equation gi-C.

y + 90

(ii) A branch affected by one or more other branches.— (See Figure 302/A,) Determine the 'X' values for each branch alone from Equation 91-B. Let 'X' be the value for the branch under consideration and Xa, Xb, etc, the value for the other branches.

Then X^i—C (1—Xa) Equation 91-D.

Xa-i— C fl—Xb)

etc.

Where C is a factor the value of which is to be taken from Table 362/4.

The thickness of each branch which is a component of a multiple branch shall then be determined from Equation 91-E. Equation 91-C shall not apply: —

tm = f ) • ( J + C . .. Equation 91-E.

V 2 Sex / VXt • X,. . /

Where C =- 1 mm. (-04 In.)

TABLE 362/4

C

L

dl+d2

0

O ' lO

• 34 • 66 • 80

• 90

• 94 •97 •9S •99

I

I or greater •9 •8 '7 •6 •5 •4 •3 •2 •1 •0

( L= distance between Projections of branch bores, ax ana a,;

Intermediate values by linear interpolation:

It is to be specially noted that a branch may form part of two distinct multiple branches, when its thickness shall be the greater of the thickness calculated for it as a component of each multiple branch, (iii) Mains.—(See Figures 362/A, 362/B, 362/C and 362/D.J The thickness of a main carrying a single or a multiple branch shall be determin- ed as for the single branch or one component oi' the multiple branch except that the symbols 'D' and 'e' shall apply to the main. The thickness of a main carrying more than one branch, single or multiple, shall be the greatest of the thickness of the main calculated in con- nection with each branch separately.

The additional thickness of a main for branch reinforcement shall extend over the length covered by the "branch and beyond it for a distance not less than the bore of the branch on each side.

(18) In regulation 364, in the second line, the words "wrought iron or" shall be omitted.

(19) In regulation 368, the words "iron and" in the second line shall b" omitted.

(20) For regulation 370, the following shall be substituted, namely: —

"370. Flexibility.—The pipes shall be arranged so that the system is sufficiently flexible to absorb the whole of their expansion without the sum of the longitudinal pressure stress and the longitudinal bending stress exceeding the stress (S) given in Table 3, under the operating conditions within the limits of the working pressures and temperatures, except where the torsional stress ia significant in which case the resultant combination of stress shall be taken into account. Where practicable, the requisite flexibility shall be provided in the layout of the pipes without having recourse to special expansion bends or expansion joints except for the safety valve discharge piping. The use of sliding expansion joints is pro- hibited. Additional stresses not specifically allowed for in the calculation such as circumferential bending stress, or stress concen- trations produced by abrupt changes of section should be kept to a reasonable minimum."

(21) For regulation 374, the following regulation shall be substituted, namely:—

"374 Test pressures.—(a) Each completed pipe and fitting shall be tested by hydraulic pressure to the test pressure H lbs./sq. in, determined from the following equation subject to a maximum test pressure of 316-3 kg/cm¹¹ (4500 lbs./sq. in.).

S at 260°C (500°F).

H= 1-7 P x — -- — .

S at T

P = Maximum permissible pressure. S = Maximum permissible working stress. T ==• Design temperature.

(b) Pipes and fittings with flanges for steam pressures exceeding 7 kg/ cm² (100 lbs. per sq. in.) shall be tested with blank flanges bolted or clamped on, All other pipes, if straight, may bo tested between the heads of an ordinary hydraulic pipe testing machine.

(c) Where the Joints in a pipe system are of welded construction, the system shall, after erection, be tested hydraulically to twice the maximum permissible pressure, where the pressure does not exceed 35 kg/cma (50O lbs./sq. in.) and to li times the maximum permis- sible pressure or 70 kg/cma (1000 lbs./sq. in.), whichever Is the greater wheve the maximum permissible pressure exceeds 35 kg/ cma (500 lbs./sq. in.):

Provided that stress due to all causes including the stress due to the hydraulic test pressure shall not exceed 40 per cent of the minimum tensile strength of the material of pipes.

440 THE GAZETTE OF INDIA EXTRAORDINARY [PAW H

RS.362/A

Fiff. 3621B

TYPICAV OTfcNCH VltCIS

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FOX V£AT/CAL OK A/t44LY Vf"T/c*H. P**£

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Pfi£PA8ATtOU OF GQOOVS FOR. UJ£ h//T# TflP£&

AACK/AI6 aiM6 4A/O OOU/US MOOT AOM.

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X4<$ T HE GAZETTE OE INDIA E X T R A O R D I N A RY [PART ir

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* Shape of profile,—Unless the weld is dressed flush, there shall be external weld reinforcement, preferably within the limits recommended in Table below and this reinforcement shall be substantially symmetrical about the centre line of the joint. The shape of the reinforcement may vary according to the typo of electrode or welding technique used and the welding position, out shall in all cases be of smooth contour, the profile running out smoothly into the pipe en each side without notching or reduction of thickness of the pipe at the edges of the weld.

Amount of Weld Reinforcement

limits

Pipe thickness

Recommended

Over

Maximum Upto and including

Minimum

in.

mm.

in.

m m.

in.

mm

in.

mm.

I/16

1-6

1/8 6

—

3

i

1-6

I/I6

6 nun.

3/1 13

5

i

i

13 mm.

1-6

1/16

6

1

—

i

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[No. S&PII/BL-304(12)/55.] S, N. SEN GUPTA, -Secy.

Central Boilers Board.

r-IUNTEt> IN INDIA BY THE GENERAL MANAGER. GOVERNMENT OF INDIA PRESS,

NEW DELHI AND PUBLISHED BY THE MANAGER OF PUBLICATIONS, DELHI, 1 9 62