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29 Pressure Vessels and Parts Subject to Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
: _$ w) Y6 O; r5 l29.1 Except as noted in 29.2, a pressure vessel having an inside diameter of more than 6 inches (152# r2 c9 [' k- b4 g# }3 r8 l8 w' A) b
mm) and subject to a gauge pressure of more than 15 lbf/in2 (103 kN/cm2) shall be certified by the
2 K" O1 u/ J* P0 l( YNational Board of Boiler and Pressure-Vessel Inspectors and marked in accordance with the appropriate
2 H1 Y1 ~4 ]: \. Y$ Lboiler and pressure vessel code symbol of the American Society of Mechanical Engineers (ASME) (²H²,
* O T5 q0 j5 ? Q1 @' t1 e: L! M# Y²M², ²S², or ²U²) for a working pressure not less than the pressure determined by applying 29.3.9 |0 e0 @# g5 ]& X @
29.2 If a pressure vessel, because of its application, is not covered under the inspection procedures of) D1 \5 K" N. ^+ H- T8 [
the ASME code, it shall be designed and constructed so that it complies with the requirements in 29.3.2 D$ [% A. Y1 L; Z
29.3 Except as noted in 29.4 and 29.5, a part that is subject to air or vapor pressure (including the vapor
& B+ Q* B- k: X. z' I0 j, |5 cpressure in a vessel containing only a superheated fluid) during normal or abnormal operation shall& Q2 \' Y, T1 m0 H! A
withstand without bursting or leaking a pressure equal to the highest of the following that is applicable:
# A* M, Y" h+ p4 Ta) Five times the pressure corresponding to the maximum setting of a pressure-reducing valve
+ A7 C5 j+ S, q% Wprovided as part of the assembly, but no more than five times the marked maximum supply: C! U H7 U6 A5 B+ y# z
pressure from an external source and no more than five times the pressure setting of a
1 B6 t3 D. C, fpressure-relief device provided as part of the assembly.+ f( A6 U; {# Q7 v0 t0 p. p) F* s5 y
b) Five times the marked maximum supply pressure from an external source, except as
' F4 M8 }4 ]2 q/ |: Z, _: lprovided in (a).
2 P. V1 `2 [+ Y: a3 wc) Five times the pressure setting of a pressure-relief device provided as part of the assembly.- U4 i" v4 E' \* k M
d) Five times the maximum pressure that can be developed by an air compressor that is part of2 E+ _7 `) \* n2 y( d5 F, w- c# g2 D
the assembly, unless the pressure is limited by a pressure-relief device in accordance with (a).
' H7 W" s& k6 n5 ve) Five times the working pressure marked on the part.
& C2 R) z1 u! u. K* {& r29.4 A test need not be performed to determine whether a part complies with the requirement in 29.3 if
6 Z) g, Y. p1 m$ ~3 x1 sstudy and analysis indicate that the strength of the part is adequate for the purpose as a result of its
) ]/ C3 w- Q8 C9 g" ~material and dimensions – for example, copper or steel pipe of standard size and provided with standard }9 v* t9 _. r8 Z
fittings might be considered to have adequate strength.
9 ^# t) B2 w6 d9 e9 n9 ]) h6 _9 Z, {29.5 A pressure vessel bearing the ASME code inspection symbol (²H², ²M², ²S², or ²U²) is considered) q( f+ w5 E: Z3 ^: _5 e! q7 R
to comply with the requirement in 29.3 if the vessel is marked with a value of working pressure not less
7 g6 ~7 E$ W! F+ c2 ^than that to which it is subject during normal or abnormal operation.
: y8 ~: p' r6 T9 `: y29.6 If a test is necessary to determine whether a part complies with the requirement in 29.3, two samples" `; h# n# f- H2 D% d, \+ Z
of the part are to be subjected to a hydrostatic-pressure test. Each sample is to be filled with water as to0 G% L" P5 ~3 s9 D# j! @
exclude air and is to be connected to a hydraulic pump. The pressure is to be raised gradually to the% {5 h4 c* d+ m# ]# }: _! H) f
specified test value and is to be held at that value for 1 minute. The results are not acceptable if either4 i6 D6 L( l% [
sample bursts or leaks, except as indicated in 29.7.& h, H4 Q8 y" o
29.7 Leakage at a gasket during the hydrostatic-pressure test is not unacceptable unless it occurs at a
4 r3 a+ ]- ]7 x4 Epressure 40 percent or less of the required test value.
: e! D9 O3 _/ |% A: ?/ D29.8 A means for relieving pressure shall be provided for all parts in which pressure might be generated
, l. K' e( P- Q- b! T. tin the event of fire., r5 W+ F! N* ]
29.9 Pressure-relief devices (see 29.15), fusible plugs, soldered joints, nonmetallic tubing, or other
$ _2 {/ X9 D1 C% C& Z1 Upressure-relief means or the equivalent may be employed to comply with the requirements in 29.8.
' d# x; E; _3 t0 g29.10 There shall be no shut-off valve between the pressure-relief means and the parts that it is intended3 n7 U5 G) }9 ]: o, w
to protect.- N- _2 x$ f1 t1 O' F }! z2 R& O
29.11 A vessel having an inside diameter of more than 3 inches (76.2 mm) and subject to air or steam; I, L# V/ M$ ^3 f' N1 i5 x
pressure generated or stored within the appliance shall be protected by a pressure-relief device.- s/ |- G( x# S- c4 q
29.12 The start-to-discharge pressure setting of the pressure-relief device shall not be higher than the
( I! |! R! k2 o; q6 s: @working pressure marked on the vessel. The discharge rate of the device shall acceptably relieve the2 |+ B* U7 U; \; E2 n
pressure.
) L7 k L" J" b0 [8 |. \3 [29.13 A pressure-relief device shall comply with all four of the following:
4 f6 r \' G( E' G2 ga) Shall be connected as close as possible to the pressure vessel or parts of the system that it6 ^) Q- j5 e2 \" q& \
is intended to protect;! D: u: B3 R; A; B, p
b) Shall be installed so that it is readily accessible for inspection and repair and cannot be
) J$ g2 f7 h5 m, H9 areadily rendered inoperative;! n9 [) h3 w+ n" W
c) Shall have its discharge opening located and directed so that the risk of scalding is reduced/ w$ ~% K0 v' m
to a minimum; and
+ R) C! X. Y" r' Ed) Shall have its discharge opening located and directed so that operation of the device does: [4 f$ A: y1 ]6 ~# z1 V
not deposit moisture on bare live parts or on insulation or components affected detrimentally by
, T/ G' o2 f6 e( g M$ Umoisture.0 x! Q4 ^: ?! c9 S2 s& l
29.14 A pressure-relief device having an adjustable setting shall be judged on the basis of its maximum/ { ]. i4 @; p$ T
setting unless the adjusting means is sealed at a lower setting.! |* a" ~! ^- s4 q/ C& A! m! p7 L2 z1 |
29.15 A pressure-relief device is considered to be a pressure-actuated valve or rupture member intended4 {+ X4 E: e% `3 I* }+ Y
to relieve excessive pressures automatically. `1 e: U/ e. H E! ~% f
29.16 Where a pressure relief device is required, the control responsible for limiting the pressure in the2 I8 z; n7 ^7 b/ Z
vessel shall be capable of performing under rated load for 100,000 cycles of operation and shall prevent
$ j! P# I1 o5 r5 Kthe pressure from exceeding 90 percent of the relief device setting under any condition of normal
) G8 O8 O) Z' L9 J: Q" Doperation. |
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