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29 Pressure Vessels and Parts Subject to Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
) j- J) N+ [7 T; j( J; }29.1 Except as noted in 29.2, a pressure vessel having an inside diameter of more than 6 inches (152
+ O: o; E: u: q6 e! L. Z zmm) and subject to a gauge pressure of more than 15 lbf/in2 (103 kN/cm2) shall be certified by the
" ]; u2 r. t7 m5 R2 U( x5 rNational Board of Boiler and Pressure-Vessel Inspectors and marked in accordance with the appropriate2 d% B# a% _9 C& h
boiler and pressure vessel code symbol of the American Society of Mechanical Engineers (ASME) (²H²,5 @0 \! {& O. q5 ?$ D
²M², ²S², or ²U²) for a working pressure not less than the pressure determined by applying 29.3.5 D- m+ u- x( j, f2 }, O0 U
29.2 If a pressure vessel, because of its application, is not covered under the inspection procedures of7 n% ?1 M- l* b) e
the ASME code, it shall be designed and constructed so that it complies with the requirements in 29.3.
1 g$ S2 B% b- Y, i5 T4 Y$ b4 c29.3 Except as noted in 29.4 and 29.5, a part that is subject to air or vapor pressure (including the vapor
- c( N, @7 T& X. Opressure in a vessel containing only a superheated fluid) during normal or abnormal operation shall
! c- h7 B! o# t! ~" ^& X& k4 l* Wwithstand without bursting or leaking a pressure equal to the highest of the following that is applicable:
[- z9 L: f& J) w) y" Pa) Five times the pressure corresponding to the maximum setting of a pressure-reducing valve, S' z! P3 V B. C& ?* W# A
provided as part of the assembly, but no more than five times the marked maximum supply
1 f3 ?+ t4 ~ x; G# Zpressure from an external source and no more than five times the pressure setting of a
4 t& r J+ e0 {7 F$ @pressure-relief device provided as part of the assembly.
. H4 ~0 v+ X3 G" Pb) Five times the marked maximum supply pressure from an external source, except as
; G0 P9 u; J5 d/ O% Mprovided in (a).6 o, ?+ C6 {, r/ O/ a# u
c) Five times the pressure setting of a pressure-relief device provided as part of the assembly.4 n2 p! U! j, c J$ O7 L- Z
d) Five times the maximum pressure that can be developed by an air compressor that is part of, l& M* p9 N/ B" K
the assembly, unless the pressure is limited by a pressure-relief device in accordance with (a).
( F* t/ d n6 @0 Me) Five times the working pressure marked on the part.
5 N5 j" `" d! U% [29.4 A test need not be performed to determine whether a part complies with the requirement in 29.3 if
3 U6 j# R5 m( P$ p3 Y; q# lstudy and analysis indicate that the strength of the part is adequate for the purpose as a result of its
# F) R) H D3 @9 \material and dimensions – for example, copper or steel pipe of standard size and provided with standard8 t7 u5 Q. V& e! [. ]0 {) G
fittings might be considered to have adequate strength.) E$ O. t/ t6 b& D0 Y' e2 }2 [
29.5 A pressure vessel bearing the ASME code inspection symbol (²H², ²M², ²S², or ²U²) is considered; \. s; v3 f4 X4 P8 n* s7 v
to comply with the requirement in 29.3 if the vessel is marked with a value of working pressure not less
7 Y: [8 d4 D+ v: rthan that to which it is subject during normal or abnormal operation.
$ i! m- a8 M% ^* {29.6 If a test is necessary to determine whether a part complies with the requirement in 29.3, two samples# m: {; B) R# v' D- U
of the part are to be subjected to a hydrostatic-pressure test. Each sample is to be filled with water as to
5 I! ^) }. I% M. _exclude air and is to be connected to a hydraulic pump. The pressure is to be raised gradually to the
8 Q- Z. X1 J0 H6 U, Wspecified test value and is to be held at that value for 1 minute. The results are not acceptable if either/ G( k2 R) v, ^7 w6 h v3 p
sample bursts or leaks, except as indicated in 29.7.
1 N$ h& P8 L( O p- J7 `3 z29.7 Leakage at a gasket during the hydrostatic-pressure test is not unacceptable unless it occurs at a
3 k& a. X! o+ n2 b+ w3 hpressure 40 percent or less of the required test value.8 ?7 k8 `2 u- e% `8 Q
29.8 A means for relieving pressure shall be provided for all parts in which pressure might be generated, O) n" ^2 X1 Q6 e; _
in the event of fire.
/ w! M6 }' F8 O& U! a# b29.9 Pressure-relief devices (see 29.15), fusible plugs, soldered joints, nonmetallic tubing, or other
* v2 y& v. X5 K' ~pressure-relief means or the equivalent may be employed to comply with the requirements in 29.8.
. o( `3 I% }4 L4 W29.10 There shall be no shut-off valve between the pressure-relief means and the parts that it is intended
) S. a$ O" c |to protect.
9 o( V2 C: h: k4 X29.11 A vessel having an inside diameter of more than 3 inches (76.2 mm) and subject to air or steam: `4 q/ k8 ~4 X. O# x s4 s
pressure generated or stored within the appliance shall be protected by a pressure-relief device.
/ c/ w1 {( q% v& ~; o+ A29.12 The start-to-discharge pressure setting of the pressure-relief device shall not be higher than the
$ Z' L6 j7 g% s+ c, l) Tworking pressure marked on the vessel. The discharge rate of the device shall acceptably relieve the
; O! y. P4 Z1 W: x$ v. ~( qpressure.) T$ l$ M: S6 j7 k; O0 p
29.13 A pressure-relief device shall comply with all four of the following:) z. x$ l0 {/ j0 M9 v
a) Shall be connected as close as possible to the pressure vessel or parts of the system that it
( W3 u1 a" {$ k! d0 Vis intended to protect;
0 o1 a: f5 ]3 Ib) Shall be installed so that it is readily accessible for inspection and repair and cannot be5 I+ M# ~3 G6 `0 P( B
readily rendered inoperative;. M1 r: L; @: [# Y( a# \; c1 L$ i
c) Shall have its discharge opening located and directed so that the risk of scalding is reduced
# k! n7 D3 b7 g0 P. Cto a minimum; and) E' V- |0 ]+ R- |8 B6 s- {
d) Shall have its discharge opening located and directed so that operation of the device does/ p8 L2 w5 z. I" {7 {1 H
not deposit moisture on bare live parts or on insulation or components affected detrimentally by
/ A0 ~+ \; k) c( v V/ w/ D5 c- ?moisture./ W+ y# U w, s( A. d4 A2 l
29.14 A pressure-relief device having an adjustable setting shall be judged on the basis of its maximum
2 }* M( I5 G& F2 |: Psetting unless the adjusting means is sealed at a lower setting.1 H; l, z6 B+ {2 E: g: g
29.15 A pressure-relief device is considered to be a pressure-actuated valve or rupture member intended
# |9 t7 R* O! l0 }to relieve excessive pressures automatically.8 g( U h7 a* y i0 O7 X2 b+ V
29.16 Where a pressure relief device is required, the control responsible for limiting the pressure in the
& L# w5 I6 {" [: E+ a. w2 Q1 dvessel shall be capable of performing under rated load for 100,000 cycles of operation and shall prevent
0 H, i4 k+ N; @) b9 f) `the pressure from exceeding 90 percent of the relief device setting under any condition of normal) Q. R3 d' x- O9 G$ _. P% t
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