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29 Pressure Vessels and Parts Subject to Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
3 M" k& D4 V/ V6 k6 K5 ~ V29.1 Except as noted in 29.2, a pressure vessel having an inside diameter of more than 6 inches (1525 F' n5 h0 o) K5 Q G
mm) and subject to a gauge pressure of more than 15 lbf/in2 (103 kN/cm2) shall be certified by the1 F M& Z5 t, m7 e) F2 z
National Board of Boiler and Pressure-Vessel Inspectors and marked in accordance with the appropriate
4 {$ d% U/ a6 C4 N; }9 Aboiler and pressure vessel code symbol of the American Society of Mechanical Engineers (ASME) (²H²,
- f3 \# K4 p( [$ y+ C2 M8 z) h/ [5 u²M², ²S², or ²U²) for a working pressure not less than the pressure determined by applying 29.3.) y! [; d8 {# L
29.2 If a pressure vessel, because of its application, is not covered under the inspection procedures of0 E% V' w5 k0 p f
the ASME code, it shall be designed and constructed so that it complies with the requirements in 29.3.& [8 N% V; m3 n3 n* n
29.3 Except as noted in 29.4 and 29.5, a part that is subject to air or vapor pressure (including the vapor2 l+ ?3 z0 A2 \) [
pressure in a vessel containing only a superheated fluid) during normal or abnormal operation shall
+ {# F5 o# o# b T9 R+ Ewithstand without bursting or leaking a pressure equal to the highest of the following that is applicable:- _( |, E- s2 B# m; n4 X8 l$ J! o
a) Five times the pressure corresponding to the maximum setting of a pressure-reducing valve
- o4 E' K" ]" G* y, g/ rprovided as part of the assembly, but no more than five times the marked maximum supply. q4 d$ A8 x' r C+ E
pressure from an external source and no more than five times the pressure setting of a
" @: h E0 ]7 c7 e" Hpressure-relief device provided as part of the assembly.$ P( H1 P8 W; y' r! p1 ]
b) Five times the marked maximum supply pressure from an external source, except as: o1 j$ c# N9 k3 @* G# @# G
provided in (a).
9 B# A% \$ ^5 |! a" Fc) Five times the pressure setting of a pressure-relief device provided as part of the assembly.. F2 J9 H5 Y: j! n
d) Five times the maximum pressure that can be developed by an air compressor that is part of9 B5 v4 C7 O7 @2 ?5 q' x# ^
the assembly, unless the pressure is limited by a pressure-relief device in accordance with (a).
2 U. \2 R3 @1 @& Q# F% P* ~: we) Five times the working pressure marked on the part.
5 S1 E" D$ y! {29.4 A test need not be performed to determine whether a part complies with the requirement in 29.3 if) G4 E( L, Z# c6 H" ^
study and analysis indicate that the strength of the part is adequate for the purpose as a result of its- u; O9 S/ L8 T' ]: k/ |0 D) F0 d
material and dimensions – for example, copper or steel pipe of standard size and provided with standard! W% T. G" g7 ^: W) j
fittings might be considered to have adequate strength.
, C1 P5 Z9 b+ f9 m" |+ `; |2 w29.5 A pressure vessel bearing the ASME code inspection symbol (²H², ²M², ²S², or ²U²) is considered
8 z+ ?$ O. \' E* L) ato comply with the requirement in 29.3 if the vessel is marked with a value of working pressure not less
; D8 F: Z0 h- W8 ^/ nthan that to which it is subject during normal or abnormal operation.
' @/ H# t& u; }" M! _29.6 If a test is necessary to determine whether a part complies with the requirement in 29.3, two samples
8 q' Y5 a! q. H8 m) u7 J, n0 mof the part are to be subjected to a hydrostatic-pressure test. Each sample is to be filled with water as to: ?& m7 \% @ o8 A9 v: P
exclude air and is to be connected to a hydraulic pump. The pressure is to be raised gradually to the; X2 G7 C+ n. x' D( }' Z: ], Y
specified test value and is to be held at that value for 1 minute. The results are not acceptable if either
' x3 ^4 v3 _5 v$ V& [; }) \% Psample bursts or leaks, except as indicated in 29.7.
/ L" y/ D4 g7 d3 T- L- b29.7 Leakage at a gasket during the hydrostatic-pressure test is not unacceptable unless it occurs at a
# w; ], h- c& s5 C* o3 V$ B* Npressure 40 percent or less of the required test value.& c; j0 h; ]" H9 t$ ~; X8 r0 l
29.8 A means for relieving pressure shall be provided for all parts in which pressure might be generated
7 m" @& e5 L. V# E$ Y1 B' U5 Rin the event of fire.' O/ {& t+ W' ]2 z8 P4 p" n
29.9 Pressure-relief devices (see 29.15), fusible plugs, soldered joints, nonmetallic tubing, or other
( q$ _" P& a+ Gpressure-relief means or the equivalent may be employed to comply with the requirements in 29.8./ i4 `5 ~8 q8 \4 f6 g
29.10 There shall be no shut-off valve between the pressure-relief means and the parts that it is intended
+ v5 [' g3 x' i M& z/ u' Lto protect." K! x8 p7 t4 w* q
29.11 A vessel having an inside diameter of more than 3 inches (76.2 mm) and subject to air or steam( ?& `: ]0 g2 r8 v/ u( P
pressure generated or stored within the appliance shall be protected by a pressure-relief device.4 p+ F7 F4 k5 B; p4 {
29.12 The start-to-discharge pressure setting of the pressure-relief device shall not be higher than the. k" d, [- v6 H1 g
working pressure marked on the vessel. The discharge rate of the device shall acceptably relieve the8 q& w$ h) j0 F/ C
pressure.
9 N6 @) |0 s6 d2 y29.13 A pressure-relief device shall comply with all four of the following:
- K& ?! Z0 E9 D' @a) Shall be connected as close as possible to the pressure vessel or parts of the system that it
$ S6 `; b! W2 o# `is intended to protect;
% i0 l- L% f6 M8 K s6 o. t; Fb) Shall be installed so that it is readily accessible for inspection and repair and cannot be- m: n5 U% z- X0 |
readily rendered inoperative;5 [ _( O# y) ^+ v
c) Shall have its discharge opening located and directed so that the risk of scalding is reduced+ p z: W: l4 W
to a minimum; and2 _" @) A# w/ f% X. r
d) Shall have its discharge opening located and directed so that operation of the device does
: h) g4 }, s6 pnot deposit moisture on bare live parts or on insulation or components affected detrimentally by
9 G' A& B4 z/ {, N# G2 Kmoisture.- a. j8 I( J: m7 |
29.14 A pressure-relief device having an adjustable setting shall be judged on the basis of its maximum
. p0 y4 u. w0 G" Psetting unless the adjusting means is sealed at a lower setting.
. G: s' T( c+ V/ E: v* l9 P1 u: P29.15 A pressure-relief device is considered to be a pressure-actuated valve or rupture member intended2 M7 b6 R5 E# c, b" |
to relieve excessive pressures automatically.1 E: r+ L0 Q5 U$ D8 v
29.16 Where a pressure relief device is required, the control responsible for limiting the pressure in the
1 V5 e2 k% e9 S0 V+ m* mvessel shall be capable of performing under rated load for 100,000 cycles of operation and shall prevent( G. G+ _* k9 S1 G7 Y z5 D9 I6 F8 ^
the pressure from exceeding 90 percent of the relief device setting under any condition of normal" K6 K' o+ B. T) N1 g
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