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29 Pressure Vessels and Parts Subject to Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
, j/ ~+ k: I- a/ t4 \+ C29.1 Except as noted in 29.2, a pressure vessel having an inside diameter of more than 6 inches (152
8 p, o" _4 c: `( p9 K% q0 \, V4 bmm) and subject to a gauge pressure of more than 15 lbf/in2 (103 kN/cm2) shall be certified by the
( j" b, ^6 N: S2 ANational Board of Boiler and Pressure-Vessel Inspectors and marked in accordance with the appropriate/ m& J! x8 a" w: p, `
boiler and pressure vessel code symbol of the American Society of Mechanical Engineers (ASME) (²H²,( V. w& V/ ^3 r6 k( p/ _
²M², ²S², or ²U²) for a working pressure not less than the pressure determined by applying 29.3.
8 x0 l8 Z; y( i4 W29.2 If a pressure vessel, because of its application, is not covered under the inspection procedures of4 K2 q% N! q' G! |) {" c
the ASME code, it shall be designed and constructed so that it complies with the requirements in 29.3.
* b0 i$ n1 p: T! _- E5 }29.3 Except as noted in 29.4 and 29.5, a part that is subject to air or vapor pressure (including the vapor! C3 X* i( y8 c) J9 h/ n6 ?
pressure in a vessel containing only a superheated fluid) during normal or abnormal operation shall6 l) i: v' f+ _. R% ?% ~1 p
withstand without bursting or leaking a pressure equal to the highest of the following that is applicable:1 g4 N! [; K1 V" ?& z; A
a) Five times the pressure corresponding to the maximum setting of a pressure-reducing valve
& P$ Y$ H* T% b$ a' [provided as part of the assembly, but no more than five times the marked maximum supply2 B) @ l% g# |5 ]- \' h: D `5 e
pressure from an external source and no more than five times the pressure setting of a
7 }/ u* \" C! o* _! Npressure-relief device provided as part of the assembly.! J1 `( k% r) k) J' ^
b) Five times the marked maximum supply pressure from an external source, except as
& `: e2 ?1 v& H; Bprovided in (a)., ~: N8 k& `, g0 I# k
c) Five times the pressure setting of a pressure-relief device provided as part of the assembly.
) K9 M) Q6 E4 |7 E# ]0 j7 W. d/ T4 K. dd) Five times the maximum pressure that can be developed by an air compressor that is part of
) @& T2 g6 l" I0 `+ Z; z O. t8 pthe assembly, unless the pressure is limited by a pressure-relief device in accordance with (a).5 @8 ~9 q; y+ C
e) Five times the working pressure marked on the part.
. d6 N( l6 K1 g4 M8 [7 R% e29.4 A test need not be performed to determine whether a part complies with the requirement in 29.3 if
) |8 L1 y: ~4 `study and analysis indicate that the strength of the part is adequate for the purpose as a result of its6 f, m/ `9 b$ u2 E
material and dimensions – for example, copper or steel pipe of standard size and provided with standard
; f; L" Z5 E4 o" D3 jfittings might be considered to have adequate strength.
$ O7 y- N, ~/ m. e6 E6 |29.5 A pressure vessel bearing the ASME code inspection symbol (²H², ²M², ²S², or ²U²) is considered
3 J* m! v8 l. W6 y) tto comply with the requirement in 29.3 if the vessel is marked with a value of working pressure not less* A* z# L8 i" v* Z/ m; f% [$ `
than that to which it is subject during normal or abnormal operation.
3 S! `6 G# Z4 u1 j) G' [29.6 If a test is necessary to determine whether a part complies with the requirement in 29.3, two samples9 k- i- r" e% t1 k, W4 _! v s9 T% D8 ?
of the part are to be subjected to a hydrostatic-pressure test. Each sample is to be filled with water as to
6 p9 V; o3 @2 i% V$ U, X Cexclude air and is to be connected to a hydraulic pump. The pressure is to be raised gradually to the* e& A# I! C; ^( _( k3 V
specified test value and is to be held at that value for 1 minute. The results are not acceptable if either
7 ^' e2 A* x. W5 b! v y$ v+ I& Csample bursts or leaks, except as indicated in 29.7.
/ j( n; N7 d0 l" Y29.7 Leakage at a gasket during the hydrostatic-pressure test is not unacceptable unless it occurs at a
0 g/ O- Q7 F+ qpressure 40 percent or less of the required test value.8 H& J# o9 W, l$ v! D$ M
29.8 A means for relieving pressure shall be provided for all parts in which pressure might be generated
+ L" u; L X7 V/ G1 m7 h, n2 }in the event of fire.) h; z! w# W( k: m* t- Q* Y
29.9 Pressure-relief devices (see 29.15), fusible plugs, soldered joints, nonmetallic tubing, or other
- Z1 D! _7 v' b4 @pressure-relief means or the equivalent may be employed to comply with the requirements in 29.8.
9 G0 j: n* f. K2 j29.10 There shall be no shut-off valve between the pressure-relief means and the parts that it is intended
6 W; C+ r4 K% C! y1 d8 |* v7 dto protect.) A. g7 d9 j5 L
29.11 A vessel having an inside diameter of more than 3 inches (76.2 mm) and subject to air or steam
% J( e. J& i$ d+ j. y( o% `4 `pressure generated or stored within the appliance shall be protected by a pressure-relief device.
8 A' a5 Y6 ?# |/ {9 V& p29.12 The start-to-discharge pressure setting of the pressure-relief device shall not be higher than the/ m3 j! f" @3 h" V2 |2 q4 J x
working pressure marked on the vessel. The discharge rate of the device shall acceptably relieve the
& N4 K5 q8 J6 L# m' Ypressure.
3 q( m- c6 j# A& ^. Y. \ y29.13 A pressure-relief device shall comply with all four of the following:
$ P2 C6 P% B' n9 l. u! va) Shall be connected as close as possible to the pressure vessel or parts of the system that it
" x! a" e5 ?9 h% ris intended to protect;0 I" F6 C) P% h' v
b) Shall be installed so that it is readily accessible for inspection and repair and cannot be" i8 z) L0 ^7 N
readily rendered inoperative;) v3 g( q9 k& A$ {9 ]
c) Shall have its discharge opening located and directed so that the risk of scalding is reduced2 a* Y, i. A" i& Z8 ]7 [/ `6 ^
to a minimum; and
9 I9 b% N2 R, kd) Shall have its discharge opening located and directed so that operation of the device does! A4 @% |+ @ ]$ _
not deposit moisture on bare live parts or on insulation or components affected detrimentally by
5 [8 f0 d% ]/ Smoisture.9 `& T( u/ @1 u# J, E0 e2 R4 k
29.14 A pressure-relief device having an adjustable setting shall be judged on the basis of its maximum
; n B( \. Q# r3 Vsetting unless the adjusting means is sealed at a lower setting.
, {6 P+ S. o$ C4 T) k& D29.15 A pressure-relief device is considered to be a pressure-actuated valve or rupture member intended6 J5 n# h9 p1 v
to relieve excessive pressures automatically.
8 c" t3 r$ {" h' i29.16 Where a pressure relief device is required, the control responsible for limiting the pressure in the
7 T* c6 b, |4 P# W5 m' Ovessel shall be capable of performing under rated load for 100,000 cycles of operation and shall prevent
1 n" m: \' }. G( S7 lthe pressure from exceeding 90 percent of the relief device setting under any condition of normal
7 K8 t3 V n# Y9 c4 p xoperation. |
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