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29 Pressure Vessels and Parts Subject to Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . .41. T, A; X; _' Y. Y0 ]* x, m
29.1 Except as noted in 29.2, a pressure vessel having an inside diameter of more than 6 inches (152* n8 f7 n; F- _ K2 R
mm) and subject to a gauge pressure of more than 15 lbf/in2 (103 kN/cm2) shall be certified by the' Q; W& D- u9 Q/ F9 }) k, A
National Board of Boiler and Pressure-Vessel Inspectors and marked in accordance with the appropriate) M- i. `. G* j
boiler and pressure vessel code symbol of the American Society of Mechanical Engineers (ASME) (²H²,
5 j* p. F j: U" [& @- Q²M², ²S², or ²U²) for a working pressure not less than the pressure determined by applying 29.3.
8 J8 Q# d2 A' \8 I# f1 J5 t29.2 If a pressure vessel, because of its application, is not covered under the inspection procedures of
3 C, r/ l$ X) x# Uthe ASME code, it shall be designed and constructed so that it complies with the requirements in 29.3. ~% A* \4 Q& X+ t h) A( f: m8 e
29.3 Except as noted in 29.4 and 29.5, a part that is subject to air or vapor pressure (including the vapor3 r* f" c8 H; D% g. s
pressure in a vessel containing only a superheated fluid) during normal or abnormal operation shall
# p3 P. ~% R1 h) Y% Lwithstand without bursting or leaking a pressure equal to the highest of the following that is applicable:5 m- O1 o2 L. S h, c! f6 X% }
a) Five times the pressure corresponding to the maximum setting of a pressure-reducing valve
7 v2 I' B, x/ ?" j- N) hprovided as part of the assembly, but no more than five times the marked maximum supply
0 K+ L$ M* Y/ m: ~8 G0 R+ apressure from an external source and no more than five times the pressure setting of a
% X+ m8 I2 X% M& |5 ]( K$ M* _pressure-relief device provided as part of the assembly.& M3 u3 \3 i7 G5 m% O
b) Five times the marked maximum supply pressure from an external source, except as
5 M! v6 } o' J" Oprovided in (a).: i4 h7 l( {/ O1 h) n0 y
c) Five times the pressure setting of a pressure-relief device provided as part of the assembly.7 c) ~/ t# H7 a" U' C9 W4 T% b
d) Five times the maximum pressure that can be developed by an air compressor that is part of
. a/ L: A0 p7 I3 Nthe assembly, unless the pressure is limited by a pressure-relief device in accordance with (a).
2 @% a% k+ c3 G" F- ~' F, d% Ve) Five times the working pressure marked on the part.) P1 X. U/ l0 u, T! W6 B5 }
29.4 A test need not be performed to determine whether a part complies with the requirement in 29.3 if) R' [, e, }: Y3 D
study and analysis indicate that the strength of the part is adequate for the purpose as a result of its
) W7 F# n+ a% tmaterial and dimensions – for example, copper or steel pipe of standard size and provided with standard: p/ W2 T0 n0 N
fittings might be considered to have adequate strength.
# W8 {9 [3 ^ i+ Q8 j29.5 A pressure vessel bearing the ASME code inspection symbol (²H², ²M², ²S², or ²U²) is considered
. X1 g- m: h; u2 i8 I( K; jto comply with the requirement in 29.3 if the vessel is marked with a value of working pressure not less
4 p& o/ @% t0 H8 {. C; ]than that to which it is subject during normal or abnormal operation.$ j! g& T- X; Z3 R% k+ ] c
29.6 If a test is necessary to determine whether a part complies with the requirement in 29.3, two samples
! d/ \" N( S& P* Jof the part are to be subjected to a hydrostatic-pressure test. Each sample is to be filled with water as to3 B. [0 n) _9 K) B3 v4 ]) _
exclude air and is to be connected to a hydraulic pump. The pressure is to be raised gradually to the- t, @, u1 x: P2 h0 ~9 I) A: L& G
specified test value and is to be held at that value for 1 minute. The results are not acceptable if either- J2 y! y' C' o
sample bursts or leaks, except as indicated in 29.7.0 f" @$ I& T* H: c% @5 Y1 i
29.7 Leakage at a gasket during the hydrostatic-pressure test is not unacceptable unless it occurs at a7 T0 g/ U7 t! X1 T
pressure 40 percent or less of the required test value., H/ p+ p: T o& x
29.8 A means for relieving pressure shall be provided for all parts in which pressure might be generated8 a* Z* G# s4 O; i, U
in the event of fire.$ P: L" B, I9 l7 S) ~! ?) L* w3 }
29.9 Pressure-relief devices (see 29.15), fusible plugs, soldered joints, nonmetallic tubing, or other
+ C J9 v) q$ C M* k, }pressure-relief means or the equivalent may be employed to comply with the requirements in 29.8.7 j! ?8 I0 `8 U8 x/ X
29.10 There shall be no shut-off valve between the pressure-relief means and the parts that it is intended8 w6 h8 g. z0 Y
to protect.
6 B! z, I+ E' {$ X! \. Q29.11 A vessel having an inside diameter of more than 3 inches (76.2 mm) and subject to air or steam
& V. e# g9 J5 i4 [- K4 i; R- z4 Upressure generated or stored within the appliance shall be protected by a pressure-relief device.0 Z0 h2 n2 {! o+ Z. E9 G; V
29.12 The start-to-discharge pressure setting of the pressure-relief device shall not be higher than the
w$ U) t5 F# s1 ?working pressure marked on the vessel. The discharge rate of the device shall acceptably relieve the: P. `1 n! j( J) m8 H* u( M2 H
pressure.
& y; n% [3 y# u4 P29.13 A pressure-relief device shall comply with all four of the following:! C6 j* v: q; _
a) Shall be connected as close as possible to the pressure vessel or parts of the system that it2 M. q$ ~* O: N8 e
is intended to protect;
* l+ }" J2 Z9 z# ~& G: I3 w# Rb) Shall be installed so that it is readily accessible for inspection and repair and cannot be
- b: a( H5 a5 n! X8 _readily rendered inoperative;
4 l! P0 l/ j+ e. J qc) Shall have its discharge opening located and directed so that the risk of scalding is reduced
1 O1 h9 o) {1 C; vto a minimum; and/ h8 w$ X1 ^$ w% q1 S/ Y- w
d) Shall have its discharge opening located and directed so that operation of the device does8 J v3 b2 F3 S. L) k/ ]
not deposit moisture on bare live parts or on insulation or components affected detrimentally by8 `8 {5 M# d9 i w
moisture.
, |+ W q1 V2 r1 J2 }, }9 {29.14 A pressure-relief device having an adjustable setting shall be judged on the basis of its maximum6 q2 \- v: \: c8 _' a' v4 G" p
setting unless the adjusting means is sealed at a lower setting.* O& a' `( J4 e4 b/ |
29.15 A pressure-relief device is considered to be a pressure-actuated valve or rupture member intended
& L9 }. t' S Y! K! ~; g2 M! v0 Y/ cto relieve excessive pressures automatically.
" h* k. B3 X. ?6 {, H29.16 Where a pressure relief device is required, the control responsible for limiting the pressure in the
; F) t" I1 G& F- v8 ?" B9 Wvessel shall be capable of performing under rated load for 100,000 cycles of operation and shall prevent7 ^, t Z" {6 H( x% u3 j
the pressure from exceeding 90 percent of the relief device setting under any condition of normal
( o$ z9 p$ O( Y! M3 N5 i1 n$ ?' aoperation. |
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