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29 Pressure Vessels and Parts Subject to Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . .41% d0 k [( v5 e% M3 J( c
29.1 Except as noted in 29.2, a pressure vessel having an inside diameter of more than 6 inches (152
$ M1 w) P4 [. z }0 _: O7 emm) and subject to a gauge pressure of more than 15 lbf/in2 (103 kN/cm2) shall be certified by the) F1 Z; d) V! }( ?+ w
National Board of Boiler and Pressure-Vessel Inspectors and marked in accordance with the appropriate* m2 ]* ~7 r/ b, A9 Q
boiler and pressure vessel code symbol of the American Society of Mechanical Engineers (ASME) (²H²,0 D& r0 @9 L" J# b! T
²M², ²S², or ²U²) for a working pressure not less than the pressure determined by applying 29.3. S- p. c8 p) u0 X2 a
29.2 If a pressure vessel, because of its application, is not covered under the inspection procedures of
1 a- F9 I- o7 T- j. Xthe ASME code, it shall be designed and constructed so that it complies with the requirements in 29.3. w$ L/ L0 V, d; S0 a/ U
29.3 Except as noted in 29.4 and 29.5, a part that is subject to air or vapor pressure (including the vapor
, C4 T1 G8 N" L0 o/ I$ Ppressure in a vessel containing only a superheated fluid) during normal or abnormal operation shall
1 ^7 u9 C8 w8 D8 @: g( fwithstand without bursting or leaking a pressure equal to the highest of the following that is applicable:2 ~! F% D. r6 A# d1 G2 P
a) Five times the pressure corresponding to the maximum setting of a pressure-reducing valve
4 L/ s; d3 N5 R1 h( Q3 ]2 gprovided as part of the assembly, but no more than five times the marked maximum supply
! j2 B) g4 N: spressure from an external source and no more than five times the pressure setting of a
/ _( d+ q5 }( e W2 I0 ^pressure-relief device provided as part of the assembly.
% x) g. k& W. g2 z' T$ [b) Five times the marked maximum supply pressure from an external source, except as: h9 Z! ]( E$ K" D: i
provided in (a).
. ^7 R& e9 R, R* z5 M: Wc) Five times the pressure setting of a pressure-relief device provided as part of the assembly.% {7 F7 Z# r2 u7 @! l+ K
d) Five times the maximum pressure that can be developed by an air compressor that is part of8 L6 f$ C6 M/ K) \$ ?6 C2 R1 e
the assembly, unless the pressure is limited by a pressure-relief device in accordance with (a).$ ~0 L# g! g! z. L6 m0 [; [/ R
e) Five times the working pressure marked on the part.
5 I+ q, y* j* ~; C {0 M3 \6 x29.4 A test need not be performed to determine whether a part complies with the requirement in 29.3 if* T( u: g5 B" ^6 w' q% \
study and analysis indicate that the strength of the part is adequate for the purpose as a result of its
( _' c. C6 ?; B# c( smaterial and dimensions – for example, copper or steel pipe of standard size and provided with standard
$ s# `# ?8 y' E+ ]2 K# w5 Ofittings might be considered to have adequate strength.
' f1 `: d! ^% ^29.5 A pressure vessel bearing the ASME code inspection symbol (²H², ²M², ²S², or ²U²) is considered! |) |* D6 w. H2 {; V' }
to comply with the requirement in 29.3 if the vessel is marked with a value of working pressure not less
9 x0 e5 K8 V2 ?$ i( _than that to which it is subject during normal or abnormal operation.
. n/ `) K4 Y. W$ e29.6 If a test is necessary to determine whether a part complies with the requirement in 29.3, two samples
& ]; a2 b0 X( @# hof the part are to be subjected to a hydrostatic-pressure test. Each sample is to be filled with water as to
$ K" l& i, q* A/ i) o$ ~exclude air and is to be connected to a hydraulic pump. The pressure is to be raised gradually to the
/ f' N7 b. _; ispecified test value and is to be held at that value for 1 minute. The results are not acceptable if either; K& o& B& i2 ?6 l4 C, R
sample bursts or leaks, except as indicated in 29.7.: I. I$ Q/ f) ^! @( B& g0 W$ |! k) c, s4 f
29.7 Leakage at a gasket during the hydrostatic-pressure test is not unacceptable unless it occurs at a) l4 w7 [/ h( L+ Z7 [
pressure 40 percent or less of the required test value.8 a+ q4 f# d" \3 y
29.8 A means for relieving pressure shall be provided for all parts in which pressure might be generated
+ o1 f3 q8 }2 B# _in the event of fire.
; P; c. k1 e# [) @7 L) \29.9 Pressure-relief devices (see 29.15), fusible plugs, soldered joints, nonmetallic tubing, or other
" v0 m/ {8 x9 [1 L3 X% C' Upressure-relief means or the equivalent may be employed to comply with the requirements in 29.8.5 h) F; ?/ ^) \* h8 r/ E! @# _
29.10 There shall be no shut-off valve between the pressure-relief means and the parts that it is intended6 y" ]" W7 C/ ~
to protect.7 \* u0 x! E- R/ a1 p8 H
29.11 A vessel having an inside diameter of more than 3 inches (76.2 mm) and subject to air or steam2 l! z4 Y6 `" ?, Y. `% n( o+ X* h
pressure generated or stored within the appliance shall be protected by a pressure-relief device.# {8 I* [! Y" }4 h1 e. e& j- V4 l+ ^8 r
29.12 The start-to-discharge pressure setting of the pressure-relief device shall not be higher than the7 A! u$ C: h0 B( X' M
working pressure marked on the vessel. The discharge rate of the device shall acceptably relieve the9 c% f8 [: b' v7 D, k/ H
pressure.) i. K, l" ~ ]! i
29.13 A pressure-relief device shall comply with all four of the following:
* L! F7 \; S0 F3 S3 Q* Ma) Shall be connected as close as possible to the pressure vessel or parts of the system that it
# `) l7 L0 z6 i( a& Z/ Z+ Jis intended to protect;
; k4 Q( d3 C7 v7 N6 K+ l zb) Shall be installed so that it is readily accessible for inspection and repair and cannot be
) z( M# @8 V7 ^ Q% g7 G2 Oreadily rendered inoperative;3 b: M# s4 ^ D3 J
c) Shall have its discharge opening located and directed so that the risk of scalding is reduced8 \* P4 {6 ^- n2 P' R; @5 ]5 O8 l' j
to a minimum; and; a0 y( a" m1 b4 F
d) Shall have its discharge opening located and directed so that operation of the device does
: {6 s) I, [+ a; o Knot deposit moisture on bare live parts or on insulation or components affected detrimentally by o" b* C8 b0 O0 \/ g3 o
moisture.
* I @" y; v+ q- {' {1 E* P" v29.14 A pressure-relief device having an adjustable setting shall be judged on the basis of its maximum
# `* H8 v( t' h! ^8 C: G# ssetting unless the adjusting means is sealed at a lower setting.( y/ Y9 I" ]9 ]
29.15 A pressure-relief device is considered to be a pressure-actuated valve or rupture member intended. N# ]& f( b3 W
to relieve excessive pressures automatically.
, V ^* F& b& C29.16 Where a pressure relief device is required, the control responsible for limiting the pressure in the; l6 M- c# I( x* H9 \
vessel shall be capable of performing under rated load for 100,000 cycles of operation and shall prevent
# ~. K$ U3 t$ R- t, _- u: Fthe pressure from exceeding 90 percent of the relief device setting under any condition of normal% y( ]0 J/ |# i+ a- N
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