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29 Pressure Vessels and Parts Subject to Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
# v9 y2 C& H. D8 L29.1 Except as noted in 29.2, a pressure vessel having an inside diameter of more than 6 inches (152
+ |! @5 }7 {6 i$ U( t; Jmm) and subject to a gauge pressure of more than 15 lbf/in2 (103 kN/cm2) shall be certified by the4 v0 O8 ~# m' b1 k: b3 a
National Board of Boiler and Pressure-Vessel Inspectors and marked in accordance with the appropriate
3 }. ?8 D3 |0 m) x$ @boiler and pressure vessel code symbol of the American Society of Mechanical Engineers (ASME) (²H²,
6 x& o K$ N& y- j²M², ²S², or ²U²) for a working pressure not less than the pressure determined by applying 29.3.; `/ Z5 d. M# n" ^
29.2 If a pressure vessel, because of its application, is not covered under the inspection procedures of
& K" Q" r4 w* O1 k% g! g6 `the ASME code, it shall be designed and constructed so that it complies with the requirements in 29.3.
2 M5 d) b6 \& ?5 v0 s29.3 Except as noted in 29.4 and 29.5, a part that is subject to air or vapor pressure (including the vapor8 O' W2 k5 a, k1 c* T1 K) b! F
pressure in a vessel containing only a superheated fluid) during normal or abnormal operation shall
, w1 `2 P/ S# K, m: T, x5 Awithstand without bursting or leaking a pressure equal to the highest of the following that is applicable:: D T4 |2 @- d
a) Five times the pressure corresponding to the maximum setting of a pressure-reducing valve
6 U1 g- \1 ]: t7 l7 hprovided as part of the assembly, but no more than five times the marked maximum supply
+ X' p# V4 r; E6 k7 Npressure from an external source and no more than five times the pressure setting of a
8 D( Z* L, H5 E d- Cpressure-relief device provided as part of the assembly.
# Z1 I' y% a z8 A# bb) Five times the marked maximum supply pressure from an external source, except as
+ S& r$ \# c/ i ^/ Uprovided in (a).9 C5 G( l' o! A F- p& L+ m
c) Five times the pressure setting of a pressure-relief device provided as part of the assembly.5 D% o; X/ |! I1 K
d) Five times the maximum pressure that can be developed by an air compressor that is part of$ K; i( a8 D( X* v# d5 {" Z
the assembly, unless the pressure is limited by a pressure-relief device in accordance with (a).2 U# u. Z/ E' H" L; Z& B
e) Five times the working pressure marked on the part.# v% c! D& Q2 s" N, T
29.4 A test need not be performed to determine whether a part complies with the requirement in 29.3 if( R% h) h" |+ T/ u* o6 L
study and analysis indicate that the strength of the part is adequate for the purpose as a result of its: ~& [5 n! C1 G4 g* }1 G
material and dimensions – for example, copper or steel pipe of standard size and provided with standard
* X. B) C; P1 y b+ l+ L$ Xfittings might be considered to have adequate strength.+ e+ d( S) D- k+ Z }
29.5 A pressure vessel bearing the ASME code inspection symbol (²H², ²M², ²S², or ²U²) is considered
- z. z( W4 w& i1 s6 c+ {6 n# Eto comply with the requirement in 29.3 if the vessel is marked with a value of working pressure not less* |8 Y+ T7 D; f0 i6 T
than that to which it is subject during normal or abnormal operation.
+ U, x+ A, p( f8 g& L3 O [9 P- x$ {4 e29.6 If a test is necessary to determine whether a part complies with the requirement in 29.3, two samples
: S# [" j+ z* Y' G1 w+ D4 kof the part are to be subjected to a hydrostatic-pressure test. Each sample is to be filled with water as to
6 b2 F$ L- H0 o3 Y/ Rexclude air and is to be connected to a hydraulic pump. The pressure is to be raised gradually to the
; ]# U, Q0 d2 K8 ?specified test value and is to be held at that value for 1 minute. The results are not acceptable if either
; s% M" T+ ^, [5 Zsample bursts or leaks, except as indicated in 29.7.
% r C2 C K! W; v5 J' q! W29.7 Leakage at a gasket during the hydrostatic-pressure test is not unacceptable unless it occurs at a
; T: ^; I$ u a4 spressure 40 percent or less of the required test value.* f8 K! s! s. P8 {6 }
29.8 A means for relieving pressure shall be provided for all parts in which pressure might be generated# k( B5 q" {9 @) F
in the event of fire.8 {! K$ a- P- q" m. q
29.9 Pressure-relief devices (see 29.15), fusible plugs, soldered joints, nonmetallic tubing, or other3 D8 i i0 |1 e. U/ O
pressure-relief means or the equivalent may be employed to comply with the requirements in 29.8.
% C6 a" ~/ Q+ U7 e29.10 There shall be no shut-off valve between the pressure-relief means and the parts that it is intended
4 u, [. U5 d9 Y+ jto protect.' j2 m8 j- L1 \. h8 ~. ?; Y ]" I
29.11 A vessel having an inside diameter of more than 3 inches (76.2 mm) and subject to air or steam5 W8 M4 x) t, o( s8 f- v
pressure generated or stored within the appliance shall be protected by a pressure-relief device.; S6 }5 K6 z; A2 R
29.12 The start-to-discharge pressure setting of the pressure-relief device shall not be higher than the. B- }' ]! R3 J+ `
working pressure marked on the vessel. The discharge rate of the device shall acceptably relieve the1 d, Q* k# b" a( {+ N2 K y8 Y5 ]
pressure.
- t" d8 z6 `* {. p2 ?; g29.13 A pressure-relief device shall comply with all four of the following:/ k" S( _$ _2 ^0 w
a) Shall be connected as close as possible to the pressure vessel or parts of the system that it$ A3 q/ C: ?, C. D2 w) h7 A* m* R
is intended to protect;
9 M- j5 ^4 e* {1 A# S. ib) Shall be installed so that it is readily accessible for inspection and repair and cannot be
: V1 d N1 u8 N& U1 Jreadily rendered inoperative;
- E4 r$ B+ P" A3 fc) Shall have its discharge opening located and directed so that the risk of scalding is reduced
l* X$ M4 i4 N* z- o! ` g Ato a minimum; and
# e1 J+ m6 w$ g% U- N8 ad) Shall have its discharge opening located and directed so that operation of the device does
6 Y. I: \7 G2 s2 O* ~/ Vnot deposit moisture on bare live parts or on insulation or components affected detrimentally by
+ Q2 D/ z8 \ F4 bmoisture.7 N5 G1 B* q1 g. m! S
29.14 A pressure-relief device having an adjustable setting shall be judged on the basis of its maximum
( |9 C' u1 d. Q% V5 Osetting unless the adjusting means is sealed at a lower setting.9 {) n8 A! s( \& L4 ?+ i7 f
29.15 A pressure-relief device is considered to be a pressure-actuated valve or rupture member intended
" G/ l/ }( I7 mto relieve excessive pressures automatically.
! V: t# [; }: U' D& {2 z29.16 Where a pressure relief device is required, the control responsible for limiting the pressure in the! M4 |7 B5 b! n( H, C& ^
vessel shall be capable of performing under rated load for 100,000 cycles of operation and shall prevent
# R4 N3 h w6 @& }7 rthe pressure from exceeding 90 percent of the relief device setting under any condition of normal
3 c& R8 K( i& O- A6 M1 moperation. |
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