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29 Pressure Vessels and Parts Subject to Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
: X, s$ @; ]( a$ [4 n0 }! V( d29.1 Except as noted in 29.2, a pressure vessel having an inside diameter of more than 6 inches (152 x, |0 V3 _' B) _
mm) and subject to a gauge pressure of more than 15 lbf/in2 (103 kN/cm2) shall be certified by the- U0 h. V- W0 F. ?& F9 z) E O8 k
National Board of Boiler and Pressure-Vessel Inspectors and marked in accordance with the appropriate& H; _# S0 h' M& }
boiler and pressure vessel code symbol of the American Society of Mechanical Engineers (ASME) (²H²,
) e3 ^; |0 Y/ Z- M+ @* W²M², ²S², or ²U²) for a working pressure not less than the pressure determined by applying 29.3.$ _7 r3 Y; r5 ]/ |
29.2 If a pressure vessel, because of its application, is not covered under the inspection procedures of( p! \! n' g) p' q6 n5 B R
the ASME code, it shall be designed and constructed so that it complies with the requirements in 29.3.
% d! I9 F& G1 g3 X& X29.3 Except as noted in 29.4 and 29.5, a part that is subject to air or vapor pressure (including the vapor
. \' e) q z3 Z: z+ xpressure in a vessel containing only a superheated fluid) during normal or abnormal operation shall2 x( x) s9 |2 _5 f; {% x
withstand without bursting or leaking a pressure equal to the highest of the following that is applicable:
! i8 W+ H, O! n9 O( @a) Five times the pressure corresponding to the maximum setting of a pressure-reducing valve# Q' O4 ^- V, P/ N
provided as part of the assembly, but no more than five times the marked maximum supply
$ r: _/ `1 {% cpressure from an external source and no more than five times the pressure setting of a x' f9 y9 a0 A& c" E0 @3 M! G
pressure-relief device provided as part of the assembly.
9 j* N4 K: S8 d9 m& x; Lb) Five times the marked maximum supply pressure from an external source, except as
/ U& \ u- o0 _9 K" s- tprovided in (a).
* Z( | Y% ?8 b5 B: P1 a1 ?c) Five times the pressure setting of a pressure-relief device provided as part of the assembly.% O4 s3 r& {- K/ Y8 J5 ^$ M
d) Five times the maximum pressure that can be developed by an air compressor that is part of. l6 ~: y1 w/ y7 {7 E
the assembly, unless the pressure is limited by a pressure-relief device in accordance with (a).+ K( p; o' C. {7 M
e) Five times the working pressure marked on the part.- l2 S A# r' J7 K3 r4 C5 }! q
29.4 A test need not be performed to determine whether a part complies with the requirement in 29.3 if: K* Q# K/ T6 O' Y. i5 f0 u
study and analysis indicate that the strength of the part is adequate for the purpose as a result of its# b8 G9 e i: ~) u$ @, w4 }
material and dimensions – for example, copper or steel pipe of standard size and provided with standard5 t5 _9 Q$ U2 @8 [
fittings might be considered to have adequate strength.
9 e- U; |7 R; e( U) C/ s8 X29.5 A pressure vessel bearing the ASME code inspection symbol (²H², ²M², ²S², or ²U²) is considered
2 l5 j" `& [. b7 u& bto comply with the requirement in 29.3 if the vessel is marked with a value of working pressure not less B% D+ u. \: L$ F
than that to which it is subject during normal or abnormal operation.8 J) Q0 \( b/ U% V* l
29.6 If a test is necessary to determine whether a part complies with the requirement in 29.3, two samples9 e+ ^& v, h" V: k
of the part are to be subjected to a hydrostatic-pressure test. Each sample is to be filled with water as to
6 J& C0 B, E; m2 A+ l( X% ^( o3 Eexclude air and is to be connected to a hydraulic pump. The pressure is to be raised gradually to the
) i1 k. A# i6 ?6 Z" ~. Qspecified test value and is to be held at that value for 1 minute. The results are not acceptable if either
- f3 o7 d# z, C# _. Hsample bursts or leaks, except as indicated in 29.7.
3 k/ b& {4 ^, R* l29.7 Leakage at a gasket during the hydrostatic-pressure test is not unacceptable unless it occurs at a
3 [* ?1 b) ~9 S; E4 L' _" P7 u# U. L2 cpressure 40 percent or less of the required test value. m5 h! D5 @6 I% e0 @* K5 p
29.8 A means for relieving pressure shall be provided for all parts in which pressure might be generated
! z% O$ f% y+ s* _8 I. \1 Z9 f: pin the event of fire. Y5 w1 s+ Z. P6 @
29.9 Pressure-relief devices (see 29.15), fusible plugs, soldered joints, nonmetallic tubing, or other
' L7 E, j- A% N$ F1 qpressure-relief means or the equivalent may be employed to comply with the requirements in 29.8.* g G+ q8 b0 A: q! c4 K) k% v' C
29.10 There shall be no shut-off valve between the pressure-relief means and the parts that it is intended c0 z( S/ N$ i* W# N4 O. j j6 t2 X
to protect.. q9 |; F) Z4 T6 n9 b
29.11 A vessel having an inside diameter of more than 3 inches (76.2 mm) and subject to air or steam
, G' m" l4 ?0 o, c: k9 t: ?pressure generated or stored within the appliance shall be protected by a pressure-relief device.
w( m' z2 I( |) u# |6 O29.12 The start-to-discharge pressure setting of the pressure-relief device shall not be higher than the* u! a& Q# e% [# N. ?
working pressure marked on the vessel. The discharge rate of the device shall acceptably relieve the+ P& D* v7 f8 g& b# @
pressure.
# E: a% B: X) S( c J29.13 A pressure-relief device shall comply with all four of the following:8 I/ |# F& {- P; Y
a) Shall be connected as close as possible to the pressure vessel or parts of the system that it5 d, c5 ]" M) k: K
is intended to protect;8 a/ E3 e+ I; g( | ] \7 H+ v
b) Shall be installed so that it is readily accessible for inspection and repair and cannot be7 t. `# V- l" y! d4 B& G Q
readily rendered inoperative;
# @* A4 K9 p+ x' a, m zc) Shall have its discharge opening located and directed so that the risk of scalding is reduced# y: I: S4 Y+ l
to a minimum; and
' S. H. \2 ~+ |* ud) Shall have its discharge opening located and directed so that operation of the device does
, T( v& p6 m+ |8 q5 e* ?0 M. ^not deposit moisture on bare live parts or on insulation or components affected detrimentally by4 P! B" @: [. R& }
moisture.! C- ?8 n! R) w0 l7 f& [5 B
29.14 A pressure-relief device having an adjustable setting shall be judged on the basis of its maximum4 s/ t5 M) f- f* o
setting unless the adjusting means is sealed at a lower setting.% H+ k, m: K; l, r4 z
29.15 A pressure-relief device is considered to be a pressure-actuated valve or rupture member intended
# q9 M+ z) x0 @; v% p! Kto relieve excessive pressures automatically.1 q5 A( i4 X5 [- o- \! V3 H
29.16 Where a pressure relief device is required, the control responsible for limiting the pressure in the
& b; f- ]! e# F: A4 Q& Mvessel shall be capable of performing under rated load for 100,000 cycles of operation and shall prevent
1 F0 g2 u7 M1 l+ Q/ r- Q- sthe pressure from exceeding 90 percent of the relief device setting under any condition of normal
, Q( F$ Q1 T' S. q; \6 Doperation. |
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