|
29 Pressure Vessels and Parts Subject to Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
3 @: ^( \% r8 j3 q) G1 |29.1 Except as noted in 29.2, a pressure vessel having an inside diameter of more than 6 inches (1523 z/ z' G8 Y# X
mm) and subject to a gauge pressure of more than 15 lbf/in2 (103 kN/cm2) shall be certified by the7 x/ n7 I; O* F; ~% N( k
National Board of Boiler and Pressure-Vessel Inspectors and marked in accordance with the appropriate
# c' N6 i: V, i+ c) Jboiler and pressure vessel code symbol of the American Society of Mechanical Engineers (ASME) (²H²,
: f: X5 q- g2 p' ^( j5 I0 O²M², ²S², or ²U²) for a working pressure not less than the pressure determined by applying 29.3.# q+ B( e5 F% X! ~/ P- l% T* a. J
29.2 If a pressure vessel, because of its application, is not covered under the inspection procedures of9 `5 z# y$ ^! L% P
the ASME code, it shall be designed and constructed so that it complies with the requirements in 29.3.. T) p# ^1 S7 {5 o) J4 c, 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, G8 T4 {: |; e1 L* r" V4 h' u
pressure in a vessel containing only a superheated fluid) during normal or abnormal operation shall
: @1 I. i" o, F/ R `7 Dwithstand without bursting or leaking a pressure equal to the highest of the following that is applicable:
$ t/ p$ ^' e% V/ pa) Five times the pressure corresponding to the maximum setting of a pressure-reducing valve
; N+ _; [$ M D Z% h. I, Yprovided as part of the assembly, but no more than five times the marked maximum supply
8 y0 U9 r, ?# r3 J/ Jpressure from an external source and no more than five times the pressure setting of a
9 `3 ^1 y( `1 Q) Z, R1 G1 tpressure-relief device provided as part of the assembly.
4 X8 s k9 o. M4 q: U4 f I/ Lb) Five times the marked maximum supply pressure from an external source, except as
+ V$ d2 ~% s/ d) u+ O: X/ eprovided in (a).7 z* _ w! u1 U n L
c) Five times the pressure setting of a pressure-relief device provided as part of the assembly.
/ o7 T! _1 y- q6 Q: Yd) Five times the maximum pressure that can be developed by an air compressor that is part of
- I. D3 t9 t" |% ?0 a6 Zthe assembly, unless the pressure is limited by a pressure-relief device in accordance with (a).
4 f$ R5 ?- P$ p) }9 Y; De) Five times the working pressure marked on the part.& a9 v( [/ H# h6 [+ }) K6 n
29.4 A test need not be performed to determine whether a part complies with the requirement in 29.3 if
) A$ D5 ~( X( v1 Sstudy and analysis indicate that the strength of the part is adequate for the purpose as a result of its
2 r$ U+ H }% F0 Q6 S; f2 U) Xmaterial and dimensions – for example, copper or steel pipe of standard size and provided with standard. I. x% R! I$ e; `; v! d4 n
fittings might be considered to have adequate strength.7 S8 }0 j0 X) @1 `3 Z- d
29.5 A pressure vessel bearing the ASME code inspection symbol (²H², ²M², ²S², or ²U²) is considered
+ E6 e# ?9 F( D# cto comply with the requirement in 29.3 if the vessel is marked with a value of working pressure not less
: Q J$ |# {! }/ y4 xthan that to which it is subject during normal or abnormal operation.
7 X4 Q% u, e* H: W# b# q29.6 If a test is necessary to determine whether a part complies with the requirement in 29.3, two samples5 f' H+ s8 U3 ~; g. K; u/ U
of the part are to be subjected to a hydrostatic-pressure test. Each sample is to be filled with water as to
$ a8 N4 a1 s5 E$ R0 L; qexclude air and is to be connected to a hydraulic pump. The pressure is to be raised gradually to the
8 d+ u: P; p" M1 q; gspecified test value and is to be held at that value for 1 minute. The results are not acceptable if either `, v0 g" W2 U0 D* \7 m; `
sample bursts or leaks, except as indicated in 29.7.+ r7 n U3 |5 k+ ~+ a
29.7 Leakage at a gasket during the hydrostatic-pressure test is not unacceptable unless it occurs at a2 J0 h( Q, J3 y0 o
pressure 40 percent or less of the required test value." k5 {; Y4 _- j9 Q- _; ]8 T
29.8 A means for relieving pressure shall be provided for all parts in which pressure might be generated
" `* Q/ C& b% z4 d8 r4 xin the event of fire.* V4 {; p6 |4 _/ D9 _% D% P
29.9 Pressure-relief devices (see 29.15), fusible plugs, soldered joints, nonmetallic tubing, or other2 E% ` a7 L) l( E# l
pressure-relief means or the equivalent may be employed to comply with the requirements in 29.8.% J m4 P; Y+ V1 Q7 |# d$ @
29.10 There shall be no shut-off valve between the pressure-relief means and the parts that it is intended
: p, i/ S w% c; D( uto protect.: p: E5 Q( H4 s# N5 [' i3 ^& ?
29.11 A vessel having an inside diameter of more than 3 inches (76.2 mm) and subject to air or steam
. P! p I) y$ s! apressure generated or stored within the appliance shall be protected by a pressure-relief device.# \2 N2 Q' l. P6 _! H) c) \
29.12 The start-to-discharge pressure setting of the pressure-relief device shall not be higher than the0 M# H$ E# O) x" A9 |: u
working pressure marked on the vessel. The discharge rate of the device shall acceptably relieve the/ f0 v, c) o+ |2 t6 K, u v' a
pressure.
; u! E5 |' W ^3 z- y29.13 A pressure-relief device shall comply with all four of the following:
3 ]3 F# F4 ~+ j, o/ E( X* ga) Shall be connected as close as possible to the pressure vessel or parts of the system that it/ `" ?6 u# J# b* s7 b5 j! U R
is intended to protect;
[6 t' L" X0 I7 X" ob) Shall be installed so that it is readily accessible for inspection and repair and cannot be! @7 t8 _3 ^$ ]+ @3 e
readily rendered inoperative;
, }. X. l1 @, U& D4 L" dc) Shall have its discharge opening located and directed so that the risk of scalding is reduced+ c/ ?! k' |& ^* e" C% ^# y
to a minimum; and, c7 Z# b. g$ s
d) Shall have its discharge opening located and directed so that operation of the device does
7 W8 B2 q9 M5 d; m A- e0 Vnot deposit moisture on bare live parts or on insulation or components affected detrimentally by
7 q: R- w: y) t1 ~8 I3 j+ M$ N5 E/ Bmoisture.; c+ d2 V. n2 K' A# ^0 N
29.14 A pressure-relief device having an adjustable setting shall be judged on the basis of its maximum
0 Y9 S1 V8 a0 }, R( C! T7 Csetting unless the adjusting means is sealed at a lower setting.7 w- }. _+ _: K
29.15 A pressure-relief device is considered to be a pressure-actuated valve or rupture member intended: o& {: `" o4 A( Q/ c' W0 B% _
to relieve excessive pressures automatically.
8 B" Z# l A$ \2 t29.16 Where a pressure relief device is required, the control responsible for limiting the pressure in the
. _3 a0 {, u. Nvessel shall be capable of performing under rated load for 100,000 cycles of operation and shall prevent
& ]1 e- ]* J2 j% p7 y% Ethe pressure from exceeding 90 percent of the relief device setting under any condition of normal! I) ?0 {6 ]- V# s% L% F
operation. |
|