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ASME 1331.3-2016
<br /> Table 304.4.1 BPV Code References for Closures (d) The total cross-sectional area required for rein-
<br /> Concave to Convex to forcement in any given plane passing through the center
<br /> Type of Closure Pressure Pressure of the opening shall not be less than that defined in
<br /> UG-37(b), UG-38, and UG-39.
<br /> Ellipsoidal UG-32(d) UG-33(d) (e) The reinforcement area and reinforcement zone
<br /> Torispherical UG-32(e) UG-33(e) shall be calculated in accordance with para. 304.3.3 or
<br /> Hemispherical UG-32(f) UG-33(c)
<br /> Conical (no transition UG-32(g) UG-33(0 304.3.4,considering the subscript h and other references
<br /> to knuckle) to the run or header pipe as applying to the closure.
<br /> Toriconical UG-32(h) UG-33(0 Where the closure is curved,the boundaries of the rein-
<br /> Flat (pressure on UG-34 forcement zone shall follow the contour of the closure,
<br /> either side) and dimensions of the reinforcement zone shall be mea-
<br /> sured parallel to and perpendicular to the closure
<br /> GENERAL NOTE: Paragraph numbers are from the BPV Code,Section surface.
<br /> VIII, Division 1.
<br /> (f) If two or more openings are to be located in a
<br /> closure, the rules in paras. 304.3.3 and 304.3.4 for the
<br /> (b) For materials and design conditions covered reinforcement of multiple openings apply.
<br /> therein, closures may be designed in accordance with (g) The additional design considerations for branch
<br /> the rules in the BPV Code,Section VIII,Division 1,calcu- connections discussed in para. 304.3.5 apply equally to
<br /> lated from eq. (13) openings in closures.
<br /> tm = t+c (13) 304.5 Pressure Design of Flanges and Blanks
<br /> where 304.5.1 Flanges — General
<br /> c = sum of allowances defined in para. 304.1.1 (a) Flanges not in accordance with para. 303, or
<br /> t = pressure design thickness, calculated for the 304.5.1(b) or (d), shall be qualified as required by
<br /> type of closure and direction of loading,shown para. 304.7.2.
<br /> in Table 304.4.1, except that the symbols used (b) A flange may be designed in accordance with the
<br /> to determine t shall be as follows: BPV Code, Section VIII, Division 1, Appendix 2, using
<br /> E = same as defined in para. 304.1.1 the allowable stresses and temperature limits of the B31.3
<br /> P = design gage pressure Code.Nomenclature shall be as defined in Appendix 2,
<br /> S = S times W,with S and W as defined in except as follows:
<br /> para. 304.1.1 P = design gage pressure
<br /> t,,, = minimum required thickness, including SQ = bolt design stress at atmospheric temperature
<br /> mechanical, corrosion, and erosion allowance Sb = bolt design stress at design temperature
<br /> Sf = product SEW [of the stress value S,the appro-
<br /> 304.4.2 Openings in Closures priate quality factor E from Table A-IA or A-113,
<br /> (a) The rules in paras.304.4.2(b)through(g)apply to and weld joint strength reduction factor in
<br /> openings not larger than one-half the inside diameter accordance with para. 302.3.5(e)] for flange or
<br /> of the closure as defined in Section VIII, Division 1, pipe material. See para. 302.3.2(e).
<br /> UG-36. A closure with a larger opening should be
<br /> designed as a reducer in accordance with para. 304.6 (c) The rules in (b) above are not applicable to a
<br /> or, if the closure is flat, as a flange in accordance with flanged joint having a gasket that extends outside the
<br /> para. 304.5. bolts (usually to the outside diameter of the flange).
<br /> (b) A closure is weakened by an opening and,unless (d) For flanges that make solid contact outside the
<br /> the thickness of the closure is sufficiently in excess of bolts, Section VIII, Division 1, Appendix Y should be
<br /> that required to sustain pressure,it is necessary to pro- used.
<br /> vide added reinforcement. The need for and amount of (e) See Section VIII, Division 1,Appendix S,for con-
<br /> reinforcement required shall be determined in accor- siderations applicable to bolted joint assembly
<br /> dance with the subparagraphs below except that it shall
<br /> be considered that the opening has adequate reinforce- 304.5.2 Blind Flanges
<br /> ment if the outlet connection meets the requirements in (a) Blind flanges not in accordance with para. 303 or
<br /> para. 304.3.2(b) or (c). 304.5.2(b)shall be qualified as required by para.304.7.2.
<br /> (c) Reinforcement for an opening in a closure shall (b) A blind flange may be designed in accordance
<br /> be so distributed that reinforcement area on each side with eq. (14). The minimum thickness, considering the
<br /> of an opening(considering any plane through the center manufacturer's minus tolerance,shall be not less than t,,,
<br /> of the opening normal to the surface of the closure)will
<br /> equal at least one-half the required area in that plane. tm = t +c (14)
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