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ASME B31.3-2016 <br /> Fig. 304.3.4 Extruded Outlet Header Nomenclature (Cont'd) <br /> This Figure illustrates the nomenclature of para. 304.3.4. It does not indicate complete details or a preferred <br /> method of construction. <br /> Branch pipe <br /> T �b or nozzle <br /> b d <br /> b <br /> t Limits of <br /> b 7rv, <br /> reinforcement <br /> A3 A3 zone <br /> \1 /I T <br /> A4 _ A4 <br /> L5 Extruded outlet <br /> rx <br /> hx dx <br /> Required area Header <br /> Th th Tx At =K(th) (dx) <br /> A2 p`2 <br /> Dh dh I_ d2 d2 �I <br /> Mill tolerance <br /> GENERAL NOTE: Sketch is drawn for condition where K= 1.00 and dx<db. <br /> (d) <br /> (h) Identification. The manufacturer shall establish the of tee fittings or complete encirclement types of <br /> design pressure and temperature for each extruded out- reinforcement. <br /> let header and shall mark the header with this informa- (c) Adequate flexibility shall be provided in a small <br /> tion, together with the symbol "B31.3" (indicating the line that branches from a large run, to accommodate <br /> applicable Code Section) and the manufacturer's name thermal expansion and other movements of the larger <br /> or trademark. line (see para. 319.6). <br /> 304.3.5 Additional Design Considerations. The (d) If ribs, gussets, or clamps are used to stiffen the <br /> requirements of paras. 304.3.1 through 304.3.4 are branch connection,their areas cannot be counted as con- <br /> intended to ensure satisfactory performance of a branch tributing to the reinforcement area determined in <br /> connection subject only to pressure. The designer shall para. 304.3.3(c) or 304.3.4(f). However, ribs or gussets <br /> also consider the following: may be used for pressure-strengthening a branch con- <br /> (a) In addition to pressure loadings, external forces nection in lieu of reinforcement covered in paras.304.3.3 <br /> and movements are applied to a branch connection by and 304.3.4 if the design is qualified as required by <br /> thermal expansion and contraction,dead and live loads, para. 304.7.2. <br /> and movement of piping terminals and supports.Special (e) For branch connections that do not meet the <br /> consideration shall be given to the design of a branch requirements of para.304.3.1(b),integral reinforcement, <br /> connection to withstand these forces and movements. complete encirclement reinforcement,or other means of <br /> (b) Branch connections made by welding the branch reinforcement should be considered. <br /> pipe directly to the run pipe should be avoided under 304.3.6 Branch Connections Under External <br /> the following circumstances: Pressure. Pressure design for a branch connection sub- <br /> (1) when branch size approaches run size,particu- jected to external pressure may be determined in accor- <br /> larly if pipe formed by more than 1.5%cold expansion, dance with para. 304.3.1, using the reinforcement area <br /> or expanded pipe of a material subject to work harden- requirement stated in para. 304.3.3(b). <br /> ing,is used as the run pipe <br /> (2) where repetitive stresses may be imposed on 304.4 Closures <br /> the connection by vibration,pulsating pressure,temper- <br /> ature cycling, etc. 304.4.1 General <br /> In such cases, it is recommended that the design be (a) Closures not in accordance with para. 303 or <br /> conservative and that consideration be given to the use 304.4.1(b)shall be qualified as required by para.304.7.2. <br />