1、 PFI Standard ES-7 |Denotes Revision (Revised December 2013) MINIMUM LENGTH AND SPACING FOR WELDED BRANCH CONNECTIONS Prepared by Pipe Fabrication Institute Engineering Committee All PFI Standards are advisory only. There is no agreement to adhere to any PFI Standard and their use by anyone is entir
2、ely voluntary. Copyright by PIPE FABRICATION INSTITUTE Dedicated to Technical Advancements and Standardization in the Pipe Fabrication Industry Since 1913 USA 511 Avenue of Americas, # 601 New York, NY 10011 CANADA 655, 32ndAvenue, # 201 Lachine, QC H8T 3G6 WEB SITE www.pfi-institute.org PFI Standar
3、d ES-7 |Denotes Revision (Revised December 2013) MINIMUM LENGTH AND SPACING FOR WELDED BRANCH CONNECTIONS METRIC CONVERSIONS The conversion of quantities between systems of units involves a determination of the number of significant digits to be retained. All conversions depend upon the intended pre
4、cision of the original and are rounded to the appropriate accuracy. Pipe sizes together with applicable wall thicknesses are not shown with metric equivalents. The SI (metric) values where included with the customary U. S. values in this Standard are the rounded equivalents of the U. S. values and a
5、re for reference only. Metric units were derived utilizing the following conversion factor: Conversion Factor inches to millimeter 25.4 1. Scope 1.1 This Standard covers the minimum recommended branch connection length, branch connection distance from open end on run, and spacing dimensions of adjac
6、ent welded branch connections. 2. Branch Connection s without Saddles or Reinforcement 2.1 The branch connection spacings are based on practical access requirements for fit-up, welding and examination. Dimensions recommended for branch connections without saddles or reinforcements are as shown in Fi
7、g. l and Table l. 3. Branch Connections with Reinforcing Saddles or Rings 3.1 Dimensions recommended for branch connections with saddles or rings are as shown in Fig. 2 and Table 2. 4. Branch Connections Integrally Reinforced 4.1 Dimensions recommended for integrally reinforced branch connections ar
8、e as shown in Fig. 3 and Table 3. These dimensions do not apply to integrally reinforced insert butt weld branch connections. 5. Design Considerations 5.1 Certain materials and combinations of branch connection and header pipe size and wall thickness together with multiple branch openings welded to
9、a header may result in distortion of the header pipe. The elimination or reduction of such distortion is beyond the scope of this Standard. For some recommendations to reduce or eliminate such distortion refer to PFI standard ES-49. 5.2 All branch connection welds should be checked for compliance wi
10、th the applicable Code requirements. 5.3 It is preferred that multiple branch openings of in-line branch connections be spaced so that their reinforcement zones do not overlap. If closer spacing is necessary, the reinforcement requirements of the applicable construction Code shall be met. 5.4 Some c
11、onfigurations of integrally reinforced branch connections in combination with certain header sizes may present a problem in the radiographic examination of the attachment weld due to inability to meet the geometric unsharpness requirements of the construction Code. 5.5 Where attachments such as flan
12、ges, fittings, valves and pipe insulation are involved, minimum dimensions tabulated may have to be increased to allow for required clearances. 5.6 In special cases, it may be possible to reduce the dimensions given in the tabulation. Such design should then be submitted to the fabricator for indivi
13、dual consideration, as close spacing may involve additional shop operations to prevent, or correct distortion. PFI Standard ES-7 |Denotes Revision (Revised December 2013) 5.7 Integrally reinforced branch connections are considered to be the commercially available types. 5.8 In cases of different bra
14、nch connection diameters, dimension “C“, (Fig. A complete list of PFI members and available membership CHARTER MEMBERS CONTRACTOR MEMBERS ASSOCIATE MEMBERS AFFILIATE MEMBERS HONORARY MEMBERS Associate and Affiliate member contributors Walter Sperko Sperko Engineering Services, Inc. Greensboro, NC Th
15、omas Warrelmann Victaulic Company of America Easton, PA Sheryl Michalak Welding Outlets, Inc. Houston, TX PFI Standards and Technical Bulletins are published to serve proven needs of the pipe fabricating industry at the design level and in actual shop operations. Hence, such needs are continually co
16、nsidered and reviewed by the Engineering Committee of the Pipe Fabrication Institute to provide recommended procedures, which have been demonstrated by collective experiences to fulfill requirements in a manner for Code compliance. However, as the PFI Standards are for minimum requirements the designer or fabricator always has the option of specifying supplementary conditions in the form of requirements beyond the scope of the PFI publications.
