1、PFI Standard ES-3 | Denotes Revision (Revised March 2009) FABRICATING TOLERANCES 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 entirely voluntary. Copyright by PIPE FABR
2、ICATION 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 Standard ES-3 | Denotes Revision (Revised Ma
3、rch 2009) FABRICATING TOLERANCES 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 precision of the original quantity and are rounded to the appropriate accura
4、cy. Pipe sizes together with applicable wall thickness 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 are for reference only. Metric units were derived utilizing the follo
5、wing conversion factor: Conversion Factor _ _ inches to 25.4 millimeter 1. Scope 1.1 This standard covers general pipe shop fabricating tolerances for prefabricated piping assemblies. This standard shall not apply to field erected pipe. 2. Linear Tolerances 2.1 The tolerances on linear dimensions (i
6、ntermediate or overall) apply to the face to face, face to end, and end to end measurements of fabricated straight pipe and headers; center to end or center to face of nozzles or other attachments; or center to face of bends; as illustrated on Fig. 1. These tolerances are not accumulative. 2.2 Linea
7、r tolerances on “A” are 1/8“ (3.0 mm) for sizes 10“ and under, 3/16“ (5.0 mm) for sizes 12“ through 24“ and 1/4“ (6.0 mm) for sizes over 24“ through 36“. 2.3 Linear tolerances on “A” for sizes over 36“ are subject to tolerances of 1/4“ (6.0 mm), increasing by plus or minus 1/16“ (2.0 mm) for each 12
8、“ in diameter over 36“. 2.4 Due to the cumulative effects of tolerances on fittings or flanges, when joined without intervening pipe segments, deviations in excess of those specified in paragraphs 2.2 and 2.3 may occur, and are acceptable. 3. Angularity and Rotation Tolerances 3.1 Angularity toleran
9、ce across the face of flanges, weld end preparation and on rotation of flanges are as stated on Fig. 1. 4. Closer Tolerances 4.1 When closer tolerances than those given in paragraphs 2.2, 2.3 and 2.4 are absolutely necessary, they shall be subject to agreement between the Purchaser and Fabricator.PF
10、I Standard ES-3 | Denotes Revision (Revised March 2009) “A“A“A“A“A“A“A“A“A“A“SECTION X-XX XEND PREPARATION FOR WELDSHALL NOT DEVIATE FROMINDICATED POSITION BY MORETHAN 1/32“ (1.0 mm) ACROSSTHE LAND FOR INERT GAS WELDJOINTS OR 3/32“ (3.0 mm) FOROTHER JOINTSFOR BENDING TOLERANCE, MINIMUMRADIUS AND MIN
11、IMUM TANGENT SEEPFI STANDARD ES-24TOLERANCES ON DIMENSIONS WHICH DONOT INCLUDE PIPE SEGMENTS ARE TOBE BASED ON ANSI SPECIFICATIONS FORFITTINGS OR FLANGES INVOLVED(SEE PARAGRAPH 2.4)ROTATION OF FLANGESFROM THE INDICATEDPOSITION MEASURED ASSHOWN, 1/16“ (2.0 mm) MAX.1/8“ (3.0 mm)ALIGNMENT OF FACINGS OR
12、ENDS SHALL NOT DEVIATEFROM THE INDICATEDPOSITION MEASURED ACROSSANY DIAMETER MORE THAN3/64“ PER FOOT (1.0 mm PER25.0 cm) OR 1/32“ (1.0 mm)WHICHEVER IS GREATERFIGURE 1APPLICATION OF PIPE FABRICATION TOLERANCESCURRENT INDEX OF 2014-2015 PFI STANDARDS A complete list of PFI members and available member
13、ship CHARTER MEMBERS CONTRACTOR MEMBERS ASSOCIATE MEMBERS AFFILIATE MEMBERS HONORARY MEMBERS Associate and Affiliate member contributors Walter Sperko Sperko Engineering Services, Inc. Greensboro, NC Thomas Warrelmann Victaulic Company of America Easton, PA Sheryl Michalak Welding Outlets, Inc. Hous
14、ton, 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 considered and reviewed by the Engineering Committee of the Pipe Fabrication Institute to provide re
15、commended 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.
