1、ANSI/MSS SP-25-2013 Standard Marking System for Valves, Fittings, Flanges, and Unions Standard Practice Developed and Approved by the Manufacturers Standardization Society of the Valve and Fittings Industry, Inc. 127 Park Street, NE Vienna, Virginia 22180-4602 Phone: (703) 281-6613 Fax: (703) 281-66
2、71 E-mail: standardsmss-hq.org www.mss-hq.org MSS STANDARD PRACTICE SP-25 This MSS Standard Practice was developed under the consensus of the MSS Technical Committee 302 and the MSS Coordinating Committee. The content of this Standard Practice is the resulting efforts of competent and experienced vo
3、lunteers to provide an effective, clear, and non-exclusive standard that will benefit the industry as a whole. This MSS Standard Practice describes minimal requirements and is intended as a basis for common practice by the manufacturer, the user, and the general public. The existence of an MSS Stand
4、ard Practice does not in itself preclude the manufacture, sale, or use of products not conforming to the Standard Practice. Mandatory conformance to this Standard Practice is established only by reference in other documents such as a code, specification, sales contract, or public law, as applicable.
5、 MSS has no power, nor does it undertake, to enforce or certify compliance with this document. Any certification or other statement of compliance with the requirements of this Standard Practice shall not be attributable to MSS and is solely the responsibility of the certifier or maker of the stateme
6、nt. “Unless indicated otherwise within this MSS Standard Practice, other standards documents referenced to herein are identified by the date of issue that was applicable to this Standard Practice at the date of approval of this MSS Standard Practice (see Annex C). This Standard Practice shall remain
7、 silent on the validity of those other standards of prior or subsequent dates of issue even though applicable provisions may not have changed.” By publication of this Standard Practice, no position is taken with respect to the validity of any potential claim(s) or of any patent rights in connection
8、therewith. MSS shall not be held responsible for identifying any patent rights. Users are expressly advised that determination of patent rights and the risk of infringement of such rights are entirely their responsibility. In this Standard Practice, all text, notes, annexes, tables, figures, and ref
9、erences are construed to be essential to the understanding of the message of the standard, and are considered normative unless indicated as “supplemental”. All appendices, if included, that appear in this document are construed as “supplemental”. Note that supplemental information does not include m
10、andatory requirements. U.S. customary units in this Standard Practice are the standard; the (SI) metric units are for reference only. This Standard Practice has been substantially revised from the previous 2008 edition. It is suggested that if the user is interested in knowing what changes have been
11、 made, that direct page by page comparison should be made of this document and that of the previous edition. Non-toleranced dimensions in this Standard Practice are nominal unless otherwise specified. Excerpts of this Standard Practice may be quoted with permission. Credit lines should read Extracte
12、d from MSS SP-25-2013 with permission of the publisher, Manufacturers Standardization Society of the Valve and Fittings Industry. Reproduction and/or electronic transmission or dissemination is prohibited under copyright convention unless written permission is granted by the Manufacturers Standardiz
13、ation Society of the Valve and Fittings Industry Inc. All rights reserved. Originally Approved: July 1934 Originally Published: July 1935 Current Edition Approved by MSS: June 2013 Current Edition Approved by ANSI: September 2013 Current Edition Published: January 2014 MSS is a registered trademark
14、of Manufacturers Standardization Society of the Valve and Fittings Industry, Inc. Copyright 2013 by Manufacturers Standardization Society of the Valve and Fittings Industry, Inc. Printed in U.S.A. i MSS STANDARD PRACTICE SP-25 FOREWORD The original publication of the Standard Marking System was deve
15、loped by MSS in 1934. It stated the basic rules but was considered to need more details for general use. A second edition was therefore prepared with additional details and examples and was published in 1936. The third edition, published in 1954, recognized the use of new materials, increased operat
16、ing temperatures and pressures, and added more examples of markings for regular products. In 1958, the fourth edition incorporated relatively minor changes and updates; including some additional marking examples. For the fifth edition, published in 1960, the format was revised to permit the use of n
17、ameplates on valve bodies. In addition, this version added requirements for the marking of ductile iron products. The sixth edition, published in 1964, broadened the scope of this marking standard and revised the examples and sections of the text to reflect changes in piping requirements. The sevent
18、h edition, published in 1978, was substantially revised and re-written to simplify its cross references and to improve readability. This edition incorporated the marking features of pressure-temperature marking designations contained in existing American National Standards involving products and mat
19、erials. It was also rearranged so that the General Rules were stated in Sections 1 through 11 and amplified in Sections 12 through 18; which gave specific rules and examples of marking requirements relating to various products and materials. In 1993, the eighth edition incorporated relatively minor
20、changes and updates; including minor revisions required to harmonize this document with then-current MSS Standard Practices. The tenth edition was published in 2008 and included revisions to ASME B16.34 example markings and mandatory MSS conformance markings, in addition to clarifications of other g
21、eneral requirements. This eleventh edition, published in 2013, includes new Annexes for Reference Tables and Marking Requirement Examples, the addition of laser marking techniques and country of origin marking, substantial revision and re-formatting to update the document text and tables, and other
22、revisions to provide clarification as warranted. This 2013 edition has been approved as an American National Standard. ii MSS STANDARD PRACTICE SP-25 TABLE OF CONTENTS SECTION GENERAL RULES PAGE 1 SCOPE 1 2 GENERAL MARKING REQUIREMENTS 1 3 MANUFACTURERS NAME OR TRADEMARK . 1 4 RATING DESIGNATION 2 5
23、 MATERIAL DESIGNATION 3 6 MELT IDENTIFICATION . 3 7 VALVE TRIM IDENTIFICATION 3 8 SIZE DESIGNATION 4 9 IDENTIFICATION OF THREADED ENDS . 4 10 RING-JOINT FACING IDENTIFICATION 5 11 PERMISSIBLE OMISSION OF MARKINGS . 5 SPECIFIC RULES 12 MARKING REQUIREMENTS FOR FLANGES, FLANGED FITTINGS, AND FLANGED U
24、NIONS . 5 13 MARKING REQUIREMENTS FOR THREADED FITTINGS AND UNION NUTS . 6 14 MARKING REQUIREMENTS FOR WELDING AND SOLDER JOINT FITTINGS AND UNIONS 7 15 MARKING REQUIREMENTS FOR NON-FERROUS VALVES 8 16 MARKING REQUIREMENTS FOR GRAY IRON VALVES 8 17 MARKING REQUIREMENTS FOR DUCTILE IRON VALVES 8 18 M
25、ARKING REQUIREMENTS FOR STEEL VALVES 9 TABLE 1 Common Symbols for Metallic Materials 10 2 Common Symbols for Non-Metallic Materials 10 3 Size Identification and Equivalency: NPS and DN 11 4 Examples of Thread Type Symbols . 11 5 ASME B16.1 Rating Designations . 11 ANNEX A Reference Tables 10 B Marki
26、ng Requirement Examples 12 C Referenced Standards and Applicable Dates 24 iii MSS STANDARD PRACTICE SP-25 This Page Intentionally Left Blank Manufacturers Standardization Society of the Valve and Fittings Industry iv MSS STANDARD PRACTICE SP-25 1. SCOPE 1.1 This standard marking system applies to va
27、lves, fittings, flanges, and unions used in piping connections which include (but are not limited to) flanged, soldered, brazed, threaded, or welded joints. 1.2 The markings specified within this Standard Practice serve to identify the manufacturer, the rating designation, materials of construction,
28、 and special service limitations imposed by the manufacturer. They are used for product identification and to assist in proper application. 2. GENERAL MARKING REQUIREMENTS 2.1 Each product, of a size and shape permitting legible marking, shall be marked in accordance with the provisions of this Stan
29、dard Practice. 2.2 Markings shall be applied to the body of valves, fittings, and the nut of unions, or on an identification plate. For quarter-turn valves, markings shall be applied to the body, identification plate, or handle. Markings on covered quarter-turn valve handles may not be integral with
30、 the base handle material. 2.3 Markings shall consist of numerals, letters, or symbols that are cast, forged, stamped, electro-etched, vibro-etched, laser-etched, or otherwise made integral with the product, or as markings on an identification plate attached to the product, or both. Where stamping i
31、s used on pressure containing walls, low stress stamps which produce a round bottom impression shall be used; such low stress stamps are not required on flanged edges or on raised pads provided for marking purposes. 2.4 Markings indicating conformance with recognized documents, such as the ASME Boil
32、er and Pressure Vessel Codes, or applicable API, FM, and UL conformance, testing, and/or certification requirements, may be applied only by authorized, licensed, or approved manufacturers. Such markings shall be applied only to products fully conforming to the applicable qualification, conformance,
33、and/or certification requirements and may be shown on the body or an attached plate, at the option of the manufacturer. 2.5 Manufacturers may apply markings indicating conformance with codes and standards such as API, ASME, ASTM, AWWA, and MSS, on products that fully conform to the standards. Certai
34、n codes and standards specify mandatory product conformance markings and methods. Such markings may be shown on the body, on an attached plate, or as otherwise specified. 2.6 International and Federal commerce laws may require marking of finished products with country of origin. When required, the m
35、arkings shall be conspicuous and positioned to prevent concealment during use. 2.7 Flow or pressure indication shall be marked on unidirectional valves. Commonly used markings include arrows or the words “inlet” or “outlet” or “high pressure side” marked at an appropriate end. 2.8 Nothing in this St
36、andard Practice shall be construed as prohibiting the use of additional markings such as catalog reference numbers, pattern numbers, patent numbers, dates, customer specification numbers, etc. Product markings that indicate special designs, particular requirements, or special limitations, should als
37、o carry additional special marking to distinguish them from regularly available and standard products. All additional markings shall be applied in such a manner as to avoid confusion with standardized symbols or markings. 3. MANUFACTURERS NAME OR TRADEMARK All valves, fittings, flanges, and unions s
38、hall be marked with the manufacturers (Mfrs) name, trademark, or symbol, unless size or shape does not permit. STANDARD MARKING SYSTEM FOR VALVES, FITTINGS, FLANGES, AND UNIONS 1 MSS STANDARD PRACTICE SP-25 NOTES: (a)CWP (Cold Working Pressure) is the maximum pressure rating allowed under normal “am
39、bient“ temperature conditions, which are usually understood to be -20 F to 100 F (-29 C to 38 C). Certain “ambient“ temperature standards and practices have a different range or are limited by recognized codes and standards. Consult the applicable codes, standards, or manufacturers technical data fo
40、r specific information. Other symbols which are in common usage throughout the industry include: SP Steam pressure WSP Working steam pressure Correspond to SWP S Steam (Steam Working Pressure) WO Water, oil pressure WOG Water, oil, gas pressure GLP Gas, liquid pressure Correspond to CWP WWP Working
41、water pressure (Cold Working Pressure) W Water pressure These markings may be continued in use at the manufacturers option, unless prohibited by codes, standards, or specifications applicable to a particular product. (b)The pressure unit of 1 bar is equal to 14.5 pounds per square inch. The conversi
42、on factor of 1 bar is equal to 100 kilopascals. 4. RATING DESIGNATION 4.1 The expression “Rating Designation” includes the intent of the expressions “Pressure Designation”, “Class Designation”, “Pressure Class”, and similar terms used to define the pressure and temperature limitations of the product
43、. The rating designation shall be shown by one of the systems in the sections that follow. 4.1.1 The rating designation for products that fully conform to recognized standards may be designated by the Class numbers alone (e.g., a steam pressure rating or a pressure class designation). Pressure Ratin
44、g Values may be abbreviated by using “M“ to designate units of one thousand (e.g., “3M” used in place of “3000”). 4.1.2 The rating designation for products that may conform to recognized standards, however, are not suitable for the full range of pressures or temperatures of these standards (where al
45、lowed), shall be marked as prescribed in Section 4.1.3 and 4.1.4, as appropriate, and shall also show the numbers and letters representing the service limitation at the limiting condition. 4.1.3 The rating designation for products that do not conform to recognized product standards may be shown by n
46、umbers and letters representing the pressure ratings at the corresponding temperatures in the following format: “2000 AT 100F 725 AT 925F” The rating designation may also be shown as the maximum pressure followed by “CWP”(a)and the allowed pressure at the maximum temperature, seen in the following f
47、ormat: “2000 CWP 725 AT 925F” Products intended for ambient room temperature may show the allowable pressure followed by letters CWP or equivalent, seen in the following format: “2000 CWP” 4.1.4 Products with dual or multiple rating designations may be marked with maximum pressure at CWP and the all
48、owable pressure at the maximum temperature, seen in the following format: “2000 CWP 725 AT 925 F” 4.2 When marking in (SI) metric notation, the units of preference will be bar(b) or kilopascals (kPa) of gauge pressure, and degrees Celsius for temperature. Numbers designating pressure will be followe
49、d by the term “BAR” or “KPA”, and temperature designation by the letter “C”. Conversion of direct pressure values is permitted, but conversion of pressure classes to “metric equivalents” should not be attempted. 4.3 Products made to attach to a specific pipe may be marked with the appropriate pipe schedule number or pipe wall designation. 4.4 Special markings for rating designation may be specified in individual product standards. 2 MSS STANDARD PRACTICE SP-25 5. MATERIAL DESIGNATION 5.1 Products made of conforming materials shall be marked in a
