1、i/.d I MSS SP-25-1998 Standard Marking System for Valves,Fittings,Flanges and Unions Standard Practice Developed and Approved b!y the Manufacturers Standardization Society of the Valve and Fittings Industry,Inc.127 Park Street,NE Vienna,Virginia 221 80(703)281-661 3 COPYRIGHT Manufacturers Standardi
2、zation Society of the Valve and FittingsLicensed by Information Handling ServicesCOPYRIGHT Manufacturers Standardization Society of the Valve and FittingsLicensed by Information Handling ServicesMSS STANDARD PRACTICE SP-25 An MSS Standard Practice is intended as a basis for common practice by the ma
3、nufacturer,the user,and the general public.The existence of an MSS Standard Practice does not in itself preclude the manufacture,sale,or use of products not conforming to the Standard Practice.Mandatory conformance is established only by reference in a code,specification,sales contract,or public law
4、,as applicable.Unless otherwise specifically noted in this MSS SP,any standard referred to herein is identified by the date of issue that was applicable to the referenced standard(s)at the date of issue of this MSS SP.See Annex A.US.customary units in this SP are the standard;the metric units are fo
5、r reference only.I Substantive changes in this 1998 edition are“flagged”by parallel bars as shown on the margins of this paragraph.The specific details of the changes may be determined by comparing the material flagged with that in the previous edition.I Any part of thk standardmqy be quoted Credit
6、lines shouldread Extractedfrom MSS SP-25-1998,with permission of the publisher,the Manufacturers Standardization Society.Reproduction prohibited under copyright convention unless written permission is granted by the Manufacturers Standardization Society of the Valve and Fittings Industry,Inc.Origina
7、lly approved July,1934 Copyright 0,1978 by Manufacturers Standardization Society of the Valve and Fittings Industry,Inc.Printed in U.S.A.1 i COPYRIGHT Manufacturers Standardization Society of the Valve and FittingsLicensed by Information Handling ServicesCOPYRIGHT Manufacturers Standardization Socie
8、ty of the Valve and FittingsLicensed by Information Handling ServicesMSS STANDARD PRACTICE SP-25 FOREWORD The initial issue of the Standard Marking System was made by the Manufacturers Standardization Society in 1934.It stated the.basic rules but was considered to need more details for general use.A
9、 second edition was therefore prepared with additional details and exam,ples and was published in 1936.The third edition,in 1954,recogniied the use of new materials,increased operating temperatures and pressures and added more examples of markings for regular products.In 1958,the fourth edition inco
10、rporated relatively minorchangesand updates 1 and included some additional examples.The format was revised for the fifth edition in 1960.It permitted the use of nameplates on valve bodies,and added requirements for making ductile iron products.The 1964 edition broadened the scope of the Marking Stan
11、dard Practice and revised the examples and sections of the text to reflect changes in piping requirements.The seventh edition in 1978 was completely revised and rewritten to simplify its cross references and to improve its readability.It also incorporated the marking features of pressure-temperature
12、 marking designations contained in American National Standards on products and materials.Itwas rearranged so that the General Rules were stated in Sections 1 to 11.These were.amplified in Sections 12 to 18 which gave specific rules and examples of marking requirements for various products and materi
13、als.In 1993,the eighth edition incorporated relatively minor changes and updates.This 1998 ninth edition includes minor revisions required per current MSS practices.1 1 i COPYRIGHT Manufacturers Standardization Society of the Valve and FittingsLicensed by Information Handling ServicesCOPYRIGHT Manuf
14、acturers Standardization Society of the Valve and FittingsLicensed by Information Handling ServicesMSS STANDARD PRACTICE SP-25 TABLE OF CONTENTS SECTION PAGE TERMS AND CONDITIONS.i FOREWORD U TABLE OF CONTENTS.u1.GENERAL RULES I SCOPE.1 2 GENERAL MARKING REQUIREMENTS.1 3 MANUFACTURERS NAME OR TRADEM
15、ARK.1 4 RATING DESIGNATION.2 5 MATERIAL DESIGNATION.3 6 MELT IDENTIFICATION.4 7 VALVE TRIM IDENTIFICATION.4 8 SIZEDESIGNATION.5 9 IDENTIFICATION OF THREADED ENDS.6 11 PERMISSIBLE OMISSION OF MARKINGS.7 10 RING-JOINT FACING IDENTIFICATION.6 SPECIFIC 12 13 14 15 16 17 18 RULES MARKING REQUIREMENTS FOR
16、 FLANGES.FLANGED FITTINGS.AND FLANGEDUNIONS.7 MARKING REQUIREMENTS FOR THREADED FITTINGS AND UNION NUTS.10 MARKING REQUIREMENTS F0 WELDING AND SOLDER JOINT FITIINGS AND UNIONS.13 MARKING REQUIREMENTS FOR NON-FERROUS VALVES.15 MARKING REQUIREMENTS FOR CAST IRON VALVES.15 MARKING REQUIREMENTS FOR DUCT
17、ILE IRON VALVES.16 MARKING REQUIREMENTS FOR STEEL VALVES.17 TABLE 1.COMMON SYMBOLS FOR METALLIC MATERIALS.3 2.COMMON SYMBOLS FOR NON-METALLIC MAATERIALS.4 I 3.SIZE IDENTIFICATION-NOMINAL DIAMETER.5 4.EXAMPLES OF THREADED TYPE SYMBOLS.6 5.ASME/ANSI B16.1 RATING RATING MARKINGS.7 ANNEX A REFERENCED ST
18、ANDARDS AND APPLICABLE DATES.23.1 1 1 COPYRIGHT Manufacturers Standardization Society of the Valve and FittingsLicensed by Information Handling ServicesCOPYRIGHT Manufacturers Standardization Society of the Valve and FittingsLicensed by Information Handling ServicesMSS STANDARD PRACTICE SP-25 STANDA
19、RD MARKING SYSTEM FOR VALVES,FITTINGS,FLANGES AND UNIONS 1-SCOPE 1.1 This marking system applies to valves,fittings,flanges,and unions used in piping connections which include(but are not limited to)flanged,soldered,brazed,threaded,or welded joints.1.2 mese specified markings serve to iden-tify the
20、manufacturer,the rating designation,materials of construction 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 per-mitting legible marking shall
21、 be marked in accordance with the provisions of this Stan-dard Practice.2.2 Markings shall be applied to the body of valves,fittings and the nut of onions or on an identification plate.For quarter turn valves,markings shall be applied to the body,identifi-cation plate,or handle.Markings on covered q
22、uarter turn valve handles do not need to be integral with the base handle material.I The markings shall consist of numerals,letters,or symbols cast,forged,stamped,or otherwise made integral.with the product;or markings on an identification plate attached to the product;or -both.Where stamping is use
23、d on pressure-containing walls,low stress stamps which pro-duce 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.I Markings obliterated during manufacturing of steel products may be rephced by weld deposi
24、-tion or welded plates when permitted,or stamp-ing,at the option of the manufacturer.2.3 Markings indicating conformance with recognized documents such as ASME Boiler Pressure Vessel Codes,API,Factory Mutual,and Underwriters Laboratories may be applied only by authorized,licensed,or approved manufac
25、turers.Such markings shall be applied only to products fully conforming to the code qualification requirements,and may be shown on the body or an attached plate,at the option of the manufacturer.2.4 Manufacturers may apply markings indi-cating conformance with codes and standards such as ANSI,ASME,M
26、SS,AWWA,for example,on products which fully conform,to the standards.Such markings may be shown on the body or on an attached plate.2.5 Nothing in this Standard Practice shall be construed as prohibiting the use of addi-tional markings such as “Made in U.S.A.”,catalog reference numbers,pattern numbe
27、rs,patent numbers,dates,customer specification numbers,etc.Product markings indicating special designs,particular requirements,or specific limitations,should also carry addi-tional special marking to distinguish them from regularly available standard products.All additional markings shall be applied
28、 in such a manner as to avoid confusion with standard markings.2.6 Flow direction 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.I I 3.MANUFACTURERS NAME OR TRADEMARK All produc
29、ts within the scope of this Stan-dard shall be marked with the Manufac-turers name,trademark,or symbol,unless size or shape do not permit.-1-COPYRIGHT Manufacturers Standardization Society of the Valve and FittingsLicensed by Information Handling ServicesCOPYRIGHT Manufacturers Standardization Socie
30、ty of the Valve and FittingsLicensed by Information Handling ServicesSTD.MSS SP-25-ENGL 1798 H 5770bllU 0501031 557 MSS STANDARD PRACXICE SP-25 4.RATING DESIGNATION 4.1 The expression“Rating Designation”includes the intent of the expressions“Pres-sure Designation”,“Service Designation”,“Pressure Cla
31、ss”,and similar terms used to de-fme the pressure/fluid/materials temperature limitation of the product.The Rating Desig-nation shall be shown by one of the systems in the paragraphs that follow.4.1.1 The Rating Designation for products may be designated by the class numbers alone,e.g.,a steam press
32、ure rating or a pressure class designation.Pressure Rating Values may be abbreviated by using“M”to designate units of one thousand(for example,3M in place of 3000).4.1.2 The Rating Designation for products which conform to recognized standards,but are not suitable for the full range of pressures or
33、temperatures of those standards may be marked as prescribed in Subsection 4.1.1 as appropriate and shall also show the numbers and letters representing the pressure rating at the limiting condition.NOTES:4.1.3 The Rating Designation for products which do not conform to recognized national product st
34、andards may be shown by numbers and letters representing the pressure ratings at maximum and minimum temperatures.If desired,the rating designation may be shown as the maximum pressure followed by“CWP”and the allowed pressure at the maxi-mum temperature (for example,2000 CWP 725/925 F).Products inte
35、nded for ambient Toom temperature may show the allowable pressure followed by letters CWP or equiv-alent (see ndte(a).4.2 For applications where marking in metric or SI notation is required,the units of preference will be bar or kilopascals(kPa)of gauge pressure and degrees Celsius.Numbers desig-nat
36、ing pressure will be followed by the term,“bar or kPa”,and temperature designation by the letter,“C”.Conversion,of direct pressure values is permitted(see note(b)j,but conversion of ANSI classes to“metric equivalents”should not be attempted.4.3 Products made to attach to specific pipe may be marked
37、with the appropriate pipe schedule number or pipe wall designation.(a)CWP(Cold Working Pressure)is the maximum pressure rating allowed under normal“ambient”temperature conditions,which are Usually understood to be-20F to 100F(-29C to 38C).Certain“ambient temperature”standards and practices have a di
38、fferent range or are limited by recognized Codes and Standards.Consult the applicable Codes,Standards,or Manufacturers Technical Data for specific infor-mation.Other symbols which are in common usage throughout the industry include:SP-Steam pressure WSP-Working steam pressure Correspond to SWP s-ste
39、am(Steam Working Pressure)WO-Water,Oil pressure OWG-Oil,water,gas pressure 1 WOG-Water,oil,gas pressure GLP-Gas.liauidmessure)Correspond to CWP WWP-Working waterpressure W-Water pressure.-These m k i R p s may be continued in use at the manufacturers option unless prohibited by Codes,Standards,or Sp
40、ecifications applicable to a particular product.Applicable symbols listed in this Note may be substituted for those used in the statements and examples in this Standard I ib)The pressure unit of 1 bar is equal to 14.5 pounds per square inch.The conversion factor of 1 bar i s equal to 100 kilopascals
41、.1-2-COPYRIGHT Manufacturers Standardization Society of the Valve and FittingsLicensed by Information Handling ServicesCOPYRIGHT Manufacturers Standardization Society of the Valve and FittingsLicensed by Information Handling ServicesSTD-MSS SP-25-ENLL 3778 577Db40 0503032 495 STANDARD PRACTICE SP-25
42、 MSS 4.4 Special markings for Rating Designa-and C 84400,cast copper alloy threaded or tion may be specified in individual product solder-joint fittings,flanges,unions,valves,or standards.on wrought copper solder-joint products.1 I 5.MATERIAL DESIGNATION 5.1 Products made of conforming materials sha
43、ll be marked in accordance with ASTM,ASME,or other recognized materials speci-fications,as described in the Product Marking sections which follow.In a composite struc-ture made of several materials,the material which must be marked is the one which is most important to its pressure-temperature ratin
44、g.Products may be marked instead with proprietary materials designations,provided confusion is avoided with nationally recog-nized material standards symbols,and provided confusion is avoided with other sections of this Standard Practice.5.4 Material marking is not required for gray iron,except as s
45、hown in subsection 12.2.Alloyed gray iron may be identified by a manufacturers symbol provided that confusion with standard symbols is avoided.5.5 The symbols for metals shown in Table 1 are in common use and may be used as standard references for marking nameplates and bodies.Non-ferrous body mater
46、ials may be marked with the symbols shown.Products with steel bodies shall be marked with the ASTM specification grade identification symbol.Other symbols including manufac-turers tradenames and material codes are permitted if confusion is avoided with stan-dard symbols.5.2 Products made of one mate
47、rial and lined 5.6 The non metallic symbols,shown in Table with another shall carry the regular markings 2,are typical.The use of specific names and specified by this Standard Practice and tradenames is also permitted if confusion is additional markings which indicate that the avoided with standard
48、symbols.For valves product is lined and state the material used trimmed with composite construction ele-for lining.ments,the dominant functional material 5.3 Material markings are not required on ASTM B 61,B 62 and B 584 alloys,C 83800 I I should be named.TABLE 1-COMMON SYMBOLS FOR METALLIC MATERIAL
49、S Aluminum.AL Brass.BRS Bronze.BRZ Carbon Steel.CS Gray Iron.GI Copper-Nickel Alloy.CU31 Ductile Iron.DI Hardfacing.HF Integral Seats.INT Malleable Iron.MI Nickel-Copper Alloy.NI CU Soft Metal(for example,lead babbitt,copper,etc.).SM Stainless Steel.SS Steel,13 Chromium.CR 13 Steel,18 Chromium.CR 18
50、 Steel,28 Chromium.CR28 Steel,18-8.18-8 Steel,18-8 with Molybdenum.18-8SM0 Steel,18-8 with Columbium.18-8SCB Surface Hardened Steel(for example nitrided surfaces).SH-3-COPYRIGHT Manufacturers Standardization Society of the Valve and FittingsLicensed by Information Handling ServicesCOPYRIGHT Manufact
