1、 MSS SP-142-2012 Excess Flow Valves for Fuel Gas Service, NPS 1 through 12 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) 281-6671 E-mail:
2、infomss-hq.org MSS www.mss-hq.org MSS STANDARD PRACTICE SP-142i This MSS Standard Practice was developed under the consensus of the MSS Technical Committee 501 and the MSS Coordinating Committee. The content of this Standard Practice is the resulting efforts of competent and experienced volunteers t
3、o 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 Standard Practi
4、ce 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. MSS has n
5、o 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 statement. “Unles
6、s 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 silent on
7、 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 therewith.
8、 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 references ar
9、e 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 mandatory r
10、equirements. U.S. customary units in this Standard Practice are the standard; SI (metric) units are for reference only. Non-toleranced dimensions in the Standard Practice are nominal, and, unless otherwise specified, shall be considered “for reference only.“ Excerpts of this Standard Practice may be
11、 quoted with permission. Credit lines should read Extracted from MSS SP-142-2012 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 wr
12、itten permission is granted by the Manufacturers Standardization Society of the Valve and Fittings Industry Inc. All rights reserved. Originally Approved: August 2011 Originally Published: November 2011 (2012 Edition) MSS is a registered trademark of the Manufacturers Standardization Society of the
13、Valve and Fittings Industry, Inc. Copyright , 2011 by Manufacturers Standardization Society of the Valve and Fittings Industry, Inc. Printed in U.S.A. MSS STANDARD PRACTICE SP-142ii TABLE OF CONTENTS SECTION PAGE PURPOSE . 1 1 SCOPE 1 2 DEFINITIONS AND ABBREVIATIONS . 1 3 VALVE DESIGNS, TYPES, AND S
14、IZES 2 4 SERVICE PRESSURE-TEMPERATURE RATINGS 2 5 MATERIALS . 2 6 DESIGN 2 7 MARKING . 3 8 DESIGN QUALIFICATION TESTING 3 9 PRODUCTION TESTING REQUIREMENTS . 5 FIGURE A1 Snap-Acting Loads Test Setup . 6 B1 Spring Loaded . 7 B2 Magnetic . 7 B3 Adjustable Spring Loaded 7 B4 Diaphragm 7 B5 Gravity 7 AN
15、NEX A Snap-Acting Loads Test Setup . 6 B Valve Designs Figures B1 through B5 7 C Referenced Standards and Applicable Dates 8 MSS STANDARD PRACTICE SP-1421 PURPOSE To provide a Standard Practice for Excess Flow Valves, NPS 1 through 12, designed for use in fuel gas piping systems to reduce the flow o
16、f gas should the flow in the system exceed some predetermined level. 1. SCOPE 1.1 This Standard Practice covers Excess Flow Valves of pipe size NPS 1 through 12, used in fuel gas piping systems. 2. DEFINITIONS AND ABBREVIATIONS 2.1 Excess Flow Valve (EFV) A device installed in a fuel gas piping syst
17、em having the ability to automatically stop or limit the flow of gas in the event that the flow in the piping system exceeds a predetermined level. 2.1.1 Excess Flow Valve Bypass (EFVB) An EFV which is designed to limit the flow of gas upon closure to a small predetermined level. EFVBs are designed
18、to reset automatically once the piping system downstream is made gas tight and pressure is equalized across the valve. 2.1.2 Excess Flow Valve Non-Bypass (EFVNB) An EFV which is designed to stop the flow of gas upon closure. EFVNBs must be manually reset. 2.2 Closure Flow Rate The predetermined leve
19、l of gas flow through an EFV at a given inlet pressure which causes closure. 2.3 Bleed-by Flow Rate The amount of gas flow at a given inlet pressure through an EFVB after closure. 2.4 Leak Rate The amount of gas flow at a given inlet pressure through an EFVNB after closure. 2.5 EFV Minimum Design In
20、let Pressure The minimum pressure at which the EFV is designed to function, as specified by the manufacturer. 2.6 EFV Maximum Design Inlet Pressure The maximum pressure at which the EFV is designed to function, as specified by the manufacturer. 2.7 Fuel Gas Natural gas, manufactured gas, LP-Gas, and
21、 similar gases commonly used for commercial or residential purposes such as heating, cooling, or cooking. 2.8 Fuel Gas Piping System All pipe, valves, and fittings used for the transmission or distribution of fuel gas. 2.9 Abbreviations Abbreviations of terms used in this Standard Practice are as fo
22、llows: a) EFV Excess Flow Valve b) EFVB Excess Flow Valve Bypass c) EFVNB Excess Flow Valve Non-Bypass d) SCFH Standard Cubic Feet per Hour e) psig pounds per square inch gage pressure f) psia pounds per square inch absolute pressure g) ”w.c. inches water column pressure h) SG Specific Gravity i) CT
23、S Copper Tube Size j) NPS Nominal Pipe Size (U.S. customary) k) F degrees Fahrenheit EXCESS FLOW VALVES FOR FUEL GAS SERVICE, NPS 1 THROUGH 12 MSS STANDARD PRACTICE SP-1422 3. VALVE DESIGNS, TYPES, AND SIZES 3.1 Valve Designs a) Spring Loaded (See Figure B1) (1)b) Magnetic (See Figure B2) (1)c) Adju
24、stable Spring Loaded (See Figure B3) (1)d) Diaphragm (See Figure B4) (1)e) Gravity (See Figure B5) (1)f) Miscellaneous Designs 3.2 Valve Types a) Excess Flow Valve Bypass (EFVB) (See Section 2.1.1) b) Excess Flow Valve Non-Bypass (EFVNB) (See Section 2.1.2) 3.3 Nominal Pipe Sizes EFVs covered herein
25、 are those for use with NPS 1 through 12, or nominal tubing sizes, conforming to one of the following standards: Steel: ASTM A53, ASTM A333, ASTM A106, ASTM A513 Polyethylene: ASTM D2513 3.3.1 Stainless Steel Tubing of austenitic stainless steel alloy of the 300-series shall be used. 4. SERVICE PRES
26、SURE-TEMPERATURE RATINGS 4.1 EFVs covered by this Standard Practice will normally have the following characteristics, except when otherwise agreed upon by purchaser and manufacturer: Note: (1)The figures in Annex B are for the purpose of illustration only. They are not intended to exclude any design
27、 meeting this Standard Practice. 4.1.1 A minimum design inlet pressure of 5”w.c. or greater. 4.1.2 A maximum operating pressure of 125 psig or less. 4.1.3 A minimum temperature rating of -20 F. 4.1.4 A maximum temperature rating of 140 F. 4.2 EFVs shall be capable of withstanding a pressure test of
28、1.5 times the maximum design inlet pressure. 5. MATERIALS 5.1 General Materials used in the manufacture of an EFV shall be compatible with the applicable fuel gas and suitable for the intended purpose. 6. DESIGN 6.1 General All data reported from tests performed in this Standard Practice shall be ba
29、sed on standard conditions of 60 F and 14.7 psia. All flow rates (closure, bleed-by, leak rate, etc.) referred to in this Standard Practice are stated in Standard Cubic Feet per Hour (SCFH) for 0.6 Specific Gravity (SG) Natural Gas unless stated otherwise. Corrections shall be made to data measured
30、at conditions other than those stated above. 6.1.1 All valves for single residential service lines shall comply with U.S. federal regulation 49CFR 192.381 as required in 49CFR 192.383. Supplementary Information: 192.383 contains the U.S. DOT definition for single family residence. 6.2 EFV Closure Fl
31、ow Rate All EFVs shall have a closure flow rate no less than the EFV manufacturers minimum specified closure flow rate and no greater than 50% above the specified minimum closure flow rate at any given operating pressure. MSS STANDARD PRACTICE SP-1423 6.3 EFV Bleed-by or Leak Rate The maximum bleed-
32、by shall comply with Section 6.1.1 7. MARKING 7.1 General Each EFV shall be marked on their outermost surface for installation in accordance with MSS SP-25 with at least the following: a) Manufacturers identification; b) Type of EFV: Bypass (EFVB) or Non-bypass (EFVNB); c) Flow direction arrow; d) N
33、ominal Pipe Size; e) Pressure rating designation; f) Lot identification. 7.2 Optional Markings 7.2.1 Low Pressure (5”w.c. to 5 psig) At the discretion of the manufacturer, additional markings may be applied in accordance with MSS SP-25 and IAS (CSA/IAS) 3-92. 7.2.2 High Pressure (5 psig and above) A
34、t the discretion of the manufacturer, additional markings may be applied in accordance with MSS SP-25. 7.3 Meter Location It is recommended that the manufacturer supply an EFV tag or label which can be affixed at the meter location to identify that an EFV is installed. 8. DESIGN QUALIFICATION TESTIN
35、G 8.1 General This section is intended to provide technical information to users of EFVs on the performance characteristics of a manufacturers valve. The technical information produced from this testing will assist the user in determining the proper application of an EFV. This section is also intend
36、ed to provide specific EFV performance requirements and to outline the testing that shall be performed by user, manufacturer, or other party to evaluate EFVs. 8.2 Apparatus The test apparatus, equipment, and procedure used in performing the outlined tests shall be such that data obtained from the te
37、sts can be confirmed. The following standards shall be referenced when testing to this Standard Practice: Low Pressure (5”w.c. to 5 psig): IAS (CSA/IAS) 3-92, MSS SP-133 High Pressure (5 psig and above): ASTM F1802, ASTM F2138, MSS SP-115 8.3 Orientation Testing is required in each intended mounting
38、 position unless otherwise specified by the manufacturer. Test apparatus and procedures referenced in the above mentioned standards may need to be modified to accommodate manufacturers required valve orientation in positions other than horizontal. 8.4 Lot Size The following tests shall be made by th
39、e manufacturer on a sample of EFVs. The sample size shall be no fewer than three valves. For production lots of fewer than three valves, qualification tests shall be performed on each valve. Each rated minimum closure flow rate model must be design qualified under this section. 8.5 Temperature Testi
40、ng shall be performed at 67 F (+/-10 F). Alternate optional test temperatures are -20 F (+/-10 F), and 140 F (+/-10 F). 8.6 Closure Flow Test EFVs shall be tested at the minimum design inlet pressure. Additional tests at other inlet pressures may be performed. The closure flow rate of the valve shal
41、l be within manufacturers specification and the limits specified in Section 6.2. 8.7 Bleed-by Flow Rate/Leak Rate After Closure Test EFVs shall be tested at the minimum and maximum design inlet pressure. Additional tests at other inlet pressures may be performed. The bleed-by flow rate of the valve
42、shall be within the limits specified in Section 6.1.1 and 6.3. The bleed-by flow rate of the valve shall be within the manufacturers specifications. MSS STANDARD PRACTICE SP-1424 8.8 Pressure Drop Across EFV Tests 8.8.1 Pressure Drop at Flow Rates Less than Closure Pressure drop measurements shall b
43、e taken at the following percentages of the valves minimum closure flow rate at the given inlet test pressure: 10, 20, 30, 40, 50, 60, 70, 80, and 90. Additional tests at inlet pressures and flow rates other than those listed here may be performed. The pressure drop values shall be within manufactur
44、ers specifications. 8.8.1.1 EFVs shall be tested per Section 8.8.1 at the minimum design inlet pressure. Examples include: a) If a valves minimum design inlet pressure is 40 psig and its minimum closure flow rate at 40 psig is 10000 SCFH, then pressure drop measurements at 40 psig inlet pressure sha
45、ll be taken at 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, and, 9000 SCFH. b) If a valves minimum design inlet pressure is 5 psig and its minimum closure flow rate at 5 psig is 1800 SCFH, then pressure drop measurements at 5 psig inlet pressure shall be taken at 180, 360, 540, 720, 900, 1080, 12
46、60, 1440, and 1620 SCFH. 8.8.2 Pressure Drop just Prior to Closure The maximum obtainable pressure drop across the valve prior to closure shall be measured. This reading may be taken at a flow rate equal to a minimum of 99% of the manufacturers specified minimum closure flow rate. The pressure drop
47、values shall be within manufacturers specifications. 8.8.2.1 EFVs shall be tested per Section 8.8.2 at the minimum inlet pressure. Additional tests at other inlet pressures may be performed. 8.9 Valve Resetability Tests 8.9.1 EFVs shall be capable of resetting after closure, as per manufacturers pro
48、cedure. EFVs shall be tested at the minimum and maximum design inlet pressure. Additional tests at other inlet pressures may be performed. Snap-Acting Loads Test Procedure: See Annex A for test setup. A test apparatus shall be assembled and consist of the following components, in order: (1) Inlet su
49、pply connections to EFV, no more than 60 ft. (18.3 m) of NPS pipe of the same diameter size as the EFV being tested; (2) Full port quarter (1/4) turn ball valve or equivalent, no more than 2 ft. (0.6 m) of pipe or tubing of the same outlet diameter as the EFV being tested; (3) A flow control valve, no more than 4 ft. (1.2 m) of pipe or tubing of the same outlet diameter as the EFV being tested; and (4) A flow meter venting to atmosphere. The inlet pressure shall be 10 psig (0.07 Mpa). With ball valve open, set the f
