1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL UL 1478A Pressure Relief Valves for Sprinkler Systems STANDARD FOR SAFETYUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM ULUL COPYRIGHTED
2、 MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL UL Standard for Safety for Pressure Relief Valves for Sprinkler Systems, UL 1478A First Edition, Dated May 20, 2013 Summary of Topics This revision of ANSI/UL 1478A is being issued to update the title page t
3、o reect reaffirmation of ANSI approval. Text that has been changed in any manner or impacted by ULs electronic publishing system is marked with a vertical line in the margin. The requirements are substantially in accordance with Proposal(s) on this subject dated June 16, 2017. All rights reserved. N
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8、chasers computer system. The following table lists the future effective dates with the corresponding reference. Future Effective Dates References May 20, 2015 Entire Standard AUGUST 4, 2017 UL 1478A tr1UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION
9、 FROM UL AUGUST 4, 2017 UL 1478A tr2 No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL MAY 20, 2013 (Title Page Reprinted: August 4, 2017) 1 UL 1478A Standard for Pressure Relief Valves for Sprinkler Systems Prior to the rs
10、t edition, the requirements for the products covered by this standard were included in the Outline of Investigation for Pressure Relief Valves for Sprinkler Systems, Subject 1478A. First Edition May 20, 2013 This ANSI/UL Standard for Safety consists of the First Edition including revisions through A
11、ugust 4, 2017. The most recent designation of ANSI/UL 1478A as a Reaffirmed American National Standard (ANS) occurred on August 4, 2017. ANSI approval for a standard does not include the Cover Page, Transmittal Pages, and Title Page. Comments or proposals for revisions on any part of the Standard ma
12、y be submitted to UL at any time. Proposals should be submitted via a Proposal Request in ULs On-Line Collaborative Standards Development System (CSDS) at https:/. ULs Standards for Safety are copyrighted by UL. Neither a printed nor electronic copy of a Standard should be altered in any way. All of
13、 ULs Standards and all copyrights, ownerships, and rights regarding those Standards shall remain the sole and exclusive property of UL. COPYRIGHT 2017 UNDERWRITERS LABORATORIES INC. ANSI/UL 1478A-2013 (R2017)UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERM
14、ISSION FROM UL AUGUST 4, 2017 PRESSURE RELIEF VALVES FOR SPRINKLER SYSTEMS - UL 1478A 2 No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL CONTENTS INTRODUCTION 1 Scope .4 2 Components 4 3 Units of Measurement .4 4 Glossary
15、.5 CONSTRUCTION 5 Sizes 5 6 Use and Set Pressure .5 7 Materials .6 PERFORMANCE 8 General 6 9 Elastomeric Parts (Except Gaskets) Test 6 10 Leakage Test 7 11 Hydrostatic Strength and Body Leakage Test .7 12 Relief Valve Operation, Flow Capacity and Reseat Tests .7 13 Spring Cycling Test 8 14 Contamina
16、ted-water Cycle Test 8 15 10-Day Moist Ammonia Air Stress Cracking Test 9 MANUFACTURING AND PRODUCTION TESTS 16 General .9 MARKING 17 General 10 INSTRUCTIONS 18 General 10 MAY 20, 2013 PRESSURE RELIEF VALVES FOR SPRINKLER SYSTEMS - UL 1478A 3UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODU
17、CTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL INTRODUCTION 1 Scope Section 1 effective May 20, 2015 1.1 These requirements cover pressure relief valves intended for use in sprinkler systems for re protection service to relieve excessive pressures caused by thermal expansion, downstream of a press
18、ure reducing valve or in valve trim. 1.2 Requirements for installation of these valves are included in the Standard for the Installation of Sprinkler Systems, NFPA 13. 2 Components Section 2 effective May 20, 2015 2.1 Except as indicated in 2.2, a component of a product covered by this standard shal
19、l comply with the requirements for that component. 2.2 A component is not required to comply with a specic requirement that: a) Involves a feature or characteristic not required in the application of the component in the product covered by this standard; or b) Is superseded by a requirement in this
20、Standard. 2.3 A component shall be used in accordance with its recognized rating established for the intended conditions of use. 2.4 Specic components are recognized as being incomplete in construction features or restricted in performance capabilities. Such components are intended for use only unde
21、r limited conditions, such as certain temperatures not exceeding specied limits, and shall be used only under those specic conditions for which they have been recognized. 3 Units of Measurement Section 3 effective May 20, 2015 3.1 If a value for measurement is followed by a value in other units in p
22、arentheses, the rst stated value is the requirement. MAY 20, 2013 PRESSURE RELIEF VALVES FOR SPRINKLER SYSTEMS - UL 1478A 4UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 4 Glossary Section 4 effective May 20, 2015 4.1 For the purpose of thi
23、s standard the following denitions apply. 4.2 OPENING PRESSURE The internal pressure at which the relief valve is intended to start to allow the ow of water. 4.3 RESEATING PRESSURE The internal pressure at which the relief valve is intended to prevent the ow of water. 4.4 SET PRESSURE The pressure v
24、alue marked on the valve which represents the pressure at which the valve is intended to relieve pressure from a water supply system. CONSTRUCTION 5 Sizes Section 5 effective May 20, 2015 5.1 The inlet shall have a nominal 1/2-inch size or larger male or female NPT pipe thread in accordance with the
25、 Standard for Pipe Threads, General Purpose (Inch), ANSI/ASME B1.20.1 or other suitable means of connection such as a grooved end. Exception: Valves with threaded tting ends intended for use in installations where ttings incorporate pipe threads other than NPT type threads shall be permitted to be p
26、rovided with pipe threads complying with a national pipe thread standard compatible with those ttings. 6 Use and Set Pressure Section 6 effective May 20, 2015 6.1 A pressure relief valve shall have a xed set pressure or adjustable pressure settings. 6.2 An adjustable pressure relief valve shall be p
27、rovided with a means, such as a fastening nut, to secure the intended set pressure. MAY 20, 2013 PRESSURE RELIEF VALVES FOR SPRINKLER SYSTEMS - UL 1478A 5UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 7 Materials Section 7 effective May 20,
28、 2015 7.1 The valve body and its internal operating parts shall be made of compatible materials having corrosion resistance equivalent to or exceeding that of brass, bronze or Series 300 stainless steel. An internal spring used in the pressure relief valve shall be made of material having corrosion
29、resistance equivalent to or exceeding that of Series 300 stainless steel or phosphor bronze. PERFORMANCE 8 General Section 8 effective May 20, 2015 8.1 Representative samples of pressure relief valves are to be subjected to the tests described in these requirements. 9 Elastomeric Parts (Except Gaske
30、ts) Test Section 9 effective May 20, 2015 9.1 An elastomeric part used to provide a seal shall have the following properties when tested as specied in the Standard for Gaskets and Seals, UL 157: a) For silicone rubber (having poly-organo-siloxane as its constituent characteristic), a minimum tensile
31、 strength of 500 psi (3.4 MPa) and a minimum ultimate elongation of 100 percent. b) For natural rubber and synthetic rubber other than silicone rubber, a minimum tensile strength of 1500 psi (10.3 MPa) and minimum ultimate elongation of 150 percent; or a minimum tensile strength of 2200 psi (15.2 MP
32、a) and a minimum ultimate elongation of 100 percent. c) Those properties relating to maximum tensile set; minimum tensile strength and elongation after oven aging; and hardness after oven aging, all as specied in UL 157. The maximum service temperature used to determine the oven time and temperature
33、 for oven aging is 60C (140F). 9.2 The Standard for Gaskets and Seals, UL 157, provides for the testing of either nished elastomeric parts or sheets or slab material. Sheet or slab material is to be tested when the elastomeric parts are O-rings having diameters of less than 1 inch (25.4 mm). The mat
34、erial tested is to be the same as that used in the product, regardless of whether nished elastomeric parts or sheet or slab material is tested. MAY 20, 2013 PRESSURE RELIEF VALVES FOR SPRINKLER SYSTEMS - UL 1478A 6UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOU
35、T PERMISSION FROM UL 10 Leakage Test Section 10 effective May 20, 2015 10.1 A pressure relief valve shall withstand an internal hydrostatic pressure equal to 90 percent of the minimum and maximum set pressures for 1 minute without leakage past the seat. 10.2 The inlet of the valve is to be connected
36、 to a hydrostatic pressure source and subjected to a gradually increasing pressure until 90 percent of the set pressure is achieved and then held for 1 minute. Observations are to be made for leakage past the seat. 11 Hydrostatic Strength and Body Leakage Test Section 11 effective May 20, 2015 11.1
37、An assembled valve shall withstand an internal hydrostatic pressure equal to four times the maximum set pressure of the valve, but not less than 700 psig (48 bar), without rupture; and 1.5 times the maximum set pressure of the valve, but not less than 250 psig (17 bar), without leakage. 11.2 The inl
38、et of the valve is to be connected to a hydrostatic pressure source with the valve seat opened to allow the test pressure to be exerted on the entire valve assembly including the outlet portion of the valve. The valve assembly is to be vented of all entrapped air with the outlet plugged or capped. T
39、he inlet pressure is to be gradually increased to 1.5 times the maximum set pressure of the valve and then held for 1 minute. Observations are to be made for leakage through the body. The inlet pressure is then to be gradually increased until four times the maximum set pressure is achieved and then
40、held for 5 minutes. Observations are to be made for cracking or rupture of the valve body. 12 Relief Valve Operation, Flow Capacity and Reseat Tests Section 12 effective May 20, 2015 12.1 When the valve is adjusted to pressure settings encompassing the intended set pressure range, the pressure at wh
41、ich the relief valve opens shall not be less than 95 percent of the set pressure nor more than 105 percent of the set pressure. Additionally, the relief valve shall be capable of discharging at least 14 oz (414 ml) of water per minute at an inlet pressure not greater than 110 percent of the set pres
42、sure and then reseat at a pressure equal to or greater than 90 percent of the opening pressure. 12.2 Testing shall be conducted in both horizontal and vertical orientations if intended for use in both installation orientations. 12.3 Each size relief valve shall be subjected to these tests. Each valv
43、e is to be installed in a piping system that is equipped with a pressure gauge at the relief valve inlet and a ow measuring instrument. After the valve has been set in accordance with the manufacturers instructions, the inlet pressure is to be increased until the valve opens. The inlet pressure is t
44、hen to be further increased until 110 percent of the set pressure is achieved to determine that the ow through the relief valve is not less than 14 oz (414 ml) of water per minute. The pressure is then to be slowly decreased until the valve reseats. The reseat pressure shall be a minimum of 90 perce
45、nt of the opening pressure. The inlet pressure at each of these test conditions is to be recorded. MAY 20, 2013 PRESSURE RELIEF VALVES FOR SPRINKLER SYSTEMS - UL 1478A 7UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 13 Spring Cycling Test S
46、ection 13 effective May 20, 2015 13.1 A spring mechanism of a relief valve shall cycle 500 times through its intended travel distance without malfunction. 13.2 The spring mechanism of the valve shall be tested in a manner so that it is moved to its maximum travel distance. Each cycle of operation is
47、 to consist of compressing the spring to its minimum intended operating length (maximum compression during operation) and then extending it back to its original length. 13.3 After cycling, a valve with the cycled spring is to be subjected to and demonstrate compliance with the Relief Valve Operation
48、, Flow Capacity and Reseat Tests, Section 12 and the Relief Valve Leakage Test, Section 10. 14 Contaminated-water Cycle Test 14.1 After 100 cycles of operation using water that has been contaminated as described in 14.2, the opening pressure shall be maintained within 95 percent to 105 percent of th
49、e set pressure. Slight weeping not exceeding 20 milliliters per minute complies with the requirement when the opening pressure is maintained in this range. Revised 14.1 effective May 20, 2015 14.2 The water used during the cycling specied in 14.1 is to consist of 15 gallons (0.06 m 3 ) of tap water into which has been mixed 1.584 kilograms of contaminants which sieve as described in Table 14.1. A relief valve provided with an integral means for ushing the seat shall be permitted to be ushed during this test
