1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL UL 525 Flame ArrestersUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM ULUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION O
2、R DISTRIBUTION WITHOUT PERMISSION FROM UL UL Standard for Safety for Flame Arresters, UL 525 Eighth Edition, Dated May 9, 2008 Summary of Topics This revision of ANSI/UL 525 is being issued to reect the reaffirmation of ANSI approval. No changes in requirements have been made. Text that has been cha
3、nged in any manner or impacted by ULs electronic publishing system is marked with a vertical line in the margin. Changes in requirements are marked with a vertical line in the margin and are followed by an effective date note indicating the date of publication or the date on which the changed requir
4、ement becomes effective. The revisions dated August 10, 2012 include a reprinted title page (page 1) for this standard. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form by any means, electronic, mechanical photocopying, reco
5、rding, or otherwise without prior permission of UL. UL provides this Standard as is without warranty of any kind, either expressed or implied, including but not limited to, the implied warranties of merchantability or tness for any purpose. In no event will UL be liable for any special, incidental,
6、consequential, indirect or similar damages, including loss of prots, lost savings, loss of data, or any other damages arising out of the use of or the inability to use this Standard, even if UL or an authorized UL representative has been advised of the possibility of such damage. In no event shall U
7、Ls liability for any damage ever exceed the price paid for this Standard, regardless of the form of the claim. Users of the electronic versions of ULs Standards for Safety agree to defend, indemnify, and hold UL harmless from and against any loss, expense, liability, damage, claim, or judgment (incl
8、uding reasonable attorneys fees) resulting from any error or deviation introduced while purchaser is storing an electronic Standard on the purchasers computer system. The requirements in this Standard are now in effect, except for those paragraphs, sections, tables, gures, and/or other elements of t
9、he Standard having future effective dates as indicated in the note following the affected item. The prior text for requirements that have been revised and that have a future effective date are located after the Standard, and are preceded by a SUPERSEDED REQUIREMENTS notice. AUGUST 10, 2012 UL 525 tr
10、1UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL AUGUST 10, 2012 UL 525 tr2 No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL MAY 9, 2008 (Title Page Reprinted: Aug
11、ust 10, 2012) 1 UL 525 Standard for Flame Arresters The rst and second editions were titled Flame Arresters for Use in Open Vent Pipes of Oil Storage Tanks. The third, fourth, and fth editions were titled Flame Arresters for Use on Vents of Storage Tanks for Petroleum Oil and Gasoline. First Edition
12、 December, 1936 Second Edition July, 1946 Third Edition September, 1973 Fourth Edition June, 1979 Fifth Edition December, 1984 Sixth Edition December, 1994 Seventh Edition February, 2004 Eighth Edition May 9, 2008 This ANSI/UL Standard for Safety consists of the Eighth edition including revisions th
13、rough August 10, 2012. The most recent designation of ANSI/UL 525 as a Reaffirmed American National Standard (ANS) occurred on August 10, 2012. ANSI approval for a standard does not include the Cover Page, Transmittal Pages, Title Page, or effective date information. Comments or proposals for revisi
14、ons on any part of the Standard may 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 http:/. ULs Standards for Safety are copyrighted by UL. Neither a printed nor electronic copy of a Standard sho
15、uld be altered in any way. All of ULs Standards and all copyrights, ownerships, and rights regarding those Standards shall remain the sole and exclusive property of UL. COPYRIGHT 2012 UNDERWRITERS LABORATORIES INC. ANSI/UL 525-2004 (R2012)UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTI
16、ON OR DISTRIBUTION WITHOUT PERMISSION FROM UL MAY 9, 2008 FLAME ARRESTERS - UL 525 2 No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL CONTENTS INTRODUCTION 1 Scope .5 2 Glossary .5 3 Units of Measurement .6 4 Undated Refer
17、ences 6 5 Terminology 6 CONSTRUCTION 6 Materials .6 7 Casings 7 8 Provisions for Connection and Inspection 7 PERFORMANCE GENERAL 9 General 7 TANK VENT DEFLAGRATION FLAME ARRESTERS 10 Flow Capacity .8 11 Endurance Burn and Continuous Flame Tests .8 11.1 General 8 11.2 Endurance burn test .8 11.3 Cont
18、inuous ame test 9 12 Explosion and Flashback Tests .10 12.1 General .10 12.2 Explosion tests .10 12.3 Flashback tests 12 13 Hydrostatic Pressure Test .14 14 Corrosion Test .15 IN-LINE DETONATION FLAME ARRESTERS 15 Samples .15 16 Flow Capacity 15 17 Endurance Burn and Continuous Flame Tests 15 17.1 G
19、eneral .15 17.2 Continuous ame 16 18 Detonation and Deagration Tests 16 18.1 General .16 18.2 Detonation tests 18 18.3 Deagration tests 18 19 Hydrostatic-Pressure Test .19 20 Pneumatic-Leakage Test 20 21 Corrosion Test .20 MAY 9, 2008 FLAME ARRESTERS - UL 525 3UL COPYRIGHTED MATERIAL NOT AUTHORIZED
20、FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL MANUFACTURING AND PRODUCTION TESTS 22 Pneumatic-Leakage Test 20 MARKING 23 General 20 24 Tank Vent Deagration Flame Arresters .21 25 In-Line Detonation Flame Arresters .21 MAY 9, 2008 FLAME ARRESTERS - UL 525 4UL COPYRIGHTED MATERIA
21、L NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL INTRODUCTION 1 Scope 1.1 These requirements cover tank vent deagration ame arresters and in-line detonation ame arresters. 1.2 The requirements for tank vent deagration ame arresters cover arresters for use on vents
22、 of storage tanks for petroleum oil and gasoline. These ame arresters are intended to prevent propagation of ame into the storage tank. Combination ame arrester-vent valves are also covered. 1.3 The requirements for in-line detonation ame arresters cover arresters for use in piping systems containin
23、g ammable vapors and gases in mixture with air. These ame arresters are unidirectional or bidirectional and are intended to prevent the transmission of detonation and deagration. 2 Glossary 2.1 For the purpose of this Standard, the following denitions apply. 2.2 BIDIRECTIONAL An in-line detonation a
24、me arrester is determined to be bidirectional with respect to direction of ow when: a) The investigation shows that the ame arrester performs its intended function with a detonation or deagration approaching from either direction; or b) The design of the ame arrester is symmetrical and each end is d
25、etermined as identical when approached by a detonation or deagration from either direction. 2.3 DEFLAGRATION A very rapid burning of a ammable gas- or vapor-air mixture where the ame front of the combustion wave propagates at subsonic velocity. 2.4 DETONATION An extremely rapid burning of a ammable
26、gas- or vapor-air mixture where the ame front of the combustion wave propagates at sonic or supersonic velocity and a shock wave precedes the ame front. 2.5 DETONATION, STABLE A detonation that has a velocity equal to the speed of sound in the gas- or vapor-air mixture. 2.6 DETONATION, UNSTABLE (OVE
27、RDRIVEN) A detonation that has a velocity higher than the speed of sound in the gas- or vapor-air mixture. 2.7 FLASHBACK The transmission of ame through an arrester. 2.8 TYPE I FLAME ARRESTER A ame arrester that will not ash back when subjected to the Endurance Burn Test. 2.9 TYPE II FLAME ARRESTER
28、A ame arrester that: a) Flashes back when subjected to the Endurance Burn Test, 11.2, and b) Is marked with a continuous burn time. MAY 9, 2008 FLAME ARRESTERS - UL 525 5UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 2.10 UNIDIRECTIONAL An
29、in-line detonation ame arrester is considered to be unidirectional with regard to direction of ow if it is not symmetrical and is investigated with detonations approaching only from one direction. 3 Units of Measurement 3.1 Values stated without parentheses are the requirement. Values in parentheses
30、 are explanatory or approximate information. 4 Undated References 4.1 Any undated reference to a code or standard appearing in the requirements of this standard shall be interpreted as referring to the latest edition of that code or standard. 5 Terminology 5.1 The term ame arrester as used in this S
31、tandard refers to all ame arresters covered by the scope of this Standard unless specically noted otherwise in the text or in the headings preceding the text. For example, Sections 10 14 apply only to tank vent deagration ame arresters, as noted in 9.1 and by the heading preceding Section10. CONSTRU
32、CTION 6 Materials 6.1 A ame arrester element shall be of a metal resistant to corrosion under conditions of use. 6.2 The casing or housing shall be of cast aluminum, stainless steel, ductile cast iron in accordance with ASTM A395, or the equivalent. Exception: Cast, malleable, or ductile iron may be
33、 used for a tank vent deagration ame arrester. 6.3 A gasket such as one made of animal or vegetable bers shall not be used in the construction or assembly of a ame arrester. Nonmetallic gaskets shall be noncombustible. For the purpose of these requirements a material classed 5VA in accordance with t
34、he Standard for Tests for Flammability of Plastic Materials for Parts in Devices and Appliances, UL 94, is considered to be noncombustible. MAY 9, 2008 FLAME ARRESTERS - UL 525 6UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 7 Casings 7.1 T
35、he casing or housing of a ame arrester shall withstand the internal pressure resulting from explosions without damage. See Explosion and Flashback Tests, Section 12 and Detonation and Deagration Tests, Section 18. 7.2 The casing or housing of an in-line detonation ame arrester shall be gas tight. Se
36、e Pneumatic-Leakage Test, Section 20. 7.3 A at joint in a ame arrester and a at surface to be mounted to a tank or pipe shall be machined to provide an arithmetical average roughness of not more than 250 microinches in accordance with the Standard for Surface Texture, ANSI/ASME B46.1-1995. The machi
37、ned surface shall provide for a joint having a metal-to-metal width of not less than 1/4 inch (6.4 mm). 7.4 All fastenings shall be protected against loosening by some means such as lock washers. 8 Provisions for Connection and Inspection 8.1 A ame arrester shall have provisions for anged or threade
38、d connection to pipe. 8.2 An in-line detonation ame arrester shall be constructed to permit ease of inspection and cleaning without removing the complete arrester from the system. PERFORMANCE GENERAL 9 General 9.1 The performance requirements for tank vent deagration ame arresters are covered in Sec
39、tions 10 14. 9.2 The performance requirements for in-line detonation ame arresters are covered in Sections 15 21. 9.3 At the manufacturers request, the Endurance Burn and Continuous Flame Tests, Sections 11 and 17, the Explosion and Flashback Tests, Section 12, and the Detonation and Deagration Test
40、s, Section 18, are able to be conducted with a different ammable gas or vapor than those specied when the arrester is marked in accordance with 23.4. 9.4 The propane and n-hexane used in the tests is to be technical grade. The gasoline is to be Naphtha R , a nonleaded distillate consisting essential
41、ly of aliphatic hydrocarbon compounds and having a specic gravity of 60 70 degrees API at 15.6C (60F). 9.5 With the exception of the Continuous Flame Test following the Endurance Burn Test 17.1.2, the tests are able to be conducted in whatever order is convenient. MAY 9, 2008 FLAME ARRESTERS - UL 52
42、5 7UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL TANK VENT DEFLAGRATION FLAME ARRESTERS 10 Flow Capacity 10.1 The ow capacity of a ame arrester shall be determined at the operating pressures (both positive and negative) specied for the arr
43、ester by the manufacturer. 10.2 When a ame arrester is intended for use as an emergency vent, the ow capacity shall be determined at the pressure at which the valve reaches the full open position. If the pressure at full open position is greater than 2.5 psi, and the start to open pressure is less t
44、han 2.5 psi, the ow capacity shall also be determined at 2.5 psi. 11 Endurance Burn and Continuous Flame Tests 11.1 General 11.1.1 A Type I ame arrester shall be subjected to the Endurance Burn Test described in 11.2.1 11.2.9 and there shall be no passage of ame, both during the test and when the ga
45、s valve is closed at the conclusion of the test. 11.1.2 A Type II ame arrester shall be subjected to the Continuous Flame Test specied in 11.3.1 11.3.5 and marked in accordance with 24.1(e). 11.1.3 When a ame arrester is to be provided with cowls, weatherhoods, deectors, and similar components, it i
46、s to be tested in each conguration in which it is to be provided. 11.2 Endurance burn test 11.2.1 The ammable mixture for the test is to be a 2.5 percent mixture by volume of n-hexane in air or a 1.9 percent mixture by volume of gasoline vapor in air. 11.2.2 The ame arrester is to be mounted on a ta
47、nk so that the mixture emission is vertically upwards, or mounted in the position for which it is designed and which will result in the most severe heating of the arrester. When the arrester is provided with a vent valve, the valve is to be open for the test. 11.2.3 The tank mentioned in 11.2.2 is t
48、o be provided with a burst diaphragm at one end and an inlet for the mixture at the other end. 11.2.4 The burst diaphragm is to be made of 0.0015- to 0.010-inch (0.038- to 0.2540-mm) thick cellulose acetate lm, polyester lm, polyethylene terephthalate lm, or the equivalent. 11.2.5 The mixture is to
49、be introduced into the tank and is to be ignited by a pilot ame or spark plug at the outlet of the ame arrester. The mixture may be reignited as necessary during the test. 11.2.6 Temperatures are to be measured on the surface of the protected side of the arrester element at its center, at its edge, and halfway between the center and the edge. MAY 9, 2008 FLAME ARRESTERS - UL 525 8UL COPYRIGHTED MATERI
