1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULDecember 7, 20061SUBJECT 1724OUTLINE OF INVESTIGATIONFORFIRE TESTS FOR ELECTRICAL CIRCUIT PROTECTIVE SYSTEMSIssue Number: 3December 7, 2006Summary of TopicsThis new issue of SU 1724 is being issu
2、ed through ULs electronicpublishing system to ensure format uniformity between the PDF andHTML versions of the document. No substantive changes have beenincorporated in the document.The UL Foreword is no longer located within the UL Standard. For informationconcerning the use and application of the
3、requirements contained in thisStandard, the current version of the UL Foreword is located onULStandardsInfoNet at: http:/ 2006 UNDERWRITERS LABORATORIES INC.UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULDECEMBER 7, 2006SUBJECT 17242No Text o
4、n This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULCONTENTSINTRODUCTION .6GENERAL1 Scope .72 Glossary .83 Units of Measurement .9PERFORMANCE4 External Fire Exposure Test 94.1 Test sample .94.2 Conditioning 104.3 Protection of assembly
5、and sample 104.4 Furnace temperature control and measurement .104.5 Furnace thermocouple preparation 114.6 Sample temperature measurement 124.7 Electrical circuit integrity 134.8 Differential pressure measurements .134.9 Duration of test 155 Hose Stream Test .156 Internal Fire Exposure Test .166.1 T
6、est sample 166.2 Conditioning 186.3 Protection of sample .186.4 Ignition flame source .196.5 Flame penetration indicator .206.6 Sample temperature measurement 206.7 Duration of test 21CONDITIONS OF ACCEPTANCE7 General .217.1 External fire exposure 217.2 Internal fire exposure 217.3 Correction Extern
7、al fire exposure test 21REPORT8 Results .229 Application of Results 23DECEMBER 7, 2006 SUBJECT 1724 3UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULAPPENDIX A STANDARD TIME-TEMPERATURE CURVE FOR CONTROL OF FIRE TESTSAPPENDIX B QUALIFICATION T
8、EST FOR CIRCUIT INTEGRITY OF INSULATED ELECTRICALWIRES AND CABLES IN ELECTRICAL CIRCUIT PROTECTION SYSTEMSB1 General .B1B2 Test Sample .B1B3 Apparatus .B1B3.1 Raceway .B1B3.2 Air oven B3B3.3 Air oven/sample temperature control .B4B3.4 Compression loading .B4B3.5 Electrical circuit integrity B4B3.6 I
9、mpact force .B5B4 Test Method .B6B4.1 Preparation of test sample B6B4.2 Choice of temperature end point .B6B4.3 Elevated temperature exposure B6B4.4 Impact force .B7B5 Results B7DECEMBER 7, 2006SUBJECT 17244UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMIS
10、SION FROM ULDECEMBER 7, 2006 SUBJECT 1724 5No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULINTRODUCTIONOn February 19, 1981, a new FIRE PROTECTION PROGRAM FOR OPERATING NUCLEAR POWERPLANTS (Appendix R to 10 CFR 50) became e
11、ffective. This action was taken to upgrade fire protectionat nuclear power plants licensed to operate prior to January 1, 1979.One section of Appendix R deals with the specification of certain methods to protect redundant safetytrains. One of the specified methods in Appendix R requires the Enclosur
12、e of cable and equipment andassociated nonsafety circuits of one redundant train in a fire barrier having a 1 hour rating.In addition to the protection of redundant safety trains in nuclear power plants, some municipalities haveadopted requirements that, in all buildings where an emergency generator
13、 is installed for protection oflife-safety, the feeder conductors from the generator to the emergency panel and any feeders required tooperate an elevator shall be protected by a 2 hour enclosure.The requirement for protection of vital electrical circuits during exposure to an external fire has prom
14、ptedthe development of fire resistive enclosures or coatings, identified as electrical circuit protection systems.An electrical circuit protective system consists of materials or protective coatings installed around, orapplied to, electrical conductors, cable trays, busways, cablebus, conduits, junc
15、tion boxes and otherelectrical conductor raceways. Electrical circuit protective systems are classified with respect to theirability to maintain the integrity of electrical circuits during a standardized exposure to an external fire.Several factors influence the ability of an electrical circuit prot
16、ective system to maintain the integrity ofelectrical circuits under fire exposure conditions. Factors such as the electrical conductor raceway typeand size and the severity of the standardized fire exposure to which the electrical circuit protective systemis exposed may be specified by the test proc
17、edure. Other factors such as the electrical conductorinsulation type, the electrical conductor size and construction type, the percentage of electrical conductorfill within the raceway and the temperature of the electrical conductors within the electrical circuitprotective system during normal opera
18、tion are variables which must be assessed for each application.This Outline of Proposed Investigation describes a standard test method to develop the data necessaryfor classifying electrical circuit protective systems for specific applications.DECEMBER 7, 2006SUBJECT 17246UL COPYRIGHTED MATERIAL NOT
19、 AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULGENERAL1 Scope1.1 These requirements cover the fire test investigation of electrical circuit protective systems of variousmaterials and construction.1.2 Under these requirements, samples of electrical circuit protective sy
20、stems are exposed to an externalfire for a predetermined time, and then to an application of a water hose stream. The followingmeasurements and determinations are made during the fire exposure and water hose stream tests:a) Measurement of temperature changes within the electrical circuit protective
21、system causedby the heat transfer through the electrical circuit protective system to the electrical conductor orraceway, or both, during the external fire exposure test.b) Determination of the integrity of the electrical circuit protective system during the external fireexposure and water hose stre
22、am test.c) Determination of the ability of insulated electrical conductors to maintain electrical circuitintegrity at the temperature conditions present within the electrical circuit protective systemduring the external fire exposure test and during the water hose stream test.1.3 The external fire e
23、xposure and water hose stream test may be cited as the Standard Fire Test, andthe performance is expressed in terms of maximum temperature rise within the electrical circuit protectivesystem at various increments of fire exposure time.1.4 The external fire exposure and water hose stream tests may no
24、t be representative of all fireconditions; conditions may vary with changes in the amount, nature, and distribution of fire loading,ventilation, compartment size an configuration, and heat conducting and dissipating characteristics of thecompartment in which the electrical circuit protective system
25、is installed. These requirements provide arelative measure of fire performance of comparable assemblies under these specified fire exposureconditions. Any variation from the construction or operating condition tested, such as size, method ofassembly, and materials, may substantially change the perfo
26、rmance characteristics of the system.1.5 These requirements also cover sample systems which are subjected to an internal fire exposure toevaluate their ability to contain fires originating within the electrical circuit protective system if, for example,the system contains ventilation means such as h
27、oles, slots, louvers, or dampers. The internal fireexposure test may be waived at the discretion of the testing body if the material or installation, or both,obviate the need for such testing.1.6 These requirements do not cover:a) Accumulation of data as to performance of electrical circuit protecti
28、ve systems constructedwith components or sizes other than those tested.b) Evaluation of the contribution of the electrical circuit protective systems to generation ofsmoke, toxic gases, or other products of combustion.c) Measurement of flame spread over the surface of the tested elements.d) Evaluati
29、on of the firestop system in floor openings penetrated by the electrical circuitprotective systems, unless specifically provided for in the system tested.DECEMBER 7, 2006 SUBJECT 1724 7UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULe) Evaluat
30、ion of the ampacity of electrical conductors within the electrical circuit protectivesystems.1.7 The results obtained by use of this test method are intended to develop data that will assist authoritieshaving jurisdiction, and others, in determining the acceptability, with reference to circuit integ
31、rity, ofelectrical circuit protective systems for use with specific electrical conductors in specific applications.1.8 Tests for burning characteristics of building materials, based on rate of flame spread and the densityof smoke developed when exposed to a standard fire, can be found in the require
32、ments for surfaceburning characteristics of building materials, UL 723.1.9 Tests for fire resistance of firestop systems which penetrate through walls and floors can be found inthe requirements for Through-Penetrate Firestop Systems, UL 1479.1.10 By the prescribing of the standard fire and water hos
33、e stream exposures for comparing theperformance of electrical circuit protective systems, the results of these tests represent one factor indetermining the acceptability, with reference to circuit integrity, of electrical circuit protective systems foruse with specific electrical conductors in speci
34、fic applications. Application of these test results to predictcircuit integrity of electrical conductors in actual installations requires careful evaluation of the electricalconductor insulation materials and the temperature within the electrical circuit protective system undernormal operating condi
35、tions.2 Glossary2.1 For the purpose of this Outline the following definitions apply.2.2 ELECTRICAL CIRCUIT PROTECTIVE SYSTEM A specific construction of devices, materials orprotective coatings installed around, or applied to, electrical conductors, raceways, or both, to maintainthe integrity of elec
36、trical circuits subjected to a standardized exposure to an external fire.2.3 ELECTRICAL CONDUCTORS Insulated wires and cables, cablebus, and busbars.2.4 RACEWAY Cable trays and enclosed channels, of metal or insulating material, designed to holdelectrical wires, cables, cablebus, or busbars. A racew
37、ay includes rigid metal conduit, intermediatemetal conduit, liquid-tight flexible metal conduit, flexible metallic tubing, flexible metal conduit, electricalmetallic tubing, under-floor raceways, cellular concrete floor raceways, cellular metal floor raceways,surface raceways, wireways, and busways.
38、DECEMBER 7, 2006SUBJECT 17248UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL3 Units of Measurement3.1 If a value or measurement is followed by a value in other units in parentheses, the second value maybe only approximate. The first stated va
39、lue is the requirement.PERFORMANCE4 External Fire Exposure Test4.1 Test sample4.1.1 Each representative type of electrical circuit protective system for which rating is desired is to betested beneath a floor assembly unless it is determined that all features of its intended use can beevaluated by te
40、sting in a wall assembly.4.1.2 The floor or wall assembly is to be constructed of materials which offer adequate support for theelectrical circuit protective system during both the fire exposure and water hose stream tests, but whichdo not influence the physical fire performance of the electrical ci
41、rcuit protective system due to excessivedeflection or falling debris.4.1.3 The raceways protected by electrical circuit protective systems are to be representative of thesmallest and largest sizes for which rating is desired. The raceways are to be installed as completesystems and are to each incorp
42、orate at least one intermediate support which is representative of that forwhich rating is desired. The raceways are to terminate a maximum of 36 inches (914 mm) beyond theunexposed surface of the floor or wall assembly.4.1.4 The electrical conductors within the electrical circuit protective system
43、are to be simulated by No. 8AWG (8.38 mm2) stranded medium or hard-drawn temper bare copper conductors weighing 0.051 poundper foot (75 g/m). The bare copper conductors are to have an outside diameter of 0.146 inch (3.71 mm)and are to consist of seven 0.049 inch (1.24 mm) diameter strands. The bare
44、copper conductors are to beinstalled along the entire length of the electrical circuit protective system, and are to terminate within thefloor or wall firestop system. The bare copper conductor fill within the electrical circuit protective systemshall be in the minimum fill which will effectively co
45、ver the supporting surface of the raceway.4.1.5 If rating is desired only for specific insulated electrical conductors, they are to be installed in theelectrical circuit protective system so as to simulate both the minimum and maximum percent fills forwhich rating is desired. The insulated electrica
46、l conductors are to be installed along the entire length ofthe electrical circuit protective system and are to terminate a maximum of 36 inch (914 mm) beyond theunexposed surface of the floor or wall assembly.4.1.6 Unless rating is desired for a specific construction, the firestop system for the flo
47、or opening is to beconstructed using materials and techniques that provide an effective heat and smoke seal withoutinfluencing the performance of the electrical circuit protective system as a result of degradation orexcessive heat transfer to the electrical conductors within the firestop system.4.1.
48、7 The periphery of the test sample is to be not closer than 12 inches (305 mm) from the furnace edge.The distance between the test sample periphery and furnace edge may be reduced if it is demonstratedthat the edge effects do not affect the test results.DECEMBER 7, 2006 SUBJECT 1724 9UL COPYRIGHTED
49、MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL4.2 Conditioning4.2.1 Prior to fire testing, each system and floor or wall assembly is to be conditioned, if necessary, toprovide a moisture condition representative of that likely to exist in similar constructions in buildings. Thefloor or wall assembly may be conditioned independently of the electrical circuit protective systems. Thetest moisture condition is to be considered as that which would be established in equilibri
