1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULDecember 12, 20061SUBJECT 1712OUTLINE OF INVESTIGATIONFORTESTS FOR AMPACITY OF INSULATED ELECTRICAL CONDUCTORSINSTALLED IN THE FIRE PROTECTIVE SYSTEMIssue Number: 4DECEMBER 12, 2006Summary of Top
2、icsThis new issue of SU 1712 is being issued 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 information
3、concerning the use and application of the 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 FRO
4、M ULDECEMBER 12, 2006SUBJECT 17122No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULCONTENTSINTRODUCTION .4GENERAL1 Scope .52 Glossary .53 Units of Measurement .6TEST METHOD4 Control of Tests .64.1 Test enclosure .64.2 Test e
5、nclosure temperature 64.3 Electrical conductor temperature .64.4 Electrical current .95 Test Samples .105.1 Through-penetration firestops .105.2 Electrical circuit protective systems 105.3 Protection and conditioning of test specimen 10TESTS6 Reference Ampacity Test .117 Ampacity Test .118 Determina
6、tion of Ampacity Reduction 119 Report of Results 12DECEMBER 12, 2006 SUBJECT 1712 3UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULINTRODUCTIONBecause dielectric insulating materials tend to deteriorate at elevated temperatures, the size of an
7、electrical conductor insulated with these materials is typically selected so that the operating temperatureof the conductor is below that at which rapid deterioration of the insulation begins. The operatingtemperature of a specific type of electrical conductor is affected by the current flowing thro
8、ugh theconductor as well as other factors.Ampacity is the maximum current, expressed in amperes, that an electrical conductor can carrycontinuously under conditions of use without exceeding the temperature rating specified for the conductor.The National Electrical Code (NEC) publishes the ampacities
9、 of electrical conductors used for generalwiring.The heat dissipation characteristics of cables can be affected at areas where cables are enclosed in fireprotective systems.Fire protective systems in which insulated electrical conductors are installed include through-penetrationfirestops and electri
10、cal circuit protective systems. A through-penetration firestop is a device or specificconstruction of fill materials designed to resist the penetration of fire through openings made in fireresistive floors or walls to accommodate penetrating items such as insulated electrical wires and cables,cable
11、trays, busways, cablebus, conduits, ducts and pipes. The Standard for Fire Tests ofThrough-Penetration Firestops, UL 1479 (ASTM E814) describes the method used to measure thefire-resistive performance of the devices, materials and assemblies. An electrical circuit protective systemis a specific cons
12、truction of devices, materials or protective coatings, installed around, or applied to,insulated electrical wires and cables, cable trays, busways, cablebus, conduits, junction boxes and otherinsulated electrical conductor raceways. Electrical circuit protective systems are classified with respect t
13、otheir ability to maintain the integrity of the electrical circuits during a standardized exposure to an exteriorfire. The Outline of Investigation for Fire Tests of Electrical Circuit Protective Systems, UL 1724, describesthe method used to measure to the fire resistive performance of the device, m
14、aterials or protectivecoatings.Both the materials and construction features of devices or systems used to protect insulated electricalconductors used in fire protective systems may impede the dissipation of heat from these conductors andcause higher operating temperatures than similar unprotected co
15、nductors carrying the same current. Theeffect of this reduced heat dissipation can be compensated for by reducing the ampacity of theconductors.This Outline of Investigation describes a standard test method for measuring the reduction in ampacity ofinsulated electrical conductors which are enclosed
16、in specific fire protective systems. The ampacityreduction is expressed in terms applicable to a wide variety of materials, cable configurations and ambienttemperatures.Ampacity reduction of insulated electrical conductors used in fire protective systems is defined as thereduction in ampacity necess
17、ary to prevent those conductors from exceeding their rated operatingtemperature applicable to installations covered by the National Electrical Code, NFPA 70. Ampacityreduction is reported as a percent reduction of published rated current.DECEMBER 12, 2006SUBJECT 17124UL COPYRIGHTED MATERIAL NOT AUTH
18、ORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULGENERAL1 Scope1.1 These requirements cover the investigation of ampacity of insulated electrical conductors used inspecific fire protective systems employing various materials and construction types.1.2 This test method is inte
19、nded to determine the ampacity reduction required when insulated electricalconductors are used in specific fire protective systems under normal operating conditions.1.3 The results obtained by use of this test method are intended to develop data that will assist authoritieshaving jurisdiction, and o
20、thers, in determining the acceptability, with reference to their ampacity, ofinsulated electrical conductors installed in specific fire protective systems.2 Glossary2.1 For the purpose of this outline the following definitions apply.2.2 AMPACITY The current, in amperes, that an electrical conductor
21、can carry continuously underconditions of use without exceeding the temperature rating of the conductor.2.3 ELECTRICAL CIRCUIT PROTECTIVE SYSTEM A specific construction of devices, materials orprotective coatings, installed around, or applied to, electrical conductors, raceways, or both, to maintain
22、the integrity of electrical circuits subjected to a standardized exposure to an exterior fire. The Outline ofProposed Investigation for Fire Tests of Electrical Circuit Protective Systems, Subject 1724, describesthe method used to measure the fire resistive performance of the devices, materials or p
23、rotectivecoatings.2.4 ELECTRICAL CONDUCTORS Insulated wires, cables, cablebus, and busbars.2.5 FIRE PROTECTIVE SYSTEM Through-penetration firestops and electrical circuit protectivesystems.2.6 RACEWAY Cable trays and enclosed channels designed to hold wires, cables, cablebus, orbusbars may be of met
24、al or insulating material. A raceway includes rigid metal conduit, rigid nonmetallicconduit, intermediate metal conduit, liquidtight flexible metal conduit, flexible metallic tubing, flexiblemetal conduit, electrical metallic tubing, under-floor raceways, cellular concrete floor raceways, cellularme
25、tal floor raceways, surface raceways, wireways, and busways.2.7 STEADY-STATE TEMPERATURE A temperature varying by not more than 0.5C (0.9F) asdetermined by three consecutive readings taken at 15 minute intervals.2.8 THROUGH-PENETRATION FIRESTOP A specific construction of devices, fill materials, or
26、both,designed to resist the penetration of fire through those openings in fire resistive floors or walls that areintended to accommodate electric conductors, raceways and mechanical service penetrations. TheStandard for Fire Tests of Through-Penetration Firestops, UL 1479 (ASTM E814), describes the
27、methodused to measure the fire resistive performance of the devices, materials and assemblies.DECEMBER 12, 2006 SUBJECT 1712 5UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL3 Units of Measurement3.1 If a value for measurement is followed by a
28、 value in other units, in parentheses, the second value maybe only approximate. The first stated value is the requirement.TEST METHOD4 Control of Tests4.1 Test enclosure4.1.1 The ampacity tests are to be conducted in a draft-free, controlled-temperature enclosure of a sizesufficient to accommodate t
29、he test sample with a minimum clearance of 24 inches (610 mm) between thetest sample and all sides of the enclosure.4.2 Test enclosure temperature4.2.1 The temperature within the test enclosure is to be the average temperature obtained from thereadings of thermocouples symmetrically disposed and dis
30、tributed to measure the temperature atlocations 12 inches (305 mm) directly above and 12 inches directly below the test sample.4.2.2 The chromel-alumel thermocouples used to measure the temperatures within the test enclosure areto be not larger than No. 22 AWG (0.32 mm2) and are to be provided with
31、inconel sheaths. Thethermocouple assembly is to have a time constant no greater than 0.5 second.4.2.3 The steady-state temperatures of the test enclosure are to be recorded concurrently with thesteady-state temperatures of the electrical conductor(s).4.3 Electrical conductor temperature4.3.1 The tem
32、peratures of the individual electrical conductors are to be obtained from the readings ofchromel-alumel thermocouples fabricated by fusion-welding the twisted ends of the No. 24 AWG (0.21mm2), or smaller, thermocouple wires. The thermocouple leads are to be electrically insulated with a heat-and moi
33、sture-resistant coating.4.3.2 The thermocouples are to be installed by slitting the insulation of the electrical conductor andplacing the thermocouple junction in intimate contact with the electrical conductor. Following installation ofthe thermocouple, the slit in the insulation is to be sealed usi
34、ng electrical tape, or the equivalent, to restorethe electrical conductor construction, as practically as possible, to its original state. To prevent thethermocouple junction from being dislodged, the thermocouple leads are to be additionally affixed withelectrical tape, or the equivalent, to the ou
35、tside of the electrical conductor construction, within 2 inches (51mm) of the thermocouple junction.4.3.3 Thermocouples attached to bundles of electrical conductors are to be located at the center of thebundle, as illustrated in Figure 4.1.This is generated text for figtxt.DECEMBER 12, 2006SUBJECT 1
36、7126UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL4.3.4 Thermocouples on the electrical conductors in through-penetration firestops are to be located sothat temperatures are measured in the interior of the firestop at the firestop middepth,
37、as illustrated inFigure 4.2.This is generated text for figtxt.Figure 4.1Typical thermocouple location on bundled electrical conductorsDECEMBER 12, 2006 SUBJECT 1712 7UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL4.3.5 Thermocouples on electr
38、ical conductors in electrical circuit protective systems are to be located sothat temperatures are measured at the center of the system, as illustrated in Figure 4.3.This is generated text for figtxt.Figure 4.2Location of thermocouple-through-penetration firestopDECEMBER 12, 2006SUBJECT 17128UL COPY
39、RIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL4.4 Electrical current4.4.1 The conductor bundle is to be connected in series with a variable resistive load and this seriescombination is to be connected to the output of a 60 hertz transformer. By var
40、ying the load resistance, thecurrent in each electrical conductor is to be adjusted to the value necessary to attain a steady-statetemperature that is within 0.5C (0.9F) of the rated temperature of the conductor. The electrical currentrequired to attain the rated conductor temperature is to be measu
41、red and recorded concurrently with thesteady-state temperatures of the test enclosure and electrical conductors.Figure 4.3Location of thermocouple-electrical circuit protective systemDECEMBER 12, 2006 SUBJECT 1712 9UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOU
42、T PERMISSION FROM UL5 Test Samples5.1 Through-penetration firestops5.1.1 A through-penetration firestop intended for installation in a fire resistive floor assembly, wallassembly, or both, is to be installed in a wall section so that the electrical conductors pass horizontallythrough the wall. The t
43、hrough-penetration firestop is to be installed in accordance with all requirementsspecified for the firestop being tested.5.1.2 The sample wall section is to be representative of that specified for the through-penetration firestop.The thickness of the wall section is to be equal to the maximum thick
44、ness of the firestop system or device.The size of the through opening in the wall section is to be representative of the through opening sizespecified for the through-penetration firestop.5.1.3 The electrical conductor(s) and raceway(s) penetrating the sample wall section are to berepresentative of
45、those specified for the through-penetration firestop and are to be of sufficient length toproject a minimum of 24 inches (610 mm) beyond both sides of the wall section.5.2 Electrical circuit protective systems5.2.1 An electrical circuit protective system is to be tested with the electrical conductor
46、s installedhorizontally.5.2.2 The electrical conductor(s) and raceway(s) are to be representative of those specified for thesystem. The minimum length of the electrical conductor(s) and raceway(s) is to be 72 inches (1830 mm).5.2.3 The electrical circuit protective system is to be installed around t
47、he electrical conductor(s) andraceway(s) in accordance with all requirements specified for the system being tested. The ends of theprotective system that are intended to terminate at wall or floor through-penetration firestops are to besealed with nonmetallic duct tape to effectively block convectiv
48、e heat loss.5.3 Protection and conditioning of test specimen5.3.1 Prior to the ampacity tests described in Section 8 10, the wall specimen and test materials are tobe conditioned to provide a moisture condition within the specimen and materials approximatelyrepresentative of that likely to exist in
49、similar construction in buildings. This moisture condition isconsidered the equilibrium condition that would be established by exposure to an ambient atmosphere of50 percent relative humidity and 73F (23C). However, it may be difficult or impossible to achieve theequilibrium moisture condition with some specimens and materials within a reasonable period of time.Therefore, specimens are materials may be tested when their dampest portion has achieved anequilibrium moisture content corresponding to drying in ai
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