ASTM D6194-2018 Standard Test Method for Glow-Wire Ignition of Materials.pdf

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1、Designation: D6194 18Standard Test Method forGlow-Wire Ignition of Materials1This standard is issued under the fixed designation D6194; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parenthe

2、ses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the minimum temperaturerequired to ignite insulating materials using a glowing heatsource. In a preliminary fashion, this test m

3、ethod differentiatesbetween the susceptibilities of different materials with respectto their resistance to ignition due to an electrically-heatedsource.1.2 This test method applies to molded or sheet materialsavailable in thicknesses ranging from 0.25 to 6.4 mm.1.3 This test method is not valid for

4、determining the ignitionbehavior of complete electrotechnical equipment, since thedesign of the electrotechnical product influences the heattransfer between adjacent parts.1.4 This test method measures and describes the response ormaterials, products, or assemblies to heat and flame undercontrolled

5、conditions, but does not by itself incorporate allfactors required for fire hazard or fire risk assessment of thematerials, products, or assemblies under actual fire conditions.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard

6、. (See IEEE/ASTM SI-10 for further details.)Forspecific precautionary statements, see Section 9.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health, and

7、 environmental practices and deter-mine the applicability of regulatory limitations prior to use.For specific precautionary statements, see Section 9.1.7 Fire testing is inherently hazardous. Adequate safe-guards for personnel and property shall be employed inconducting these tests.NOTE 1Although th

8、is test method and IEC 60695-2-13 differ inapproach and in detail, data obtained using either are technically equiva-lent.1.8 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevel

9、opment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1711 Terminology Relating to Electrical InsulationE176 Terminology of Fire StandardsE220 Test Method for Calibr

10、ation of Thermocouples ByComparison TechniquesE230/E230M Specification for Temperature-ElectromotiveForce (emf) Tables for Standardized ThermocouplesIEEE/ASTM SI-10 International System of Units (SI), TheModernized Metric System2.2 IEC Standard:IEC 60695-4 Fire Hazard TestingPart 4: TerminologyConce

11、rning Fire Tests3IEC 60695-2-12 Fire Hazard TestingPart 212: Glowing/Hot-Wire Based Test MethodsGlow-Wire FlammabilityTest Method for Materials3IEC 60695-2-13 Fire Hazard TestingSection 20: Glowing/Hot-Wire Based Test MethodsGlow-Wire Coil Ignit-ability Test Method for Materials32.3 ISO Standard:4IS

12、O 13943 Fire SafetyVocabulary3. Terminology3.1 Definitions:3.1.1 Use Terminology E176, ISO 13943, and IEC 60695-4for definitions of terms used in this test method and associatedwith fire issues. Where differences exist in definitions, thosecontained in Terminology E176 shall be used. Use Terminol-og

13、y D1711 for definitions of terms used in this test method and1This test method is under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating Materials and is the direct responsibility ofSubcommittee D09.17 on Fire and Thermal Properties.Current edition approved Nov. 1, 2018.

14、 Published December 2018. Originallyapproved in 1997. Last previous edition approved in 2014 as D6194 14. DOI:10.1520/D6194-18.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information

15、, refer to the standards Document Summary page onthe ASTM website.3Available from International Electrotechnical Commission (IEC), 3 Rue deVaremb, Case postale 131, CH-1211, Geneva 20, Switzerland, http:/www.iec.ch.4Use undyed, soft, strong, lightweight tissue paper weighing between 12 and30 g m2.*A

16、 Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization establ

17、ished in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1associated with electrical insulation materials. The 2017 edi-tion of ISO 13943 has incorporated many of t

18、he relevant termsof IEC 60695-4.3.1.2 ignition, nthe initiation of combustion (TerminologyE176).3.1.2.1 DiscussionThe combustion may be evidenced byglow, flame, detonation, or explosion. The combustion may besustained or transient (Terminology E176).3.2 Definitions of Terms Specific to This Standard

19、:3.2.1 glow-wire, na wire of specified dimensions that canbe controllably heated electrically to determine ignitability of amaterial.3.2.2 glow-wire flammability index (GWFI), nthe highesttest temperature, during three subsequent tests for a testspecimen of a given thickness, at which one of the fol

20、lowingconditions are fulfilled: a) flames or glowing of the testspecimen extinguish within 30 s after removal of the glow-wireand there is no ignition of the wrapping tissue placed under-neath the test specimen; b) there is no ignition of the testspecimen.3.2.3 glow-wire ignition temperature (GWIT),

21、 nthe tem-perature which is 25C (30C between 900 and 960C) higherthan the GWFI.4. Summary of Test Method4.1 In this test method, a standardized test specimen (eithersquare or round), is supported vertically and is exposed toelectrical heating from a glow-wire set at pre-determinedtemperatures. The m

22、inimum temperature for glow-wire igni-tion is assessed through testing at incremental temperatures.4.2 In this test method, ignition is deemed to have takenplace when the first of the following occurs: sustained flamingon the test specimen surface for over 5 s, or falling particlescausing the appear

23、ance of flames on a tissue paper placedunderneath the test specimen.5. Significance and Use5.1 During operation of electrical equipment, includingwires, resistors, and other conductors, it is possible for over-heating to occur under certain conditions of operation, or whenmalfunctions occur. When th

24、is happens, a possible result isignition of the adjacent insulation material.5.2 This test method assesses the susceptibility of electricalinsulating materials to ignition as a result of exposure to aglowing wire.5.3 This test method determines the minimum temperaturerequired to ignite a material by

25、 the effect of a glowing heatsource, under the specified conditions of test.5.4 This method is suitable, subject to the appropriatelimitations of an expected precision of 615 %, to categorizematerials.5.5 In this procedure, the specimens are subjected to one ormore specific sets of laboratory condit

26、ions. If different testconditions are substituted or the end-use conditions arechanged, it is not always possible by or from this test to predictchanges in the fire-test-response characteristics measured.Therefore, the results are valid only for the fire test exposureconditions described in this pro

27、cedure.6. Apparatus6.1 Glow-wireThe glow-wire shall be a Nichrome(Nickel-Chrome) wire that is iron free, with the followingnominal properties: a wire composition of 20 % chromium-80 % nickel, a diameter of 4 mm, and it shall be formed to thedimensions shown in Fig. 1, which describes the glow wire a

28、ndits positioning.6.2 ThermocoupleUse Type K sheathed fine-wirethermocouple, having an overall diameter of 1.0 mm max, andwires suitable for continuous operation at temperatures up to960C, with the welded point located inside the sheath, formeasuring the temperature of the glow-wire. Examples ofsuit

29、able wire compositions are Nickel-Chromium (NiCr) andNickel-Aluminum (NiAl).6.2.1 Construct the thermocouple sheath of a metal that willallow the thermocouple to perform its function in air at sheathtemperatures of at least 1050C. Arrange the thermocouple ina pocket hole, drilled in the tip of the g

30、low-wire, as shown inFig. 1. Maintain the thermal contact between the walls of thebored hole in the glow-wire by pinning the sheathed thermo-couple in place. Ensure that the thermocouple follows themovement of the tip of the glow-wire resulting from elongationcaused by thermal heating.6.3 Temperatur

31、e IndicatorUse a temperature indicator forType K thermocouples capable of reading up to 1000C.Calibrate the combination thermocouple and temperature indi-cator in accordance with the general procedures outlined inTest Method E220. The initial calibration tolerance is definedin the tables of Specific

32、ation and Temperature-ElectromotiveForce (EMF) Tables E230/E230M.6.4 Supply CircuitThe supply circuit shall be capable ofsupplying up to 150 A at 2.1 V, with smooth continuousadjustment of voltage to provide the required current as neededto maintain the desired glow-wire tip temperature.6.5 Test Fix

33、tureAs shown in Fig. 2, the test fixture shall becapable of holding the glow-wire in a horizontal plane andmoving it against the vertical test specimen, maintaining aforce of 1.0 6 0.2 N over a distance of at least 7 mm.6.5.1 Use a weight of 100 6 20 g to provide the requiredforce.6.6 Indicator Boar

34、dUse as indicator a flat pine woodboard with a smooth finish, approximately 10 mm thick, and inclose contact with a single layer of tissue paper,4located at adistance of 200 6 5 mm below the glow-wire tip.6.7 Test ChamberUse as a test chamber a closed draft-freechamber that permits observation of th

35、e specimen and has avolume of at least 0.3 m3. The test chamber shall be positivelyvented to the outside of the test facility before and after the test,but it shall remain closed and unvented during the test. Thechamber shall be equipped with an observation window.7. Test Specimen7.1 Prepare square

36、specimens that are approximately 60 60 mm or round specimens that are approximately 60 mm inD6194 182NOTE 1All dimensions in millimetres.FIG. 1 Glow-Wire and Positioning of ThermocoupleFIG. 2 Test Apparatus (Example)D6194 183diameter, and of a thickness commonly encountered in prac-tice. Thicknesses

37、 less than 0.25 mm or greater than 6.4 mm arenot valid for this test method. Generally, ten specimens willsuffice to complete the procedure specified in Section 9.8. Conditioning8.1 Condition specimens, test board and tissue paper at 236 2C and 50 6 5 % relative humidity for at least 40 h priorto te

38、sting.9. Safety Precautions9.1 It is possible that fumes and products of incompletecombustion are liberated from the specimen when conductingthis test. Avoid the inhalation of such fumes and products ofcombustion and exhaust them from the test chamber after eachrun.9.2 Take precautions to safeguard

39、the health of personnelagainst the risk of explosion or fire, the inhalation of smoke orother products of combustion, or the exposure to the residuespotentially remaining on the specimen after testing.10. Procedure10.1 Before each test, clean the tip of the glow-wire with awire brush to remove any r

40、esidue left from previously testedmaterials.10.2 Mount the specimen in the test fixture so that thesurface that comes in contact with the tip of the glow-wire isvertical and any heat losses to the supporting means areinsignificant. Adjust the equipment so the depth of penetrationis limited to 7 mm b

41、elow the surface of the specimen. Shieldthe specimen during the heating of the glow-wire.10.3 Close the chamber vents and doors, making the testchamber draft free, and heat the glow-wire to the pre-determined temperature. Use the calibrated thermocouple torecord the glow-wire temperature. Maintain t

42、he pre-selectedglow-wire temperature for at least 60 s prior to conducting thetest.10.4 Bring the specimen in contact with the tip of theglow-wire at an applied force of 1.0 6 0.2 N for 30 6 1s.NOTE 2The glow-wire temperature will decrease when the tipcontacts the test specimen.10.5 Observe to see w

43、hether ignition occurs during theapplication of the glow-wire (see 3.2.1). For the purposes ofthis test, ignition will be deemed to have occurred if eithersustained flaming occurs (appearance of a flame on the surfaceof the test specimen which lasts for more than 5 s) or the tissuepaper on the indic

44、ator board placed underneath the apparatusexhibits flames caused by particles falling from the testspecimen.10.5.1 If ignition occurs, repeat the test with a new testspecimen, and at a temperature 50C lower than that usedduring the previous test. If the resulting temperature hasalready been used, do

45、 not retest at that temperature.10.5.2 If ignition does not occur, repeat the test with a newtest specimen, and at a temperature 50 higher than that usedduring the previous test. If the resulting temperature hasalready been used, do not retest at that temperature.10.6 When a maximum temperature has

46、been determined,following the procedure in 10.5, repeat the test with a new testspecimen with a temperature interval of 25C in the finalapproach, to determine the maximum test temperature whichwill not cause ignition during three consecutive tests.10.7 The glow-wire ignition temperature is that temp

47、eraturethat is 25C higher than the highest temperature at which thetip of the glow-wire does not cause ignition during threeconsecutive tests.10.8 The glow-wire flammability index (GWFI) is thehighest test temperature, during three subsequent tests for a testspecimen of a given thickness, at which o

48、ne of the followingconditions are fulfilled:10.8.1 Flames or glowing of the test specimen extinguishwithin 30 s after removal of the glow-wire and there is noignition of the wrapping tissue placed underneath the testspecimen.10.8.2 There is no ignition of the test specimen.11. Report11.1 Report the

49、following information:11.1.1 Complete identification of the material tested includ-ing type, source, and manufacturers code number,11.1.2 Thickness of specimens tested,11.1.3 The glow-wire ignition temperature, and11.1.4 The glow-wire flammability index.12. Precision and Bias12.1 PrecisionIt is not possible to specify the precision ofthe procedure in this test method for measuring the glow-wireignition temperature because insufficient data has been devel-oped and compiled for a reliable statistical analysis.12.2 BiasNo information can be pre