ASTM D6194-2008 488 Standard Test Method for Glow-Wire Ignition of Materials.pdf

1、Designation: D 6194 08An American National StandardStandard Test Method forGlow-Wire Ignition of Materials1This standard is issued under the fixed designation D 6194; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last

2、 revision. A number in parentheses 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 p

3、reliminary fashion, this test method 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 Thi

4、s test method is not valid for 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

5、heat and flame undercontrolled 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 measureme

6、nt are included in thisstandard. (See IEEE/ASTM SI-10 for further details.)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 and health practices and determin

7、e the applica-bility of regulatory limitations prior to use. For specificprecautionary statements, see Section 9.1.7 Fire testing of products and materials is inherentlyhazardous, and adequate safeguards for personnel and propertyshall be employed in conducting these tests. Fire testinginvolves haza

8、rdous materials, operations, and equipment.NOTE 1Although this test method and IEC 60695-2-13 differ inapproach and in detail, data obtained using either are technically equiva-lent.2. Referenced Documents2.1 ASTM Standards:2D 1711 Terminology Relating to Electrical InsulationE 176 Terminology of Fi

9、re StandardsE 220 Test Method for Calibration of Thermocouples ByComparison TechniquesE 230 Specification and Temperature-Electromotive Force(EMF) Tables for Standardized ThermocouplesIEEE/ASTM SI-10 International System of Units (SI), TheModernized Metric System2.2 IEC Standard:IEC 60695-4 Fire Haz

10、ard TestingPart 4: TerminologyConcerning 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 CoilIgnitability Test Method fo

11、r Materials32.3 ISO Standard:ISO 13943 Fire SafetyVocabulary43. Terminology3.1 Definitions:3.1.1 Use Terminology E 176, 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 E

12、176 shall be used. Use Terminol-ogy D 1711 for definitions of terms used in this test method andassociated with electrical insulation materials.3.2 Definitions of Terms Specific to This Standard:1This test method is under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating

13、Materials and is the direct responsibility ofSubcommittee D09.21 on Fire Performance Standards.Current edition approved June 1, 2008. Published July 2008. Originally approvedin 1997. Last previous edition approved in 2004 as D 6194 04.2For referenced ASTM standards, visit the ASTM website, www.astm.

14、org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from International Electrotechnical Commission (IEC), 3 Rue deVarembe, Geneva, Switzerland.4Use undyed, soft, stron

15、g, lightweight tissue paper weighing between 12 and 30g/m2.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.1 glow wire, na wire of specified dimensions that canbe

16、controllably-heated electrically to determine ignitability of amaterial.3.2.1.1 DiscussionFig. 1 shows a glow wire and itspositioning.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 fo

17、llowingconditions 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)

18、, nthe tem-perature which is 25 C (30 C between 900 and 960 C)higher than the GWFI.3.2.4 ignition, ninitiation of combustion.3.2.4.1 DiscussionIgnition is deemed to have taken placewhen the first of the following occurs: sustained flaming on thetest specimen surface for over5sorfalling particles cau

19、singthe appearance of flames on a tissue paper placed underneaththe test specimen.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. Th

20、e minimum temperature for glow-wire igni-tion is assessed through testing at incremental temperatures.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,

21、or whenmalfunctions occur. When this 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 temperatu

22、rerequired to ignite a material by 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

23、specific sets of laboratory conditions. 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 exposu

24、reconditions described in this procedure.NOTE 1All dimensions in millimetres.FIG. 1 Glow-Wire and Positioning of the ThermocoupleD61940826. 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 %

25、 chromium-80 % nickel, a diameter of 4 mm, and it shall be formed to thedimensions shown in Fig. 1.6.2 ThermocoupleUse Type K sheathed fine-wire thermo-couple, having an overall diameter of 1.0 mm max, and wiressuitable for continuous operation at temperatures up to 960 C,with the welded point locat

26、ed inside the sheath, for measuringthe temperature of the glow-wire. Examples of suitable wirecompositions are Nickel-Chromium (NiCr) and Nickel-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

27、at least 1050 C. Arrange the thermocouple isarranged in a pocket hole, drilled in the tip of the glow-wire, asshown in Fig. 1. Maintain the thermal contact between thewalls of the bored hole in the glow-wire by pinning thesheathed thermocouple in place. Ensure that the thermocouplefollows the moveme

28、nt of the tip of the glow-wire resultingfrom elongation caused by thermal heating.6.3 Temperature IndicatorUse a temperature indicator forType K thermocouples capable of reading up to 1000 C.Calibrate the combination thermocouple and temperature indi-cator in accordance with the general procedures o

29、utlined inTest Method E 220. The initial calibration tolerance is definedin the tables of Specification and Temperature-ElectromotiveForce (EMF) Tables E 230.6.4 Supply CircuitThe supply circuit shall be capable ofsupplying up to 150 A at 2.1V, with smooth continuousadjustment of voltage to provide

30、the required current as neededto maintain the desired glow-wire tip temperature.6.5 Test FixtureAs shown in Fig. 2, the test fixture shallbe capable 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

31、 least 7 mm.NOTE 2A weight of 100 6 20 g, as shown in Fig. 2, will provide therequired force.6.6 Indicator BoardUse 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 th

32、e glow-wire tip.6.7 Test ChamberUse as a test chamber a closed draft-freechamber that permits observation of the 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 unvent

33、ed during the test. Thechamber shall be equipped with an observation window.7. Test Specimen7.1 Prepare square specimens that are approximately 60 360 mm or round specimens that are approximately 60 mm indiameter, and of a thickness commonly encountered in prac-tice. Thicknesses less than 0.25 mm or

34、 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 2 C and 50 6 5 % relative humidity for at least 40 h priorto testing.FIG. 2 Test Ap

35、paratus (Example)D61940839. 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 precau

36、tions to safeguard 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 b

37、rush to remove any residue 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 penetration

38、is limited to 7 mm below 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 temp

39、erature. Maintain the 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 3The glow-wire temperature will decrease when the tip con-tacts the test specimen.

40、10.5 Observe to see whether 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 tis

41、suepaper on the indicator 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 50 C lower than that usedduring the previous test. If the resulting temperature ha

42、salready been used, do 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 ma

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

44、emperature is that temperaturethat is 25 C 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 giv

45、en thickness, at which one 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

46、. Report11.1 Report the 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 Bias

47、12.1 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 presented on the bias ofthe proc

48、edure in this test method for measuring the glow-wireignition temperature because no material having an acceptablereference value is available.13. Keywords13.1 electrically heated sources; flame; glow-wire; ignitabil-ity; ignition; plastic electrical insulating materialsD6194084SUMMARY OF CHANGESCom

49、mittee D09 has identified the location of selected changes to this test method since the last issue,D 6194 04, that may impact the use of this test method. (Approved June 1, 2008)(1) Added IEC 60695-2-12 to Referenced Documents. (2) Added new 3.2.2, 3.2.3, 10.8, and 11.1.4.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infrin