BS ISO 871-2006 Plastics - Determination of ignition temperature using a hot-air furnace《塑料 热空气炉的点燃温度的测定》.pdf

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1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58using a hot-air furnaceICS 13.220.40; 83.080.01Plastics Determination of ignition temperature BRITI

2、SH STANDARDBS ISO 871:2006BS ISO 871:2006This British Standard was published under the authority of the Standards Policy and Strategy Committee on 29 December 2006 BSI 2006ISBN 0 580 49847 6Amendments issued since publicationAmd. No. Date Commentscontract. Users are responsible for its correct appli

3、cation.Compliance with a British Standard cannot confer immunity from legal obligations.National forewordThis British Standard was published by BSI. It is the UK implementation of ISO 871:2006. It supersedes BS ISO 871:1996 which is withdrawn. The UK participation in its preparation was entrusted to

4、 Technical Committee PRI/26, Burning behaviour of plastics and rubbers.A list of organizations represented on PRI/26 can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a INTERNATIONALSTANDARDISO871Third edition2006-11-15Reference

5、numberISO 871:2006(E)Plastics Determination of ignition temperature using a hot-air furnacePlastiques Dtermination de la temprature dallumage au moyen dun four air chaudBS ISO 871:2006iiiiiContents Page1 Scope 12 Normative references 13 Terms and definitions 14 Principle 25 Apparatus . 26 Location o

6、f thermocouples . 37 Test specimens 38 Procedure . 58.1 Flash-ignition temperature (FIT) 58.2 Spontaneous-ignition temperature (SIT) . 69 Precision . 610 Test report 6Annex A (informative) Results obtained by interlaboratory trials . 7BS ISO 871:2006ivForewordISO (the International Organization for

7、Standardization) is a worldwide federation of national standards bodies(ISO member bodies). The work of preparing International Standards is normally carried out through ISOtechnical committees. Each member body interested in a subject for which a technical committee has beenestablished has the righ

8、t to be represented on that committee. International organizations, governmental andnon-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the InternationalElectrotechnical Commission (IEC) on all matters of electrotechnical standardization.International Sta

9、ndards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.The main task of technical committees is to prepare International Standards. Draft International Standardsadopted by the technical committees are circulated to the member bodies for voting. Publication as anInter

10、national Standard requires approval by at least 75 % of the member bodies casting a vote.Attention is drawn to the possibility that some of the elements of this document may be the subject of patentrights. ISO shall not be held responsible for identifying any or all such patent rights.ISO 871 was pr

11、epared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 4, Burning behaviour.This third edition cancels and replaces the second edition (ISO 871:1996), which has been technically revised.BS ISO 871:20061Plastics Determination of ignition temperature using a hot-air furnace1Scope1.1 This I

12、nternational Standard specifies a laboratory method for determining the flash-ignition temperatureand spontaneous-ignition temperature of plastics using a hot-air furnace. It is one of a number of methods inuse for evaluating the reaction of plastics to the effects of ignition sources.1.2 This metho

13、d does not give a direct measure of the combustibility or rate of burning of a material or anydefinition of the safe upper limit of temperature for the plastics in use, and it should not be used alone todescribe or appraise the fire hazard or fire risk of materials, products or assemblies under actu

14、al fire conditions.However, results of this test may be used as elements of a fire hazard or fire risk assessment which takes intoaccount all of the factors pertinent to an assessment of the fire hazard of a particular end use.1.3 Tests made under conditions of this method can be of considerable val

15、ue in comparing the relative ignitioncharacteristics of different materials. Values obtained represent the lowest ambient air temperature that willcause ignition of the material under the conditions of this test. Test values are expected to rank materialsaccording to ignition susceptibility under ac

16、tual use conditions.2 Normative referencesThe following referenced documents are indispensable for the application of this document. For datedreferences, only the edition cited applies. For undated references, the latest edition of the referenced document(including any amendments) applies.ISO 291, P

17、lastics Standard atmospheres for conditioning and testingISO 13943, Fire safety VocabularyIEC 60584-2:1982, Thermocouples Part 2: Tolerances3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply in addition to those given inISO 13943.3.1 flash-ignition te

18、mperatureFITminimum temperature at which, under specified test conditions, sufficient flammable gases are emitted to ignitemomentarily on application of a pilot flame3.2 spontaneous-ignition temperatureSITminimum temperature at which, under specified test conditions, ignition is obtained by heating

19、in the absence ofany additional ignition sourceBS ISO 871:200623.3 glowing combustioncombustion of a material in the solid phase without flame but with emission of light from the combustion zone4PrincipleA specimen of the material is heated in a hot-air ignition furnace using various temperatures wi

20、thin the heatedchamber, and the flash-ignition temperature is determined with a small pilot flame directed at the opening in thetop of the furnace to ignite evolved gases.The spontaneous-ignition temperature is determined in the same manner as the flash-ignition temperature, butwithout the pilot fla

21、me.5 Apparatus5.1 Hot-air ignition furnace, similar to that shown in Figure 1, consisting primarily of an electrical heating unitand a specimen holder.5.2 Furnace tube, with an inside diameter of and a length of , made of aceramic that will withstand at least . The tube shall be positioned verticall

22、y so that it stands on thefurnace floor above a plug for the removal of accumulated residue.5.3 Inner ceramic tube, capable of withstanding at least , with an inside diameter of ,a length of and a thickness of approximately , placed centrally inside the furnace tubeand positioned above the furnace f

23、loor on three small refractory spacer blocks. The top shall becovered by a disc of heat-resistant material with a diameter opening in the centre which is usedfor observations and allows the passage of smoke and gases. The pilot flame shall be located immediatelyabove the opening.5.4 Outside air sour

24、ce, to supply clean air near the top of the annular space between the ceramic tubesthrough a copper tube at a steady and controllable rate. The air shall be heated and circulated in the spacebetween the two tubes and enter the inner ceramic tube at the bottom. The air flow shall be metered by arotam

25、eter or other suitable device.5.5 Electrical heating unit, made of 50 turns of nichrome wire or equivalent. The wires,contained within a mineral-fibre sleeve, shall be wound around the furnace tube and shall be embedded in heat-resistant cement.5.6 Insulation, consisting of a layer of mineral-fibre

26、wool approximately thick, and covered by a sheet-iron jacket.5.7 Pilot igniter, consisting of a copper tube of nominal inside diameter attached to a supply of minimum purity propane and placed horizontally above the top surface of the disc cover. Thepilot flame shall be adjusted to in length and cen

27、tred above the opening in the disc cover.5.8 Specimen support and holder, consisting of a metal specimen pan made of thickstainless steel and measuring in diameter by in depth, having a roundedbottom and held in a ring of approximately diameter stainless-steel welding rod. The ring shall be weldedto

28、 a length of the same type of rod extending through the cover of the furnace, as shown in Figure 1. The bottomof the specimen pan shall be located down from the lower edge of the pilot igniter.5.9 Thermocouples, in diameter, chromel-alumel (type K) or iron-constantan (type J), fortemperature measure

29、ment, connected to a calibrated recording instrument with a tolerance not exceeding. The thermocouple tolerance shall be in accordance with IEC 60584-2:1982, Table A.1, class 2, orbetter.5.10 Heating control, consisting of a suitable variable transformer or an automatic controller connected inseries

30、 with the heating coils.100 mm 5mm 240 mm 20 mm750C750C 75 mm 2mm240 mm 20 mm 3mm20 mm 2mm25 mm 2mm1,3 mm 0,1 mm60 mm2,0 mm 94 %5mm 1mm20 mm 2mm0,7 mm 0,2 mm40 mm 2mm 15 mm 2mm2mm185 mm 2mm0,5 mm2CBS ISO 871:200635.11 Timing device, having an accuracy of or better.6 Location of thermocouples6.1 Ther

31、mocouple (see Figure 1) measures the temperature of the specimen. It is located as close aspossible to the centre of the upper surface of the specimen when the specimen is in place within the furnace.The thermocouple wire is attached to the specimen support rod.6.2 Thermocouple gives some indication

32、 of the temperature of the air travelling past the specimen. Itis located below the centre of the specimen pan. The thermocouple wire is convenientlyattached to the specimen support rod.NOTE Thermocouple may also be installed through a hole drilled in the centre of the inspection plug below thespeci

33、men pan.6.3 Thermocouple measures the temperature of the heating coil. It is located adjacent to the furnaceheating coil and is used in preference to the inner-tube thermocouples because of its faster response.7 Test specimens7.1 Materials supplied in any form, including composites, may be used, but

34、 it is essential that the form is fullydescribed in the test report.NOTE 1 Specimens containing flame retardants and high levels of inorganic fillers may be difficult to evaluate.NOTE 2 The same material tested in different forms may give different results.7.2 For materials having a density greater

35、than , a specimen mass of shall be used.Materials may be tested in the form of pellets or powder, as normally supplied for moulding. For sheet materials,cut the sheet into squares of maximum size and stack these to a heightwhich gives the required specimen mass. For film materials, roll up a strip w

36、ide and of lengthsufficient to give the required specimen mass.7.3 For cellular materials having a density less than , remove any outer skin and cut specimens inthe form of a block measuring .NOTE If the specimen is bulky and light and easily affected by the air flow in the furnace so that it may fa

37、ll out of the tray,the specimen may be bound by a thin wire.7.4 Sufficient material is required for at least two determinations.7.5 Condition the test specimens at and relative humidity for not less than priorto test, in accordance with ISO 291.1sTC1T1TC2T210 mm 2mmTC2TC3T3100 kg/m33,0 g 0,2 g(20 mm

38、 2 mm) (20 mm 2 mm)20 mm 2mm100 kg/m3(20 mm 2 mm) (20 mm 2 mm) (50 mm 5 mm)23C 2C (50 5) % 40 hBS ISO 871:20064Dimensions in millimetresFigure 1 Cross section of hot-air ignition furnaceBS ISO 871:200658 Procedure8.1 Flash-ignition temperature (FIT)8.1.1 Set the air velocity to by adjusting the actu

39、al air-flow rate through the full section of the innertube (5.3) at the furnace temperature to a value calculated in litres per minute from the following equation:where is the temperature in K.Ensure that the air-flow rate is maintained at of the calculated value.8.1.2 Adjust the electric current su

40、pplied to the heating coil (5.5) by means of the variable transformer orautomatic controller (5.10), by reference to temperature , until the air temperature remains constant at thedesired initial test temperature.NOTE A temperature of is used when no prior knowledge of the probable flash-ignition te

41、mperature range isavailable. Other starting temperatures may be selected if information about the material indicates a better choice.8.1.3 Raise the specimen holder (see 5.8) to the cover opening and place the pan with the specimen into thering of the holder. Ensure that thermocouples and are in the

42、ir correct position (see 6.1 and 6.2) andlower the pan into the furnace. Start the timer (5.11), ignite the pilot flame and watch for evidence of a flash ormild explosion of combustible gases which may be followed by burning of the specimen.8.1.4 At the end of , lower or raise the temperature by , d

43、epending on whether ignition has orhas not occurred, and repeat the test with a fresh specimen.8.1.5 When the range within which the flash-ignition temperature lies has been determined, begin tests below the highest temperature within this range and continue by dropping the temperature in steps unti

44、lthe temperature is reached at which there is no ignition during a period.Key1 thermocouple 2 support rod3 refractory disc cover4 thermocouple 5 gasket6 thermocouple 7 heater terminals8 pilot flame9 air supply10 metal fasteners11 air-flow meter (not part of furnace)12 air flow tangential to cylinder

45、13 specimen pan14 mineral fibre wool15 50 turns of No. 16 nichrome wire in heat-resistant cement16 three refractory blocks to space inner tube and support it17 inspection plug (removable)18 thermal insulation (removable)Figure 1 Cross section of hot-air ignition furnace (continued)TC2TC1TC325 mm/s q

46、VqV= 6,62 293TT10 %T3T2400CTC1TC210 min T250C10C10C10 minBS ISO 871:200668.1.6 Record as the flash-ignition temperature the lowest air temperature at which a flash is observedduring the period.8.2 Spontaneous-ignition temperature (SIT)8.2.1 Follow the same procedure as in 8.1 but without the pilot f

47、lame.8.2.2 Ignition will be evidenced by flaming or glowing combustion of the specimen. It may be difficult, withsome materials, to detect spontaneous ignition visually when burning is by glowing combustion rather thanflaming. In such cases, a rapid rise in temperature above temperature accompanied

48、by a visualobservation is the more reliable reference.8.2.3 Record as the spontaneous-ignition temperature the lowest air temperature at which flaming orglowing combustion of the specimen is observed within the period.NOTE Determination of ignition temperatures is a process which is very sensitive t

49、o outer conditions. It is thereforenecessary to keep strictly to the test conditions and procedures specified in this International Standard.9PrecisionPrecision data based on interlaboratory trials are given in Annex A.10 Test reportThe test report shall include the following:a) a reference to this International Standard;b) the designation of the material, including name of manufacturer and composition;c) the mass of the test specimen, in grams;d) the form of the m