1、Designation: D 7309 07aStandard Test Method forDetermining Flammability Characteristics of Plastics andOther Solid Materials Using Microscale CombustionCalorimetry1This standard is issued under the fixed designation D 7309; the number immediately following the designation indicates the year oforigin
2、al adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method, which is similar to thermal analysistechniques
3、, establishes a procedure for determining flamma-bility characteristics of combustible materials such as plastics.1.2 The test is conducted in a laboratory environment usingcontrolled heating of milligram specimens and complete ther-mal oxidation of the specimen gases.1.3 Specimens of known mass are
4、 thermally decomposed inan oxygen-free (anaerobic) or oxidizing (aerobic) environmentat a constant heating rate between 0.2 and 2 K/s.1.4 The heat released by the specimen is determined fromthe mass of oxygen consumed to completely oxidize (combust)the specimen gases.1.5 The rate of heat released by
5、 combustion of the specimengases produced during controlled thermal or thermoxidativedecomposition of the specimen is computed from the rate ofoxygen consumption.1.6 The specimen temperatures over which combustion heatis released are measured.1.7 The mass of specimen remaining after the test ismeasu
6、red and used to compute the residual mass fraction.1.8 The specimen shall be a material or composite materialin any form (fiber, film, powder, pellet, droplet). This testmethod has been developed to facilitate material developmentand research.1.9 This standard is used to measure and describe theresp
7、onse of materials, products, or assemblies to heat andflame under controlled conditions, but does not by itselfincorporate all factors required for fire hazard or fire riskassessment of the materials, products, or assemblies underactual fire conditions.1.10 This standard does not purport to address
8、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 determine the applica-bility of regulatory limitations prior to use.NOTE 1There is no ISO equivalent to this test method.2. Refer
9、enced Documents2.1 ASTM Standards:2D 883 Terminology Relating to PlasticsD 5865 Test Method for Gross Calorific Value of Coal andCokeE 176 Terminology of Fire StandardsE 1591 Guide for Obtaining Data for Deterministic FireModels3. Terminology3.1 Definitions:3.1.1 For definitions of terms relating to
10、 plastics, refer toTerminology D 883.3.1.2 For definitions of terms relating to fire, refer toTerminology E 176.3.2 Definitions of Terms Specific to This Standard:3.2.1 combustion residue, nthe non-volatile chemical spe-cies remaining after controlled thermal oxidative decomposi-tion of a specimen.3
11、.2.2 combustion temperature, nthe specimen tempera-ture at which the specific combustion rate is a maximum duringcontrolled thermal oxidative decomposition.3.2.3 controlled heating, na controlled temperature pro-gram used to effect thermal decomposition or oxidative thermaldecomposition in which the
12、 temperature of the specimen isuniform throughout and increases with time at a constant rate.3.2.4 controlled thermal (or thermal oxidative) decomposi-tion, nthermal (oxidative) decomposition under controlledheating.3.2.5 heat release capacity, nthe maximum specific heatrelease rate during a control
13、led thermal decomposition dividedby the heating rate in the test.3.2.6 heating rate, nthe constant rate of temperature riseof the specimen during the controlled temperature program.1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcom
14、mittee D20.30 on Thermal Properties.Current edition approved Nov. 1, 2007. Published November 2007. Originallyapproved in 2007. Last previous edition approved in 2007 as D 7309 07.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org
15、. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.7 heat release temperature, nthe specimen tempera-ture at whic
16、h the specific heat release rate is a maximum duringcontrolled thermal decomposition.3.2.8 maximum specific combustion rate, nthe maximumvalue of the specific combustion rate recorded during the test.3.2.9 maximum specific heat release rate, nthe maximumvalue of the specific heat release rate record
17、ed during the test.3.2.10 net calorific value, nthe net heat of completecombustion of the specimen measured during controlled ther-mal oxidative decomposition per unit initial specimen mass.3.2.11 oxidative thermal decomposition, na process ofextensive chemical species change caused by heat and oxyg
18、en(thermal oxidation, oxidative pyrolysis).3.2.12 pyrolysis residue, nthe fraction of the initial speci-men mass remaining after controlled anaerobic thermal decom-position.3.2.13 specific combustion rate, nthe rate at which com-bustion heat is released per unit initial mass of specimen duringcontro
19、lled thermal oxidative decomposition.3.2.14 specific heat of combustion of specimen gases,nnet calorific value of gases.3.2.15 specific heat release rate, nthe rate at whichcombustion heat is released per unit initial mass of specimenduring controlled thermal decomposition.3.2.16 specific heat relea
20、se, nthe net heat of completecombustion of the volatiles liberated during controlled thermaldecomposition per unit initial specimen mass.3.2.17 specimen gases, nthe volatile chemical speciesliberated during controlled thermal (oxidative) decompositionof a specimen.3.3 Symbols:b = heating rate, K/sE
21、= 13.1 kJ/g-O2is the average heat released bycomplete combustion of organic compounds perunit mass of oxygen consumedF = volumetric flow rate of the combustion stream atambient temperature and pressure measured atthe terminal flow meter, cm3/shc= specific heat release of sample, J/ghco= net calorifi
22、c value of sample, J/ghc,gas= specific heat of combustion of specimen gases,J/ghc= heat release capacity, J/g-Kmo= initial specimen mass, gmc= residual specimen mass after oxidative pyrolysis,gmp= residual specimen mass after the anaerobic py-rolysis, gDO2 = the change in the concentration (volume f
23、raction)of O2in the gas stream due to combustionmeasured at the oxygen sensor at time t,cm3/cm3Q(t) = specific heat release rate at time t, W/gQmax= maximum specific heat release rate, W/gQmaxo= maximum specific combustion rate, W/gr = density of oxygen at ambient conditions, g/cm3t = time synchroni
24、zed to temperature, x - t,sTmax= heat release temperature, KTmaxo= combustion temperature, Kt = transit time of the gas stream between the speci-men location and the oxygen analyzer, sx = time at which the oxygen analyzer signal isrecorded, sYc= combustion residue, g/gYp= pyrolysis residue, g/g4. Su
25、mmary of Test Method4.1 This test method provides two procedures for determin-ing flammability characteristics of materials in a laboratory testusing controlled heating (controlled temperature program-ming) and oxygen consumption calorimetry. This test measuresflammability characteristics using a co
26、ntrolled temperatureprogram to force the release of specimen gases, thermaloxidation of the specimen gases (and optionally the specimenresidue) in excess oxygen, and measurement of the oxygenconsumed to calculate the amount, rate, and temperature ofheat released by combustion of a solid specimen dur
27、ingcontrolled heating.4.2 Controlled Thermal Decomposition, Method AIn thisprocedure the specimen is subjected to controlled heating in anoxygen-free/anaerobic environment, that is, controlled thermaldecomposition. The gases released by the specimen duringcontrolled thermal decomposition are swept f
28、rom the specimenchamber by a non-oxidizing/inert purge gas (typically nitro-gen), subsequently mixed with excess oxygen, and completelyoxidized in a high temperature combustion furnace. Thevolumetric flow rate and volumetric oxygen concentration ofthe gas stream exiting the combustion furnace are co
29、ntinuouslymeasured during the test to calculate the rate of heat release bymeans of oxygen consumption. In Method A the heat ofcombustion of the volatile component of the specimen (speci-men gases) is measured but not the heat of combustion of anysolid residue. Table X1.1 of Appendix X1 shows data f
30、or hc,hc, Yp, and Tmaxfor 14 different commercial plastics tested intriplicate (n = 3).4.3 Controlled Thermal Oxidative Decomposition,Method BIn this procedure the specimen is subjected tocontrolled heating in an oxidizing/aerobic environment, that is,controlled thermal oxidative decomposition. The
31、specimengases evolved during the controlled heating program are sweptfrom the specimen chamber by the oxidizing purge gas (forexample, dry air) and mixed with additional oxygen, ifnecessary, prior to entering a high temperature combustionfurnace where the gases are completely oxidized. The volu-metr
32、ic flow rate and volumetric oxygen concentration of thegas stream exiting the combustion furnace are continuouslymeasured during the test to calculate the specific combustionrate by means of oxygen consumption. In Method B the netD 7309 07a2calorific value of the specimen gases and solid residue are
33、measured during the test.5. Significance and Use5.1 This laboratory test method measures thermal combus-tion properties of materials (1-5).35.2 The test uses controlled thermal decomposition of speci-mens and thermal oxidation of the specimen gases as they arereleased from the specimen to simulate t
34、he condensed and gasphase processes of flaming combustion, respectively, in asmall-scale laboratory test (1-7).5.3 The thermal combustion properties measured in the testare related to flammability characteristics of the material (4-7).5.4 The amount of heat released in flaming combustion perunit mas
35、s of material is the fire load and the potential fire load(complete combustion) is estimated in Method A as hc.5.5 The net calorific value of the material (see Test MethodD 5865) is determined directly using Method B as hcowithoutthe need to know the atomic composition of the specimen tocorrect for
36、the latent heat of evaporation of the water producedby combustion, or to perform titrations to correct for the heatof solution of acid gases. See Table X1.2 for comparison ofMicroscale Combustion Calorimetry (MCC) data with TestMethod D 5865.5.6 The heat release temperature Tmaxof MethodAapproxi-mat
37、es the surface temperature at piloted ignition in accordancewith Ref. (5-7) for purposes of fire modeling (See GuideE 1591).5.7 The heat release capacity hc(J/g-K) is a flammabilityparameter measured in Method A that is unique to this testmethod.6. Limitations6.1 The heat release capacity (hc) is in
38、dependent of theform, mass, and heating rate of the specimen as long as thespecimen temperature is uniform at all times during the test(1-5).6.2 Test results obtained from small (milligram) samples bythis method do not include physical behavior such as melting,dripping, swelling, shrinking, delamina
39、tion, and char/barrierformation that can influence the results of large (decagram/kilogram) samples in flame and fire tests.6.3 Test results obtained from small (milligram) samples bythis method do not include extrinsic factors such as thickness,sample orientation, external heat flux, ignition sourc
40、e, bound-ary conditions, and ventilation rate that influence the results oflarge (decagram/kilogram) samples in flame and fire tests.6.4 The specific combustion rate and combustion tempera-ture of Method B are not generally reproducible becausesample geometry can affect the rate of surface oxidation
41、 andgas phase ignition can occur in the sample chamber atappropriate fuel/oxygen ratios. Reproducibility of QmaxoandTmaxoare improved by using low oxygen concentration in thepurge gas, small samples, and low heating rates in this test.7. Apparatus7.1 The equipment used in this test method shall be c
42、apableof displaying changes in combustion heat release rate as afunction of specimen temperature during controlled heatingand shall have the capability of subjecting the specimen todifferent atmospheres of oxygen concentration at ambientpressure.7.2 Commercial thermogravimetric analyzers, pyrolysisp
43、robes, and electrically-heated ceramic tubes in thermal con-tact with a combustor, or attached gas analyzers, or both, havebeen found suitable. Detailed apparatus design criteria aregiven in Annex A1.NOTE 2In typical materials tests a material is exposed to a particularset of test conditions and the
44、 materials response to those particular testconditions is measured and reported as the test result. In these testschanging the test conditions has an effect on the result of the test. In thistest, the heat release capacity (hc) is independent of the test parameters asit is a material property and no
45、t a response of a material to a particular setof conditions. Thus, changing the test condition (within certain con-straints) will have no effect on the test result. As such, the apparatusrequired to perform this test shall operate to provide test parameters thatremain within certain constraints for
46、each section of the device, forexample, specimen chamber, mixing section, combustor. The diameter,length and shape of each section will have no effect on the test resultprovided the section meets the performance given in Annex A1.7.3 Figure 1 illustrates the basic components of an appara-tus, (1, 5,
47、 8-11), satisfactory for this test method which include:7.4 A specimen chamber (sample chamber) that is capableof holding and heating a small (milligram sized) specimen in acontinuous flow of purge gas.7.5 Temperature controller, capable of executing a tempera-ture program that changes the specimen
48、chamber temperaturebetween ambient and 1123 K at a rate that is constant to within5 % of the nominal value in the range 0.2-2 K/s.7.6 A means of purging the specimen chamber environmentwith a constant flow of inert (for example, nitrogen) or reactive(nitrogen/oxygen mixture) gas at a rate of 50-100
49、cm3/min withan accuracy of 61%.7.7 A temperature sensor, to provide an indication of thespecimen temperature to 60.5 K.7.8 A mixing chamber, where the specimen and purge gasesare mixed with sufficient oxygen to effect complete oxidationof the specimen gases in the combustion chamber.7.9 A means of introducing oxygen into the mixing section ata constant flow rate of 0-50 cm3/min, such that the concentra-tion of oxygen is between 20-50 % (60.1 %) by volumeentering the combustion chamber.7.10 A combustor (combustion chamber) capable of main-taining a constant tem
