ASTM E659-2015 red 7743 Standard Test Method for Autoignition Temperature of Chemicals《化学品自燃温度的标准试验方法》.pdf

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1、Designation: E659 14E659 15Standard Test Method forAutoignition Temperature of Liquid Chemicals1This standard is issued under the fixed designation E659; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A

2、number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONThis test method is one of several methods developed by ASTM Committee E27 for determiningthe hazards of chemicals. It is designed to b

3、e used in conjunction with other tests to characterize thehazard potential of the chemical under test.1. Scope1.1 This test method covers the determination of hot- and cool-flame autoignition temperatures of a liquid chemical in air atatmospheric pressure in a uniformly heated vessel.NOTE 1Within ce

4、rtain limitations, this test method can also be used to determine the autoignition temperature of solid chemicals which readily meltand vaporize at temperatures below the test temperature and for chemicals that are gaseous at atmospheric pressure and temperature.NOTE 2After a round robin study, Test

5、 Method D2155 was discontinued, and replaced by Test Method E659 in 1978. See also Appendix X2.1.2 This standard should be used to measure and describe the properties of materials, products, or assemblies in response toheat and flame under controlled laboratory conditions and should not be used to d

6、escribe or appraise the fire hazard or fire riskof materials, products, or assemblies under actual fire conditions. However, results of this test may be used as elements of a firerisk assessment which takes into account all of the factors which are pertinent to an assessment of the fire hazard of a

7、particularend use.2. Referenced Documents2.1 ASTM Standards:2D2155 Test Method for Determination of Fire Resistance of Aircraft Hydraulic Fluids by Autoignition TemperatureD2883 Test Method for Reaction Threshold Temperature of Liquid and Solid MaterialsE659 Test Method for Autoignition Temperature

8、of Chemicals3. Terminology3.1 Definitions:3.1.1 ignition, nthe initiation of combustion.3.1.1.1 DiscussionIgnition, which is subjective, is defined for this test method as the appearance of a flame accompanied by a sharp rise in thetemperature of the gas mixture. The determination is made in total d

9、arkness because some flames, such as cool-flames, areobserved with difficulty.3.1.2 autoignition, nthe ignition of a material commonly in air as the result of heat liberation due to an exothermic oxidationreaction in the absence of an external ignition source such as a spark or flame.3.1.3 autoignit

10、ion temperature, nthe minimum temperature at which autoignition occurs under the specified conditions of test.1 This test method is under the jurisdiction of ASTM Committee E27 on Hazard Potential of Chemicals and is the direct responsibility of Subcommittee E27.04 onFlammability and Ignitability of

11、 Chemicals.Current edition approved Feb. 1, 2014Sept. 1, 2015. Published February 2014September 2015. Originally approved in 1978. Last previous edition approved in 20132014as E659 13.E659 14. DOI: 10.1520/E0659-14.10.1520/E0659-15.2 For referencedASTM standards, visit theASTM website, www.astm.org,

12、 or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes

13、have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official

14、document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.3.1 DiscussionAutoignition temperature is also referred to as spontaneous ignition temperature, self-ignition temperature, autogenous ignitiontemperature, and by the acronym

15、s AIT and SIT. As determined by this test method, AIT is the lowest temperature at which thesubstance will produce hot-flame ignition in air at atmospheric pressure without the aid of an external energy source such as sparkor flame. It is the lowest temperature to which a combustible mixture must be

16、 raised, so that the rate of heat evolved by theexothermic oxidation reaction will over-balance the rate at which heat is lost to the surroundings and cause ignition.3.1.4 cool-flame, na faint, pale blue luminescence or flame occurring below the autoignition temperature (AIT).3.1.4.1 DiscussionCool-

17、flames occur in rich vapor-air mixtures of most hydrocarbons and oxygenated hydrocarbons. They are the first part of themultistage ignition process.3.1.5 ignition delay time, nthe time lapse between application of heat to a material and its ignition. It is the time in secondsbetween insertion of the

18、 sample into the flask and ignition. It is maximum at the minimum autoignition temperature and alsoreferred to as ignition lag.4. Summary of Test Method4.1 A small, metered sample of the product to be tested is inserted into a uniformly heated 500-ml glass flask containing air ata predetermined temp

19、erature. The contents of the flask are observed in a dark room for 10 min following insertion of the sample,or until autoignition occurs. Autoignition is evidenced by the sudden appearance of a flame inside the flask and by a sharp rise inthe temperature of the gas mixture. The lowest internal flask

20、 temperature (T) at which hot-flame ignition occurs for a series ofprescribed sample volumes is taken to be the hot-flame autoignition temperature (AIT) of the chemical in air at atmosphericpressure. Ignition delay times (ignition time lags) are measured in order to determine the ignition delay-igni

21、tion temperaturerelationship.4.2 The temperatures at which cool-flame ignitions are observed or evidenced by small sharp rises of the gas mixturetemperature are also recorded along with the corresponding ignition delay times. The lowest flask temperature at which cool-flameignition occurs is taken t

22、o be the cool-flame autoignition temperature (CFT). Similarly, observations are made of any nonluminouspreflame reactions, as evidenced by a relatively gradual temperature rise which then falls off to the base temperature. The lowestflask temperature at which these reactions are observed is the reac

23、tion threshold temperature (RTT).NOTE 3The hot-flame autoignition, cool-flame autoignition, and reaction threshold temperatures obtained by this test method approximate thosetemperatures obtained by Test Method D2883 for hot-flame reaction, cool-flame reaction, and reaction threshold, respectively.5

24、. Significance and Use5.1 Autoignition, by its very nature, is dependent on the chemical and physical properties of the material and the method andapparatus employed for its determination. The autoignition temperature by a given method does not necessarily represent theminimum temperature at which a

25、 given material will self-ignite in air. The volume of the vessel used is particularly important sincelower autoignition temperatures will be achieved in larger vessels. (See Appendix X2.) Vessel material can also be an importantfactor.5.2 The temperatures determined by this test method are those at

26、 which air oxidation leads to ignition. These temperatures canbe expected to vary with the test pressure and oxygen concentration.5.3 This test method is not designed for evaluating materials which are capable of exothermic decomposition. For suchmaterials, ignition is dependent upon the thermal and

27、 kinetic properties of the decomposition, the mass of the sample, and the heattransfer characteristics of the system.5.4 This test method can be employed for solid chemicals which melt and vaporize or which readily sublime at the testtemperature. No condensed phase, liquid or solid, should be presen

28、t when ignition occurs.5.5 This test method is not designed to measure the autoignition temperature of materials which are solids or liquids at the testtemperature (for example, wood, paper, cotton, plastics, and high-boiling point chemicals). Such materials will thermally degradein the flask and th

29、e accumulated degradation products may ignite.5.6 This test method can be used, with appropriate modifications, for chemicals that are gaseous at atmospheric temperature andpressure.5.7 This test method was developed primarily for liquid chemicals but has been employed to test readily vaporized soli

30、ds.Responsibility for extension of this test method to solids of unknown thermal stability, boiling point, or degradation characteristicsrests with the operator.E659 1526. Apparatus6.1 FurnaceAn electrically heated crucible furnace or fluidized sand bath of appropriate internal geometry and dimensio

31、nsto contain the test flask and which will maintain a uniform temperature within the flask shall be used.Afurnace with a cylindricallyshaped interior, 5 in. (12.7 cm) in inside diameter, and 7 in. (17.8 cm) deep is minimal for this purpose. It should be capable ofattaining a temperature of 600C or h

32、igher.6.2 Temperature ControllerA temperature control system, capable of controlling the temperature in the furnace to within61C at temperatures up to 350C, and to within 62C above 350C, is required. Temperatures are monitored at the bottom, side,and neck of the flask by means of three external ther

33、mocouples. Heating adjustments are made when necessary in order to maintainuniform temperature within the flask. If a controller is not available, temperature control may be achieved by the use of suitableautotransformers or rheostats, thermocouples, and a suitable potentiometer.6.3 Test FlaskThe te

34、st flask shall be a commercial 500-ml borosilicate round-bottom, short-necked boiling flask.6.3.1 The flask is closely wrapped in reflective metal foil, such as aluminum, to promote temperature uniformity, and issuspended in the furnace so as to be completely enclosed with the top of the neck being

35、inset below the top of the insulated cover(see Fig. 1).6.3.2 The flask is suspended in the furnace or sand bath by means of a thick insulating holder, the bottom of which is alsocovered with reflective metal foil.6.4 Hypodermic SyringeA 500 or 1000-l hypodermic syringe equipped with a 6-in., No. 26

36、or finer stainless steel needle,and calibrated in units of 10 l should be used to inject liquid samples into the heated flask. It is suggested that a needle with aright-angle bend be used so that the operators fingers can be kept away from the flask opening.6.5 BalanceA laboratory balance capable of

37、 weighing to the nearest 10 mg shall be used for preparing samples that are solidat room temperature. Sample weights will range from 10 to 1000 mg.6.6 Powder FunnelA 60-mm filling funnel is used to aid the insertion of solid samples into the flask. It is suggested that aholder such as a small buret

38、clamp be used so that the operators fingers can be kept away from the flask opening.6.7 ThermocoupleA fine Chromel-Alumel thermocouple (36 B and S gage) is used for measuring the gas temperature (T)inside the flask. Position the tip of the thermocouple at the center of the flask. Thermocouples shoul

39、d be calibrated against standardFIG. 1 Autoignition Temperature ApparatusE659 153temperatures or a standard thermocouple, and should be rechecked frequently. Iron-constantan thermocouples are to be avoidedbecause they may promote catalytic oxidation on the iron-oxide surface. External flask temperat

40、ures are measured with a No. 20B and S gage or finer thermocouple mounted at the top (t1), middle (t2), and bottom (t3) of the flask.6.8 Recording PotentiometerA fast response (1 s or less for full scale pen travel) variable range and variable chart speedrecording potentiometer shall be used for rec

41、ording the signal from the internal gas thermocouple (T). An XY recorder has beenfound suitable for this purpose.6.9 TimerA stop watch or electric timer (preferably foot-switch operated) calibrated in 0.1 or 0.2-s units shall be used todetermine the time lag before ignition (time interval between th

42、e instant of sample insertion and that of ignition as evidenced bythe appearance of the flame). If visual ignition is difficult to observe, the temperature-time recorder trace may be used to estimatethe time lag.6.10 MirrorA 6-in. mirror or other suitable size, mounted above the flask so that the ob

43、server may see into the flask withouthaving to be directly over it.6.11 Hot-Air GunA suitable hot-air gun may be used to purge the product gases after a reaction is completed and before thenext test. A temperature-controlled, hot-air guncan reduce testing time if used to aid in achieving the desired

44、 flash temperaturebetween trials and upon insertion of clean test flasks.7. Safety Considerations7.1 No explosion hazard is encountered in conducting the determination as outlined in Section 7. However, flames areoccasionally emitted well above the top of the flask. Thus, the operator should always

45、use a mirror for observation of the flaskinterior. The use of a right-angle syringe and, for solids, the use of a holder for the powder funnel will remove the hands from theimmediate vicinity of the flask opening.7.2 It is recommended that the apparatus be installed in a fume hood or be equipped wit

46、h an exhaust duct to prevent exposureto potentially toxic combustion and decomposition products. All tests with toxic chemicals should involve the use of adequateexhaust ventilation.7.3 Determinations normally should not be made on potential or known explosive or propellant materials. Where such AIT

47、information is required, the determinations should be made remotely behind a barricade.8. Procedure8.1 Temperature ControlAfter the internal flask temperature (T) has reached the desired temperature, adjust the temperaturecontroller to maintain this temperature within the designated limits and allow

48、 the system to equilibrate.8.2 LightingThe lighting before sample insertion should be very subdued. Extinguish the lights as the sample is inserted.Cool-flame tests are generally conducted in total darkness. Eyes should be totally dark-adapted for optimum observation of coolflames.8.3 Sample Additio

49、n:8.3.1 LiquidsInject 100 l of the sample to be tested into the flask with the hypodermic syringe and quickly withdraw thesyringe. Extinguish the lights as the sample is injected.8.3.2 SolidsInsert a 100-mg sample by pouring it from the weighing vessel through the powder funnel which is inserted inthe neck of the flask. Quickly withdraw the powder funnel and extinguish the lights.8.3.3 GasesInject 100 mg of the sample to be tested into the flask with a syringe (or other means such as one described inAppendix X4) and quickly withdraw the sy