1、Designation: E659 78 (Reapproved 2005)E659 13Standard 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
2、 last revision. A 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. I
3、t is designed to be 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 vess
4、el.NOTE 1Within certain 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.NOTE 1Within certain limitations, this test method can also be used to determine the autoignit
5、ion temperature of solid chemicals which readily meltand vaporize at temperatures below the test temperature.NOTE 2After a round robin study, Test 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 th
6、e properties of materials, products, or assemblies in response toheat and flame under controlled laboratory conditions and should not be used to describe or appraise the fire hazard or fire riskof materials, products, or assemblies under actual fire conditions. However, results of this test may be u
7、sed 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 particularend use.2. Referenced Documents2.1 ASTM Standards:2D2155 Test Method for Determination of Fire Resistance of Aircraft Hydraulic Fluids by Autoig
8、nition TemperatureD2883 Test Method for Reaction Threshold Temperature of Liquid and Solid MaterialsE6593. Terminology3.1 Definitions:3.1.1 ignition, nthe initiation of combustion.3.1.2 Ignition, which is subjective, is defined for this method as the appearance of a flame accompanied by a sharp rise
9、 in thetemperature of the gas mixture. The determination is made in total darkness because some flames, such as cool-flames, areobserved with difficulty.3.2 autoignition, nthe ignition of a material commonly in air as the result of heat liberation due to an exothermic oxidationreaction in the absenc
10、e of an external ignition source such as a spark or flame.3.3 autoignition temperature, nthe minimum temperature at which autoignition occurs under the specified conditions of test.3.3.1 Autoignition temperature is also referred to as spontaneous ignition temperature, self-ignition temperature, auto
11、genousignition temperature, and by the acronyms AIT and SIT. As determined by this method, AIT is the lowest temperature at which1 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
12、and Ignitability of Chemicals.Current edition approved Sept. 15, 2005Oct. 15, 2013. Published December 2005November 2013. Originally approved in 1978. Last previous edition approved in20002005 as E659 78 (2000).(2005). DOI: 10.1520/E0659-78R05.10.1520/E0659-13.2 For referencedASTM standards, visit t
13、heASTM website, www.astm.org, 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 a
14、n indication of what changes 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 t
15、o be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1the substance will produce hot-flame ignition in air at atmospheric pressure without the aid of an external energy source such asspark or flame. It
16、is the lowest temperature to which a combustible mixture must be 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.3.4 cool-flame, na faint, pale blue luminescence or flame occurring be
17、low the autoignition temperature (AIT).NOTE 2Cool-flames occur in rich vapor-air mixtures of most hydrocarbons and oxygenated hydrocarbons. They are the first part of the multistageignition process.3.5 ignition delay time, nthe time lapse between application of heat to a material and its ignition. I
18、t is the time in secondsbetween insertion of the sample into the flask and ignition. It is maximum at the minimum autoignition temperature and alsoreferred to as ignition lag.3. Terminology3.1 Definitions:3.1.1 ignition, nthe initiation of combustion.3.1.1.1 DiscussionIgnition, which is subjective,
19、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 darkness because some flames, such as cool-flames, areobserved with difficulty.3.1.2 autoignition, nthe ignition of a material commonly in
20、 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 autoignition temperature, nthe minimum temperature at which autoignition occurs under the specified conditions of test.3.1.3.1 DiscussionAutoignit
21、ion temperature is also referred to as spontaneous ignition temperature, self-ignition temperature, autogenous ignitiontemperature, and by the acronyms 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 atmosp
22、heric 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 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
23、 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-flames occur in rich vapor-air mixtures of most hydrocarbons and oxygenated hydrocarbons. They are the first part of themultistage ignition process.3.
24、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 sample into the flask and ignition. It is maximum at the minimum autoignition temperature and alsoreferred to as ignition lag.4. Summary of Test Meth
25、od4.1 A small, metered sample of the product to be tested is inserted into a uniformly heated 500-ml glass flask containing air ata predetermined temperature. The contents of the flask are observed in a dark room for 10 min following insertion of the sample,or until autoignition occurs. Autoignition
26、 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 temperature (T) at which hot-flame ignition occurs for a series ofprescribed sample volumes is taken to be the hot-flame autoignition temperature (AI
27、T) of the chemical in air at atmosphericpressure. Ignition delay times (ignition time lags) are measured in order to determine the ignition delay-ignition temperaturerelationship.4.2 The temperatures at which cool-flame ignitions are observed or evidenced by small sharp rises of the gas mixturetempe
28、rature are also recorded along with the corresponding ignition delay times. The lowest flask temperature at which cool-flameignition occurs is taken to be the cool-flame autoignition temperature (CFT). Similarly, observations are made of any nonluminouspreflame reactions, as evidenced by a relativel
29、y gradual temperature rise which then falls off to the base temperature. The lowestflask temperature at which these reactions are observed is the reaction threshold temperature (RTT).NOTE 3The hot-flame autoignition, cool-flame autoignition, and reaction threshold temperatures obtained by this test
30、method approximate thosetemperatures obtained by Test Method D2883 for hot-flame reaction, cool-flame reaction, and reaction threshold, respectively.E659 1325. Significance and Use5.1 Autoignition, by its very nature, is dependent on the chemical and physical properties of the material and the metho
31、d andapparatus employed for its determination. The autoignition temperature by a given method does not necessarily represent theminimum temperature at which a given material will self-ignite in air. The volume of the vessel used is particularly important sincelower autoignition temperatures will be
32、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 which air oxidation leads to ignition. These temperatures canbe expected to vary with the test pressure and oxygen concentration.5.3 This tes
33、t method is not designed for evaluating materials which are capable of exothermic decomposition. For suchmaterials, ignition is dependent upon the thermal and kinetic properties of the decomposition, the mass of the sample, and the heattransfer characteristics of the system.5.4 This test method can
34、be employed for solid chemicals which melt and vaporize or which readily sublime at the testtemperature. No condensed phase, liquid or solid, should be present when ignition occurs.5.5 This test method is not designed to measure the autoignition temperature of materials which are solids or liquids a
35、t the testtemperature (for example, wood, paper, cotton, plastics, and high-boiling point chemicals). Such materials will thermally degradein the flask and the accumulated degradation products may ignite.5.6 This test method was developed primarily for liquid chemicals but has been employed to test
36、readily vaporized solids.Responsibility for extension of this test method to solids of unknown thermal stability, boiling point, or degradation characteristicsrests with the operator.6. Apparatus6.1 FurnaceAn electrically heated crucible furnace or fluidized sand bath of appropriate internal geometr
37、y and dimensionsto 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 temperatur
38、e of 600C or higher.6.2 Temperature ControllerA temperature control system, capable of controlling the temperature in the furnace to within61Cwithin 61C at temperatures up to 350C, and to within 62C above 350C, is required. Temperatures are monitored at thebottom, side, and neck of the flask by mean
39、s of three external thermocouples. Heating adjustments are made when necessary inorder to maintain uniform temperature within the flask. If a controller is not available, temperature control may be achieved bythe use of suitable autotransformers or rheostats, thermocouples, and a suitable potentiome
40、ter.6.3 Test FlaskThe test 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 th
41、e top of the neck being 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 equipp
42、ed with a 6-in., No. 26 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 labor
43、atory balance capable of 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 aholde
44、r such as a small buret 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 fl
45、ask. Thermocouples should be calibrated against standardtemperatures 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 temperatures are measured with a
46、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 recording the signal from th
47、e internal gas thermocouple (T). An x - yXY recorder hasbeen found 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 the instant of sample
48、insertion and that of ignition as evidenced bythe appearance of the flame). If visual ignition is difficult to observe, the temperature - timetemperature-time recorder trace maybe used to estimate the time lag.E659 1336.10 MirrorA 6-in. mirror or other suitable size, mounted above the flask so that
49、the observer 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 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
