1、Designation: E 1445 03Standard Terminology Relating toHazard Potential of Chemicals1This standard is issued under the fixed designation E 1445; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in
2、parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This standard is a compilation of terminology used inthe area of hazard potential of chemicals. Terms that aregenerally understood or adequately
3、 defined in other readilyavailable sources are not included.1.2 Although some of these definitions are general in nature,many must be used in the context of the standards in whichthey appear. The pertinent standard number is given in paren-theses after the definition.1.3 In the interest of common un
4、derstanding and standard-ization, consistent word usage is encouraged to help eliminatethe major barrier to effective technical communication.2. Referenced Documents2.1 ASTM Standards:2E 476 Test Method for Thermal Instability of ConfinedCondensed Phase Systems (Confinement Test)3E 487 Test Method f
5、or Constant-Temperature Stability ofChemical Materials3E 537 Test Method for Assessing the Thermal Stability ofChemicals by Methods of Thermal Analysis3E 659 Test Method for Autoignition Temperature of LiquidChemicals3E 680 Test Method for Drop Weight Impact Sensitivity ofSolid-Phase Hazardous Mater
6、ials3E 681 Test Method for Concentration Limits of Flammabil-ity of Chemicals (Vapors and Gases)3E 698 Test Method for Arrhenius Kinetic Constants forThermally Unstable Materials3E 771 Test Method for Spontaneous Heating Tendency ofMaterials3E 918 Practice for Determining Limits of Flammability ofCh
7、emicals at Elevated Temperature and Pressure3E 1226 Test Method for Pressure and Rate of Pressure Risefor Combustible Dusts3E 1231 Practice for Calculation of Hazard PotentialFigures-of-Merit for Thermally Unstable Materials3E 1232 Test Method for Temperature Limit of Flammabilityof Chemicals3E 1491
8、 Test Method for Minimum Autoignition Tempera-ture of Dust Clouds3E 1515 Test Method for Minimum Explosible Concentra-tion of Combustible Dusts3E 2012 Guide for the Preparation of a Binary ChemicalCompatibility Chart3E 2019 Test Method for Minimum Ignition Energy of aDust Cloud in Air3E 2021 Test Me
9、thod for Hot-Surface Ignition Temperatureof Dust Layers3E 2046 Test Method for Feaction Induction Time by Ther-mal Analysis33. Terminology3.1 Definitions:adiabatic decomposition temperature rise, (T)d, nan esti-mation of the computed temperature which a specimenwould attain if all of the enthalpy (h
10、eat) of decompositionreaction were to be absorbed by the sample itself. Highvalues represent high hazard potential. (E 1231)anvil, nthe smooth, hardened surface upon which the testsample or cup containing the sample rests. (E 680)Arrhenius equationk = ZeE/RTwhere k is the specificreaction rate const
11、ant in reciprocal minutes for first order, Zis the pre-exponential factor in reciprocal minutes, E is theArrhenius activation energy in J/mol, R is the gas constant,8.32 J/mol K, and T is the temperature in kelvin. (E 698)autoignition, nthe ignition of a material commonly in air asthe result of heat
12、 liberation due to an exothermic oxidationreaction in the absence of an external ignition source such asa spark or flame. (E 659)autoignition temperature, nthe minimum temperature atwhich autoignition occurs under the specified conditions oftest. (E 659)DISCUSSIONAutoignition temperature is also ref
13、erred to as sponta-neous ignition temperature, self-ignition temperature, autogenous igni-tion temperature, and by the acronyms AIT and SIT. AIT is the lowest1This terminology is under the jurisdiction of ASTM Committee E27 on HazardPotential of Chemicals and is the direct responsibility of Subcommi
14、ttee E27.01 onEditorial and Nomenclature.Current edition approved July 10, 2003. Published September 2003. Originallyapproved in 1991. Last previous edition approved in 2002 as E 1445 02.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at servicea
15、stm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Annual Book of ASTM Standards, Vol 14.02.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.temperature at wh
16、ich the substance will produce hot-flame ignition inair at atmospheric pressure without the aid of an external energy sourcesuch as spark or flame. It is the lowest temperature to which acombustible mixture must be raised, so that the rate of heat evolved bythe exothermic oxidation reaction will ove
17、r-balance the rate at whichheat is lost to the surroundings and cause patibility, adjthe ability of materials to exist in contactwithout specified (usually hazardous) consequences under adefined scenario. (E 2012)constant-temperature stability (CTS) value, nthe maxi-mum temperature at which a chemic
18、al compound or mixturemay be held for a 2-h period under the conditions of the testwithout exhibiting a measurable exothermic reaction.(E 487)cool-flame, na faint, pale blue luminescence or flameoccurring below the autoignition temperature (AIT).(E 659)DISCUSSIONCool-flames occur in rich vapor-air m
19、ixtures of mosthydrocarbons and oxygenated hydrocarbons. They are the first part ofthe multistage ignition process.critical half thickness, (a), nan estimation of the halfthickness of a sample in an unstirred container, in which theheat losses to the environment are less than the retained heat.This
20、buildup of internal temperature leads to a thermal-runaway reaction. (E 1231)critical temperature, (Tc), nan estimation of the lowesttemperature of an unstirred container at which the heatlosses to the environment are less than the retained heatleading to a buildup of internal temperature. This temp
21、era-ture buildup leads to a thermal-runaway reaction. (E 1231)DISCUSSIONThis description assumes perfect heat removal at thereaction boundary. This condition is not met if the reaction takes placein an insulated container such as when several containers are stackedtogether or when a container is box
22、ed for shipment. These figures-of-merit underestimate the hazard as a result of this underestimation ofthermal conductivity.deflagration index, (KSt), nmaximum dP/dt normalized to a1.0 m3volume. It is measured at the optimum dust concen-tration. KStis defined according to the following cubicrelation
23、ship:KSt5 dP/dt!maxV1/3where:P = pressure, (bar)t = time, (s)V = volume, (m3)KSt= (bar m/s)(E 1226)differential scanning calorimetry (DSC), na technique inwhich the difference in energy inputs into a substance and areference material is measured as a function of temperature,while the substance and t
24、he reference material are subjectedto a controlled temperature program. (E 698)DISCUSSIONTwo modes, power compensation differential scanningcalorimetry (power compensation DSC) and heatflux differential scan-ning calorimetry (heatflux DSC), can be distinguished depending on themethod of measurement
25、used.differential thermal analysis (DTA), na technique in whichthe temperature difference between a substance and refer-ence material is measured as a function of temperature whilethe substance and the reference material are subjected to acontrolled temperature program. (E 698)(dP/dt)ex, nthe maximu
26、m rate of pressure rise during thecourse of a single deflagration. (E 1226)(dP/dt)max, nmaximum value for the rate of pressure in-crease per unit time reached during the course of a defla-gration for the optimum concentration of the dust tested. It isdetermined by a series of tests over a large rang
27、e ofconcentrations. It is reported in bar/s. (E 1226)drop weight, nthat weight which is raised to a selectedheight and released. This weight does not impact the sampledirectly; rather it strikes another stationary weight that is incontact with the sample. (E 680)DTA (DSC) curve, na record of a therm
28、al analysis where thetemperature difference (DT) or the energy change (Dq)isplotted on the ordinate and temperature or time is plotted onthe abscissa (see Figs. 3 and 4). (E 537)dust concentration, nthe mass of dust divided by theinternal volume of the test chamber. (E 1491)extrapolated onset temper
29、ature, nempirically, the tem-perature found by extrapolating the baseline (prior to thepeak) and the leading side of the peak to their intersection(see Fig. 3). (E 537)flashpoint , nthe lowest temperature, corrected to a pressureof 101.3 kPa (760 mm Hg, 1013 mbar), at which applicationof an ignition
30、 source causes the vapors of the specimen toignite under specified conditions of test. (E 1232)general rate lawdC/dt = k (1 C)nwhere C is fractionalconversion, t is the time in minutes, and n is the reactionorder. (E 698)guide bushing, nthe steel bushing that surrounds, aligns,and holds the stationa
31、ry intermediate weight in place.(E 680)guide system, nthe rails, wires, and shaft that guide the dropweight during its fall. (E 680)hot-surface ignition temperature of a dust layer, nlowestset temperature of the hot plate that causes ignition of thedust layer. (E 2021)H50value, na drop height with a
32、 50 % probability ofreaction, as determined experimentally by the Brucetonup-and-down method. (E 680)ignition, nthe initiation of combustion. (E 659)ignition delay time, nthe time lapse between application ofheat to a material and its ignition. It is the time in secondsbetween insertion of the sampl
33、e into the flask and ignition. Itis maximum at the minimum autoignition temperature andalso referred to as ignition lag. (E 659)ignition delay time, td, nexperimental parameter defined asthe time interval between the initiation of the dust dispersionprocedure (the time at which the dispersion air st
34、arts to enterthe chamber) in an experimental apparatus and the activationof the ignition source. The ignition delay time characterizesthe turbulence level prevailing at ignition under the definedtest conditions. (E 1226)ignition of a dust layer, ninitiation of self-heating orcombustion in a material
35、 under test. (E 2021)E 1445 032ignition time, ntime between the start of heating and thepoint at which the maximum temperature or flaming com-bustion is reached. (E 2021)impact apparatus or machine, nthe total apparatus includ-ing the foundation parts, guide rails, electromagnet lift,winch, and tool
36、s. (E 680)impact tool, nthe drop weight, intermediate weight, andanvil. (E 680)lower limit of flammability or lower flammable limit (LFL),nthe minimum concentration of a combustible substancethat is capable of propagating a flame through a homoge-neous mixture of the combustible and a gaseous oxidiz
37、erunder the specified conditions of test. (E 681)lower temperature limit of flammability, (LTL), nthelowest temperature, corrected to a pressure of 101.3 kPa(760 mm Hg, 1013 mbar), at which application of an ignitionsource causes a homogeneous mixture of a gaseous oxidizerand vapors in equilibrium w
38、ith a liquid (or solid) specimento ignite and propagate a flame away from the ignitionsource under the specified conditions of test. (E 1232)minimum autoignition temperature (MAIT), nthe mini-mum temperature at which a dust cloud will self ignite underthe specified conditions of test. (E 1491)minimu
39、m ignition energy, nelectrical energy dischargedfrom a capacitor, which is just sufficient to effect ignition ofthe most ignitable mixture of a given fuel-mixture underspecific test conditions. (E 2019)onset temperature, nthe temperature at which a deflectionfrom the established baseline is first ob
40、served. (E 537)Pex, nthe maximum explosion pressure (above the pressurein the vessel at the time of ignition) reached during thecourse of a single deflagration test. (E 1226)Pignition, nthe absolute pressure at the time of ignition.(E 1515)Pex,a, nthe maximum explosion pressure (absolute) reacheddur
41、ing the course of a single deflagration test. (E 1515)DPignitor, nthe pressure rise in the chamber due to the ignitorby itself. (E 1515)Pmax, nthe maximum pressure (above pressure in the vesselat the time of ignition) reached during the course of adeflagration for the optimum concentration of the du
42、sttested. Pmaxis determined by a series of tests over a largerange of concentrations. It is reported in bar. (E 1226)peak, nthat part of a DTA or DSC curve which is attributableto the occurrence of a single process. It is normally charac-terized by a deviation from the established base line, amaximu
43、m deflection, and a reestablishment of a base line notnecessarily identical to that before the peak. (E 698)peak, nthat portion of a heating curve which is attributableto the occurrence of a single process. It is normally charac-terized by a deviation from the established baseline, amaximum deflecti
44、on, and a reestablishment of a baseline notnecessarily identical to that before the peak. (E 537)DISCUSSIONThere will be instances when upon scanning in tem-perature an endotherm will be observed that is immediately followed byor is in conjunction with an exotherm. This type of competing reactionsma
45、kes it difficult and at times impossible to locate the true peak andonset temperatures.peak temperature, nthe temperature corresponding to themaximum deflection of the DTA or DSC curve. (E 537)pressure ratio (PR), ndefined as PR= (Pex,a DPignitor/Pignition(E 1515)propagation of flame, nthe upward an
46、d outward movementof the flame front from the ignition source to the vesselwalls, that is determined by visual observation. (E 918)propagation of flames, na combustion reaction that pro-duces at least a 7 % rise of the initial absolute pressure,P2P15.1.07.(E 1232)DISCUSSIONThis 7 % rise in pressure
47、corresponds to 1 psia (0.007MPa) per atmosphere of initial pressure.reaction, nany transformation of material accompanied by achange of enthalpy which may be endothermic or exother-mic. (E 537)reaction induction time (RIT) value, nthe time a chemicalcompound or mixture may be held under isothermal c
48、ondi-tions until it exhibits a specified exothermic reaction.(E 2046)scenario, na detailed physical description of the processwhereby a potential inadvertent combination of materialsmay occur (E 2012)spark discharge, ntransient discrete electric discharge,which takes place between two conductors, wh
49、ich are atdifferent potentials. The discharge bridges the gap betweenthe conductors in the form of a single ionization channel.(E 2019)spontaneous heating or self heating, nan exothermic reac-tion of a material due to slow or incomplete reaction thatresults in a temperature rise above that of its surroundings.(E 771)spontaneous heating temperature or self-heating tempera-ture, nthe lowest temperature at which spontaneous orself heating occurs under the specified test conditions. Thistemperature refers to a m
