1、Designation: E1445 08 (Reapproved 2015)Standard Terminology Relating toHazard Potential of Chemicals1This standard is issued under the fixed designation E1445; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisi
2、on. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () 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 understoo
3、d or adequately 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 intere
4、st of common understanding andstandardization, consistent word usage is encouraged to helpeliminate the major barrier to effective technical communica-tion.2. Referenced Documents2.1 ASTM Standards:2E476 Test Method for Thermal Instability of Confined Con-densed Phase Systems (Confinement Test) (Wit
5、hdrawn2008)3E487 Test Method for Constant-Temperature Stability ofChemical MaterialsE537 Test Method for The Thermal Stability of Chemicalsby Differential Scanning CalorimetryE582 Test Method for Minimum Ignition Energy andQuenching Distance in Gaseous MixturesE659 Test Method for Autoignition Tempe
6、rature of LiquidChemicalsE680 Test Method for Drop Weight Impact Sensitivity ofSolid-Phase Hazardous MaterialsE681 Test Method for Concentration Limits of Flammabilityof Chemicals (Vapors and Gases)E698 Test Method for Arrhenius Kinetic Constants forThermally Unstable Materials Using Differential Sc
7、an-ning Calorimetry and the Flynn/Wall/Ozawa MethodE771 Test Method for Spontaneous Heating Tendency ofMaterials (Withdrawn 2001)3E918 Practice for Determining Limits of Flammability ofChemicals at Elevated Temperature and PressureE1226 Test Method for Explosibility of Dust CloudsE1231 Practice for
8、Calculation of Hazard Potential Figures-of-Merit for Thermally Unstable MaterialsE1232 Test Method for Temperature Limit of Flammabilityof ChemicalsE1491 Test Method for Minimum Autoignition Temperatureof Dust CloudsE1515 Test Method for Minimum Explosible Concentrationof Combustible DustsE1981 Guid
9、e for Assessing Thermal Stability of Materialsby Methods of Accelerating Rate CalorimetryE2012 Guide for the Preparation of a Binary ChemicalCompatibility ChartE2019 Test Method for Minimum Ignition Energy of a DustCloud in AirE2021 Test Method for Hot-Surface Ignition Temperature ofDust LayersE2046
10、 Test Method for Reaction Induction Time by ThermalAnalysis3. Terminology3.1 Definitions:adiabatic calorimeter, nan instrument capable of makingcalorimetric measurements while maintaining a minimalheat loss or gain between the sample and its environment,which is verifiable by the capability to conti
11、nuously measurethe temperature differential between the sample and itssurroundings. E1981adiabatic decomposition temperature rise, (T)d, nan esti-mation of the computed temperature which a specimenwould attain if all of the enthalpy (heat) of decompositionreaction were to be absorbed by the sample i
12、tself. Highvalues represent high hazard potential. E1231anvil, nthe smooth, hardened surface upon which the testsample or cup containing the sample rests. E6801This terminology is under the jurisdiction ofASTM Committee E27 on HazardPotential of Chemicals and is the direct responsibility of Subcommi
13、ttee E27.01 onEditorial and Nomenclature.Current edition approved Feb. 1, 2015. Published April 2015. Originallyapproved in 1991. Last previous edition approved in 2008 as E1445 08. DOI:10.1520/E1445-08R15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer
14、Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West
15、Conshohocken, PA 19428-2959. United States1Arrhenius equationk=ZeE/RTwhere k is the specificreaction rate constant 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 t
16、he temperature in kelvin. E698autoignition, nthe ignition of a material commonly in air asthe result of heat liberation due to an exothermic oxidationreaction in the absence of an external ignition source such asa spark or flame. E659autoignition temperature, nthe minimum temperature atwhich autoign
17、ition occurs under the specified conditions oftest. E659DISCUSSIONAutoignition temperature is also referred to as sponta-neous ignition temperature, self-ignition temperature, autogenous igni-tion temperature, and by the acronyms AIT and SIT. AIT is the lowesttemperature at which the substance will
18、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 over-balance the rate at w
19、hichheat is lost to the surroundings and cause patibility, adjthe ability of materials to exist in contactwithout specified (usually hazardous) consequences under adefined scenario. E2012constant-temperature stability (CTS) value, nthe maxi-mum temperature at which a chemical compound or mixturemay
20、be held for a 2-h period under the conditions of the testwithout exhibiting a measurable exothermic reaction. E487cool-flame, na faint, pale blue luminescence or flame occur-ring below the autoignition temperature (AIT). E659DISCUSSIONCool-flames occur in rich vapor-air mixtures of mosthydrocarbons
21、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 buildup of internal temperat
22、ure leads to a thermal-runaway reaction. E1231critical 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 tempera-ture buildup leads to a the
23、rmal-runaway reaction. E1231DISCUSSIONThis 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 boxed for shipment. These figures-of-
24、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 cubicrelationship:KSt5 dP/dt!maxV1/3where:P = p
25、ressure, (bar),t = time, (s),V = volume, (m3), andKSt= (bar m/s).E1226differential 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 the reference material are sub
26、jectedto a controlled temperature program. E698DISCUSSIONTwo modes, power compensation differential scanningcalorimetry (power compensation DSC) and heatflux differential scan-ning calorimetry (heatflux DSC), can be distinguished depending on themethod of measurement used.differential thermal analys
27、is (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. E698(dP/dt)ex, nthe maximum rate of pressure rise during thec
28、ourse of a single deflagration. E1226(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 range ofconcentrations. It is reported in
29、bar/s. E1226drop 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. E680DTA (DSC) curve, na record of a thermal analysis where thetemperature difference
30、(T) or the energy change (q)isplotted on the ordinate and temperature or time is plotted onthe abscissa (see Figs. 3 and 4). E537dust concentration, nthe mass of dust divided by theinternal volume of the test chamber. E1491extrapolated onset temperature, nempirically, the tempera-ture found by extra
31、polating the baseline (prior to the peak)and the leading side of the peak to their intersection (see Fig.3). E537final temperature (Tfinal), nthe lowest temperature, cor-rected to a pressure of 101.3 kPa (760 mm Hg, 1013 mbar),at which application of an ignition source causes the vaporsof the specim
32、en to ignite under specified conditions of test.E1232flash point, nthe observed system temperature at the end ofan exotherm, generally at the temperature where the self-heat rate of the reaction has decreased below the operator-defined slope sensitivity threshold. (1981) E1232general rate lawdC/dt =
33、 k(1 C)nwhere C is fractionalconversion, t is the time in minutes, and n is the reactionorder. E698guide bushing, nthe steel bushing that surrounds, aligns, andholds the stationary intermediate weight in place. E680E1445 08 (2015)2guide system, nthe rails, wires, and shaft that guide the dropweight
34、during its fall. E680hot-surface ignition temperature of a dust layer, nlowestset temperature of the hot plate that causes ignition of thedust layer. E2021H50value, na drop height with a 50 % probability ofreaction, as determined experimentally by the Brucetonup-and-down method. E680ideal adiabatic
35、temperature rise (DTad), nthe temperaturerise which would be observed in an exothermic reaction if allof the heat liberated were used to increase the temperature ofonly the sample. It is conveniently calculated as the productof the observed adiabatic temperature rise, DTobs, and thethermal inertia f
36、actor, f. E1981ignition, nthe initiation of combustion. E659ignition delay time, nthe time lapse between application ofheat to a material and its ignition. It is the time in secondsbetween insertion of the sample into the flask and ignition. Itis maximum at the minimum autoignition temperature andal
37、so referred to as ignition lag. E659ignition delay time, td, nexperimental parameter defined asthe time interval between the initiation of the dust dispersionprocedure (the time at which the dispersion air starts to enterthe chamber) in an experimental apparatus and the activationof the ignition sou
38、rce. The ignition delay time characterizesthe turbulence level prevailing at ignition under the definedtest conditions. E1226ignition of a dust layer, ninitiation of self-heating orcombustion in a material under test. E2021ignition quenching distance, nMaximum spacing betweenelectrode flanges that w
39、ill not permit spark ignition andflame propagation beyond the flanges, when tested under thespecified test conditions. E582ignition time, ntime between the start of heating and thepoint at which the maximum temperature or flaming com-bustion is reached. E2021impact apparatus or machine, nthe total a
40、pparatus includ-ing the foundation parts, guide rails, electromagnet lift,winch, and tools. E680impact tool, nthe drop weight, intermediate weight, andanvil. E680lower limit of flammability or lower flammable limit (LFL),nthe minimum concentration of a combustible substancethat is capable of propaga
41、ting a flame through a homoge-neous mixture of the combustible and a gaseous oxidizerunder the specified conditions of test. E681lower 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 ignitionsour
42、ce causes a homogeneous mixture of a gaseous oxidizerand vapors in equilibrium with a liquid (or solid) specimento ignite and propagate a flame away from the ignitionsource under the specified conditions of test. E1232minimum autoignition temperature (MAIT), nthe mini-mum temperature at which a dust
43、 cloud will self ignite underthe specified conditions of test. E1515minimum explosible concentration (MEC), nthe minimumconcentration of a combustible dust cloud that is capable ofpropagating a deflagration through a well dispersed mixtureof the dust and air under the specified conditions of testE14
44、91minimum 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. E2019observed adiabatic temperature rise (DTobs), nthe ob-served temperature rise in the system du
45、ring an exotherm;mathematically, it is equal to the temperature differencebetween the final temperature and the onset temperature ofan exotherm. E1981onset temperature, nthe temperature at which a deflectionfrom the established baseline is first observed. E537onset temperature (Tstart), nthe observe
46、d system tempera-ture at the start of an exotherm where the self-heating ratefirst exceeds the operator-defined slope sensitivity threshold,usually 0.02C/min; the onset temperature is not a funda-mental property of a substance, but is apparatus-dependent,based upon the inherent sensitivity of the ca
47、lorimetricsystem. (1981)Pex, nthe maximum explosion pressure (above the pressurein the vessel at the time of ignition) reached during thecourse of a single deflagration test. E1226Pignition, nthe absolute pressure at the time of ignition. E1515Pex,a, nthe maximum explosion pressure (absolute) reache
48、dduring the course of a single deflagration test. E1515Pignitor, nthe pressure rise in the chamber due to the ignitorby itself. E1515Pmax, nthe maximum pressure (above pressure in the vesselat the time of ignition) reached during the course of adeflagration for the optimum concentration of the dustt
49、ested. Pmaxis determined by a series of tests over a largerange of concentrations. It is reported in bar. E1226peak, nthat part of a DTAor DSC curve which is attributableto the occurrence of a single process. It is normally charac-terized by a deviation from the established base line, amaximum deflection, and a reestablishment of a base line notnecessarily identical to that before the peak. E698peak, nthat portion of a heating curve which is attributable tothe occurrence of a single process. It is normally ch
