1、Designation: E 1445 08Standard 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 () 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 und
4、erstanding 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)E 487 Test Method for
5、 Constant-Temperature Stability OfChemical MaterialsE 537 Test Method for The Thermal Stability Of ChemicalsBy Differential Scanning CalorimetryE 582 Test Method for Minimum Ignition Energy andQuenching Distance in Gaseous MixturesE 659 Test Method for Autoignition Temperature of LiquidChemicalsE 68
6、0 Test Method for Drop Weight Impact Sensitivity OfSolid-Phase Hazardous MaterialsE 681 Test Method for Concentration Limits of Flammabil-ity of Chemicals (Vapors and Gases)E 698 Test Method for Arrhenius Kinetic Constants forThermally Unstable Materials Using Differential ScanningCalorimetry and th
7、e Flynn/Wall/Ozawa MethodE 771 Test Method for Spontaneous Heating Tendency ofMaterials3E 918 Practice for Determining Limits of Flammability ofChemicals at Elevated Temperature and PressureE 1226 Test Method for Pressure and Rate of Pressure Risefor Combustible DustsE 1231 Practice for Calculation
8、of Hazard PotentialFigures-of-Merit for Thermally Unstable MaterialsE 1232 Test Method for Temperature Limit of Flammabilityof ChemicalsE 1491 Test Method for Minimum Autoignition Tempera-ture of Dust CloudsE 1515 Test Method for Minimum Explosible Concentra-tion of Combustible DustsE 1981 Guide for
9、 Assessing Thermal Stability of Materialsby Methods of Accelerating Rate CalorimetryE 2012 Guide for the Preparation of a Binary ChemicalCompatibility ChartE 2019 Test Method for Minimum Ignition Energy of aDust Cloud in AirE 2021 Test Method for Hot-Surface Ignition Temperatureof Dust LayersE 2046
10、Test Method for Reaction Induction Time by Ther-mal Analysis3. 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 cont
11、inuously measurethe temperature differential between the sample and itssurroundings. (E 1981)adiabatic 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 samp
12、le 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 constant in reciprocal minutes for first order, Zis the pre-expone
13、ntial 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)1This terminology is under the jurisdiction ofASTM Committee E27 on HazardPotential of Chemicals and is the direct responsibility of Subcom
14、mittee E27.01 onEditorial and Nomenclature.Current edition approved May 15, 2008. Published July 2008. Originallyapproved in 1991. Last previous edition approved in 2003 as E 1445 03.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.
15、org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.autoignition, nthe ignition of a material commonly i
16、n air asthe result of heat 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)DISCUSSIONAutoigniti
17、on 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 produce hot-flame ignition inair at atmospheric pressure without the aid of
18、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 whichheat is lost to the surroundings and cause patibility, adjthe ability of
19、 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 chemical compound or mixturemay be held for a 2-h period under the conditions of the testwithout exhibiti
20、ng 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 mixtures of mosthydrocarbons and oxygenated hydrocarbons. They are the first part ofthe multistage i
21、gnition 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 temperature leads to a thermal-runaway reaction. (E 1231)critical temperature,
22、(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 thermal-runaway reaction. (E 1231)DISCUSSIONThis description assumes pe
23、rfect 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-merit underestimate the hazard as a result of this underestimatio
24、n 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 = pressure, (bar)t = time, (s)V = volume, (m3)KSt= (bar m/s)(E 1226)
25、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 the reference material are subjectedto a controlled temperature program. (E 698)DISCUSSIONTwo modes,
26、 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 analysis (DTA), na technique in whichthe temperature difference between a
27、 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 maximum rate of pressure rise during thecourse of a single deflagration. (E 1226)(dP/dt)max, nmaximum val
28、ue 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 bar/s. (E 1226)drop weight, nthat weight which is raised to a
29、 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 thermal analysis where thetemperature difference (DT) or the energy change (Dq)isplotted on the ordinate
30、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 temperature, nempirically, the tem-perature found by extrapolating the baseline (prior to thepeak) and the
31、 leading side of the peak to their intersection(see Fig. 3). (E 537)final 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 specimen to ignite under specified conditions of tes
32、t.(E 1232)flash 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) (E 1232)general rate lawdC/dt = k (1 C)nwhere C is fractionalconversio
33、n, t is the time in minutes, and n is the reactionorder. (E 698)guide bushing, nthe steel bushing that surrounds, aligns,and holds the stationary 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 temp
34、erature of a dust layer, nlowestset temperature of the hot plate that causes ignition of thedust layer. (E 2021)H50value, na drop height with a 50 % probability ofreaction, as determined experimentally by the Brucetonup-and-down method. (E 680)E 1445 082ideal adiabatic temperature rise (DTad), nthe
35、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 factor, f. (E 1981)ignition, nt
36、he 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 sample into the flask and ignition. Itis maximum at the minimum autoignition temperature andalso referred to as igniti
37、on 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 starts to enterthe chamber) in an experimental apparatus and the activationof the ignition source. The ignition del
38、ay 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 under test. (E 2021)ignition quenching distance, nMaximum spacing betweenelectrode flanges that will not permit
39、spark ignition andflame propagation beyond the flanges, when tested under thespecified test conditions. (E 582)ignition 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
40、includ-ing the foundation parts, guide rails, electromagnet lift,winch, and tools. (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 propagatin
41、g a flame through a homoge-neous mixture of the combustible and a gaseous oxidizerunder 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 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. (E 1232)minimum autoignition temperature (MAIT), nthe mini-mum temperature at which a d
43、ust cloud will self ignite underthe specified conditions of test. (E 1515)minimum explosible concentration (MEC), nthe mini-mum concentration of a combustible dust cloud that iscapable of propagating a deflagration through a well dis-persed mixture of the dust and air under the specifiedconditions o
44、f test (E 1491)minimum 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)observed adiabatic temperature rise (DTobs), nthe ob-served temperature rise
45、in the system during an exotherm;mathematically, it is equal to the temperature differencebetween the final temperature and the onset temperature ofan exotherm. (E 1981)onset temperature, nthe temperature at which a deflectionfrom the established baseline is first observed. (E 537)onset temperature
46、(Tstart), nthe observed 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
47、 sensitivity of the calorimetricsystem (1981)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
48、pressure (absolute) reachedduring 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 o
49、ptimum concentration of the dusttested. Pmaxis determined by a series of tests over a largerange of concentrations. It is reported in bar. (E 1226)peak, 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. (E 698)peak, nthat portion of a heating curve which is attributableto the occurrence of
