ASTM_E_1981_-_98_2012e2.pdf

Designation:E198198(Reapproved 2012)2Standard Guide forAssessing Thermal Stability of Materials by Methods ofAccelerating Rate Calorimetry1This standard is issued under the fixed designation E1981;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 parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1NOTEEditorial corrections were made to source and reference information in December 2012.2NOTEEditorial corrections were made throughout in June 2013.INTRODUCTIONThis guide is one of several standards being developed by ASTM Committee E27 for determiningthe physicochemical hazards of chemicals and chemical mixtures.This guide should be used inconjunction with other test methods,as a complete assessment of the hazard potential of chemicalsmust take into account a number of realistic factors not necessarily considered in this guide.Theexpression hazard potential as used by this committee is defined as the degree of susceptibility ofmaterial to ignition or release of energy under varying environmental conditions.It is the intent of this guide to include any calorimetric device consistent with the principles ofadiabatic calorimetry.Device-specific information and specifications are located in appendices to theguide.Any reference to specific devices in the guide are for purposes of illustration or clarity only.1.Scope1.1 This guide covers suggested procedures for the opera-tion of a calorimetric device designed to obtain temperatureand pressure data as a function of time for systems undergoinga physicochemical change under nearly adiabatic conditions.1.2 This guide outlines the calculation of thermodynamicparameters from the time,temperature,and pressure datarecorded by a calorimetric device.1.3 The assessment outlined in this guide may be used overa pressure range from full vacuum to the rated pressure of thereaction container and pressure transducer.The temperaturerange of the calorimeter typically varies from ambient to500C,but also may be user specified(see 6.6).1.4 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.5 This statement does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety practices and to determine the applicability ofregulatory limitations prior to use.Specific safety precautionsare outlined in Section 7.2.Referenced Documents2.1 ASTM Standards:2E476 Test Method for Thermal Instability of Confined Con-densed Phase Systems(Confinement Test)(Withdrawn2008)3E487 Test Method for Constant-Temperature Stability ofChemical MaterialsE537 Test Method for The Thermal Stability of Chemicalsby Differential Scanning CalorimetryE680 Test Method for Drop Weight Impact Sensitivity ofSolid-Phase Hazardous MaterialsE698 Test Method for Arrhenius Kinetic Constants forThermally Unstable Materials Using Differential Scan-ning Calorimetry and the Flynn/Wall/Ozawa MethodE1231 Practice for Calculation of Hazard Potential Figures-of-Merit for Thermally Unstable Materials3.Terminology3.1 Definitions of Terms Specific to This Standard:1This guide is under the jurisdiction of ASTM Committee E27 on HazardPotential of Chemicals and is the direct responsibility of Subcommittee E27.02 onThermal Stability and Condensed Phases.Current edition approved Dec.1,2012.Published December 2012.Originallypublished in 1998.Last previous edition approved in 2004 as E1981 98(2004).DOI:10.1520/E1981-98R12E02.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer 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 Conshohocken,PA 19428-2959.United States1 3.1.1 adiabatic calorimeter,nan instrument capable ofmaking calorimetric measurements while maintaining a mini-mal heat loss or gain between the sample and its environment,which is verifiable by the capability to continuously measurethe temperature differential between the sample and its sur-roundings.3.1.2 autocatalytic reaction,na chemical reaction inwhich a product or reaction intermediate functions as acatalyst.3.1.3 drift,na gradual unintended increase or decrease inthe system(sample container and surroundings)temperaturedue to limitations in the system calibration,or to changeswhich occur in the system after calibration.3.1.4 final temperature(Tfinal),nthe observed systemtemperature at the end of an exotherm,generally at thetemperature where the self-heat rate of the reaction hasdecreased below the operator-defined slope sensitivity thresh-old.3