ASTM_D_5423_-_22.pdf

Designation:D542322Standard Specification forForced-Convection Laboratory Ovens for Evaluation ofElectrical Insulation1This standard is issued under the fixed designation D5423;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.1.Scope1.1 This specification covers forced-convection ventilatedelectrically-heated ovens,operating over all or part of thetemperature range from 20 C above the ambient temperatureto 500 C,and used for thermal endurance evaluation ofelectrical insulating materials.1.2 The specification requirements for Type I ovens arebased on IEC Publication 60216-4-1,and are technicallyidentical to it.The requirements for Type II ovens are essen-tially identical to the requirements of Specification D2436.This specification and an associated test method,D5374,havereplaced Specification D2436.1.3 While the ovens covered by this specification areintended primarily for thermal endurance evaluation,theircharacteristics make them suitable for other applications asapplicable.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 standard 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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D2436 Specification for Forced-Convection Laboratory Ov-ens for Electrical Insulation(Withdrawn 1994)3D5374 Test Methods for Forced-Convection Laboratory Ov-ens for Evaluation of Electrical Insulation2.2 Other Document:IEC Publication 60216-4-1 Electrical Insulating MaterialsThermalEndurancePropertiesPart4-1:AgeingOvensSingle-Chamber Ovens43.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 rate of ventilation,nthe number of air changes perhour in the oven chamber.3.1.2 set temperature,nthe average of all of the measuredtemperatures within the oven,averaged over the period of anycyclic temperature variation that occurs.3.1.2.1 DiscussionThis is the actual operating temperatureof the oven.In IEC 60216-4-1,this term is called the exposuretemperature.3.1.3 temperature fluctuation,nmaximum change in tem-perature at one point in the oven over a period of time.3.1.3.1 DiscussionThis property depends upon the sensi-tivity and type(on/off or proportional)of control used and theheater mass in relation to surface area.3.1.4 temperature gradient,nthe maximum temperaturedifference at one time between any two points in the ovenchamber.1This specification is under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating Materials and is the direct responsibility ofSubcommittee D09.17 on Fire and Thermal Properties.Current edition approved May 1,2022.Published May 2022.Originallyapproved in 1993.Last previous edition approved in 2014 as D5423 14.DOI:10.1520/D5423-22.2For 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.4Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.13.1.4.1 DiscussionThis property depends on such factorsas uniformity of heater temperature,heater distribution aboutthe oven,and air flow patterns within the oven.In IEC60216-4-1,this term is called the temperature difference.3.1.5 temperature variation,nmaximum change in tem-perature with time and location due to the combination oftemperature gradient and temperature fluctuation.3.1.6 thermal lag time,nthe time required for a definedspecimen to reach a specified temperature(or range of tem-perature).3.1.6.1 DiscussionThis property is largely dependentupon the rate of air circulation within the oven.In IEC60216-4-1,thi