ASTM_D_7969_-_16.pdf

Designation:D796916Standard Specification forGravity Convection and Forced Ventilation Ovens1This standard is issued under the fixed designation D7969;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 the performance requirementsfor general purpose air ovens ordinarily used in testingoperations,which have a testing chamber up to 0.6 m3(25 ft3)in volume.1.2 It is applicable to gravity convection ovens designed tooperate over all or part of the temperature range from 20Cabove ambient room temperature to 200C.1.3 It is applicable to forced ventilation ovens designed tooperate over all or part of the temperature range from 20Cabove ambient room temperature to 500C.1.4 This specification does not include safety requirementsthat are essential for ovens used in the presence of combustiblematerials.1.5 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for referenceonly and may be approximate.1.5.1 The SI base unit of the expression of temperature isKelvin(K),the unit of measure used in this specification isCelsius(C)and has been derived mathematically.1.6 Calibration ovens to this standard are necessary toassure their operative performance under typical conditions ofuse and shall be performed periodically,either according to themanufacturers recommendations,the quality requirements ofthe end user,their customers,or suppliers.1.7 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 and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E145 Specification for Gravity-Convection and Forced-Ventilation Ovens3.Terminology3.1 Definitions:3.1.1 ambientroomtemperatureatemperatureasrecorded,typically but not necessarily,close to room tempera-ture.3.1.2 room temperaturea temperature in the range from 20to 30C(68 to 86F).3.1.3 standard laboratory atmospherean atmosphere hav-ing a temperature of 23 6 2C(73.4 6 3.6F)and a relativehumidity of 50 6 10%RH(40 to 60%RH)shall be thestandard laboratory atmosphere.3.1.4 standard laboratory temperaturea temperature of 236 2C(73.4 6 3.6F)shall be the standard laboratorytemperature.4.Oven Types4.1 This specification covers the following four types of airovens:4.1.1 Type IAGCAn oven ventilated by gravity convectionhaving a uniformity of temperature within 62%of thedifferential between oven and ambient temperatures.4.1.2 Type IBGCAn oven ventilated by gravity convectionhaving a uniformity of temperature within 65%of thedifferential between oven and ambient temperatures.4.1.3 Type IIAFVAn oven having forced ventilation and auniformity of temperature within 61%of the differentialbetween oven and ambient temperatures.4.1.4 Type IIBFVAn oven having forced ventilation and auniformity of temperature within 62.5%of the differentialbetween oven and ambient temperatures.5.Performance Requirements5.1 The temperature within the testing chamber shall becontrollable by an automatic device,and shall be uniformwithin the tolerances given in Table 1 for the particular type ofoven when tested in accordance with Section 6.5.1.1 Conformance to temperature uniformity(Section 6)isa requirement.5.2 The time constant measurement is nonmandatory and isfound in Appendix X1 of this specification.1This specification is under the jurisdiction ofASTM Committee D11 on Rubberand is the direct responsibility of Subcommittee D11.15 on Degradation Tests.Current edition approved Jan.1,2016.Published January 2016.Originallyapproved in 2015.Last previous edition approved in 2015 as D7969 15.DOI:10.1520/D7969-16.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.3 The rate of ventilation of the testing chamber shallconform to the requirements specified in Table 1 for theparticular type of oven when measured in accordance with theprocedure given in Section 7.5.3.1 Conformance to the rate of ventilation(Section 7)is arequirement.TEST PROCEDURES6.Temperature Uniformity6.1 Place nine calibrated thermocouples approximately 0.5mm in diameter(No.24 gauge)and having a junction size ofnot more than 2 mm(0.08 in.),in a clean,properly maintained,empty testing chamber with any shelves or commonly usedappurtenances in place and all vents fully open.6.1.1 Locate one thermocouple in each of the eight cornersof the oven ap