ASTM_E_1897_-_14.pdf

Designation:E189714Standard Practice forMeasuring and Compensating for Transmittance of anAttenuating Medium Using Infrared Imaging Radiometers1This standard is issued under the fixed designation E1897;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.Scope*1.1 This practice covers procedures for measuring andcompensating for transmittance when using an infrared imag-ing radiometer to measure the temperature of a specimenthrough an attenuating medium,such as a window,filter oratmosphere.21.2 The values stated in SI units are to be regarded as thestandard.1.3 These procedures may involve use of equipment andmaterials in the presence of heated or electrically-energizedequipment,or both.1.4 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:3E1316 Terminology for Nondestructive Examinations3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 attenuating mediuma semi-transparent solid,liquidor gas,such as a window,filter,external optics or an atmo-sphere that attenuates radiation.3.1.2 blackbody simulatora device with an emissivityclose to 1.00 that can be heated or cooled to a stabletemperature.3.1.3 filtera semi-transparent material that attenuates cer-tain wavelengths of radiation.3.1.4 infrared thermographerthe person using an infraredimaging radiometer.3.1.5 reflected temperaturethe temperature of the energyincident upon and reflected by the measurement surface of thespecimen.3.1.6 windowa semi-transparent material that separatesconditioned and unconditioned atmospheres and attenuatescertain wavelengths of radiation.3.2 See also Terminology E1316.4.Summary of Practice4.1 Using the computer built into an infrared imagingradiometer,a method is given for measuring the transmittanceof an attenuating medium.4.2 Using the computer built into an infrared imagingradiometer,a method is given for compensating for errorswhen measuring the temperature of a specimen through anattenuating medium when the emissivity of the specimen andthe transmittance of the attenuating medium are known.4.3 Using the computer built into an infrared imagingradiometer,a method is given for measuring and compensatingfor unknown transmittance and emissivity errors when thespecimen temperature is known.5.Significance and Use5.1 The transmittance of an attenuating medium can causeerrors for an infrared thermographer using an infrared imagingradiometer to measure the temperature of a specimen throughthe medium.Three test methods are given for measuring andcompensating for this error source.5.1.1 A procedure is given for measuring the transmittanceof an attenuating medium.5.1.2 Aprocedure is given for compensating for errors whenmeasuring the temperature of a specimen having a knownemissivity through an attenuating medium with a knowntransmittance.5.1.3 A procedure is given for measuring and compensatingfor transmittance and emissivity errors when the specimentemperature is known.1This practice is under the jurisdiction of ASTM Committee E07 on Nonde-structive Testing and is the direct responsibility of Subcommittee E07.10 onSpecialized NDT Methods.Current edition approved Dec.1,2014.Published December 2014.Originallyapproved 1997.Last previous edition approved in 2010 as E1897 97(2010).DOI:10.1520/E1897-14.2This practice was originally adapted in 1997,by agreement,from the Guidelinefor Measuring and Compensating for Reflected Temperature,Emittance andTransmittance developed by Infraspection Institute,425 Ellis Street,Burlington,NJ08016.3For 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.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.2 These procedures can be used in the field or laboratoryusing commonly available materials.5.3 These procedures can be used with any infrared radi-ometers that have the required computer capabilities.5.4 The values of transmittance are defined only in terms ofthe procedure for the purpose of process control and nonde-structive evaluation of materials.6.Interferences6.1 Practice for Measuring the Transmittance of an Attenu-ating Medium:6.1.1 This practice requires a blackbody simulator with anemissivity of 0.95 or greater that is at least 20C warmer thanambient temperature.Potential errors