ASTM_E_2847_-_14.pdf

Designation:E284714Standard Test Method forCalibration and Accuracy Verification of Wideband InfraredThermometers1This standard is issued under the fixed designation E2847;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 test method covers electronic instruments intendedfor measurement of temperature by detecting the intensity ofthermal radiation exchanged between the subject of measure-ment and the sensor.1.2 The devices covered by this test method are referred toas infrared thermometers in this document.1.3 The infrared thermometers covered in this test methodare instruments that are intended to measure temperaturesbelow 1000C,measure thermal radiation over a wide band-width in the infrared region,and are direct-reading in tempera-ture.1.4 This guide covers best practice in calibrating infraredthermometers.It addresses concerns that will help the userperform more accurate calibrations.It also provides a structurefor calculation of uncertainties and reporting of calibrationresults to include uncertainty.1.5 Details on the design and construction of infraredthermometers are not covered in this test method.1.6 This test method does not cover infrared thermometryabove 1000C.It does not address the use of narrowbandinfrared thermometers or infrared thermometers that do notindicate temperature directly.1.7 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.1.8 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.2.Referenced Documents2.1 ASTM Standards:2E344 Terminology Relating to Thermometry and Hydrom-etryE1256 Test Methods for Radiation Thermometers(SingleWaveband Type)E2758 Guide for Selection and Use of Wideband,LowTemperature Infrared Thermometers3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 cavity bottom,nthe portion of the cavity radiationsource forming the end of the cavity.3.1.1.1 DiscussionThe cavity bottom is the primary areawhere an infrared thermometer being calibrated measuresradiation.3.1.2 cavity radiation source,na concave shaped geom-etry approximating a perfect blackbody of controlled tempera-ture and defined emissivity used for calibration of radiationthermometers.3.1.2.1 DiscussionA cavity radiation source is a subset ofthermal radiation sources.3.1.2.2 DiscussionTo be a cavity radiation source ofpractical value for calibration,at least 90%of the field-of-viewof a radiation thermometer is expected to be incident on thecavity bottom.In addition,the ratio of the length of the cavityversus the cavity diameter is expected to be greater than orequal to 5:1.3.1.3 cavity walls,nthe inside surfaces of the concaveshape forming a cavity radiation source.3.1.4 customer,nthe individual or institution to whom thecalibration or accuracy verification is being provided.3.1.5 distance-to-size ratio(D:S),nsee field-of-view.1This practice is under the jurisdiction ofASTM Committee E20 on TemperatureMeasurement and is the direct responsibility of Subcommittee E20.02 on RadiationThermometry.Current edition approved May 1,2014.Published May 2014.Originallyapproved in 2011.Last previous edition approved in 2013 as E2847131.DOI:10.1520/E284714.2For 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 3.1.6 effective emissivity,nthe ratio of the amount ofenergy over a given spectral band exiting a thermal radiationsource to that predicted by Plancks Law at a given tempera-ture.3.1.7 field-of-view,na usually circular,flat surface of ameasured object from which the radiation thermometer re-ceives radiation.(1)33.1.7.1 DiscussionMany handheld infrared thermometersmanufacturers include distance-to-size ratio(D:S)in theirspecifications.Distance-to-size ratio relates to the followingphysical situation:at a given distance(D),the infrared ther-mometer measures a size(S)or diameter,and a certainpercentage of the thermal radiation received by the infraredthermometer is within this size.Field-of-view is a measure ofthe property described by distance-to-size ratio.(1)3.1.8 flatplate radiation source,na planar surface ofcontrolled temperature and defined emissivity used for calibra-tions of radiation thermometers.3.1.8.1 DiscussionA flatplate radiation source is a subsetof thermal radiation sources.3.1.9 measuring temperature range,ntemperature