1、Designation: E2758 15E2758 15aStandard Guide forSelection and Use of Wideband, Low Temperature InfraredThermometers1This standard is issued under the fixed designation E2758; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、 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 guide covers electronic instruments intended for measurement of temperature by detecting intensity of thermal
3、radiation exchanged between the subject of measurement and the sensor.1.2 The devices covered by this guide are referred to as IR thermometers.1.3 The IR thermometers covered in this guide are instruments that are intended to measure temperatures below 1000 C1000C and measure a wide band of thermal
4、radiation in the infrared region.1.4 This guide covers best practice in using IR thermometers. It addresses concerns that will help the user make bettermeasurements. It also provides graphical tables to help determine the accuracy of measurements.1.5 Details on the design and construction of IR ther
5、mometers are not covered in this guide.1.6 This guide does not cover medium- and high-temperature IR thermometry (above 1000 C). 1000C). It does not addressthe use of narrowband IR thermometers.1.7 The values of quantities stated in SI units are to be regarded as the standard. The values of quantiti
6、es in parentheses are notin SI and are optional.1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regu
7、latorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E1256 Test Methods for Radiation Thermometers (Single Waveband Type)E1862 Practice for Measuring and Compensating for Reflected Temperature Using Infrared Imaging RadiometersE1897 Practice for Measuring and Compensating for Tr
8、ansmittance of an Attenuating Medium Using Infrared ImagingRadiometersE1933 Practice for Measuring and Compensating for Emissivity Using Infrared Imaging Radiometers2.2 IEC Standards:3IEC 62492-1 TS Industrial Process Control DevicesRadiation ThermometersPart 1: Technical Data for Radiation Ther-mom
9、eters2.3 BIPM Standards:JCGM 200:2012 International Vocabulary of MetrologyBasic and General Concepts and Associated Terms (VIM)3. Terminology3.1 Definitions:3.1.1 absolute zero, na temperature of 0 K (-273.15 C).(-273.15C).1 This guide is under the jurisdiction of ASTM Committee E20 on Temperature
10、Measurement and is the direct responsibility of Subcommittee E20.02 on RadiationThermometry.Current edition approved March 1, 2015May 1, 2015. Published March 2015May 2015. Originally approved in 2010.1910. Last previous edition approved in 20102015as E2758 10.E2758 15. DOI:10.1520/E2758-15.DOI:10.1
11、520 E2758-15A.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available from International Electrotechnical
12、 Commission (IEC), 3, Rue de Varemb, CH-1211 Geneva 20, Switzerland, www.iec.ch.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequa
13、tely depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocke
14、n, PA 19428-2959. United States13.1.2 atmospheric attenuation, na ratio showing how much thermal radiation in a given spectral range is absorbed or scatteredin air over a given distance.3.1.3 atmospheric transmission, na ratio showing how well thermal radiation in a given spectral range at a given d
15、istancetravels through a certain distance of air.3.1.4 attenuating medium, na semi-transparent solid, liquid or gas, such as a window, filter, external optics, or an atmospherethat reduces thermal radiation, or combinations thereof.3.1.5 background radiationsee reflected radiation.3.1.6 blackbody, n
16、the perfect or ideal source of thermal radiant power having a spectral distribution described by PlancksLaw.3.1.7 blackbody simulator, na device with an emissivity close to unity that can be heated or cooled to a stable temperature.3.1.8 calibration adjustment, nthe correction to an IR thermometer b
17、ased on its calibration.3.1.9 center wavelength, nthe simple average of the lower and upper spectral range limits.3.1.10 celestial radiation, nflux coming from the sky.3.1.11 contact thermometer, nan instrument that is adapted for measuring temperature by means of thermal conductance bydetermining t
18、he temperature at the moment when negligible thermal energy flows between the thermometer and the object ofmeasurement.3.1.12 dew point, nthe temperature at which water vapor condenses into liquid water.3.1.13 diffuse reflector, na surface that produces a diffuse image of a reflected source.3.1.14 d
19、istance ratio, nthe ratio of the measuring distance to the diameter of the field-of-view, when the target is in focus.43.1.15 electromagnetic radiation, nphysically occurring radiant flux classified according to wavelength or frequency.3.1.16 emissivity (), nthe emissivity of a surface is the ratio
20、between the radiation emitted from this surface and the radiationfrom a blackbody at the same temperature.3.1.16.1 DiscussionThe emissivity describes a thermo-physical material characteristic, which in addition to the chemical composition of the materialmay also be dependent on the surface structure
21、 (rough, smooth), the emission direction as well as on the observed wavelength andthe temperature of the measured object.43.1.17 emissivity setting, nan adjustment on an IR thermometer to compensate for an emissivity of non-unity.3.1.17.1 DiscussionIn most measuring situations a radiation thermomete
22、r is used on a surface with an emissivity significantly lower than one. For thispurpose most thermometers have the possibility of adjusting the emissivity setting. The temperature reading is then automaticallycorrected.43.1.18 emissivity tables, na list of objects and their measured emissivity for a
23、 particular IR thermometer.3.1.19 field-of-view (FOV), na usually circular, flat surface of a measured object from which the radiation thermometerreceives radiation.43.1.20 frost point, nthe temperature at which water vapor condenses into solid water or ice.3.1.21 infrared (IR), adjreferring to elec
24、tromagnetic radiation with a wavelength from approximately 0.7 to 30 m.3.1.22 infrared reflector, na material with a reflectance in the infrared region as close as possible to unity.3.1.23 infrared sensing device, none of a wide class of instruments used to display or record (or both) information re
25、lated tothe thermal radiation received from any object surfaces viewed by the instrument.3.1.24 infrared (IR) thermometer, noptoelectronic instrument adapted for noncontact measurement of temperature of a subjectby utilizing thermal radiation exchange between the subject and the sensor.3.1.24.1 Disc
26、ussion4 See IEC 62492-1.E2758 15a2IR thermometers are a subset of radiation thermometers. Most manufacturers use the term IR thermometer for handheld radiationthermometers. In general, these devices are wideband and use a thermopile detector.3.1.25 IR thermometry, nthe use of IR thermometers to dete
27、rmine temperature by measuring thermal radiation.3.1.26 irradiance (E), nthe radiant flux (power) per unit area incident on a given surface in units of W/m2.3.1.27 limit of error, nthe extreme value of measurement error of an infrared thermometer reading, relative to referencetemperature standards,
28、as permitted by a specification.3.1.27.1 DiscussionManufacturers sometimes use the term accuracy in their specifications to represent limit of error.3.1.27.2 DiscussionA manufacturers accuracy specification may apply only to well defined conditions.3.1.28 low-temperature, adjfor radiation and IR the
29、rmometry, referring to any temperature below 660 C.660C.3.1.29 measurement uncertainty (accuracy), nnon-negative parameter, characterizing the dispersion of the values that couldreasonably be attributed to the measurement of the quantity values being attributed to a measurand, based on the informati
30、onused.4,53.1.30 measuring distance, ndistance or distance range between the radiation thermometer and the target (measured object)for which the radiation thermometer is designed.43.1.31 measuring temperature range, ntemperature range for which the radiation thermometer is designed.43.1.32 noise equ
31、ivalent temperature difference (NETD), nparameter which indicates the contribution of the measurementuncertainty in C, which is due to instrument noise.43.1.33 opaque, adjreferring to the property of a material whose transmittance is zero for a given spectral range.3.1.34 operating temperature range
32、 and air humidity range, nthe permissible temperature range and humidity range withinwhich the radiation thermometer may be operated. For this temperature range and humidity range the specifications are valid.43.1.34.1 DiscussionThis is the range of ambient temperature and humidity the instrument ma
33、y operate within and be expected to meet its specification.It may be thought of as the ambient operating temperature range and the ambient operating humidity range.3.1.35 radiance (L), nthe flux per unit projected area per unit solid angle leaving a source or, in general, any reference surface.3.1.3
34、5.1 DiscussionIf 2 is the flux emitted into a solid angle by a source element of projected area Acos(), the radiance is defined as:L 5 2Acos!where: = the angle between the outward surface normal of the area element A and the direction of observation (unit = W/srm2).3.1.36 radiant power density (M),
35、nthe radiant flux per unit area leaving a surface that is,M 5Awhere: = flux leaving a surface element A (unit = W/m2).3.1.37 reflectance, nthe ratio of the radiant flux reflected from a surface to that incident upon it.3.1.38 reflected radiation, nthe thermal radiation incident upon and reflected fr
36、om the measurement surface of the specimen.3.1.39 reflected temperature, nthe temperature of the radiant flux incident upon and reflected from the measurement surfaceof a specimen.5 See BIPM JCGM 200:2012.E2758 15a33.1.40 response time, ntime interval between the instant of an abrupt change in the v
37、alue of the input parameter (objecttemperature or object radiation) and the instant from which the measured value of the radiation thermometer (output parameter)remains within specified limits of its final value.43.1.41 sensor, ndevice designed to respond to IR radiation and convert that response in
38、to electrical signals.3.1.42 size-of-source effect, nthe difference in the radiance- or temperature reading of the radiation thermometer whenchanging the size of the radiating area of the observed source.43.1.43 spectral range, nparameter which gives the lower and upper limits of the wavelength rang
39、e over which the radiationthermometer operates.43.1.43.1 DiscussionSpectral range is sometimes referred to as bandwidth.3.1.43.2 DiscussionThese limits are generally defined as the wavelengths where the power or signal is attenuated by a defined amount.3.1.44 spectral response, nthe numerical quanti
40、ty of a given phenomenon at a specific wavelength in the electromagneticspectrum.3.1.45 standard atmosphere, na model of how electromagnetic radiation is transmitted through the atmosphere based onvariations in pressure, temperature and humidity.3.1.46 surface-modifying material, nany material that
41、is used to change the emissivity of the specimen surface.3.1.47 table of offsets, na list of calibration points and calibration adjustments to be used when no internal calibrationadjustment is available.3.1.48 thermal radiation, nelectromagnetic radiation which is caused by an objects temperature an
42、d is predicted by PlancksLaw.3.1.49 thermal shock, nsubjecting an IR thermometer to a rapid temperature change.3.1.50 thermopile detector, na series of thermocouples connected in series to a disk of finite mass.thermopile detectors outputis voltage. Incident radiation heats the disk. When the disk i
43、s heated, its temperature rises above the sensors reference temperature(ambient temperature) producing a temperature difference (T). The potential of the thermopile is related to the temperaturedifference based on the Seebeck Effect.3.1.50.1 Discussiona thermopile detectors output is voltage. Incide
44、nt radiation heats the disk. When the disk is heated, its temperature rises above thesensors reference temperature (ambient temperature) producing a temperature difference (T). The potential of the thermopile isrelated to the temperature difference based on the Seebeck Effect.3.1.51 transmittance (t
45、), nthe ratio of the radiant flux transmitted through a body to that incident upon it.3.1.52 true temperature, ntemperature attributed to a particular site of a subject or object of measurement and accepted ashaving a specified uncertainty.3.1.53 wideband, adjreferring to the situation where the spe
46、ctral range of an instrument is at least 110 of its center wavelength.4. Significance and Use4.1 This guide provides guidelines and basic test methods for the use of infrared thermometers. The purpose of this guide is toprovide a basis for users of IR thermometers to make more accurate measurements,
47、 to understand the error in measurements, andreduce the error in measurements.5. Basic Use of IR Thermometry5.1 General Considerations:5.1.1 An IR thermometer can be used in a number of applications. Although they are generally not as accurate as contactthermometers, their quickness of measurement a
48、nd their ability to measure the temperature of an opaque surface without contactingit make them desirable instruments for some temperature measurements.5.1.2 Most handheld IR thermometers are equipped with a trigger to start and stop the measurements.5.1.3 As objects vary in temperature, they emit a
49、 varying amount of thermal radiation. This amount of thermal radiation ispredictable based on the objects temperature, emissivity and reflected temperature.E2758 15a45.1.4 Handheld IR thermometers measure thermal radiation in a given spectral range and determine the relationship betweenthe measured thermal radiation and temperature. The sensor mainly used in these instruments is a thermopile.5.2 Basic IR Measurement:5.2.1 Before making a measurement, the emissiv
