ASTM E1933-14(2018)

Standard Practice for Measuring and Compensating for Emissivity Using Infrared Imaging Radiometers

SIGNIFICANCE AND USE
5.1 The emissivity of a specimen can cause surface temperature measurement errors. Two procedures are provided for measuring and compensating for this error source.  
5.2 These procedures can be used in the field or laboratory, using commonly available materials.  
5.3 These procedures can be used with any infrared radiometers that have the required computer capabilities.  
5.4 The values of emissivity are defined only in terms of the procedure for the purpose of process control and nondestructive evaluation of materials.
SCOPE
1.1 This practice covers procedures for measuring and compensating for emissivity when measuring the surface temperature of a specimen with an infrared imaging radiometer.2  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 These procedures may involve use of equipment and materials in the presence of heated or electrically-energized equipment, or both.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Historical
• Publication Date: 31-Oct-2018
• ICS: 17.200.10 - Heat. Calorimetry
• Technical Committee: E07 - Nondestructive Testing
• Drafting Committee: E07.10 - Specialized NDT Methods

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: E1933 − 14 (Reapproved 2018)
Standard Practice for
Measuring and Compensating for Emissivity Using Infrared
Imaging Radiometers
This standard is issued under the fixed designation E1933; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.1 reflected temperature—the temperature of the energy
incident upon and reflected from the measurement surface of
1.1 This practice covers procedures for measuring and
the specimen.
compensating for emissivity when measuring the surface
temperature of a specimen with an infrared imaging radiom- 3.1.2 surface-modifying material—any tape, spray, paint, or
the like that is used to change the emissivity of the specimen
eter.
surface.
1.2 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this 3.2 See also Terminology E1316.
standard.
4. Summary of Practice
1.3 These procedures may involve use of equipment and
materials in the presence of heated or electrically-energized
4.1 Two procedures are given for measuring the emissivity
equipment, or both. of a specimen surface, the contact thermometer method and the
non-contact thermometer method.
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
4.2 Aprocedure is also given for compensating for the error
responsibility of the user of this standard to establish appro-
produced by emissivity using the computer built into an
priate safety, health, and environmental practices and deter-
infrared imaging radiometer.
mine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accor-
5. Significance and Use
dance with internationally recognized principles on standard-
5.1 The emissivity of a specimen can cause surface tem-
ization established in the Decision on Principles for the
perature measurement errors. Two procedures are provided for
Development of International Standards, Guides and Recom-
measuring and compensating for this error source.
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee. 5.2 These procedures can be used in the field or laboratory,
using commonly available materials.
2. Referenced Documents
5.3 These procedures can be used with any infrared radi-
2.1 ASTM Standards:
ometers that have the required computer capabilities.
E1316 Terminology for Nondestructive Examinations
5.4 The values of emissivity are defined only in terms of the
procedure for the purpose of process control and nondestruc-
3. Terminology
tive evaluation of materials.
3.1 Definitions of Terms Specific to This Standard:
6. Interferences
This practice is under the jurisdiction of ASTM Committee E07 on Nonde- 6.1 Contact Thermometer Method—Contact thermometers
structive Testing and is the direct responsibility of Subcommittee E07.10 on
can act as heat sinks and change the temperature of the
Specialized NDT Methods.
specimen.
Current edition approved Nov. 1, 2018. Published December 2018. Originally
approved in 1997. Last previous edition approved in 2014 as E1933 – 14. DOI:
6.2 Noncontact Thermometer Method:
10.1520/E1933-14R18.
6.2.1 The use of surface-modifying materials can change
These procedures are adapted from the Guideline for Measuring and Compen-
the heat transfer properties and temperature of the specimen.
sating for Reflected Temperature, Emittance and Transmittance developed by the
Infraspection Institute, 425 Ellis Street, Burlington, NJ 08016.
Any such errors can be minimized by applying surface-
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
modifying materials to the smallest area that satisfies the
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
measurement accuracy requirements of the radiometer and
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. infrared thermographer.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1933 − 14 (2018)
6.2.2 Before the surface-modifying material is applied to an 8.1.2 Point the infrared imaging radiometer at the specimen
area of the specimen adjacent to the area where the emissivity and focus on the portion where the emissivity is to be
is to be measured (as directed in 8.2.4), errors can be measured.
minimized by viewing the imager display to ensure that both
8.1.3 Use an appropriate infrared imaging radiometer mea-
areas have the same temperature.
surement function (such as spot temperature, crosshairs, or
6.2.3 When removing a surface-modifying material, as di-
isotherm) to measure and compensate for the reflected tem-
rected in 8.2.7, errors can be minimized by ensuring that the
perature error incident upon the specimen.
surface is returned to its original condition.
NOTE 2—Such measurements are generally more accurate when the
6.3 Both procedures require the specimen to be at a tem-
measurement is averaged over a small region of the image. Use of an
perature that is at least 10 °C warmer or cooler than the average temperature box or a narrow band isotherm will produce more
reproducible results than single pixel measurements.
ambient temperature. Potential errors can be minimized by
ensuring the stability of the temperature difference between the
8.1.4 Use the contact thermometer to measure the tempera-
specimen and the ambient temperature during the procedure.
ture of the point or area just measured in 8.1.3. Record this
Also, the emissivity measurement accuracy can be increased
temperature.
by increasing this
...

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. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E1933 − 14 E1933 − 14 (Reapproved 2018)
Standard Practice for
Measuring and Compensating for Emissivity Using Infrared
Imaging Radiometers
This standard is issued under the fixed designation E1933; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*Scope
1.1 This practice covers procedures for measuring and compensating for emissivity when measuring the surface temperature of
a specimen with an infrared imaging radiometer.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 These procedures may involve use of equipment and materials in the presence of heated or electrically-energized equipment,
or both.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
E1316 Terminology for Nondestructive Examinations
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 reflected temperature—the temperature of the energy incident upon and reflected from the measurement surface of the
specimen.
3.1.2 surface-modifying material—any tape, spray, paint, or the like that is used to change the emissivity of the specimen
surface.
3.2 See also Terminology E1316.
4. Summary of Practice
4.1 Two procedures are given for measuring the emissivity of a specimen surface, the contact thermometer method and the
non-contact thermometer method.
4.2 A procedure is also given for compensating for the error produced by emissivity using the computer built into an infrared
imaging radiometer.
5. Significance and Use
5.1 The emissivity of a specimen can cause surface temperature measurement errors. Two procedures are provided for
measuring and compensating for this error source.
This practice is under the jurisdiction of ASTM Committee E07 on Nondestructive Testing and is the direct responsibility of Subcommittee E07.10 on Specialized NDT
Methods.
Current edition approved Oct. 1, 2014Nov. 1, 2018. Published October 2014December 2018. Originally approved in 1997. Last previous edition approved in 20052014
as E1933 - 99a (2010).E1933 – 14. DOI: 10.1520/E1933-14.10.1520/E1933-14R18.
These procedures are adapted from the Guideline for Measuring and Compensating for Reflected Temperature, Emittance and Transmittance developed by the
Infraspection Institute, 425 Ellis Street, Burlington, NJ 08016.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1933 − 14 (2018)
5.2 These procedures can be used in the field or laboratory, using commonly available materials.
5.3 These procedures can be used with any infrared radiometers that have the required computer capabilities.
5.4 The values of emissivity are defined only in terms of the procedure for the purpose of process control and nondestructive
evaluation of materials.
6. Interferences
6.1 Contact Thermometer Method—Contact thermometers can act as heat sinks and change the temperature of the specimen.
6.2 Noncontact Thermometer Method:
6.2.1 The use of surface-modifying materials can change the heat transfer properties and temperature of the specimen. Any such
errors can be minimized by applying surface-modifying materials to the smallest area that satisfies the measurement accuracy
requirements of the radiometer and infrared thermographer.
6.2.2 Before the surface-modifying material is applied to an area of the specimen adjacent to the area where the emissivity is
to be measured (as directed in 8.2.4), errors can be minimized by viewing the imager display to ensure that both areas have the
same temperature.
6.2.3 When removing a surface-modifying material, as directed in 8.2.7, errors can be minimized by ensuring that the surface
is returned to its original condition.
6.3 Both procedures require the specimen to be at a temperature that is at least 10°C10 °C warmer or cooler than the ambient
temperature. Potential errors can be minimized by ensuring the stability of the temperature difference between the specimen and
the ambient temperature during the procedure. Also, the emissivity measurement accuracy can be increased by increasing this
temperature difference.
6.4 The emissivity of a specimen may be specific to the temperature of the specimen and the spectral waveband of the infrared
imaging radiometer used to make the measurement. Therefore, the temperature of the specimen and the spectral waveband of the
radiometer should be noted along with the measured emissivity value.
6.5 These procedures are valid only for specimens that are opaque in the waveband of the infrared imaging radiometer.
6.6 As the emissivity of a specimen decreases, its reflectivity increases. Careful consideration and avoidance of potential error
sources, including the precise determination of reflected temperature in 8.1.3 and 8.2.3, is required to accurately measure the
emissivity values of specimens having lower emissivi
...