ASTM E1897-97(2010)
(Test Method)Standard Test Methods for Measuring and Compensating for Transmittance of an Attenuating Medium Using Infrared Imaging Radiometers
Standard Test Methods for Measuring and Compensating for Transmittance of an Attenuating Medium Using Infrared Imaging Radiometers
SIGNIFICANCE AND USE
The transmittance of an attenuating medium can cause errors for an infrared thermographer using an infrared imaging radiometer to measure the temperature of a specimen through the medium. Three test methods are given for measuring and compensating for this error source.
A test method is given for measuring the transmittance of an attenuating medium.
A test method is given for compensating for errors when measuring the temperature of a specimen having a known emissivity through an attenuating medium with a known transmittance.
A test method is given for measuring and compensating for transmittance and emissivity errors when the specimen temperature is known.
These test methods can be used in the field or laboratory using commonly available materials.
These test methods can be used with any infrared radiometers that have the required computer capabilities.
SCOPE
1.1 These test methods cover procedures for measuring and compensating for transmittance when using an infrared imaging radiometer to measure the temperature of a specimen through an attenuating medium, such as a window, filter or atmosphere.
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 test methods 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 and health practices and determine the applicability of regulatory limitations prior to use.
General Information
Relations
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: E1897 − 97(Reapproved 2010)
Standard Test Methods for
Measuring and Compensating for Transmittance of an
Attenuating Medium Using Infrared Imaging Radiometers
This standard is issued under the fixed designation E1897; 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 3.1.4 infrared thermographer—the person using an infrared
imaging radiometer.
1.1 These test methods cover procedures for measuring and
3.1.5 reflected temperature—the temperature of the energy
compensating for transmittance when using an infrared imag-
incident upon and reflected by the measurement surface of the
ing radiometer to measure the temperature of a specimen
specimen.
through an attenuating medium, such as a window, filter or
atmosphere.
3.1.6 window—a semi-transparent material that separates
conditioned and unconditioned atmospheres and attenuates
1.2 The values stated in SI units are to be regarded as the
certain wavelengths of radiation.
standard.
3.2 See also Terminology E1316.
1.3 These test methods may involve use of equipment and
materials in the presence of heated or electrically-energized
4. Summary of Test Method
equipment, or both.
4.1 Using the computer built into an infrared imaging
1.4 This standard does not purport to address all of the
radiometer, a method is given for measuring the transmittance
safety concerns, if any, associated with its use. It is the
of an attenuating medium.
responsibility of the user of this standard to establish appro-
4.2 Using the computer built into an infrared imaging
priate safety and health practices and determine the applica-
radiometer, a method is given for compensating for errors
bility of regulatory limitations prior to use.
when measuring the temperature of a specimen through an
2. Referenced Documents
attenuating medium when the emissivity of the specimen and
the transmittance of the attenuating medium are known.
2.1 ASTM Standards:
E1316 Terminology for Nondestructive Examinations
4.3 Using the computer built into an infrared imaging
radiometer, a method is given for measuring and compensating
3. Terminology
for unknown transmittance and emissivity errors when the
3.1 Definitions of Terms Specific to This Standard: specimen temperature is known.
3.1.1 attenuating medium—a semi-transparent solid, liquid
5. Significance and Use
or gas, such as a window, filter, external optics or an atmo-
5.1 The transmittance of an attenuating medium can cause
sphere that attenuates radiation.
errors for an infrared thermographer using an infrared imaging
3.1.2 blackbody simulator—a device with an emissivity
radiometer to measure the temperature of a specimen through
close to 1.00 that can be heated or cooled to a stable
the medium. Three test methods are given for measuring and
temperature.
compensating for this error source.
3.1.3 filter—a semi-transparent material that attenuates cer-
5.1.1 Atest method is given for measuring the transmittance
tain wavelengths of radiation.
of an attenuating medium.
5.1.2 A test method is given for compensating for errors
when measuring the temperature of a specimen having a
These test methods are under the jurisdiction of ASTM Committee E07 on
known emissivity through an attenuating medium with a
Nondestructive Testing and is the direct responsibility of Subcommittee E07.10 on
Specialized NDT Methods.
known transmittance.
Current edition approved June 15, 2010. Published November 2010. Originally
5.1.3 A test method is given for measuring and compensat-
´1
approved 1997. Last previous edition approved 2002 as E1897 – 97 (2002) . DOI:
ing for transmittance and emissivity errors when the specimen
10.1520/E1897-97R10.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or temperature is known.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
5.2 These test methods can be used in the field or laboratory
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. using commonly available materials.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1897 − 97 (2010)
5.3 These test methods can be used with any infrared 8.1.1 Place the infrared imaging radiometer on the tripod or
radiometers that have the required computer capabilities. support device at the desired location and distance from the
blackbody simulator.
6. Interferences
8.1.2 Point the infrared imaging radiometer at the black-
6.1 Test Method for Measuring the Transmittance of an
body simulator and focus on a portion that has an emissivity of
Attenuating Medium:
0.95 or greater. Make sure that the blackbody simulator is at a
6.1.1 This test method requires a blackbody simulator with
stable temperature at least 20°C above the ambient tempera-
an emissivity of 0.95 or greater that is at least 20°C warmer
ture.
than ambient temperature. Potential errors can be minimized
8.1.3 Use an appropriate infrared imaging radiometer mea-
by ensuring the stability of the temperature difference between
surement function (such as spot temperature, crosshairs or
the source and the ambient temperature during the test. Also,
isotherm) to measure and compensate for the reflected tem-
the transmittance measurement accuracy can be increased by
perature error incident upon the blackbody simulator.
increasing this temperature difference.
8.1.4 With the imager’s computer emittance control still set
6.1.2 Errors can be minimized by ensuring that the tempera-
to 1.00, measure and record the apparent temperature of this
ture of the attenuating medium is as close as possible to the
same portion of the blackbody simulator.
reflected temperature incident upon the specimen.
8.1.5 Position the attenuating medium between the imager’s
6.1.3 The compositions and thicknesses of attenuating me-
detector or lens and the blackbody simulator.
dia can vary within the same specimen. Errors can be mini-
8.1.6 Without moving the imager, adjust its computer’s
mized by measuring through the same portion of the specimen
emissivity control until the imager’s computer indicates the
every time.
same temperature recorded in 8.1.4.The indicated “emissivity”
6.2 Test Method for Compensating for Unknown Errors
value is the transmittance of the attenuating medium, at this
When Measuring the Temperature of a Specimen With a Known
blackbody s
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.