ASTM E1897-14(2022)

Standard Practice for Measuring and Compensating for Transmittance of an Attenuating Medium Using Infrared Imaging Radiometers

SIGNIFICANCE AND USE
5.1 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.  
5.1.1 A procedure is given for measuring the transmittance of an attenuating medium.  
5.1.2 A procedure 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.  
5.1.3 A procedure is given for measuring and compensating for transmittance and emissivity errors when the specimen temperature is known.  
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 transmittance 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 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.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: Published
• Publication Date: 30-Nov-2022
• ICS: 17.200.10 - Heat. Calorimetry
• Technical Committee: E07 - Nondestructive Testing
• Drafting Committee: E07.10 - Specialized NDT Methods

Relations

• Refers: ASTM E1316-24 - Standard Terminology for <?Pub Dtl?>Nondestructive Examinations
• Effective Date: 01-Feb-2024
• Refers: ASTM E1316-19b - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Dec-2019
• Refers: ASTM E1316-19 - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Mar-2019
• Refers: ASTM E1316-18 - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Jan-2018
• Refers: ASTM E1316-17a - Standard Terminology for Nondestructive Examinations
• Effective Date: 15-Jun-2017
• Refers: ASTM E1316-17 - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Feb-2017
• Refers: ASTM E1316-16a - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Aug-2016
• Refers: ASTM E1316-16 - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Feb-2016
• Refers: ASTM E1316-15a - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Dec-2015
• Refers: ASTM E1316-15 - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Sep-2015
• Refers: ASTM E1316-14e1 - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Jun-2014
• Refers: ASTM E1316-14 - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Jun-2014
• Refers: ASTM E1316-13d - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Dec-2013
• Refers: ASTM E1316-13c - Standard Terminology for Nondestructive Examinations
• Effective Date: 15-Jun-2013
• Refers: ASTM E1316-13b - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Jun-2013

Overview

ASTM E1897-14(2022) - Standard Practice for Measuring and Compensating for Transmittance of an Attenuating Medium Using Infrared Imaging Radiometers - provides established procedures for assessing and correcting the impact of attenuating media when using infrared imaging radiometers. Infrared thermographers frequently encounter semi-transparent materials such as windows, filters, and atmospheric layers, all of which can interfere with accurate temperature readings by reducing infrared radiation transmission. This standard outlines comprehensive test methods and guidance for both field and laboratory settings to ensure reliable temperature measurements and process control, particularly in nondestructive testing and evaluation contexts.

Key Topics

• Attenuating Medium and Infrared Measurement: Defines key concepts such as attenuating medium (any semi-transparent solid, liquid, or gas that reduces infrared radiation), blackbody simulator, emissivity, and reflected temperature.
• Transmittance Measurement: Procedures for accurately measuring the transmittance of a window, filter, or other medium, crucial for compensating measurement errors.
• Temperature Compensation Methods: Test methods for compensating for transmittance and emissivity errors depending on the available information, whether it is the known emissivity, known transmittance, or known specimen temperature.
• Practical Test Procedures: Step-by-step guidance for using calibrated infrared imaging radiometers and related equipment to assess transmittance and adjust measurement parameters.
• Process Control and Nondestructive Evaluation: Application of transmittance values to ensure precise process control and material evaluation.

Applications

The practical value of ASTM E1897-14(2022) lies in its robust applicability across many industries where infrared thermography serves as a critical nondestructive testing method. Common uses include:

• Industrial Inspections: Verifying temperature profiles through protective windows or filters in furnaces, electrical enclosures, and process vessels.
• Building Diagnostics: Measuring surface temperatures through glass or atmospheric conditions for energy audits, moisture analysis, or heat loss assessments.
• Materials Testing: Nondestructive evaluation of components where a transparent or semi-transparent barrier is present.
• Research and Development: Ensuring accuracy in experiments that require temperature measurements through various optical materials.
• Quality Assurance: Supporting QA processes where reliable temperature measurement is essential for product conformity and safety.

The standard allows practitioners to use widely available materials and infrared radiometers with computer capabilities, making it accessible in both controlled laboratory environments and field applications.

Related Standards

For a comprehensive approach to infrared imaging, nondestructive testing, and precise radiometric measurements, ASTM E1897-14(2022) is often used in conjunction with related standards, such as:

• ASTM E1316: Terminology for Nondestructive Examinations, which provides essential definitions for the terms used in ASTM E1897.
• Other Infrared Thermography Standards: Refer to ASTM and ISO documents regarding infrared testing methods and equipment specifications.
• Guidelines on Emissivity and Reflected Temperature: Supplementary documents and manufacturer guidance to enhance measurement accuracy in complex environments.

Summary

ASTM E1897-14(2022) establishes reliable procedures for measuring and compensating for the transmittance of attenuating media in infrared temperature measurement. It ensures precise temperature readings by addressing error sources associated with windows, filters, and atmospheric conditions, supporting process control and nondestructive evaluation in various technical fields. The standard's practical guidance helps maximize the value and reliability of infrared imaging radiometers, contributing to improved safety, quality, and efficiency in thermal measurements.

Standards Content (Sample)

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.
Designation: E1897 − 14 (Reapproved 2022)
Standard Practice 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. Terminology
3.1 Definitions of Terms Specific to This Standard:
1.1 This practice covers procedures for measuring and
3.1.1 attenuating medium—a semi-transparent solid, liquid,
compensating for transmittance when using an infrared imag-
or gas, such as a window, filter, external optics or an atmo-
ing radiometer to measure the temperature of a specimen
sphere that attenuates radiation.
through an attenuating medium, such as a window, filter, or
atmosphere.
3.1.2 blackbody simulator—a device with an emissivity
close to 1.00 that can be heated or cooled to a stable
1.2 The values stated in SI units are to be regarded as
temperature.
standard. No other units of measurement are included in this
standard. 3.1.3 filter—a semi-transparent material that attenuates cer-
tain wavelengths of radiation.
1.3 These procedures may involve use of equipment and
3.1.4 infrared thermographer—the person using an infrared
materials in the presence of heated or electrically-energized
imaging radiometer.
equipment, or both.
3.1.5 reflected temperature—the temperature of the energy
1.4 This standard does not purport to address all of the
incident upon and reflected by the measurement surface of the
safety concerns, if any, associated with its use. It is the
specimen.
responsibility of the user of this standard to establish appro-
3.1.6 window—a semi-transparent material that separates
priate safety, health, and environmental practices and deter-
conditioned and unconditioned atmospheres and attenuates
mine the applicability of regulatory limitations prior to use.
certain wavelengths of radiation.
1.5 This international standard was developed in accor-
dance with internationally recognized principles on standard-
3.2 See also Terminology E1316.
ization established in the Decision on Principles for the
4. Summary of Practice
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
4.1 Using the computer built into an infrared imaging
Barriers to Trade (TBT) Committee.
radiometer, a method is given for measuring the transmittance
of an attenuating medium.
2. Referenced Documents
4.2 Using the computer built into an infrared imaging
2.1 ASTM Standards:
radiometer, a method is given for compensating for errors
E1316 Terminology for Nondestructive Examinations
when measuring the temperature of a specimen through an
attenuating medium when the emissivity of the specimen and
the transmittance of the attenuating medium are known.
This practice is under the jurisdiction of ASTM Committee E07 on Nonde-
4.3 Using the computer built into an infrared imaging
structive Testing and is the direct responsibility of Subcommittee E07.10 on
radiometer, a method is given for measuring and compensating
Specialized NDT Methods.
for unknown transmittance and emissivity errors when the
Current edition approved Dec. 1, 2022. Published December 2022. Originally
specimen temperature is known.
approved in 1997. Last previous edition approved in 2018 as E1897 – 14(2018).
DOI: 10.1520/E1897-14R22.
This practice was originally adapted in 1997, by agreement, from the Guideline
5. Significance and Use
for Measuring and Compensating for Reflected Temperature, Emittance and
5.1 The transmittance of an attenuating medium can cause
Transmittance developed by Infraspection Institute, 425 Ellis Street, Burlington, NJ
08016.
errors for an infrared thermographer using an infrared imaging
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
radiometer to measure the temperature of a specimen through
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
the medium. Three test methods are given for measuring and
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. compensating for this error source.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1897 − 14 (2022)
5.1.1 A procedure is given for measuring the transmittance 7.2 The procedure for measuring the transmittance of an
of an attenuating medium. attenuating medium requires a tripod or device to support the
5.1.2 Aprocedureisgivenforcompensatingforerrorswhen infrared imaging radiometer.
measuring the temperature of a specimen having a known
7.3 The procedure for measuring the transmittance of an
emissivity through an attenuating medium with a known
attenuating medium requires a high-emissivity source that is
transmittance.
heated to a stable temperature at least 20 °C above ambient
5.1.3 Aprocedure is given for measuring and compensating
temperature.
for transmittance and emissivity errors when the specimen
7.4 The procedure for measuring and compensating for
temperature is known.
unknown transmittance and emissivity errors when the speci-
5.2 These procedures can be used in the field or laboratory
men temperature is known requires a calibrated thermometer to
using commonly available materials.
measure the temperature of the specimen.
5.3 These procedures can be used with any infrared radi-
ometers that have the required computer capabilities.
8. Procedure
5.4 The values of transmittance are defined only in terms of
8.1 To measure the transmittance of an attenuating medium,
the procedure for the purpose of process control and nonde-
use the following sequential steps:
structive evaluation of materials.
8.1.1 Place the infrared imaging radiometer on the tripod or
support device at the desired location and distance from the
6. Interferences
blackbody simulator.
6.1 Practice for Measuring the Transmittance of an Attenu-
8.1.2 Point the infrared imaging radiometer at the black-
ating Medium:
body simulator and focus on a portion that has an emissivity of
6.1.1 This practice requires a blackbody simulator with an
0.95 or greater. Make sure that the blackbody simulator is at a
emissivity of 0.95 or greater that is at least 20 °C warmer than
stable temperature at least 20 °C above the ambient tempera-
ambient temperature. Potential errors can be minimized by
ture.
ensuring the stability of the temperature difference between the
8.1.3 Use an appropriate infrared imaging radiometer mea-
sourceandtheambienttemperatureduringtheprocedure.Also,
...