ASTM E1477-98a(2022)
(Test Method)Standard Test Method for Luminous Reflectance Factor of Acoustical Materials by Use of Integrating-Sphere Reflectometers
Standard Test Method for Luminous Reflectance Factor of Acoustical Materials by Use of Integrating-Sphere Reflectometers
SIGNIFICANCE AND USE
5.1 Acoustical materials are often used as the entire ceiling of rooms and are therefore an important component of the lighting system. The luminous reflectance of all important components must be known in order to predict the level of illumination that will be obtained.
5.2 The reflecting properties of a surface are measured relative to those of a standard reflector, the perfect reflecting diffuser, to provide a reflectance factor. The luminous reflectance factor is calculated for a standard illuminant, and a standard observer, for the standard hemispherical (integrating-sphere) geometry of illumination and viewing, in which all reflected radiation from an area of the surface is collected. In this way the reflecting properties of an acoustical material can be represented by a single number measured and calculated under standard conditions.
5.3 Acoustical materials generally have a non-glossy white or near-white finish. The types of surface cover a wide range from smooth to deeply fissured. Measurement with integrating-sphere reflectometers has been satisfactory although multiple measurements may be required to sample the surface adequately. Instruments with other types of optical measuring systems may be used if it can be demonstrated that they provide equivalent results.
5.4 The use of this test method for determining the luminous reflectance factor is required by Classification E1264.
SCOPE
1.1 This test method covers the measurement of the luminous reflectance factor of acoustical materials for use in predicting the levels of room illumination.
1.2 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.
1.3 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
Relations
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: E1477 −98a (Reapproved 2022)
Standard Test Method for
Luminous Reflectance Factor of Acoustical Materials by Use
of Integrating-Sphere Reflectometers
This standard is issued under the fixed designation E1477; 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 Definitions of appearance terms in Terminology E284
are applicable to this test method.
1.1 This test method covers the measurement of the lumi-
3.1.2 integrating sphere, n—an optical device used either to
nous reflectance factor of acoustical materials for use in
collect flux reflected or transmitted from a specimen into a
predicting the levels of room illumination.
hemisphere or to provide isotropic irradiation of a specimen
1.2 This standard does not purport to address all of the
from a complete hemisphere, consisting of an approximately
safety concerns, if any, associated with its use. It is the
spherical cavity with apertures (ports) for admitting and
responsibility of the user of this standard to establish appro-
detecting flux, and usually having additional apertures over
priate safety, health, and environmental practices and deter-
which sample and reference specimens are placed and for
mine the applicability of regulatory limitations prior to use.
including or excluding the specularly reflected components.
1.3 This international standard was developed in accor-
(E284)
dance with internationally recognized principles on standard-
3.1.3 luminous, adj—weighted according to the spectral
ization established in the Decision on Principles for the
luminous efficiency function V(λ) of the CIE. (E284)
Development of International Standards, Guides and Recom-
3.1.4 reflectance factor, R, n—ratioofthefluxreflectedfrom
mendations issued by the World Trade Organization Technical
the specimen to the flux reflected from the perfect reflecting
Barriers to Trade (TBT) Committee.
diffuser under the same geometric and spectral conditions of
2. Referenced Documents
measurement. (E284)
2.1 ASTM Standards:
3.1.5 perfect reflecting diffuser—ideal reflecting surface that
E284 Terminology of Appearance
neither absorbs nor transmits light, but reflects light in a
E308 PracticeforComputingtheColorsofObjectsbyUsing
diffused manner with the radiance of the reflecting surface
the CIE System
being the same for all reflecting angles, regardless of the
E1164 PracticeforObtainingSpectrometricDataforObject-
angular distribution of the incident light. (E284)
Color Evaluation
4. Summary of Test Method
E1264 Classification for Acoustical Ceiling Products
E1331 Test Method for Reflectance Factor and Color by
4.1 Test specimens are measured for (total) luminous reflec-
Spectrophotometry Using Hemispherical Geometry
tance factor by standard color-measurement techniques using a
E1345 Practice for Reducing the Effect of Variability of
spectrophotometer, tristimulus (filter) colorimeter, or other
Color Measurement by Use of Multiple Measurements
reflectometer having a hemispherical optical measuring
E1347 Test Method for Color and Color-Difference Mea-
system, such as an integrating sphere. The specular component
surement by Tristimulus Colorimetry
isincludedtoprovidethetotalreflectancefactorcondition.The
instrument standard is referenced to the perfect reflecting
3. Terminology
diffuser. Luminous reflectance factor is calculated as CIE
3.1 Definitions:
tristimulus value Y for the CIE 1964 (10°) standard observer
and CIE standard illuminant D65 (daylight) or F2 (cool white
This test method is under the jurisdiction of ASTM Committee E12 on Color fluorescent).
and Appearance and is the direct responsibility of Subcommittee E12.02 on
Spectrophotometry and Colorimetry.
5. Significance and Use
Current edition approved Oct. 1, 2022. Published November 2022. Originally
ɛ1
5.1 Acoustical materials are often used as the entire ceiling
approved in 1992. Last previous edition approved in 2017 as E1477 – 98a (2017) .
DOI: 10.1520/E1477-98AR22.
of rooms and are therefore an important component of the
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
lighting system. The luminous reflectance of all important
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
components must be known in order to predict the level of
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. illumination that will be obtained.
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E1477 − 98a (2022)
5.2 The reflecting properties of a surface are measured 7.3 Operate the reflectometer with the largest available area
relative to those of a standard reflector, the perfect reflecting of illumination or view. Measure at least three test specimens
diffuser, to provide a reflectance factor. The luminous reflec- randomly selected fro
...
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