ASTM E809-08
(Practice)Standard Practice for Measuring Photometric Characteristics of Retroreflectors
Standard Practice for Measuring Photometric Characteristics of Retroreflectors
SIGNIFICANCE AND USE
This practice describes procedures used to measure photometric quantities that relate to the visual perception of retroreflected light. The most significant usage is in the relation to the nighttime vehicle headlamp, retroreflector, and driver's eye geometry. For this reason the CIE Standard Source A is used to represent a tungsten vehicle headlamp and the receptor has the photopic, V (λ), spectral responsivity corresponding to the light adapted human eye. Although the geometry must be specified by the user, it will, in general, correspond to the relation between the vehicle headlamp, the retroreflector, and the vehicle driver's eye position.
SCOPE
1.1 This practice describes the general procedures for instrumental measurement of the photometric characteristics of retroreflective materials and retroreflective devices.
1.2 This practice is a comprehensive guide to the photometry of retroreflectors but does not include geometric terms that are described in Practice E 808.
1.3 This practice describes the parameters that are required when stating photometric measurements in specific tests and specifications for retroreflectors.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 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.
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Designation: E809 −08
StandardPractice for
1
Measuring Photometric Characteristics of Retroreflectors
This standard is issued under the fixed designation E809; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
3
1. Scope Illuminance Meters and Luminance Meters
1.1 This practice describes the general procedures for in-
3. Terminology
strumental measurement of the photometric characteristics of
3.1 Terms and definitions in Terminology E284 and E808
retroreflective materials and retroreflective devices.
are applicable to this practice. In general, the terminology in
1.2 This practice is a comprehensive guide to the photom-
thispracticeagreeswiththatinCIEPublications17.4and54.2.
etryofretroreflectorsbutdoesnotincludegeometrictermsthat
3.2 Definitions of Terms Specific to This Standard:
are described in Practice E808.
3.2.1 annular aperture, n—the difference between the an-
1.3 This practice describes the parameters that are required
gulardiametersoftheexternalboundarycircleandtheinternal
when stating photometric measurements in specific tests and
boundary circle.
specifications for retroreflectors.
3.2.2 circular aperture, n—the angular diameter of a circu-
1.4 The values stated in SI units are to be regarded as
lar aperture surface.
standard. No other units of measurement are included in this
3.2.3 goniometer, n—an instrument for measuring or setting
standard.
angles.
1.5 This standard does not purport to address all of the
3.2.4 photopic receiver, n—a receiver of radiation with a
safety concerns, if any, associated with its use. It is the
spectral responsivity which conforms to the V (λ) distribution
responsibility of the user of this standard to establish appro-
of the CIE Photopic Standard Observer that is specified in
priate safety and health practices and determine the applica-
Practice E308.
bility of regulatory limitations prior to use.
3.2.5 receiver aperture, n—angular dimensions from the
2. Referenced Documents retroreflector center to the entrance aperture or pupil of the
2 receiver.
2.1 ASTM Standards:
E284Terminology of Appearance 3.2.6 rectangular aperture, n—the angular height and width
of a rectangular aperture surface.
E308PracticeforComputingtheColorsofObjectsbyUsing
the CIE System 3.2.6.1 Discussion—The orientation of the sides of the
rectangular aperture surface should be supplied together with
E808Practice for Describing Retroreflection
the angular height and width.
2.2 CIE Documents:
CIE Publication No. 54.2Retroreflection—Definition and 3.2.7 reflected illuminance, E,n—illuminance at the re-
r
3
Measurement
ceiver measured on a plane perpendicular to the observation
3
CIEPublicationNo.17.4InternationalLightingVocabulary axis.
CIE Publication No. 69-1987Methods of Characterizing 3.2.7.1 Discussion—This quantity is used in the calculation
of the coefficient of luminous intensity,
2
R: R =(I/E )=(E d )/E , where dis the distance from the
I I ' r '
1
This practice is under the jurisdiction ofASTM Committee E12 on Color and
retroreflector to the receptor.
Appearance and is the direct responsibility of Subcommittee E12.10 on Retrore-
3.2.8 retroreflectometer aperture angles, n—the maximum
flection.
Current edition approved Jan. 1, 2008. Published February 2008. Originally
angular diameter of the pencil of light (see Fig. 1).
approved in 1981. Last previous edition approved in 2002 as E809–02. DOI:
3.2.8.1 Discussion—In practice the illumination arrives at
10.1520/E0809-08.
the retroreflector center within a narrow pencil of light sur-
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
rounding the illumination axis and the light reflected to the
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
photoreceptor is contained within another narrow pencil. The
the ASTM website.
distribution of light within such pencils is the “aperture”
3
AvailablefromU.S.NationalCommitteeoftheCIE(InternationalCommission
functionandthemaximumangulardiameterofthepencilisthe
on Illumination), C/o Thomas M. Lemons, TLA-Lighting Consultants, Inc., 7 Pond
St., Salem, MA 01970, http://www.cie-usnc.org. “aperture angle.” It is generally assumed that the aperture
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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E809 − 08
eye geometry. For this reason the CIE Standard Source A is
used to represent a tungsten vehicle headlamp and the receptor
has the photopic, V (λ), spectral responsivity cor
...
This document is not anASTM standard and is intended only to provide the user of anASTM 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:E809–02 Designation: E 809 – 08
Standard Practice for
1
Measuring Photometric Characteristics of Retroreflectors
This standard is issued under the fixed designation E809; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This practice describes the general procedures for instrumental measurement of the photometric characteristics of
retroreflective materials and retroreflective devices.
1.2This1.2 Thispracticeisacomprehensiveguidetothephotometryofretroreflectorsbutdoesnotincludegeometrictermsthat
are described in Practice E808.
1.3 This practice describes the parameters that are required when stating photometric measurements in specific tests and
specifications for retroreflectors.
1.4
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 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.
2. Referenced Documents
2
2.1 ASTM Standards:
E284 Terminology of Appearance
E308 Practice for Computing the Colors of Objects by Using the CIE System
E808 Practice for Describing Retroreflection
2.2 CIE Documents:
3
CIE Publication No. 54.2,54.2 Retroreflection—Definition and Measurement
3
CIE Publication No. 17.4,17.4 International Lighting Vocabulary
3
CIE Publication No. 69-1987,69-1987 Methods of Characterizing Illuminance Meters and Luminance Meters
3. Terminology
3.1 Terms and definitions in Terminology E284 and E808 are applicable to this practice. In general, the terminology in this
practice agrees with that in CIE Publications 17.4 and 54.2 and 54.2.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 retroreflectometer aperture angles —the maximum angular diameter of the pencil of light (see Fig. 1).
3.2.1.1Discussion—In practice the illumination arrives at the retroreflector center within a narrow pencil of light surrounding
theilluminationaxisandthelightreflectedtothephotoreceptoriscontainedwithinanothernarrowpencil.Thedistributionoflight
within such pencils is the “aperture” function and the maximum angular diameter of the pencil is the “aperture angle.” It is
generally assumed that the aperture functions are rotationally symmetrical and even uniform, but this is often false, especially for
illumination. annular aperture, n—the difference between the angular diameters of the external boundary circle and the internal
boundary circle.
3.2.2 retroreflector aperture surface—the aperture surface of a retroreflector is given by the retroreflector itself, or by a
diaphragm enclosing part of the retroreflector. circular aperture, n—the angular diameter of a circular aperture surface.
3.2.3 retroreflector (or specimen) aperture— angular dimensions from the source point of reference to the aperture surface of
the retroreflector (or specimen).
1
This practice is under the jurisdiction ofASTM Committee E12 on Color andAppearance and is the direct responsibility of Subcommittee E12.10 on Retroreflection.
Current edition approved June 10, 2002. Published August 2002. Originally published as E809–81. Last previous edition E809–94a(2000).
Current edition approved Jan. 1, 2008. Published February 2008. Originally approved in 1981. Last previous edition approved in 2002 as E809–02.
2
ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,orcontactASTMCustomerServiceatservice@astm.org.For Annual Book of ASTM Standards
, Vol 06.01.volume information, refer to the standard’s Document Summary page on the ASTM website.
3
Available from USNC/CIE Publications Office; TLA Lighting Consultants, Inc., 77 Pond St., Salem, MA 01970.
3
Available from U.S. National Committee of the CIE (International Commission on Illumination), C/o Thomas M. Lemons, TLA-Lighting Consultants, Inc., 7 Pond St.,
Salem, MA 01970, http://www.cie-usnc.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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E809–08
FIG. 1 Illustration of Apertures used in Retroreflection
Measurement
3.2.3.1Discussion—Asthesourceandreceiveraregenerallyclosetoeachothe
...
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