ASTM E808-23

Standard Practice for Describing Retroreflection

SIGNIFICANCE AND USE
4.1 This practice applies to any measurement of reflectance in which the angle at the sample between the direction of the incident radiation and the direction of viewing is less than approximately 10°, and the reflected radiation is concentrated in a direction opposite to the direction of incidence.  
4.2 The CIE (goniometer) system described in 6.1.1 was developed by the Subcommittee on Retroreflection of Committee 2.3 on Materials of the International Commission on Illumination (Commission International de l'Eclairage, CIE). It is intended to provide a common basis for the measurement of retroreflection, which should be used worldwide.  
4.3 This practice provides alternative geometric coordinate systems useful for visualizing relationships between various angles in actual use.
SCOPE
1.1 This practice covers terminology, alternative geometrical coordinate systems, and procedures for designating angles in descriptions of retroreflectors, specifications for retroreflector performance, and measurements of retroreflection.  
1.2 Terminology defined herein includes terms germane to other ASTM documents on retroreflection.  
1.3 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.  
1.4 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-2023
• ICS: 17.180.20 - Colours and measurement of light
• Technical Committee: E12 - Color and Appearance
• Drafting Committee: E12.10 - Retroreflection

Relations

• Replaces: ASTM E808-01(2016) - Standard Practice for Describing Retroreflection
• Effective Date: 01-Dec-2023
• Referred By: ASTM E3320-21 - Standard Test Method for Measurement of Retroreflective Pavement Marking Materials Using a Mobile Retroreflectometer Unit (MRU)
• Effective Date: 01-Dec-2023
• Referred By: ASTM E809-21 - Standard Practice for Measuring Photometric Characteristics of Retroreflectors
• Effective Date: 01-Dec-2023
• Referred By: ASTM D8514/D8514M-23 - Standard Specification for Flexible, Retroreflective Sheeting for Use in High Visibility Vehicle Markings
• Effective Date: 01-Dec-2023
• Referred By: ASTM D4956-19 - Standard Specification for Retroreflective Sheeting for Traffic Control
• Effective Date: 01-Dec-2023
• Referred By: ASTM E179-17(2022) - Standard Guide for Selection of Geometric Conditions for Measurement of Reflection and Transmission Properties of Materials
• Effective Date: 01-Dec-2023
• Referred By: ASTM D4383-21 - Standard Specification for Plowable, Raised Retroreflective Pavement Markers
• Effective Date: 01-Dec-2023
• Referred By: ASTM E1696-15(2022) - Standard Test Method for Field Measurement of Raised Retroreflective Pavement Markers Using a Portable Retroreflectometer
• Effective Date: 01-Dec-2023
• Referred By: ASTM D7585/D7585M-10(2022) - Standard Practice for Evaluating Retroreflective Pavement Markings Using Portable Hand-Operated Instruments
• Effective Date: 01-Dec-2023
• Referred By: ASTM E810-20 - Standard Test Method for Coefficient of Retroreflection of Retroreflective Sheeting Utilizing the Coplanar Geometry
• Effective Date: 01-Dec-2023
• Referred By: ASTM E811-09(2020)e1 - Standard Practice for Measuring Colorimetric Characteristics of Retroreflectors Under Nighttime Conditions
• Effective Date: 01-Dec-2023
• Referred By: ASTM E1709-16(2022) - Standard Test Method for Measurement of Retroreflective Signs Using a Portable Retroreflectometer at a 0.2 Degree Observation Angle
• Effective Date: 01-Dec-2023
• Referred By: ASTM D4061-13(2018) - Standard Test Method for Retroreflectance of Horizontal Coatings
• Effective Date: 01-Dec-2023
• Referred By: ASTM E2540-16(2022) - Standard Test Method for Measurement of Retroreflective Signs Using a Portable Retroreflectometer at a 0.5 Degree Observation Angle
• Effective Date: 01-Dec-2023
• Referred By: ASTM E3165-18 - Standard Test Method for Nighttime Retroreflected Chromaticity of Retroreflective Sheeting
• Effective Date: 01-Dec-2023

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: E808 − 23
Standard Practice for
1
Describing Retroreflection
This standard is issued under the fixed designation E808; 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
1.1 This practice covers terminology, alternative geometri-
3.1 Terms and definitions in Terminology E284 are appli-
cal coordinate systems, and procedures for designating angles
cable to this standard.
in descriptions of retroreflectors, specifications for retroreflec-
3.1.1 In accordance with the convention appearing in the
tor performance, and measurements of retroreflection.
Significance and Use section of Terminology E284, the super-
script B appearing after [CIE] at the end of a definition
1.2 Terminology defined herein includes terms germane to
indicates that the given definition is a modification of that cited
other ASTM documents on retroreflection.
with little difference in essential meaning.
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
NOTE 1—The terminology given here describes visual observation of
responsibility of the user of this standard to establish appro-
luminance as defined by the CIE V (λ) spectral weighting function for the
photopic observer. Analogous terms for other purposes can be defined by
priate safety, health, and environmental practices and deter-
using appropriate spectral weighting.
mine the applicability of regulatory limitations prior to use.
3.2 Definitions:
1.4 This international standard was developed in accor-
dance with internationally recognized principles on standard-
3.2.1 The delimiting phrase “in retroreflection” applies to
ization established in the Decision on Principles for the each of the following definitions when used outside the context
Development of International Standards, Guides and Recom-
of this or other retroreflection standards.
mendations issued by the World Trade Organization Technical
3.2.2 coeffıcient of line retroreflection, R , n—of a retrore-
M
Barriers to Trade (TBT) Committee.
flecting stripe, the ratio of the coefficient of luminous intensity
(R ) to the length (l), expressed in candelas per lux per metre
I
–1 –1
2. Referenced Documents
(cd·lx ·m ). R = R /l.
M I
2
3.2.2.1 Discussion—R depends on the spectral composi-
2.1 ASTM Standards:
M
E284 Terminology of Appearance tion of the illumination which is usually CIE illuminant A.
2.2 Federal Standard: 3.2.3 coeffıcient of luminous intensity, R , n—of a
I
Fed. Std. No. 370 Instrumental Photometric Measurements retroreflector, ratio of the luminous intensity (I) of the retrore-
3
of Retroreflecting Materials and Retroreflecting Devices flector in the direction of observation to the illuminance (E )
'
at the retroreflector on a plane perpendicular to the direction of
2.3 CIE Document:
–1
the incident light, expressed in candelas per lux (cd·lx ). R =
I
CIE Publication 54.2 Retroreflection: Definition and Mea-
4 (I/E ).
'
surement
3.2.3.1 Discussion—In a given measurement one obtains the
average R over the solid angles of incidence and viewing
I
subtended by the source and receiver apertures, respectively. In
1
This practice is under the jurisdiction of ASTM Committee E12 on Color and
practice, I is often determined as the product of the illuminance
Appearance and is the direct responsibility of Subcommittee E12.10 on Retrore-
2
at the observer and the distance squared (I = E d ). R depends
flection.
r I
Current edition approved Dec. 1, 2023. Published December 2023. Originally
on the spectral composition of the illumination which is usually
approved in 1981. Last previous edition approved in 2016 as E808 – 01 (2016).
CIE illuminant A.
DOI: 10.1520/E0808-23.
2
3.2.3.2 Discussion—Also called coeffıcient of (retrore-
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
flected) luminous intensity. Equivalent commonly used terms
Standards volume information, refer to the standard’s Document Summary page on
are CIL and SI (specific intensity). CIE Publication 54 uses the
the ASTM website.
symbol R for R . The ASTM recommendation is to use the
3
Available from Standardization Documents Order Desk, DODSSP, Bldg. 4, I
Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http:// symbol R .
I
www.dodssp.daps.mil.
4
3.2.4 coeffıcient of retroreflected luminance, R , n—the ratio
Available from U.S. Natio
...

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: E808 − 01 (Reapproved 2016) E808 − 23
Standard Practice for
1
Describing Retroreflection
This standard is issued under the fixed designation E808; 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
1.1 This practice providescovers terminology, alternative geometrical coordinate systems, and procedures for designating angles
in descriptions of retroreflectors, specifications for retroreflector performance, and measurements of retroreflection.
1.2 Terminology defined herein includes terms germane to other ASTM documents on retroreflection.
1.3 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 healthsafety, health, and environmental practices and determine
the applicability of regulatory limitations prior to use.
1.4 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
2.1 ASTM Standards:
E284 Terminology of Appearance
2.2 Federal Standard:
3
Fed. Std. No. 370 Instrumental Photometric Measurements of Retroreflecting Materials and Retroreflecting Devices
2.3 CIE Document:
4
CIE Publication No. 5454.2 Retroreflection-Definition Retroreflection: Definition and Measurement
3. Terminology
3.1 Terms and definitions in Terminology E284 are applicable to this standard.
3.1.1 In accordance with the convention appearing in the Significance and Use section of Terminology E284, the superscript B
appearing after [CIE] at the end of a definition indicates that the given definition is a modification of that cited with little difference
in essential meaning.
NOTE 1—The terminology given here describes visual observation of luminance as defined by the CIE V (λ) spectral weighting function for the photopic
1
This practice is under the jurisdiction of ASTM Committee E12 on Color and Appearance and is the direct responsibility of Subcommittee E12.10 on Retroreflection.
Current edition approved Jan. 1, 2016Dec. 1, 2023. Published January 2016December 2023. Originally approved in 1981. Last previous edition approved in 20092016
as E808 – 01 (2009).(2016). DOI: 10.1520/E0808-01R16.10.1520/E0808-23.
2
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.
3
Available from Standardization Documents Order Desk, DODSSP, Bldg. 4, Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http://www.dodssp.daps.mil.
4
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.Illumination) (http://www.cie-usnc.org) or the CIE (cie.co.at) Webshop.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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E808 − 23
observer. Analogous terms for other purposes can be defined by using appropriate spectral weighting.
3.2 Definitions:
3.2.1 The delimiting phrase “in retroreflection” applies to each of the following definitions when used outside the context of this
or other retroreflection standards.
3.2.2 coeffıcient of line retroreflection, R , n—of a retroreflecting stripe, the ratio of the coefficient of luminous intensity (R ) to
M I
–1 –1
the length (l), expressed in candelas per lux per metre (cd·lx ·m ). R = R /l.
M I
3.2.2.1 Discussion—
R depends on the spectral composition of the illumination which is usually CIE illuminant A.
M
3.2.3 coeffıcient of luminous intensity, R , n—of a retroreflector, ratio of the luminous intensity (I) of the retroreflector in the
I
direction of observation to the illuminance (E ) at the retroreflector on a plane perpendicular to the direction of the incident light,
'
–1
expressed in candelas per lux (cd·lx ). R = (I/E ).
I '
3.2.3.1 Discussion—
In a given measurement o
...