ASTM E808-01(2016)
(Practice)Standard Practice for Describing Retroreflection
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 provides 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 health practices and determine the applicability of regulatory limitations prior to use.
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: E808 −01 (Reapproved 2016)
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 3.1.1 In accordance with the convention appearing in the
Significance and Use section of Terminology E284, the super-
1.1 This practice provides terminology, alternative geo-
script B appearing after [CIE] at the end of a definition
metrical coordinate systems, and procedures for designating
indicates that the given definition is a modification of that cited
angles in descriptions of retroreflectors, specifications for
with little difference in essential meaning.
retroreflector performance, and measurements of retroreflec-
tion.
NOTE 1—The terminology given here describes visual observation of
luminance as defined by the CIE V (λ) spectral weighting function for the
1.2 Terminology defined herein includes terms germane to
photopic observer. Analogous terms for other purposes can be defined by
other ASTM documents on retroreflection.
using appropriate spectral weighting.
1.3 This standard does not purport to address all of the
3.2 Definitions:
safety concerns, if any, associated with its use. It is the
3.2.1 The delimiting phrase “in retroreflection” applies to
responsibility of the user of this standard to establish appro-
each of the following definitions when used outside the context
priate safety and health practices and determine the applica-
of this or other retroreflection standards.
bility of regulatory limitations prior to use.
3.2.2 coeffıcient of line retroreflection, R ,n—of a retrore-
M
flecting stripe, the ratio of the coefficient of luminous intensity
2. Referenced Documents
(R ) to the length (l), expressed in candelas per lux per metre
I
2 –1 –1
2.1 ASTM Standards: (cd·lx ·m ). R = R /l.
M I
E284 Terminology of Appearance 3.2.2.1 Discussion—R depends on the spectral composi-
M
tion of the illumination which is usually CIE illuminant A.
2.2 Federal Standard:
Fed. Std. No. 370 Instrumental Photometric Measurements 3.2.3 coeffıcient of luminous intensity, R,n—of a
I
3
of Retroreflecting Materials and Retroreflecting Devices retroreflector, ratio of the luminous intensity (I) of the retrore-
flector in the direction of observation to the illuminance (E )
'
2.3 CIE Document:
at the retroreflector on a plane perpendicular to the direction of
CIE Publication No. 54 Retroreflection-Definition and Mea-
–1
4
the incident light, expressed in candelas per lux (cd·lx ). R =
I
surement
(I/E ).
'
3.2.3.1 Discussion—Inagivenmeasurementoneobtainsthe
3. Terminology
average R over the solid angles of incidence and viewing
I
3.1 Terms and definitions in Terminology E284 are appli-
subtendedbythesourceandreceiverapertures,respectively.In
cable to this standard.
practice, Iisoftendeterminedastheproductoftheilluminance
2
at the observer and the distance squared (I=E d ). R depends
r I
onthespectralcompositionoftheilluminationwhichisusually
1
This practice is under the jurisdiction of ASTM Committee E12 on Color and
CIE illuminant A.
Appearance and is the direct responsibility of Subcommittee E12.10 on Retrore-
3.2.3.2 Discussion—Also called coeffıcient of (retrore-
flection.
flected) luminous intensity. Equivalent commonly used terms
Current edition approved Jan. 1, 2016. Published January 2016. Originally
approved in 1981. Last previous edition approved in 2009 as E808 – 01 (2009). are CIL and SI (specific intensity). CIE Publication 54 uses the
DOI: 10.1520/E0808-01R16.
symbol R for R . The ASTM recommendation is to use the
I
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
symbol R .
I
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
3.2.4 coeffıcient of retroreflected luminance, R ,n—the ratio
L
the ASTM website.
of the luminance, L, in the direction of observation to the
3
Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,
normal illuminance, E , at the surface on a plane normal to the
Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http:// '
www.dodssp.daps.mil. incident light, expressed in candelas per square metre per lux
4
–2 –1
Available from U.S. National Committee of the CIE (International Commission
[(cd·m )·lx ].
on Illumination), C/o Thomas M. Lemons, TLA-Lighting Consultants, Inc., 7 Pond
St., Salem, MA 0197
...
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