ASTM D7897-18

Standard Practice for Laboratory Soiling and Weathering of Roofing Materials to Simulate Effects of Natural Exposure on Solar Reflectance and Thermal Emittance

SIGNIFICANCE AND USE
5.1 The solar reflectance of a building envelope surface affects surface temperature and near-surface ambient air temperature. Surfaces with low solar reflectance absorb a high fraction of the incoming solar energy. Sunlight absorbed by a roof or by other building envelope surfaces can be conducted into the building, increasing cooling load and decreasing heating load in a conditioned building, or raising indoor temperature in an unconditioned building. It can also warm the outside air by convection. Determination of solar reflectance can help designers and consumers choose appropriate materials for their buildings and communities.  
5.1.1 The solar reflectance of a new building envelope surface often changes within one to two years through deposition and retention of soot and dust; microbiological growth; exposure to sunlight, precipitation, and dew; and other processes of soiling and weathering. For example, light-colored “cool” envelope surfaces with high initial reflectance can experience substantial reflectance loss as they are covered with dark soiling agents. Current product rating programs require roofing manufacturers to report values of solar reflectance and thermal emittance measured after three years of natural exposure (2, 3). A rapid laboratory process for soiling and weathering that simulates the three-year-aged radiative properties of roof and other building envelope surface materials expedites the development, testing, and introduction to market of such products.  
5.2 Thermal emittance describes the efficiency with which a surface exchanges thermal radiation with its environment. High thermal emittance enhances the ability of a surface to stay cool in the sun. The thermal emittance of a bare metal surface is initially low, and often increases as it is soiled or oxidized (4). The thermal emittance of a typical non-metal surface is initially high, and remains high after soiling (5).  
5.3 This practice allows measurement of the solar reflectance a...
SCOPE
1.1 Practice D7897 applies to simulation of the effects of field exposure on the solar reflectance and thermal emittance of roof surface materials including but not limited to field-applied coatings, factory-applied coatings, single-ply membranes, modified bitumen products, shingles, tiles, and metal products. The solar reflectance and thermal emittance of roof surfacing materials can be changed by exposure to the outdoor environment. These changes are caused by three factors: deposition and retention of airborne pollutants; microbiological growth; and changes in physical or chemical properties. This practice applies to simulation of changes in solar reflectance and thermal emittance induced by deposition and retention of airborne pollutants and, to a limited extent, changes caused by microbiological growth.  
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

• Status: Historical
• Publication Date: 14-Mar-2018
• ICS: 91.060.20 - Roofs
• Technical Committee: D08 - Roofing and Waterproofing
• Drafting Committee: D08.20 - Roofing Membrane Systems

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D7897 − 18
Standard Practice for
Laboratory Soiling and Weathering of Roofing Materials to
Simulate Effects of Natural Exposure on Solar Reflectance
1
and Thermal Emittance
This standard is issued under the fixed designation D7897; 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 C1549 Test Method for Determination of Solar Reflectance
Near Ambient Temperature Using a Portable Solar Reflec-
1.1 Practice D7897 applies to simulation of the effects of
tometer
field exposure on the solar reflectance and thermal emittance of
E691 Practice for Conducting an Interlaboratory Study to
roof surface materials including but not limited to field-applied
Determine the Precision of a Test Method
coatings, factory-applied coatings, single-ply membranes,
G151 Practice for Exposing Nonmetallic Materials in Accel-
modified bitumen products, shingles, tiles, and metal products.
erated Test Devices that Use Laboratory Light Sources
The solar reflectance and thermal emittance of roof surfacing
G154 Practice for Operating Fluorescent Ultraviolet (UV)
materials can be changed by exposure to the outdoor environ-
Lamp Apparatus for Exposure of Nonmetallic Materials
ment. These changes are caused by three factors: deposition
2.2 Other Standards:
and retention of airborne pollutants; microbiological growth;
ANSI/CRRC S100 Standard Test Methods for Determining
and changes in physical or chemical properties. This practice
3
Radiative Properties of Materials
applies to simulation of changes in solar reflectance and
thermal emittance induced by deposition and retention of
3. Terminology
airborne pollutants and, to a limited extent, changes caused by
3.1 Definitions:
microbiological growth.
3.1.1 solar energy—the radiant energy originating from the
1.2 This standard does not purport to address all of the
sun.
safety concerns, if any, associated with its use. It is the
3.1.1.1 Discussion—Approximately 99 % of terrestrial solar
responsibility of the user of this standard to establish appro-
radiation lies between the wavelengths of 0.3 and 2.5 µm, with
priate safety, health, and environmental practices and deter-
peak radiation near 0.5 µm. This spectrum includes ultraviolet,
mine the applicability of regulatory limitations prior to use.
visible, and near-infrared radiation.
1.3 This international standard was developed in accor-
3.1.2 solar reflectance—the fraction of incident solar flux
dance with internationally recognized principles on standard-
reflected by a surface.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
3.1.3 thermal emittance—efficiency with which a surface
mendations issued by the World Trade Organization Technical
emits thermal radiation, measured on a scale from 0 to 1, where
Barriers to Trade (TBT) Committee.
a value of 1 indicates perfect emission (that is, equal to that of
a black body).
2. Referenced Documents
3.1.4 thermal radiation—the radiant energy originating
2
2.1 ASTM Standards:
from a 300 K (about 27°C) black body.
C1371 Test Method for Determination of Emittance of
3.1.4.1 Discussion—Approximately 99 % of thermal radia-
Materials Near Room Temperature Using Portable Emis-
tion lies between the wavelengths of 4 and 80 µm, with peak
someters
radiation near 10 µm.
1
This practice is under the jurisdiction of ASTM Committee D08 on Roofing and
4. Summary of Practice
Waterproofing and is the direct responsibility of Subcommittee D08.20 on Roofing
Membrane Systems.
4.1 This practice presents a rapid laboratory method for
Current edition approved March 15, 2018. Published July 2018. Originally
weathering and soiling, which simulates natural changes in
approved in 2015. Last previous edition approved in 2015 as D7897 – 15. DOI:
solar reflectance and thermal emittance of materials in the field.
10.1520/D7897-18.
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
3
Standards volume information, refer to the standard’s Document Summary page on Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
the ASTM website. 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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D7897 − 18
The practice describes a simulated field exposure protocol that scatter or weakly absorb sunlight. A notable exception is black
consists of spraying an aqueou
...

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: D7897 − 15 D7897 − 18
Standard Practice for
Laboratory Soiling and Weathering of Roofing Materials to
Simulate Effects of Natural Exposure on Solar Reflectance
1
and Thermal Emittance
This standard is issued under the fixed designation D7897; 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 Practice D7897 applies to simulation of the effects of field exposure on the solar reflectance and thermal emittance of roof
surface materials including but not limited to field-applied coatings, factory-applied coatings, single-ply membranes, modified
bitumen products, shingles, tiles, and metal products. The solar reflectance and thermal emittance of roof surfacesurfacing
materials can be changed by exposure to the outdoor environment. These changes are caused by three factors: deposition and
retention of airborne pollutants; microbiological growth; and changes in physical or chemical properties. This practice applies to
simulation of changes in solar reflectance and thermal emittance induced by deposition and retention of airborne pollutants and,
to a limited extent, changes caused by microbiological growth.
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 safety, health, and healthenvironmental 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.
2. Referenced Documents
2
2.1 ASTM Standards:
C1371 Test Method for Determination of Emittance of Materials Near Room Temperature Using Portable Emissometers
C1549 Test Method for Determination of Solar Reflectance Near Ambient Temperature Using a Portable Solar Reflectometer
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
G151 Practice for Exposing Nonmetallic Materials in Accelerated Test Devices that Use Laboratory Light Sources
G154 Practice for Operating Fluorescent Ultraviolet (UV) Lamp Apparatus for Exposure of Nonmetallic Materials
2.2 Other Standards:
3
ANSI/CRRC S100 Standard Test Methods for Determining Radiative Properties of Materials
3. Terminology
3.1 Definitions:
3.1.1 solar energy—the radiant energy originating from the sun.
3.1.1.1 Discussion—
Approximately 99 % of terrestrial solar radiation lies between the wavelengths of 0.3 and 2.5 μm, with peak radiation near 0.5 μm.
This spectrum includes ultraviolet, visible, and near-infrared radiation.
3.1.2 solar reflectance—the fraction of incident solar flux reflected by a surface.
1
This practice is under the jurisdiction of ASTM Committee D08 on Roofing and Waterproofing and is the direct responsibility of Subcommittee D08.20 on Roofing
Membrane Systems.
Current edition approved Jan. 1, 2015March 15, 2018. Published March 2015July 2018. Originally approved in 2015. Last previous edition approved in 2015 as
D7897 – 15. DOI: 10.1520/D7897-15.10.1520/D7897-18.
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 American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
D7897 − 18
3.1.3 thermal emittance—efficiency with which a surface emits thermal radiation, measured on a scale from 0 to 1, where a
value of 1 indicates perfect emission (that is, equal to that of a black body).
3.1.4 thermal radiation—the radiant energy originating from a 300 K (about 27°C) black body.
3.1.4.1 Discussion—
Approximately 99 % of thermal radiation lies between the wavelengths of 4 and 80 μm, with peak radiation near 10 μm.
4. Summary of Practice
4.1 This practice presents a
...