ASTM E824-10
(Test Method)Standard Test Method for Transfer of Calibration From Reference to Field Radiometers
Standard Test Method for Transfer of Calibration From Reference to Field Radiometers
SIGNIFICANCE AND USE
The methods described represent the preferable means for calibration of field radiometers employing standard reference radiometers. Other methods involve the employment of an optical bench and essentially a point source of artificial light. While these methods are useful for cosine and azimuth correction analyses, they suffer from foreground view factor and directionality problems. Transfer of calibration indoors using artificial sources is not covered by this test method.
Traceability of calibration of global pyranometers is accomplished when employing the method using a reference global pyranometer that has been calibrated, and is traceable to the World Radiometric Reference (WRR). For the purposes of this test method, traceability shall have been established if a parent instrument in the calibration chain participated in an International Pyrheliometric Comparison (IPC) conducted at the World Radiation Center (WRC) in Davos, Switzerland. Traceability of calibration of narrow- and broad-band radiometers is accomplished when employing the method using a reference ultraviolet radiometer that has been calibrated and is traceable to the National Institute of Standards and Technology (NIST), or other national standards organizations. See Zerlaut for a discussion of the WRR, the IPC's and their results.
The reference global pyranometer (for example, one measuring hemispherical solar radiation at all wavelengths) shall have been calibrated by the shading-disk or component summation method against one of the following instruments:
An absolute cavity pyrheliometer that participated in a WMO sanctioned IPC's (and therefore possesses a WRR reduction factor),
An absolute cavity radiometer that has been intercompared (in a local or regional comparison) with an absolute cavity pyrheliometer meeting the requirements given in 5.2.1.1.
A WMO First Class pyrheliometer that was calibrated by direct transfer from such an absolute cavity.
Alternatively, the reference pyrano...
SCOPE
1.1 The method described in this standard applies to the transfer of calibration from reference to field radiometers to be used for measuring and monitoring outdoor radiant exposure levels. This standard has been harmonized with ISO 9847.
1.2 This test method is applicable to field radiometers regardless of the radiation receptor employed, but is limited to radiometers having approximately 180° (2π Steradian), field angles.
1.3 The calibration covered by this test method employs the use of natural sunshine as the source.
1.4 Calibrations of field radiometers may be performed at tilt as well as horizontal (at 0° from the horizontal to the earth). The essential requirement is that the reference radiometer shall have been calibrated at essentially the same tilt from horizontal as the tilt employed in the transfer of calibration.
1.5 The primary reference instrument shall not be used as a field instrument and its exposure to sunlight shall be limited to calibration or intercomparisons.
Note 1—At a laboratory where calibrations are performed regularly it is advisable to maintain a group of two or three reference radiometers that are included in every calibration. These serve as controls to detect any instability or irregularity in the standard reference instrument.
1.6 Reference standard instruments shall be stored in a manner as to not degrade their calibration.
1.7 The method of calibration specified for total solar pyranometers shall be traceable to the World Radiometric Reference (WRR) through the calibration methods of the reference standard instruments (Test Methods G167 and E816), and the method of calibration specified for narrow- and broad-band ultraviolet radiometers shall be traceable to the National Institute of Standards and Technology (NIST), or other internationally recognized national standards laboratories (Test Method G138).
1.8 This standard does not purport to address all of the safety con...
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Designation: E824 − 10
Standard Test Method for
Transfer of Calibration From Reference to Field
1
Radiometers
This standard is issued under the fixed designation E824; 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.
INTRODUCTION
Accurate and precise measurements of total solar and solar ultraviolet irradiance are required in: (1)
the determination of the energy incident on surfaces and specimens during exposure outdoors to
various climatic factors that characterize a test site, (2) the determination of solar irradiance and
radiant exposure to ascertain the energy available to solar collection devices such as flat-plate
collectors, and (3) the assessment of the irradiance and radiant exposure in various wavelength bands
for meteorological, climatic and earth energy-budget purposes. The solar components of principal
interest include total solar radiant exposure (all wavelengths) and various ultraviolet components of
natural sunlight that may be of interest, including both total and narrow-band ultraviolet radiant
exposure.
This test method for transferring calibration from reference to field instruments is only applicable
to pyranometers and radiometers whose field angles closely approach 180° . instruments which
therefore may be said to measure hemispherical radiation, or all radiation incident on a flat surface.
Hemisphericalradiationincludesboththedirectandsky(diffuse)geometricalcomponentsofsunlight,
while global solar irradiance refers only to hemispherical irradiance on a horizontal surface such that
the field of view includes all of the hemispherical sky dome.
For the purposes of this test method, the terms pyranometer and radiometer are used interchange-
ably.
1. Scope havebeencalibratedatessentiallythesametiltfromhorizontal
as the tilt employed in the transfer of calibration.
1.1 The method described in this standard applies to the
transfer of calibration from reference to field radiometers to be
1.5 The primary reference instrument shall not be used as a
used for measuring and monitoring outdoor radiant exposure field instrument and its exposure to sunlight shall be limited to
levels. This standard has been harmonized with ISO 9847.
calibration or intercomparisons.
NOTE 1—At a laboratory where calibrations are performed regularly it
1.2 This test method is applicable to field radiometers
is advisable to maintain a group of two or three reference radiometers that
regardless of the radiation receptor employed, but is limited to
are included in every calibration. These serve as controls to detect any
radiometers having approximately 180° (2π Steradian), field instability or irregularity in the standard reference instrument.
angles.
1.6 Reference standard instruments shall be stored in a
manner as to not degrade their calibration.
1.3 The calibration covered by this test method employs the
use of natural sunshine as the source.
1.7 The method of calibration specified for total solar
1.4 Calibrations of field radiometers may be performed at pyranometers shall be traceable to the World Radiometric
Reference (WRR) through the calibration methods of the
tilt as well as horizontal (at 0° from the horizontal to the earth).
The essential requirement is that the reference radiometer shall referencestandardinstruments(TestMethodsG167andE816),
and the method of calibration specified for narrow- and
broad-band ultraviolet radiometers shall be traceable to the
National Institute of Standards and Technology (NIST), or
1
This test method is under the jurisdiction of ASTM Committee G03 on
other internationally recognized national standards laboratories
Weathering and Durability and is the direct responsibility of Subcommittee G03.09
on Radiometry. (Test Method G138).
Current edition approved Dec. 1, 2010. Published December 2010. Originally
1.8 This standard does not purport to address all of the
approved in 1994. Last previous edition approved in 2005 as E824 – 05. DOI:
10.1520/E0824-10. safety concerns, if any, associated with its use. It is the
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
E824 − 10
responsibility of the user of this standard to establish appro- over several days duration and that data be taken in early
priate safety and health practices and determine the applica- morning or late afternoon, as well as near solar noon.
bility of regulatory limitations prior to use.
NOTE 3—Transfer of calibration to both total and narrow-band ultra-
violetradiometersmayrequirealargernumberof
...
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:E824–05 Designation:E824–10
Standard Test Method for
Transfer of Calibration From Reference to Field
1
Radiometers
This standard is issued under the fixed designation E824; 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.
INTRODUCTION
Accurate and precise measurements of total solar and solar ultraviolet irradiance are required in: (1)
the determination of the energy incident on surfaces and specimens during exposure outdoors to
various climatic factors that characterize a test site, (2) the determination of solar irradiance and
radiant exposure to ascertain the energy available to solar collection devices such as flat-plate
collectors, and (3) the assessment of the irradiance and radiant exposure in various wavelength bands
for meteorological, climatic and earth energy-budget purposes. The solar components of principal
interest include total solar radiant exposure (all wavelengths) and various ultraviolet components of
natural sunlight that may be of interest, including both total and narrow-band ultraviolet radiant
exposure.
This test method for transferring calibration from reference to field instruments is only applicable
to pyranometers and radiometers whose field angles closely approach 180° . instruments which
therefore may be said to measure hemispherical radiation, or all radiation incident on a flat surface.
Hemisphericalradiationincludesboththedirectandsky(diffuse)geometricalcomponentsofsunlight,
while global solar irradiance refers only to hemispherical irradiance on a horizontal surface such that
the field of view includes all of the hemispherical sky dome.
For the purposes of this test method, the terms pyranometer and radiometer are used interchange-
ably.
1. Scope
1.1 The method described in this standard applies to the transfer of calibration from reference to field radiometers to be used
for measuring and monitoring outdoor radiant exposure levels. This standard has been harmonized with ISO 9847.
1.2 This test method is applicable to field radiometers regardless of the radiation receptor employed, but is limited to
radiometers having approximately 180° (2p Steradian), field angles.
1.3 The calibration covered by this test method employs the use of natural sunshine as the source.
1.4 Calibrations of field radiometers may be performed at tilt as well as horizontal (at 0° from the horizontal to the earth). The
essential requirement is that the reference radiometer shall have been calibrated at essentially the same tilt from horizontal as the
tilt employed in the transfer of calibration.
1.5 The primary reference instrument shall not be used as a field instrument and its exposure to sunlight shall be limited to
calibration or intercomparisons.
NOTE 1—At a laboratory where calibrations are performed regularly it is advisable to maintain a group of two or three reference radiometers that are
included in every calibration. These serve as controls to detect any instability or irregularity in the standard reference instrument.
1.6 Reference standard instruments shall be stored in a manner as to not degrade their calibration.
1.7 The method of calibration specified for total solar pyranometers shall be traceable to the World Radiometric Reference
(WRR) through the calibration methods of the reference standard instruments (Test Methods G167 and E816), and the method of
calibration specified for narrow- and broad-band ultraviolet radiometers shall be traceable to the National Institute of Standards
and Technology (NIST), or other internationally recognized national standards laboratories (Test Method G138).
1
This test method is under the jurisdiction of ASTM Committee G03 on Durability of Nonmetallic Materials and is the direct responsibility of Subcommittee G3.09 on
Solar and Ultraviolet Radiation Measurement Standards.
Current edition approved Oct. 1, 2005. Published November 2005. Originally approved in 1994. Last previous edition approved in 2002 as E824–94(2002). DOI:
10.1520/E0824-05.on Weathering and Durability and is the direct responsibility of Subcommittee G03.09 on Radiometry.
Current edition approved Dec. 1, 2010. Published December 2010. Originally approved in 1994. Last previous edition approved in 2005 as E824 – 05. DOI:
10.1520/E0824-10.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700
...
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