ASTM E816-15

Standard Test Method for Calibration of Pyrheliometers by Comparison to Reference Pyrheliometers

SIGNIFICANCE AND USE
4.1 Though the sun trackers employed, the number of instantaneous readings, and the data acquisition equipment used will vary from instrument to instrument and from laboratory to laboratory, this test method provides for the minimum acceptable conditions, procedures, and techniques required.  
4.2 While the greatest accuracy will be obtained when calibrating pyrheliometers with a self-calibrating absolute cavity pyrheliometer that has been demonstrated by intercomparison to be within ±0.5 % of the mean irradiance of a family of similar absolute instruments, acceptable accuracy can be achieved by careful attention to the requirements of this test method when transferring calibration from a secondary reference to a field pyrheliometer.  
4.3 By meeting the requirements of this test method, traceability of calibration to the World Radiometric Reference (WRR) can be achieved through one or more of the following recognized intercomparisons:  
4.3.1 International Pyrheliometric Comparison (IPC) VII, Davos, Switzerland, held in 1990, and every five years thereafter, and the PMO-2 absolute cavity pyrheliometer that is the primary reference instrument of WMO.6  
4.3.2 Any WMO-sanctioned intercomparison of self-calibrating absolute cavity pyrheliometers held in WMO Region IV (North and Central America).  
4.3.3 Any sanctioned or non-sanctioned intercomparison held in the United States the purpose of which is to transfer the WRR from the primary reference absolute cavity pyrheliometer maintained as the primary reference standard of the United States by the National Oceanic and Atmospheric Administration's Solar Radiation Facility in Boulder, CO.7  
4.3.4 Any future intercomparisons of comparable reference quality in which at least one self-calibrating absolute cavity pyrheliometer is present that participated in IPC VII or a subsequent IPC, and in which that pyrheliometer is treated as the intercomparison's reference instrument.  
4.3.5 Any of the absolute radiometers p...
SCOPE
1.1 This test method has been harmonized with, and is technically equivalent to, ISO 9059.  
1.2 Two types of calibrations are covered by this test method. One is the calibration of a secondary reference pyrheliometer using an absolute cavity pyrheliometer as the primary standard pyrheliometer, and the other is the transfer of calibration from a secondary reference to one or more field pyrheliometers. This test method prescribes the calibration procedures and the calibration hierarchy, or traceability, for transfer of the calibrations.
Note 1: It is not uncommon, and is indeed desirable, for both the reference and field pyrheliometers to be of the same manufacturer and model designation.  
1.3 This test method is relevant primarily for the calibration of reference pyrheliometers with field angles of 5 to 6°, using as the primary reference instrument a self-calibrating absolute cavity pyrheliometer having field angles of about 5°. Pyrheliometers with field angles greater than 6.5° shall not be designated as reference pyrheliometers.  
1.4 When this test method is used to transfer calibration to field pyrheliometers having field angles both less than 5° or greater than 6.5°, it will be necessary to employ the procedure defined by Angstrom and Rodhe.2  
1.5 This test method requires that the spectral response of the absolute cavity chosen as the primary standard pyrheliometer be nonselective over the range from 0.3 to 10 μm wavelength. Both reference and field pyrheliometers covered by this test method shall be nonselective over a range from 0.3 to 4 μm wavelength.  
1.6 The primary and secondary reference pyrheliometers shall not be field instruments and their exposure to sunlight shall be limited to calibration or intercomparisons. These reference instruments shall be stored in an isolated cabinet or room equipped with standard laboratory temperature and humidity control.
Note 2: At a laboratory where calibration...

General Information

• Status: Historical
• Publication Date: 31-Jan-2015
• ICS: 27.160 - Solar energy engineering
• Technical Committee: G03 - Weathering and Durability
• Drafting Committee: G03.09 - Radiometry

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: E816 − 15
Standard Test Method for
Calibration of Pyrheliometers by Comparison to Reference
1
Pyrheliometers
This standard is issued under the fixed designation E816; 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 measurement of the direct (beam) radiation component of sunlight are
required in (1) the calibration of reference pyranometers by the shading disk or optical occluding
methods, (2) determination of the energy collected by concentrating solar collectors, including
exposure levels achieved in use of Practice G90 dealing with Fresnel-reflecting concentrator test
machines, and (3) the assessment of the direct beam for energy budget analyses, geographic mapping
of solar energy, and as an aid in the determination of the concentration of aerosol and particulate
pollution, and water vapor effects.
This test method requires calibration to the World Radiometric Reference (WRR), maintained by
the World Meteorological Organization (WMO), Geneva. The Intercomparison of Absolute Cavity
Pyrheliometers, also called Absolute Cavity Radiometers, on which the WRR depends, is covered by
procedures adopted by WMO and by various U.S. Organizations who occasionally convene such
intercomparisons for the purpose of transferring the WRR to the United States, and to maintaining the
WRR in the United States. These procedures are not covered by this test method.
1. Scope 1.4 When this test method is used to transfer calibration to
field pyrheliometers having field angles both less than 5° or
1.1 This test method has been harmonized with, and is
greater than 6.5°, it will be necessary to employ the procedure
technically equivalent to, ISO 9059.
2
defined by Angstrom and Rodhe.
1.2 Two types of calibrations are covered by this test
1.5 This test method requires that the spectral response of
method. One is the calibration of a secondary reference
the absolute cavity chosen as the primary standard pyrheliom-
pyrheliometer using an absolute cavity pyrheliometer as the
eter be nonselective over the range from 0.3 to 10 µm
primary standard pyrheliometer, and the other is the transfer of
wavelength. Both reference and field pyrheliometers covered
calibration from a secondary reference to one or more field
by this test method shall be nonselective over a range from 0.3
pyrheliometers. This test method prescribes the calibration
to 4 µm wavelength.
procedures and the calibration hierarchy, or traceability, for
transfer of the calibrations. 1.6 The primary and secondary reference pyrheliometers
NOTE 1—It is not uncommon, and is indeed desirable, for both the
shall not be field instruments and their exposure to sunlight
reference and field pyrheliometers to be of the same manufacturer and
shall be limited to calibration or intercomparisons. These
model designation.
reference instruments shall be stored in an isolated cabinet or
1.3 This test method is relevant primarily for the calibration
room equipped with standard laboratory temperature and
of reference pyrheliometers with field angles of 5 to 6°, using
humidity control.
as the primary reference instrument a self-calibrating absolute
NOTE 2—At a laboratory where calibrations are performed regularly, it
is advisable to maintain a group of two or three secondary reference
cavity pyrheliometer having field angles of about 5°. Pyrheli-
pyrheliometers that are included in every calibration. These serve as
ometers with field angles greater than 6.5° shall not be
controls to detect any instability or irregularity in the standard reference
designated as reference pyrheliometers.
pyrheliometer.
1.7 This test method is applicable to calibration procedures
1
This test method is under the jurisdiction of ASTM Committee G03 on
using natural sunshine only.
Weathering and Durabilityand is the direct responsibility of Subcommittee G03.09
on Radiometry.
Current edition approved Feb. 1, 2015. Published February 2015. Originally
2
approved in 1981. Last previous edition approved in 2010 as E816 – 05(2010). DOI: Angstrom, A., and Rodhe, B., “Pyrheliometric Measurements with Special
10.1520/E0816-15. Regard to the Circumsolar Sky Radiation,” Tellus, Vol 18, 1966, pp. 25–33.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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E816 − 15
21
2. Referenced Documents Z 5 tan R/l (1)
o
3
2.1 ASTM Standards:
The field angle is double the opening angle.
E772 Terminology of Solar Energy Conversion
3.1.6 primary standard pyrheliometers—p
...

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: E816 − 05 (Reapproved 2010) E816 − 15
Standard Test Method for
Calibration of Pyrheliometers by Comparison to Reference
1
Pyrheliometers
This standard is issued under the fixed designation E816; 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 measurement of the direct (beam) radiation component of sunlight are
required in (1) the calibration of reference pyranometers by the shading disk or optical occluding
methods, (2) determination of the energy collected by concentrating solar collectors, including
exposure levels achieved in use of Practice G90 dealing with Fresnel-reflecting concentrator test
machines, and (3) the assessment of the direct beam for energy budget analyses, geographic mapping
of solar energy, and as an aid in the determination of the concentration of aerosol and particulate
pollution, and water vapor effects.
This test method requires calibration to the World Radiometric Reference (WRR), maintained by
the World Meteorological Organization (WMO), Geneva. The Intercomparison of Absolute Cavity
Pyrheliometers, also called Absolute Cavity Radiometers, on which the WRR depends, is covered by
procedures adopted by WMO and by various U.S. Organizations who occasionally convene such
intercomparisons for the purpose of transferring the WRR to the United States, and to maintaining the
WRR in the United States. These procedures are not covered by this test method.
1. Scope
1.1 This test method has been harmonized with, and is technically equivalent to, ISO 9059.
1.2 Two types of calibrations are covered by this test method. One is the calibration of a secondary reference pyrheliometer
using an absolute cavity pyrheliometer as the primary standard pyrheliometer, and the other is the transfer of calibration from a
secondary reference to one or more field pyrheliometers. This test method proscribesprescribes the calibration procedures and the
calibration hierarchy, or traceability, for transfer of the calibrations.
NOTE 1—It is not uncommon, and is indeed desirable, for both the reference and field pyrheliometers to be of the same manufacturer and model
designation.
1.3 This test method is relevant primarily for the calibration of reference pyrheliometers with field angles of 5 to 6°, using as
the primary reference instrument a self-calibrating absolute cavity pyrheliometer having field angles of about 5°. Pyrheliometers
with field angles greater than 6.5° shall not be designated as reference pyrheliometers.
1.4 When this test method is used to transfer calibration to field pyrheliometers having field angles both less than 5° or greater
2
than 6.5°, it will be necessary to employ the procedure defined by Angstrom and Rodhe.
1.5 This test method requires that the spectral response of the absolute cavity chosen as the primary standard pyrheliometer be
nonselective over the range from 0.3 to 10 μm wavelength. Both reference and field pyrheliometers covered by this test method
shall be nonselective over a range from 0.3 to 4 μm wavelength.
1.6 The primary and secondary reference pyrheliometers shall not be field instruments and their exposure to sunlight shall be
limited to calibration or intercomparisons. These reference instruments shall be stored in an isolated cabinet or room equipped with
standard laboratory temperature and humidity control.
NOTE 2—At a laboratory where calibrations are performed regularly, it is advisable to maintain a group of two or three secondary reference
1
This test method is under the jurisdiction of ASTM Committee G03 on Weathering and Durabilityand is the direct responsibility of Subcommittee G03.09 on Radiometry.
Current edition approved Dec. 1, 2010Feb. 1, 2015. Published December 2010February 2015. Originally approved in 1981. Last previous edition approved in 20052010
as E816 – 05.E816 – 05(2010). DOI: 10.1520/E0816-05R10.10.1520/E0816-15.
2
Angstrom, A., and Rodhe, B., “Pyrheliometric Measurements with Special Regard to the Circumsolar Sky Radiation,” Tellus, Vol 18, 1966, pp. 25–33.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
E816 − 15
pyrheliometers that are included in every calibration. These serve as controls to detec
...