ASTM G183-15(2023)
(Practice)Standard Practice for Field Use of Pyranometers, Pyrheliometers and UV Radiometers
Standard Practice for Field Use of Pyranometers, Pyrheliometers and UV Radiometers
SCOPE
1.1 This practice describes deployment conditions, maintenance requirements, verification procedures and calibration frequencies for use of pyranometers, pyrheliometers and UV radiometers in outdoor testing environments. This practice also discusses the conditions that dictate the level of accuracy required for instruments of different types.
1.2 While both pyranometers and UV radiometers may be employed indoors to measure light radiation sources, the measurement of ultraviolet and light radiation in accelerated weathering enclosures using manufactured light sources generally requires specialized radiometric instruments. Use of radiometric instrumentation to measure laboratory light sources is covered in ISO 9370.
Note 1: An ASTM standard that is similar to ISO 9370 is under development and deals with the instrumental determination of irradiance and radiant exposure in weathering tests.
1.3 The characterization of radiometers is outside the scope of the activities required of users of radiometers, as contemplated by this standard.
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.
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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: G183 − 15 (Reapproved 2023)
Standard Practice for
Field Use of Pyranometers, Pyrheliometers and UV
Radiometers
This standard is issued under the fixed designation G183; 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 G90 Practice for Performing Accelerated Outdoor Weather-
ing of Materials Using Concentrated Natural Sunlight
1.1 This practice describes deployment conditions, mainte-
G113 Terminology Relating to Natural and Artificial Weath-
nance requirements, verification procedures and calibration
ering Tests of Nonmetallic Materials
frequencies for use of pyranometers, pyrheliometers and UV
2.2 ISO Standards:
radiometers in outdoor testing environments. This practice also
ISO 877 Plastics—Methods of Exposure to Direct
discusses the conditions that dictate the level of accuracy
Weathering, Indirect Weathering Using Glass-Filtered
required for instruments of different types.
Daylight and Indirect Weathering by Daylight Using
1.2 While both pyranometers and UV radiometers may be
Fresnel Mirrors
employed indoors to measure light radiation sources, the
ISO 9060 Solar Energy—Specification and Classification of
measurement of ultraviolet and light radiation in accelerated
Instruments for Measuring Hemispherical Solar and Di-
weathering enclosures using manufactured light sources gen-
rect Solar Radiation
erally requires specialized radiometric instruments. Use of
ISO 9370 Plastics—Instrumental Determination of Radiant
radiometric instrumentation to measure laboratory light
Exposure in Weathering Tests—General Guidance
sources is covered in ISO 9370.
ISO TR 9901 Solar Energy—Field Pyranometers—
NOTE 1—An ASTM standard that is similar to ISO 9370 is under
Recommended Practice for Use
development and deals with the instrumental determination of irradiance
and radiant exposure in weathering tests. 2.3 WMO Reference:
World Meteorological Organization (WMO), 1983 “Mea-
1.3 The characterization of radiometers is outside the scope
surement of Radiation,” Guide to Meteorological Instru-
of the activities required of users of radiometers, as contem-
ments and Methods of Observation, seventh ed., WMO-
plated by this standard.
No. 8, Geneva
1.4 This international standard was developed in accor-
dance with internationally recognized principles on standard-
3. Terminology
ization established in the Decision on Principles for the
3.1 Definitions—The definitions given in Terminologies
Development of International Standards, Guides and Recom-
E772 and G113 are applicable to this practice.
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
4. Radiometer Selection
2. Referenced Documents
4.1 Criteria for the Selection of Radiometers:
2.1 ASTM Standards: 4.1.1 There are several criteria that need to be considered
E772 Terminology of Solar Energy Conversion for selection of the radiometer that will be used:
G7 Practice for Natural Weathering of Materials 4.1.1.1 Function specific criteria, such as whether a
G24 Practice for Conducting Exposures to Daylight Filtered pyranometer, pyrheliometer or UV radiometer is required,
Through Glass 4.1.1.2 Task specific criteria, such as the accuracy require-
ments for the selected incident angle and temperature ranges,
and maximum response time,
This practice is under the jurisdiction of ASTM Committee G03 on Weathering
and Durability and is the direct responsibility of Subcommittee G03.09 on
4.1.1.3 Operational criteria, such as dimensions, weight,
Radiometry.
stability and maintenance, and
Current edition approved March 15, 2023. Published March 2023. Originally
approved in 2005. Last previous edition approved in 2015 as G183 – 15. DOI:
10.1520/G0183-15R23.
2 3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Available from International Organization for Standardization (ISO), 1, ch. de
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM la Voie-Creuse, CP 56, CH-1211 Geneva 20, Switzerland, http://www.iso.org.
Standards volume information, refer to the standard’s Document Summary page on Available from World Meterological Organization, 7 bis, avenue de la Paix, CP.
the ASTM website. 2300, CH-1211 Geneva 2, Switzerland, http://www.wmo.int.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
G183 − 15 (2023)
4.1.1.4 Economic criteria, such as when networks have to be 4.3.2.3 Preferably, data on the technical characteristics and
equipped, or whether the instrument is being acquired for performance obtained from independent sources such as inde-
internal reference purposes, or for research purposes, etc. pendent testing laboratories, research institutes and govern-
ment laboratories.
4.2 Selection Related to Radiometer Type:
4.3.3 If the accuracy of the highest category of instrument is
4.2.1 Pyranometers, which measure global solar irradiance
insufficient for the application contemplated, the following
in the 300 nm to 2500 nm wavelength region, are required to
recommendations are given:
assess the hemispherical solar irradiance on surfaces of test
4.3.3.1 Hemispherical solar radiation may be measured by
specimens mounted on weathering test racks that are used by
the simultaneous deployment of a pyrheliometer and a con-
the outdoor weathering exposure community. Typically, pyra-
tinuously shaded secondary standard pyranometer to achieve
nometers are required to measure the exposure levels specified
accuracies that are greater than can be achieved by a secondary
in the applicable ASTM and/or ISO outdoor weathering
standard pyranometer alone,
standards such as those described in Practices G7, G24, G90,
4.3.3.2 Direct (beam) solar radiation may be measured
and ISO 877.
using an absolute cavity pyrheliometer employing electrical
4.2.2 Pyrheliometers, which measure direct (or, beam) solar
substitution of thermally absorbed radiation to achieve accu-
irradiance in the 300 nm to 2500 nm wavelength region, are
racies that are greater than can be achieved by a First-class
required to assess the solar irradiance reflected onto the target
pyrheliometer, and
board by the mirrors of Fresnel Reflecting Concentrators used
4.3.3.3 Specific ultraviolet wavelength bands may be deter-
in outdoor accelerated tests specified by ASTM and ISO
mined by integration of the selected wavelength bands using a
Standards described in Practice G90 and ISO 877.
scanning spectroradiometer possessing good slit function and
4.2.3 Ultraviolet radiometers are either broad band or nar-
narrow band pass characteristics to achieve accuracies that are
row band instruments covering defined wavelength regions of
greater than the most accurate narrow or broad band ultraviolet
the solar ultraviolet spectrum.
radiometers currently commercially available.
4.2.3.1 Broad-band UV radiometers usually are designed to
measure either UV-A, UV-B or some component of both UV-A
5. Practice for Use—General
and UV-B radiation.
5.1 Installation of Radiometers:
NOTE 2—Certain UV radiometers that are designated as total ultraviolet
5.1.1 When performing measurements in support of testing,
radiometers are advertised to measure over the total wavelength range
the test object and the field radiometer shall be equally exposed
from the so called UV cutoff at approximately 300 nm to 385 nm or 400
with respect to field of view, ground radiation and any stray
nm, but in fact measure mostly UV-A radiation by virtue of their very low
light that may be present. This means that the test surface and
responsivity to wavelengths below 315 nm.
the radiometer shall receive the same irradiance.
4.2.3.2 Narrow-band UV radiometers are essentially con-
5.1.2 When used to determine the irradiance accumulated
structed using interference filters that isolate narrow bands of
on solar concentrating devices such as the Fresnel reflecting
radiation having FWHM values of 20 nm, or less; their center
concentrators used in Practice G90, and other types of solar
wavelengths (CW) may reside anywhere in the UV spectrum
concentrators, it is essential that the collection system of the
from 280 nm to 400 nm wavelength—depending on the appli-
solar concentrators, such as the flat mirrors used in Practice
cation for which they are intended.
G90, do not receive direct irradiance that is unavailable to the
NOTE 3—While the World Meteorological Organization (WMO) and
optical system that connotes the pyrheliometer required.
the International Standards Organization (ISO) have established require-
5.1.3 The need for easy access to the radiometer for
ments for Secondary Standard and High, Good, and Moderate Quality
maintenance operations shall be considered in selecting the
pyranometers and pyrheliometers, specifications and required operational
installation site, mount, etc.
characteristics of different classes of ultraviolet radiometers have not been
addressed by either organization.
5.2 Electrical Installation:
NOTE 4—High Quality instruments are not necessary for all applica-
5.2.1 The electrical cable employed shall be secured firmly
tions.
to the mounting stand to minimize the possibility of breakage
4.3 Selection Related to Measuring Specifications:
or intermittent disconnection in severe weather.
4.3.1 As a first step, all possible ranges of measuring
5.2.2 Wherever possible, the electrical cable shall be pro-
parameters such as temperature, irradiance levels, angles of
tected and buried underground—particularly when recording
incidence, tilt angles, and station latitude, must be compiled.
devices, controllers, or converters are located at a distance. Use
4.3.2 Next, documentation must be compiled of available
of shielded cable is highly recommended. The cable, recorder
information about the technical characteristics, and the techni-
and other electronic devices, shall be connected by a very low
cal and physical specifications of the relevant radiometers
resistance conductor to a common ground.
given by:
5.2.3 Contact the manufacturer of the radiometer being
4.3.2.1 The WMO and ISO classification of pyranometers
installed to establish the maximum allowable cable length
given in the WMO Guide, and in ISO 9060 and ISO 9370
permissible for the instrument’s impedance so as to preclude
(which together define the specifications to be met by different
significant signal loss (see 5.4.5.2 for additional requirements).
categories of pyranometers and pyrheliometers),
5.2.4 When hard wiring electrical connections, all exposed
4.3.2.2 The data specification sheets obtained from the junctions shall be weatherproofed and protected from physical
manufacturer, and damage.
G183 − 15 (2023)
5.2.5 Establish and identify the polarity of all relevant noise for subsequent attention. Further, check the condition of
connections prior to connecting to the recording device, ventillation unit filters and clean or replace as necessary.
converters, or controllers. Make all connections in accordance 5.3.2.6 Perform a cursory check of the output data on at
with the manufacturer’s instructions. least a weekly basis to determine if data being recorded are
plausible in relation to the conditions being experienced.
5.3 Required Maintenance Activities:
5.3.3 Monthly Routine Inspection and Maintenance:
5.3.1 Inspection:
5.3.3.1 Examine the color-indicating desiccant for all instru-
5.3.1.1 Whenever possible, inspect radiometers employed
ments where the silica gel container is accessible. If moisture
in continuous operation at least once each day. Inspection and
is indicated, replace the desiccant.
maintenance activities of specific attributes described in the
NOTE 8—If desiccant is consumed rapidly, the cause might be a
following sections should be carried out daily, monthly and
defective seal of the instrument’s window, a defective electrical connec-
yearly as indicated.
tion into the instrument case, or a defective O-ring associated with the
desiccant chamber.
NOTE 5—It should be noted that the quality of data obtained using total
5.3.3.2 Attention should be paid to the transmission and
solar and solar ultraviolet radiometers depends strongly on the amount of
personal attention given during the observation program.
amplification of signals. Perform both visual and electrical
checks of the cable and amplifier (when used). These inspec-
5.3.2 Daily Routine Inspection and Maintenance:
tions shall also be performed when any component of a
5.3.2.1 The exterior glass domes and/or diffusers or
measuring system has been replaced, or after any anomalies
windows, shall be inspected daily and cleaned at least once
have been detected in the data.
each week or more often whenever dust or other deposits are
5.3.4 Quarterly Inspection and Maintenance:
visible. Cleaning shall occur by spraying with deionized water
5.3.4.1 In those radiometers where the desiccant is not
and wiping dry with non-abrasive and lint-free cloth or tissue.
visible, remove the desiccant cover and inspect the desiccant
It is recommended that this inspection and possible cleaning be
for dryness. If moisture is indicated, replace the desiccant. Care
performed early each day.
should be exercised to ensure that the desiccant container’s
5.3.2.2 If frozen snow, glazed frost, hoar frost or rime is
cover is closed completely (manufacturer’s instructions should
present, remove the deposit very gently, initially with the
be followed with respect to ensuring the tightness of the cover,
sparing use of a de-icing fluid or a warm lint-free cloth,
or cap).
appropriate for the type of glass dome, window, or diffuser,
5.3.4.2 Verify that the responsivities of all radiometers have
after which the glass dome, window, or diffuser shall be wiped
not changed to the extent that they are out of tolerance. This
clean and dry.
can be done by comparison to another radiometer that has the
5.3.2.3 After heavy dew, rain, sleet, snow or frost buildup,
same spectral response function or by determination that the
check to determine if condensation is present inside the dome,
ratio of, for example, UV-B to UV-A irradiance has remained
or on the receptor or diffuser surface. If condensation is
essentially the same (if both measurements are being
discovered inside the dome, on the receptor or diffuser surface
performed), or, as will usually be the case, if the ratio of tota
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