1、Designation: G 183 05Standard Practice forField Use of Pyranometers, Pyrheliometers and UVRadiometers1This standard is issued under the fixed designation G 183; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revis
2、ion. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice describes deployment conditions, mainte-nance requirements, verification procedures and calibrationfrequencies fo
3、r use of pyranometers, pyrheliometers and UVradiometers in outdoor testing environments. This practice alsodiscusses the conditions that dictate the level of accuracyrequired for instruments of different classes.1.2 While both pyranometers and UV radiometers may beemployed indoors to measure light r
4、adiation sources, themeasurement of ultraviolet and light radiation in acceleratedweathering enclosures using manufactured light sources gen-erally requires specialized radiometric instruments. Use ofradiometric instrumentation to measure laboratory lightsources is covered in ISO 9370.NOTE 1An ASTM
5、standard that is similar to ISO 9370 is underdevelopment and deals with the instrumental determination of irradianceand radiant exposure in weathering tests.1.3 The characterization of radiometers is outside the scopeof the activities required of users of radiometers, as contem-plated by this standa
6、rd.2. Referenced Documents2.1 ASTM Standards:2E 772 Terminology Relating to Solar Energy ConversionG7 Practice for Atmospheric Environmental ExposureTesting of Nonmetallic MaterialsG24 Practice for Conducting Exposures to Daylight Fil-tered Through GlassG90 Practice for Performing Accelerated Outdoo
7、r Weath-ering of Nonmetallic Materials Using Concentrated Natu-ral SunlightG113 Terminology Relating to Natural and ArtificialWeathering Tests of Nonmetallic Materials2.2 ISO Standards:ISO 877 PlasticsMethods of Exposure to Direct Weath-ering, Indirect Weathering Using Glass-Filtered Daylightand Ind
8、irect Weathering by Daylight Using Fresnel Mir-rors3ISO 9060 Solar EnergySpecification and Classification ofInstruments for Measuring Hemispherical Solar and Di-rect Solar Radiation3ISO 9370 PlasticsInstrumental Determination of RadiantExposure in Weathering TestsGeneral Guidance3ISO TR 9901 Solar E
9、nergyField PyranometersRecommended Practice for Use32.3 Other Reference:World Meteorological Organization (WMO), 1983 “Mea-surement of Radiation,” Guide to Meteorological Instru-ments and Methods of Observation, fifth ed., WMO-No. 8,Geneva3. Terminology3.1 DefinitionsThe definitions given in Termino
10、logiesE 772 and G113are applicable to this practice.4. Radiometer Selection4.1 Criteria for the Selection of Radiometers:4.1.1 There are several criteria that need to be consideredfor selection of the radiometer that will be used:4.1.1.1 Function specific criteria, such as whether a pyra-nometer, py
11、rheliometer or UV radiometer is required,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,4.1.1.3 Operational criteria, such as dimensions, weight,stability and maintenance, and4.1.1.4 Economic criteri
12、a, such as when networks have to beequipped, or whether the instrument is being acquired forinternal reference purposes, or for research purposes, etc.4.2 Selection Related to Radiometer Type:4.2.1 Pyranometers, which measure global solar irradiancein the 300 to 2500-nm wavelength region, are requir
13、ed toassess the hemispherical solar irradiance on surfaces of testspecimens mounted on weathering test racks that are used by1This practice is under the jurisdiction of ASTM Committee G03 on Weatheringand Durability and is the direct responsibility of Subcommittee G03.09 onRadiometry.Current edition
14、 approved Feb. 1, 2005. Published March 2005.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from
15、American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.the outdoor weathering exposure community. Typically, pyra-nometers are required to measure th
16、e exposure levels specifiedin the applicable ASTM and/or ISO outdoor weatheringstandards such as those described in Practices G7, G24, G90,and ISO 877.4.2.2 Pyrheliometers, which measure direct (or, beam) solarirradiance in the 300 to 2500-nm wavelength region, arerequired to assess the solar irradi
17、ance reflected onto the targetboard by the mirrors of Fresnel Reflecting Concentrators usedin outdoor accelerated tests specified by ASTM and ISOStandards described in Practice G90and ISO 877.4.2.3 Ultraviolet radiometers are either broad band or nar-row band instruments covering defined wavelength
18、regions ofthe solar ultraviolet spectrum.4.2.3.1 Broad-band UV radiometers usually are designed tomeasure either UV-A, UV-B or some component of both UV-Aand UV-B radiation.NOTE 2Certain UV radiometers that are designated as total ultravioletradiometers are advertised to measure over the total wavel
19、ength rangefrom the so called UV cutoff at approximately 300 nm to 385 or 400 nm,but in fact measure mostly UV-A radiation by virtue of their very lowresponsivity to wavelengths below 315 nm.4.2.3.2 Narrow-band UV radiometers are essentially con-structed using interference filters that isolate narro
20、w bands ofradiation having FWHM values of 20 nm, or less; their centerwavelengths (CW) may reside anywhere in the UV spectrumfrom 280 to 400 nm wavelengthdepending on the applicationfor which they are intended.NOTE 3While the World Meteorological Organization (WMO) andthe International Standards Org
21、anization (ISO) have established require-ments for Secondary Standard and First-, Second- and Third-classpyranometers and pyrheliometers, specifications and required operationalcharacteristics of different classes of ultraviolet radiometers have not beenaddressed by either organization.NOTE 4First-c
22、lass instruments are not necessary for all applications.4.3 Selection Related to Measuring Specifications:4.3.1 As a first step, all possible ranges of measuringparameters such as temperature, irradiance levels, angles ofincidence, tilt angles, and station latitude, must be compiled.4.3.2 Next, docu
23、mentation must be compiled of availableinformation about the technical characteristics, and the techni-cal and physical specifications of the relevant radiometersgiven by:4.3.2.1 The WMO and ISO classification of pyranometersgiven in the WMO Guide, and in ISO 9060 and ISO 9370(which together define
24、the specifications to be met by differentcategories of pyranometers and pyrheliometers),4.3.2.2 The data specification sheets obtained from themanufacturer, and4.3.2.3 Preferably, data on the technical characteristics andperformance obtained from independent sources such as inde-pendent testing labo
25、ratories, research institutes and govern-ment laboratories.4.3.3 If the accuracy of the highest category of instrument isinsufficient for the application contemplated, the followingrecommendations are given:4.3.3.1 Hemispherical solar radiation may be measured bythe simultaneous deployment of a pyrh
26、eliometer and a con-tinuously shaded secondary standard pyranometer to achieveaccuracies that are greater than can be achieved by a secondarystandard pyranometer alone,4.3.3.2 Direct (beam) solar radiation may be measuredusing an absolute cavity pyrheliometer employing electricalsubstitution of ther
27、mally absorbed radiation to achieve accu-racies that are greater than can be achieved by a First-classpyrheliometer, and4.3.3.3 Specific ultraviolet wavelength bands may be deter-mined by integration of the selected wavelength bands using ascanning spectroradiometer possessing good slit function and
28、narrow band pass characteristics to achieve accuracies that aregreater than the most accurate narrow or broad band ultravioletradiometers currently commercially available.5. Practice for UseGeneral5.1 Installation of Radiometers:5.1.1 When performing measurements in support of testing,the test objec
29、t and the field radiometer shall be equally exposedwith respect to field of view, ground radiation and any straylight that may be present. This means that the test surface andthe radiometer shall receive the same irradiance.5.1.2 When used to determine the irradiance accumulatedon solar concentratin
30、g devices such as the Fresnel reflectingconcentrators used in the practice of Practice G90, and othertypes of solar concentrators, it is essential that the collectionsystem of the solar concentrators, such as the flat mirrors usedin the practice of Practice G90, do not receive direct irradiancethat
31、is unavailable to the optical system that connotes thepyrheliometer required.5.1.3 The need for easy access to the radiometer formaintenance operations shall be considered in selecting theinstallation site, mount, etc.5.2 Electrical Installation:5.2.1 The electrical cable employed shall be secured f
32、irmlyto the mounting stand to minimize the possibility of breakageor intermittent disconnection in severe weather.5.2.2 Wherever possible, the electrical cable shall be pro-tected and buried undergroundparticularly when recordingdevices, controllers, or converters are located at a distance. Useof sh
33、ielded cable is highly recommended. The cable, recorderand other electronic devices, shall be connected by a very lowresistance conductor to a common ground.5.2.3 Contact the manufacturer of the radiometer beinginstalled to establish the maximum allowable cable lengthpermissible for the instruments
34、impedance so as to precludesignificant signal loss (see 5.4.5.2 for additional requirements).5.2.4 When hard wiring electrical connections, all exposedjunctions shall be weatherproofed and protected from physicaldamage.5.2.5 Establish and identify the polarity of all relevantconnections prior to con
35、necting to the recording device,converters, or controllers. Make all connections in accordancewith the manufacturers instructions.5.3 Required Maintenance Activities:5.3.1 Inspection:5.3.1.1 Whenever possible, inspect radiometers employedin continuous operation at least once each day. Inspection and
36、G183052maintenance activities of specific attributes described in thefollowing sections should be carried out daily, monthly andyearly as indicated.NOTE 5It should be noted that the quality of data obtained using totalsolar and solar ultraviolet radiometers depends strongly on the amount ofpersonal
37、attention given during the observation program.5.3.2 Daily Routine Inspection and Maintenance:5.3.2.1 The exterior glass domes and/or diffusers or win-dows, shall be inspected daily and cleaned at least once eachweek or more often whenever dust or other deposits are visible.Cleaning shall occur by s
38、praying with deionized water andwiping dry with non-abrasive and lint-free cloth or tissue. It isrecommended that this inspection and possible cleaning beperformed early each day.5.3.2.2 If frozen snow, glazed frost, hoar frost or rime ispresent, remove the deposit very gently, initially with thespa
39、ring use of a de-icing fluid, after which the window shall bewiped clean and dry.5.3.2.3 After heavy dew, rain, sleet, snow or frost buildup,check to determine if condensation is present inside the dome,or on the receptor or diffuser surface. If condensation isdiscovered inside the dome, on the rece
40、ptor or diffuser surfaceof domed radiometers, the instruments manufacturer shall becontacted to determine a course of action.NOTE 6The user may attempt to “dry out” the radiometer by elevatingits temperature, either in natural sunlight or in the laboratory, to 50C. Ifthe condensation is eliminated,
41、the radiometers calibration constant shallbe checked prior to being returned to service.5.3.2.4 When hard-to-remove deposits of air pollution orlocal contamination is observed on a radiometers exteriorwindow, first apply deionized or distilled water on the surface.If the use of a detergent solution
42、is indicated, a prepare a 2 %solution of a mild dish washing detergent and gently apply tothe surface. Use a soft, lint-free muslin cloth to gently rub thesurface if required. In either case, thoroughly rinse the surfacewith deionized or distilled water, after which it the windowshall be wiped clean
43、 and dry. Water spots should not be evidenton the surface. However, care should be exercised to avoidscratching the surface.5.3.2.5 When used, check the operational state of theventilator or air blower at least weekly and note any unusualnoise for subsequent attention.5.3.2.6 Perform a cursory check
44、 of the output data on atleast a weekly basis to determine if data being recorded areplausible in relation to the conditions being experienced.5.3.3 Monthly Routine Inspection and Maintenance:5.3.3.1 Examine the color-indicating desiccant for all instru-ments where the silica gel container is access
45、ible. If moistureis indicated, replace the desiccant.NOTE 7If desiccant is consumed rapidly, the cause might be adefective seal of the instruments window, a defective electrical connec-tion into the instrument case, or a defective O-ring associated with thedesiccant chamber.5.3.3.2 Attention should
46、be paid to the transmission andamplification of signals. Perform both visual and electricalchecks of the cable and amplifier (when used). These inspec-tions shall also be performed when any component of ameasuring system has been replaced, or after any anomalieshave been detected in the data.5.3.4 Q
47、uarterly Inspection and Maintenance:5.3.4.1 In those radiometers where the desiccant is notvisible, remove the desiccant cover and inspect the desiccantfor dryness. If moisture is indicated, replace the desiccant. Careshould be exercised to ensure that the desiccant containerscover is closed complet
48、ely (manufacturers instructions shouldbe followed with respect to ensuring the tightness of the cover,or cap).5.3.4.2 Verify that the responsivities of all radiometers havenot changed to the extent that they are out of tolerance. Thiscan be done by comparison to another radiometer that has thesame s
49、pectral response function4or by determination that theratio of, for example, UV-B to UV-A irradiance has remainedessentially the same (if both measurements are being per-formed), or, as will usually be the case, if the ratio of total solarUV irradiance to total solar irradiance has remained essentiallythe same for clear day solar noon conditions.5.3.5 Semi-annual Inspection and Maintenance:5.3.5.1 Use an inclinometer5to determine the inclination ofall radiometers mounted at tilts from the horizontal. Inspect theinclination angles of all pyranometers and UV-radi
