1、Designation: D1494 17 An American National StandardStandard Test Method forDiffuse Light Transmission Factor of Reinforced PlasticsPanels1This standard is issued under the fixed designation D1494; the number immediately following the designation indicates the year oforiginal adoption or, in the case
2、 of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope*1.1 This
3、test method covers the determination of the diffuselight transmission factor of translucent reinforced plasticsbuilding panels.1.2 The values stated in SI units are to be regarded as thestandard. The values given in the parentheses are for informa-tion only.1.3 The text of this standard references n
4、otes and footnoteswhich provide explanatory material. These notes and footnotes(excluding those in Tables and Figures) shall not be consideredas requirements of this standard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibi
5、lity of the user of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.NOTE 1There is no known ISO equivalent to this standard.1.5 This international standard was developed in accor-dance with in
6、ternationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D6
7、18 Practice for Conditioning Plastics for TestingD883 Terminology Relating to PlasticsD1600 Terminology forAbbreviated Terms Relating to Plas-ticsE2935 Practice for Conducting Equivalence Testing inLaboratory ApplicationsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision
8、 of a Test Method2.2 ASTM Adjuncts:Test Cabinet for Diffuse Light Transmission Factor ofReinforced Panels33. Terminology3.1 GeneralDefinitions are in accordance with Terminol-ogy D883 and abbreviations with Terminology D1600, unlessotherwise indicated.4. Significance and Use4.1 The purpose of this t
9、est method is to obtain the diffuselight transmittance factor of both flat and corrugated translu-cent building panels by the use of simple apparatus and byemploying as a light source a combination of fluorescent tubeswhose energy distribution closely approximates CIE Source C.5. Apparatus5.1 The ap
10、paratus for this test method shall consist of atransmissometer, Fig. 1, comprising essentially the following:5.1.1 Light SourceThe illumination shall consist of twelve20-W fluorescent tubes which are assembled in three banks offour tubes each, according to the following schedule: daylight,deluxe coo
11、l white, blue, and daylight.5.1.2 PhotometerThe photometer shall consist of a pho-tocell and of a galvanometer. The photocell shall be of thebarrier-layer type and shall contain a visual correction filter.The assembly preferably should be hermetically sealed intoplastic as a protection against moist
12、ure. The indicating galva-nometer should contain one scale graduated from 0 to 100, anda circuit with sufficient variable resistance so that the sensitiv-ity of the photometer can be adjusted over the range of 50 to100 footcandles.1This test method is under the jurisdiction of ASTM Committee D20 on
13、Plasticsand is the direct responsibility of Subcommittee D20.24 on Plastic BuildingProducts.Current edition approved Dec. 1, 2017. Published January 2018. Originallyapproved in 1957. Last previous edition approved in 2012 as D1494 12. DOI:10.1520/D1494-17.2For referenced ASTM standards, visit the AS
14、TM 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.3Detailed working drawings and a bill of materials for this equipment can beobtained at a nominal charge
15、from ASTM Headquarters, 100 Barr Harbor Drive, POBox C700, West Conshohocken, PA 194282959. Order Adjunct: ADJD1494.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis i
16、nternational standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT)
17、 Committee.15.1.3 Test Cabinet, constructed in accordance with thefollowing dimensions.35.1.3.1 The transmitted area of the test specimen shall be610.0 6 1.6 mm by 610.0 6 1.6 mm (24 6116 in. by 24 6116 in.).5.1.3.2 The distance from the bottom of the fluorescenttubes to the bottom of the test speci
18、men shall be 203.0 6 0.8mm (8 6132 in.).5.1.3.3 A 4.8-mm (316-in.) thick, white, standard outdoor,translucent diffusing plate shall be placed between the lightsource and the test specimen so that the distance from thebottom of the diffusing plate to the bottom of the test specimenis 31.8 6 0.8 mm (1
19、14 6132 in.).5.1.3.4 The photocell shall be positioned below the centeraxis of the test specimen so that the distance from the bottomof the specimen to the top of the cell is 283.0 6 0.8 mm(1118 6132 in.).5.1.3.5 A masking plate containing a 31.8-mm (114-in.)diameter hole in its center shall be plac
20、ed between the testspecimen and the photocell so that the distance from thebottom of the test specimen to the bottom of the masking plateshall be 233.0 6 0.8 mm (934 6132 in.).6. Standardization of Transmissometer6.1 Center the photocell beneath the 31.8-mm (114-in.)diameter hole in the bottom maski
21、ng plate. Place the galva-nometer in a flat level position. Ensure that no current flows inthe electrical circuit by opening the circuit. Adjust the positionof the indicating needle on the galvanometer to read “0 bymeans of the zero adjustment knob. Close the galvanometercircuit. Turn on the illumin
22、ation in the transmissometer. Wait aminimum of 20 min to permit the transmissometer to reachequilibrium conditions. Adjust the galvanometer to read “100.”The instrument is now ready to be used for measurements ofdiffuse light transmission factor.7. Test Specimens7.1 The test specimens shall consist
23、of translucent rein-forced plastic panels having a minimum length of 610 mm (24Metric Equivalentsin. mm in. mm in. mm in. mm132 0.834 19.1 834 222 2434 634316 4.8 114 31.8 934 248 2512 648737 5.6 112 38.1 12 305 28 71114 6.4 2 50.8 14 356 2912 749932 7.1 634 172 24 610 3812 97838 9.5FIG. 1 Assembly
24、Drawing of TransmissometerD1494 172in.) and a width greater than 610 mm (24 in.), but notexceeding 711 mm (28 in.).8. Conditioning8.1 ConditioningCondition the test specimens at 23 62C (73 6 4F) and 50 6 10 % relative humidity for not lessthan 40 h prior to test in accordance with Procedure A ofPrac
25、tice D618, for those test methods where conditioning isrequired. In cases of disagreement, the tolerances shall be61C (62F) and 65 % relative humidity.8.2 Test ConditionsConduct tests in the Standard Labora-tory Atmosphere of 23 6 2C (73 6 4F) and 50 6 10 %relative humidity, unless otherwise specifi
26、ed in the test meth-ods or in this specification. In cases of disagreement, thetolerances shall be 61C (62F) and 65 % relative humidity.9. Procedure9.1 In making a measurement, place the test specimen in thetest cabinet so that it completely covers the 610 by 610-mm (24by 24-in.) space. The transmit
27、tance is read on the galvanometerin percent.10. Report10.1 The report shall include the following:10.1.1 The source and identity of test specimens.10.1.2 The percent transmission of the test specimen.10.1.3 The average thickness of the test specimen in inchesexpressed to the nearest 0.025 mm (0.001
28、in.) and comprisingat least ten individual measurements.11. Precision and Bias411.1 Table 1 is based on a round robin conducted in 1987 inaccordance with Practice E691, involving five materials testedby seven laboratories. Because of the nonuniform nature oflarge corrugated sheets, the five samples
29、were sequentially sentto the seven participating laboratories. Each test result is anindividual determination. Each laboratory obtained three testresults for each material.NOTE 2The explanation of Ir and IR (11.2 through 11.2.3) are onlyintended to present a meaningful way of considering the approxi
30、mateprecision of this test method. The data in Table 1 should not be vigorouslyapplied to acceptance or rejection of materials as these data specific to theround robin and may not be representative of other lots, conditions,materials, or laboratories.11.1.1 Users of this test method should apply the
31、 principlesoutlined in Practice E691 to generate data specific to theirlaboratory and materials or between specific laboratories. Theprinciples of 11.2 through 11.2.3 then would be valid for suchdata.11.2 Concept of Ir and IRIf Sr and SR have beencalculated from a large enough body of data, and for
32、testresults that are the individual result from testing one specimen:11.2.1 Ir: Repeatability The value below which the absolutedifference between two individual test results obtained underrepeatability conditions is likely to be expected to occur with aprobability of approximately 0.95 (95 %).11.2.
33、2 IR: Reproducibility The value below which theabsolute difference between two individual test results obtainedunder reproducibility conditions is likely to be expected tooccur with a probability of approximately 0.95 (95 %).11.2.3 Equivalence testing on numerical data from twosources shall be condu
34、cted in accordance with Practice E2935or any known method for judging the equivalence of twomeans.NOTE 3Example, a t-test.11.3 Bias is systematic error which contributes to thedifference between a test result and a true (or reference) value.There are no recognized standards on which to base an estim
35、ateof bias for this test method.12. Keywords12.1 building panels; diffuse light transmission factor; rein-forced plastics4Supporting data are available from ASTM Headquarters. Request RR:D20-1145.TABLE 1 Precision Values in the Units of PercentMaterial Average SrASRBIrCIRDSample #4 6.1 0.36 1.08 1.0
36、2 3.06Sample #5 24.1 0.59 2.48 1.67 7.02Sample #1 59.7 0.45 5.01 1.27 14.18Sample #3 73.0 0.76 3.19 2.16 9.03Sample #2 95.6 0.64 1.61 1.81 4.56ASr is the within-laboratory standard deviation of the average.BSR is the between-laboratory standard deviation of the average.CIr = 2.83 Sr; andDIR = 2.83 S
37、R.D1494 173SUMMARY OF CHANGESCommittee D20 has identified the location of the following changes to this standard since the last issue(D1494-12) that may impact the use of this standard. (December 1, 2017)(1) Revised 2.1, added reference to E2935.(2) Revised 8.1 and 8.2, changed 6 2% to 5% per D618-1
38、3.(3) Revised 8.2, corrected C to F.(4) Revised 11.2.1, 11.2.2, 11.2.3, new rewording.(5) Added Note 3.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that d
39、etermination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved
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41、that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprin
42、ts (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 174
