1、Designation: E96/E96M 15E96/E96M 16Standard Test Methods forWater Vapor Transmission of Materials1This standard is issued under the fixed designation E96/E96M; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisi
2、on. 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. Scope1.1 These test methods cover the determination
3、of water vapor transmission (WVT) of materials through which the passage ofwater vapor may be of importance, such as paper, plastic films, other sheet materials, fiberboards, gypsum and plaster products,wood products, and plastics. The test methods are limited to specimens not over 114 in. 32 mm in
4、thickness except as providedin Section 9. Two basic methods, the Desiccant Method and the Water Method, are provided for the measurement of permeance,and two variations include service conditions with one side wetted and service conditions with low humidity on one side and highhumidity on the other.
5、 Agreement should not be expected between results obtained by different methods. The method should beselected that more nearly approaches the conditions of use.1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in eachsystem may
6、not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from thetwo systems may result in non-conformance with the standard. However, derived results can be converted from one system to theother using appropriate conversion factors (see Table 1).1.
7、3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Docum
8、ents2.1 ASTM Standards:2C168 Terminology Relating to Thermal InsulationE177C1809 Practice for Use of the Terms Precision and Bias in ASTM Test MethodsPreparation of Specimens and Reportingof Results for Permeance Testing of Pressure Sensitive Adhesive Sealed Joints in Insulation Vapor RetardersD449/
9、D449M Specification for Asphalt Used in Dampproofing and Waterproofing1 These test methods are under the jurisdiction of ASTM Committee C16 on Thermal Insulation and are the direct responsibility of Subcommittee C16.33 on InsulationFinishes and Moisture.Current edition approved May 1, 2015March 1, 2
10、016. Published September 2015April 2016. Originally approved in 1953. Last previous edition approved in 20142015as E96E96/E96M 15. 14. DOI: 10.1520/E0096_E0096M-15.10.1520/E0096_E0096M-16.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at servicea
11、stm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.TABLE 1 Metric Units and Conversion FactorsA,BMultiply by To Obtain (for thesame test condition)WVTg/hm2 1.43 grains/hft2grains/hft2 0.697 g/hm2Permeanceg/Pasm2 1.75 107 1 P
12、erm (inch-pound)1 Perm (inch-pound) 5.72 108 g/Pasm2Permeabilityg/Pasm 6.88 108 1 Perm inch1 Perm inch 1.45 109 g/PasmA These units are used in the construction trade. Other units may be used in otherstandards.B All conversions of mm Hg to Pa are made at a temperature of 0C.This document is not an A
13、STM 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. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In
14、all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1D2301 Specification for Vinyl Chloride Plastic Pressure-Sensitive Electri
15、cal Insulating TapeE177 Practice for Use of the Terms Precision and Bias in ASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method3. Terminology3.1 Definitions of terms used in this standard will be found in Terminology C168, from which the
16、 following is quoted:“water vapor permeabilitythe time rate of water vapor transmission through unit area of flat material of unit thickness inducedby unit vapor pressure difference between two specific surfaces, under specified temperature and humidity conditions.DiscussionPermeability is a propert
17、y of a material, but the permeability of a body that performs like a material may be used.Permeability is the arithmetic product of permeance and thickness.water vapor permeancethe time rate of water vapor transmission through unit area of flat material or construction induced byunit vapor pressure
18、difference between two specific surfaces, under specified temperature and humidity conditions.DiscussionPermeance is a performance evaluation and not a property of a material.3.2 water vapor transmission ratethe steady water vapor flow in unit time through unit area of a body, normal to specificpara
19、llel surfaces, under specific conditions of temperature and humidity at each surface.”4. Summary of Test Methods4.1 In the Desiccant Method the test specimen is sealed to the open mouth of a test dish containing a desiccant, and the assemblyplaced in a controlled atmosphere. Periodic weighings deter
20、mine the rate of water vapor movement through the specimen into thedesiccant.4.2 In the Water Method, the dish contains distilled water, and the weighings determine the rate of vapor movement throughthe specimen from the water to the controlled atmosphere. The vapor pressure difference is nominally
21、the same in both methodsexcept in the variation, with extremes of humidity on opposite sides.5. Significance and Use5.1 The purpose of these tests is to obtain, by means of simple apparatus, reliable values of water vapor transfer throughpermeable and semipermeable materials, expressed in suitable u
22、nits. These values are for use in design, manufacture, andmarketing. A permeance value obtained under one set of test conditions may not indicate the value under a different set ofconditions. For this reason, the test conditions should be selected that most closely approach the conditions of use. Wh
23、ile any setof conditions may be used and those conditions reported, standard conditions that have been useful are shown in Appendix X1.6. Apparatus6.1 Test DishThe test dish shall be of any noncorroding material, impermeable to water or water vapor. It may be of any shape.Light weight is desirable.A
24、large, shallow dish is preferred, but its size and weight are limited when an analytical balance is chosento detect small weight changes. The mouth of the dish shall be as large as practical and at least 4.65 in.2 3000 mm2. The desiccantor water area shall be not less than the mouth area except if a
25、 grid is used, as provided in 12.1, its effective area shall not exceed10 % of the mouth area. An external flange or ledge around the mouth, to which the specimen may be attached, is useful whenshrinking or warping occurs. When the specimen area is larger than the mouth area, this overlay upon the l
26、edge is a source of error,particularly for thick specimens. This overlay material should be masked as described in 10.1 so that the mouth area defines thetest area. The overlay material results in a positive error, indicating excessive water vapor transmission. The magnitude of the erroris a complex
27、 function of the thickness, ledge width, mouth area, and possibly the permeability. This error is discussed by Joy andWilson (1)3 (see 13.4.3). This type of error should be limited to about 10 to 12 %. For a thick specimen the ledge should not exceed34 in. 19 mm for a 10-in. 254-mm or larger mouth (
28、square or circular) or 18 in. 3 mm for a 5-in. 127-mm mouth (squareor circular). For a 3-in. 76-mm mouth (square or circular) the ledge should not exceed 0.11 in. 2.8 mm wide.An allowable ledgemay be interpolated for intermediate sizes or calculated according to Joy and Wilson.(1) A rim around the l
29、edge (Fig. X2.1) maybe useful. If a rim is provided, it shall be not more than 14 in. 6 mm higher than the specimen as attached. Different depths maybe used for the Desiccant Method and Water Method, but a 34-in. 19-mm depth (below the mouth) is satisfactory for eithermethod.6.2 Test ChamberThe room
30、 or cabinet where the assembled test dishes are to be placed shall have a controlled temperature(see Note 1) and relative humidity. Some standard test conditions that have been useful are given in Appendix X1. The temperaturechosen shall be determined according to the desired application of the mate
31、rial to be tested (see Appendix X1). The relativehumidity shall be maintained at 50 6 2 %, except where extremes of humidities are desired, when the conditions shall be 100 61.8F 38 6 1C and 90 6 2 % relative humidity. Both temperature and relative humidity shall be measured frequently4 orpreferably
32、 recorded continuously. Air shall be continuously circulated throughout the chamber, with a velocity sufficient to3 The boldface numbers in parentheses refer to the list of references at the end of this standard.4 The minimum acceptable is to perform this measurement each time the sample is weighed.
33、E96/E96M 162maintain uniform conditions at all test locations. The air velocity over the specimen shall be between 0.066 and 1 ft/s 0.02 and0.3 ms-1. Suitable racks shall be provided on which to place the test dishes within the test chamber.NOTE 1Simple temperature control by heating alone is usuall
34、y made possible at 90F 32C. However, it is very desirable to enter the controlledspace, and a comfortable temperature is more satisfactory for that arrangement. Temperatures of 73.4F 23C and 80F 26.7C are in use and aresatisfactory for this purpose. With cyclic control, the average test temperature
35、may be obtained from a sensitive thermometer in a mass of dry sand. Thetemperature of the chamber walls facing a specimen over water should not be cooler than the water to avoid condensation on the test specimen.6.3 Balance and WeightsThe balance shall be sensitive to a change smaller than 1 % of th
36、e weight change during the periodwhen a steady state is considered to exist. The weights used shall be accurate to 1 % of the weight change during the steady-stateperiod (Note 2). A light wire sling may be substituted for the usual pan to accommodate a larger and heavier load.6.4 Thickness-Measuring
37、 GageThe nominal thickness of the specimen shall be determined using a thickness-measuring gagewith an accuracy of 61 % of the reading or 0.0001 in. 0.0025 mm, whichever is greater.NOTE 2For example: 1-perm 57 ngPa-1s-1m-2 specimen 10 in. 254 mm square at 80F 26.7C passes 8.6 grains or 0.56 g/day. I
38、n 18 days ofsteady state, the transfer is 10 g. For this usage, the balance must have a sensitivity of 1 % of 10 g or 0.1 g and the weights must be accurate to 0.1 g.If, however, the balance has a sensitivity of 0.2 g or the weights are no better than 0.2 g, the requirements of this paragraph can be
39、 met by continuingthe steady state for 36 days. An analytical balance that is much more sensitive will permit more rapid results on specimens below 1 perm 57ngPa-1s-1m-2 when the assembled dish is not excessively heavy.7. Materials7.1 Desiccant and Water:7.1.1 For the Desiccant Method, anhydrous cal
40、cium chloride in the form of small lumps that will pass a No. 8 2.36-mm sieve,and free of fines that will pass a No. 30 600-m sieve, shall be used (Note 3). It shall be dried at 400F 200C before use.NOTE 3If CaCl2 will react chemically on the specimen, an adsorbing desiccant such as silica gel, acti
41、vated at 400F 200C, may be used; but themoisture gain by this desiccant during the test must be limited to 4 %.7.1.2 For the Water Method, distilled water shall be used in the test dish.7.2 SealantThe sealant used for attaching the specimen to the dish, in order to be suitable for this purpose, must
42、 be highlyresistant to the passage of water vapor (and water). It must not lose weight to, or gain weight from, the atmosphere in an amount,over the required period of time, that would affect the test result by more than 2 %. It must not affect the vapor pressure in awater-filled dish. Molten asphal
43、t or wax is required for permeance tests below 4 perms 230 ngm-2 s-1Pa-1. Sealing methods arediscussed in Appendix X2.8. Sampling8.1 The material shall be sampled in accordance with standard methods of sampling applicable to the material under test. Thesample shall be of uniform thickness. If the ma
44、terial is of nonsymmetrical construction, the two faces shall be designated bydistinguishing marks (for example, on a one-side-coated sample, “I” for the coated side and “II” for the uncoated side).9. Test Specimens9.1 Test specimens shall be representative of the material tested. When a product is
45、designed for use in only one position, threespecimens shall be tested by the same method with the vapor flow in the designated direction. When the sides of a product areindistinguishable, three specimens shall be tested by the same method. When the sides of a product are different and either sidemay
46、 face the vapor source, four specimens shall be tested by the same method, two being tested with the vapor flow in eachdirection and so reported.9.2 A slab, produced and used as a laminate (such as a foamed plastic with natural “skins”) may be tested in the thickness ofuse. Alternatively, it may be
47、sliced into two or more sheets, each being separately tested and so reported as provided in 9.4,provided also, that the “overlay upon the cup ledge” (6.1) of any laminate shall not exceed 18 in. 3 mm.9.3 When the material as used has a pitted or textured surface, the tested thickness shall be that o
48、f use. When it is homogeneous,however, a thinner slice of the slab may be tested as provided in 9.4.9.4 In either case (9.2 or 9.3), the tested overall thickness, if less than that of use, shall be at least five times the sum of themaximum pit depths in both its faces, and its tested permeance shall
49、 be not greater than 5 perms 300 ngm-2s-1Pa-1.9.5 For homogeneous (not laminated) materials with thickness greater than 12 in., the overall nominal thickness of eachspecimen shall be measured with an accuracy of 61 % of the reading at the center of each quadrant and the results averaged.9.6 When testing pressure sensitive adhesive sealed joints used in insulation vapor retarder systems, prepare the specimensaccording to Practice C1809.9.7 When testing any
