1、Designation: D4279 95 (Reapproved 2017)Standard Test Methods forWater Vapor Transmission of Shipping ContainersConstant and Cycle Methods1This standard is issued under the fixed designation D4279; 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.1. Scope1.1 These test methods cover the determination of watervapor transmission rates for bulk shippin
3、g containers, asfollows:1.1.1 Method A, for Reclosable Containers, and1.1.2 Method B, for Containers Not Designed for Reclos-ing.1.2 Within each procedure details are given for the constantand cycle methods of test atmosphere.1.3 The test may be applied to the container as packed, orafter one or mor
4、e performance tests such as drum (MethodD782), vibration (Methods D999), drop (Test Method D5276),impact resistance (Test Methods D880, D4003, and D5277), orperformance tests (Practice D4169), as required.1.4 For small shipping containers requiring greater accuracyin weighing, the water vapor transm
5、ission may be determinedin accordance with Test Method D895 or Test Method D1251.1.5 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.6
6、This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1.7 This internatio
7、nal standard was developed in accor-dance with internationally 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) Commit
8、tee.2. Referenced Documents2.1 ASTM Standards:2D782 Test Method for Shipping Containers in RevolvingHexagonal Drum (Withdrawn 1999)3D880 Test Method for Impact Testing for Shipping Contain-ers and SystemsD895 Test Method for Water Vapor Permeability of Pack-ages (Withdrawn 1999)3D996 Terminology of
9、Packaging and Distribution Environ-mentsD999 Test Methods for Vibration Testing of Shipping Con-tainersD1251 Test Method for Water Vapor Permeability of Pack-ages by Cycle Method (Withdrawn 1999)3D4003 Test Methods for Programmable Horizontal ImpactTest for Shipping Containers and SystemsD4169 Pract
10、ice for Performance Testing of Shipping Con-tainers and SystemsD5276 Test Method for Drop Test of Loaded Containers byFree FallD5277 Test Method for Performing Programmed HorizontalImpacts Using an Inclined Impact Tester3. Terminology3.1 DefinitionsGeneral definitions for the packaging anddistributi
11、on environments are found in Terminology D996.3.2 Definitions of Terms Specific to This Standard:3.2.1 water vapor transmission rate of a shipping container(constant atmosphere method)for the purpose of this testmethod, the rate at which water is transmitted into the containerfrom the test atmospher
12、e (normally of 90 6 2 % relativehumidity and a temperature of 100 6 2F (37.8 6 1.1C)surrounding it while a desiccant is sealed within.3.2.2 water vapor transmission into a container (cycleatmosphere method)for this test method, the amount of water1These test methods are under the jurisdiction of AST
13、M Committee D10 onPackaging and are the direct responsibility of Subcommittee D10.21 on ShippingContainers and Systems - Application of Performance Test Methods.Current edition approved May 1, 2017. Published July 2017. Originally approvedin 1983. Last previous edition approved in 2009 as D4279 95 (
14、2009). DOI:10.1520/D4279-95R17.2For 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.3The last approved version of
15、this historical standard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in
16、the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1transmitted into the container from the test atmosphere duringone cycle while a desiccant is sealed within.3.2.3 cy
17、cleone series of test atmospheres to which the testspecimens are exposed. Normally one cycle will consist of 1week of exposure to a temperature of 0 6 5F (17.8 62.8C) to be followed by 3 weeks of exposure at a temperatureof 100 6 2F (37.8 6 1.1C) and a relative humidity of 906 2%.4. Significance and
18、 Use4.1 These test methods are normally used for the followingpurposes:4.1.1 To evaluate materials and constructions for a specifictype of container,4.1.2 To compare performance of different types ofcontainers,4.1.3 To determine adequacy of protection for a specificproduct or application, and4.1.4 T
19、o maintain quality control.METHOD ARECLOSABLE CONTAINERS5. Apparatus5.1 DesiccantA desiccant shall be used that has a power-ful affinity for water and a high drying efficiency, that is, a lowvapor pressure after absorbing a large amount of water. Thedesiccant shall be in the form of small lumps that
20、 will pass aNo. 8 (2.36-mm) sieve and be free from fines that will pass aNo. 30 (600-m) sieve. Anhydrous calcium chloride andanhydrous magnesium perchlorate have been found suitable.When the test is made to determine the suitability of a specificcontainer for a particular product, that product may b
21、e usedinside the test specimen instead of the desiccant, in which casethe specimen shall be filled to normal capacity.5.2 Weighing BalanceA weighing balance accurate towithin 1 g shall be used. When the required amount ofdesiccant is greater than can be weighed on a balance of thissensitivity, two o
22、r more receptacles shall be used and weighedindividually. When product tests are made, a regular laboratorybalance and drying oven or other appropriate equipment arerequired for making standard moisture determinations peculiarto the product.5.3 Receptacle for DesiccantA nonmoisture-absorptiverecepta
23、cle34 to 112 in. (19 to 38 mm) deep shall be used forholding the desiccant within the container being tested. Itshould be equipped with a cover that will rest on the top rim ofthe receptacle to protect the desiccant from picking up moisturewhile being weighed. The size of the weighing receptacle orr
24、eceptacles shall be such that the exposed area of desiccant isnot less than 10 % of the area of the test specimen. For testinglarge containers, this may require using two or more weighingreceptacles.5.4 Test ChamberA test room or cabinet provided withconditioned air that is continuously circulated a
25、round thespecimens under test. The conditions in the chamber shall besuch that no condensation occurs on the specimens exceptduring that portion of the cycle when the exposure is changedfrom a low temperature to a high temperature.6. Test Specimens6.1 Test specimens shall be representative of the co
26、ntainersbeing tested, and shall be closed and sealed in the normalmanner.6.2 The performance shall be based on tests of not less thantwo representative specimens of a given size and type ofcontainer.7. Procedure7.1 Locate the weighing receptacle or receptacles centrallywithin the test specimen, usin
27、g a nonabsorptive support whenrequired. Place the selected quantity of the desiccant in thereceptacle sufficient to uniformly cover the area of the recep-tacle to a depth of not less than12 in. (13 mm). Cover, and afterweighing, immediately transfer into the test specimen. Uncoverthe receptacle and
28、close and seal the specimen in the normalmanner. The desiccant may require one or more replacementsif it becomes noticeably moist during the test.NOTE 1When the test is conducted to determine the water vaportransmission of the shipping container for research, development, manu-facturing control, spe
29、cification acceptance, etc., a desiccant shall be usedas the water absorbing medium. When the test is used to determine thesuitability of the shipping container with respect to water vapor resistancefor a particular product, the product shall be used in lieu of the desiccant.7.2 Place the specimen i
30、nside the test room or cabinet in aposition where free access of the conditioned circulating air isprovided on all surfaces of the container according to thefollowing:7.2.1 Constant Atmosphere MethodNormally surroundingconditions are 90 6 2 % relative humidity and a temperature of100 6 2F (37.7 6 1.
31、1C).7.2.2 Cycle Atmosphere MethodPlace the specimen in thelow temperature test room or cabinet (normally maintained at0F (17.8C) for a period of 1 week. Follow immediately by3 weeks of exposure to the high temperature and humidity(normally 100F (37.8C) and 90 % relative humidity).7.3 Make successive
32、 weighings of the receptacle at suitableintervals and plot the mass gained against time using theseschedules:7.3.1 Constant MethodAccuracy of the test is adverselyaffected by too frequent weighings. For highly permeablecontainers a minimum weighing frequency of 3 days isrecommended. For containers h
33、aving a low rate oftransmission, a weighing frequency of biweekly to monthly isrecommended.7.3.2 Cycle MethodMake successive weighings of thereceptacle at the completion of each cycle. It is suggested thatthe test be carried on for a minimum of three complete cycles.7.4 The weighing procedure, which
34、 should be conducted asrapidly as possible, shall be as follows: Remove the specimenfrom the test chamber, open, remove the receptacle, and placethe cover on the receptacle. Temporarily close the specimen toprevent the entrance of moisture from the surrounding atmo-sphere.Weigh the receptacle, open
35、the specimen, and return thereceptacle. Uncover the receptacle, reclose the specimen, andreturn it without delay to the test room or cabinet. Continueuntil a constant rate of gain is attained as indicated by at leastD4279 95 (2017)2three successive points in a straight line. The slope of thisportion
36、 of the curve will furnish a measure of water vaportransmission.NOTE 2In instances where tests are made in which specific productsare used in place of the standard desiccant, a constant rate of gain may notbe attainable. Therefore, for product tests, the container is filled to itsnormal capacity and
37、 the moisture content determined from a compositesample taken at the start of the test.For the Constant Method the specimen is placed in the test room for apredetermined period (usually one month), removed, and the averagemoisture content determined from a composite sample taken at the end ofthis pe
38、riod).For the Cycle Method the specimen shall be subjected to one exposurecycle for a predetermined period, removed, and the average moisturecontent determined from a composite sample taken at the end of thisperiod.In either method the test can be continued by immediately closing andresealing, after
39、 which the specimen is returned without delay to the testroom or cabinet.METHOD BCONTAINERS NOT DESIGNED FORRECLOSING8. Apparatus8.1 The apparatus shall consist of a desiccant, balance, andtest chamber in accordance with 5.1, 5.2, 5.4 respectively, alsodesiccant receptacles in accordance with 5.3 if
40、 it is notpracticable to weigh the entire container with the desiccantinside.9. Test Specimens9.1 Test specimens shall be representative of the containersbeing tested, and shall be closed and sealed in the normalmanner. For containers that cannot be weighed to the accuracyprescribed in 5.2 with desi
41、ccant inside, an auxiliary openinglarge enough to permit inserting the desiccant receptacle shallbe cut in one face. A means of sealing the opening during thetest shall be provided that will permit repeated opening andreclosing during the test. Closure of this handhole can beaccomplished with a piec
42、e of sheet metal, or other impervioussheeting somewhat larger than the opening, sealing it in placewith wax (Note 3), or forming an equally impervious seal byother means.NOTE 3A satisfactory wax for this purpose consists of a mixture of60 % microcystalline wax and 40 % refined crystalline paraffin w
43、ax.10. Procedure10.1 For specimens that can be weighed accurately to therequirements prescribed in 5.2, place the selected quantity ofdesiccant or product inside the specimen, which shall then beclosed and sealed in the normal manner. Place the specimen inthe test atmosphere as described in 7.2 and
44、make successiveweighings at suitable intervals until a constant rate of gain isestablished as described in 7.3.10.2 For specimens that are not practicable to weigh asdescribed in 10.1 proceed exactly as in Section 7 except use theauxiliary opening described in Section 9 as the access opening.The reg
45、ular closure is to remain sealed throughout the test.REPORT AND PRECISION11. Report11.1 The report shall include the following:11.1.1 Identification of container including data on closure,liners, etc., and whether Method A or B was used,11.1.2 Desiccant used or identification of contents if aproduct
46、 is used. When a desiccant is used, the mass and areaexposed shall be specified, and11.1.3 Number or specimens tested.11.2 If the Constant Method is used, record the following:11.2.1 Temperature and relative humidity at which the testwas conducted. If the tolerance of 2 % relative humidity or 2F(61.
47、1C) temperature is exceeded, the variation shall bespecified, and11.2.2 Water vapor transmission reported as grams of waterper 30 days for the container as a unit.11.3 If the Cycle Method is used record the following:11.3.1 Temperature, relative humidity, and time for each testatmosphere of the cycl
48、e at which the test was conducted, and11.3.2 Water vapor transmission reported as grams of waterper cycle for the package as a unit.11.4 The water vapor transmission rate calculation shall bemade for the period of constant rate of gain. If a product is usedinstead of a desiccant, the moisture conten
49、t at the start andcompletion of each cycle shall be given, together with the netweight of contents, from which data the actual amount of waterpick up can be calculated.12. Precision and Bias12.1 PrecisionBased on limited information from onelaboratory, the repeatability coefficient of variation for theconstant atmosphere method is approximately 6 %.12.2 BiasThe procedure in this test method has no biasbecause the value is defined only in terms of this test method.13. Keywords13.1 constant rate of gain; cycle method; desiccant
