1、Designation:D 1251 94Standard Test Method forWater Vapor Permeability of Packages by Cycle Method1This standard is issued under the fixed designation D 1251;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A
2、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 test method covers the determination of the watervapor permeability of finished packages subjected to extremesof temperature and rela
3、tive humidity when closed and sealed inthe conventional manner.It is intended for“shelf-size pack-ages”that are shipped in outside containers.1.2 This test method may be applied to the package aspacked,after one or more performance tests such as drop(TestMethod D 5276),drum(Test Method D 782),vibrat
4、ion(TestMethod D 999),after a series of tests simulating the shippingenvironment(Practice D 4169),or after shipping tests havebeen completed,as required.1.3 Packages with body walls having the property of ab-sorbing water are not suitable for testing under this testmethod.1.4 This standard does not
5、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.1.5 The values stated in SI units are to be r
6、egarded as thestandard.The values in parentheses are for information only.2.Referenced Documents2.1 ASTM Standards:D 782 Test Methods for Shipping Containers in RevolvingHexagonal Drum2D 895 Test Method for Water Vapor Permeability of Pack-ages Under Constant Conditions2D 996 Terminology of Packagin
7、g and Distribution Environ-ments2D 999 Test Methods for Vibration Testing of ShippingContainers2D 4169 Practice for Performance Testing of Shipping Con-tainers and Systems2D 5276 Test Method for Drop Test of Loaded Containers byFree Fall23.Terminology3.1 DefinitionsGeneral terms for packaging and di
8、stribu-tion environments are found in Terminology D 996.3.2 Definitions of Terms Specific to This Standard:3.2.1 cycleone series of test atmospheres to which the testspecimens are exposed.3.2.2 water vapor permeabilityof a package,the rate atwhich water is transmitted into the package from the testa
9、tmosphere surrounding it while a desiccant is sealed within.4.Significance and Use4.1 This test method is normally used to:4.1.1 Evaluate materials and constructions for a specifictype of package,4.1.2 Compare performance of different types of packages,4.1.3 Determine adequacy of protection for a sp
10、ecific prod-uct or application,and4.1.4 Maintain quality control.4.2 When this test method is conducted to determine thewater vapor permeability of the packages for research,devel-opment,manufacturing control,specification acceptance,etc.,a desiccant is used as the water-absorbing medium.4.3 When th
11、is test method is used to determine the suitabil-ity of the package with respect to water vapor resistance for aparticular product,the product is used instead of the desiccant.5.Apparatus5.1 Weighing BalanceA suitable laboratory balance sen-sitive to 1 mg,or to one ten-thousandth of the mass of thep
12、ackage,whichever is larger.5.2 Test ChamberA test room or cabinet provided withtemperature and humidity controls that will allow conditionedair to circulate continuously around the specimens under test.The chamber must be capable of maintaining 38 6 2C(100 64F)and 90 6 2%relative humidity,or as othe
13、rwise specified.The conditions in the chamber must be such that no conden-sation occurs on the specimens except during that portion ofthe cycle when the exposure is changed from a low temperatureto a high-humid temperature.5.3 Cold Chamber,which must be capable of maintaining18 6 2C(0 6 4F)or as oth
14、erwise specified.6.Materials6.1 DesiccantA desiccant shall be used that has a highaffinity for water vapor and a high drying efficiency,that is,having a low water vapor pressure even after absorbing a largeamount of water.NOTE1A suitable desiccant is anhydrous calcium chloride in the1This test metho
15、d is under the jurisdiction of ASTM Committee D-10 onPackaging and is the direct responsibility of Subcommittee D10.23 on NaturalEnvironment Test Methods.Current edition approved May 15,1994.Published July 1994.Originallypublished as D 1251 53T.Last previous edition D 1251 79(1987)e1.2Annual Book of
16、 ASTM Standards,Vol 15.09.1AMERICAN SOCIETY FOR TESTING AND MATERIALS100 Barr Harbor Dr.,West Conshohocken,PA 19428Reprinted from the Annual Book of ASTM Standards.Copyright ASTMNOTICE:This standard has either been superseded and replaced by a new version or discontinued.Contact ASTM International(www.astm.org)for the latest information.form of small lumps that will pass a No.8(2.36-mm)sieve,and free offines that will pass a No.30(600-m)sieve.7.Test Specimens7.1 Test specimens shall be represent