1、Designation: D 4279 95 (Reapproved 2009)Standard Test Methods forWater Vapor Transmission of Shipping ContainersConstant and Cycle Methods1This standard is issued under the fixed designation D 4279; the number immediately following the designation indicates the year oforiginal adoption or, in the ca
2、se 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 shipp
3、ing 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 m
4、ore performance tests such as drum (MethodD 782), vibration (Methods D 999), drop (Test MethodD 5276), impact resistance (Test Methods D 880, D 4003, andD 5277), or performance tests (Practice D 4169), as required.1.4 For small shipping containers requiring greater accuracyin weighing, the water vap
5、or transmission may be determinedin accordance with Test Method D 895 or Test Method D 1251.1.5 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 st
6、andard.1.6 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.2. Refer
7、enced Documents2.1 ASTM Standards:2D 782 Test Methods for Shipping Containers in RevolvingHexagonal Drum3D 880 Test Method for Impact Testing for Shipping Con-tainers and SystemsD 895 Test Method for Water Vapor Permeability of Pack-agesD 996 Terminology of Packaging and Distribution Environ-mentsD
8、999 Test Methods for Vibration Testing of ShippingContainersD 1251 Test Method for Water Vapor Permeability of Pack-ages by Cycle MethodD 4003 Test Methods for Programmable Horizontal ImpactTest for Shipping Containers and SystemsD 4169 Practice for Performance Testing of Shipping Con-tainers and Sy
9、stemsD 5276 Test Method for Drop Test of Loaded Containers byFree FallD 5277 Test Method for Performing Programmed Horizon-tal Impacts Using an Inclined Impact Tester3. Terminology3.1 DefinitionsGeneral definitions for the packaging anddistribution environments are found in Terminology D 996.3.2 Def
10、initions of Terms Specific to This Standard: De-scriptions 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 atmosphere (
11、normally of 90 6 2 % relativehumidity and a temperature of 100 6 2F (37.86 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 watertransmitted into the container from the test atmosphere d
12、uringone cycle while a desiccant is sealed within.1These test methods are under the jurisdiction of ASTM Committee D10 onPackaging and are the direct responsibility of Subcommittee D10.23 on NaturalEnvironment Test Methods.Current edition approved March 1, 2009. Published March 2009. Originallyappro
13、ved in 1983. Last previous edition approved in 2003 as D 4279 95 (2003).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 AS
14、TM website.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.3 cycleone 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 (
15、17.8 62.8C) to be followed by 3 weeks of exposure at a temperatureof 100 6 2F (37.86 1.1C) and a relative humidity of 90 62%.4. Significance and 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 T
16、o compare performance of different types of contain-ers,4.1.3 To determine adequacy of protection for a specificproduct or application, and4.1.4 To maintain quality control.METHOD ARECLOSABLE CONTAINERS5. Apparatus5.1 DesiccantA desiccant shall be used that has a power-ful affinity for water and a h
17、igh drying efficiency, that is, a lowvapor pressure after absorbing a large amount of water. Thedesiccant shall be in the form of small lumps that 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 perchlora
18、te have been found suitable.When the test is made to determine the suitability of a specificcontainer for a particular product, that product may be usedinside the test specimen instead of the desiccant, in which casethe specimen shall be filled to normal capacity.5.2 Weighing BalanceA weighing balan
19、ce accurate towithin 1 g shall be used. When the required amount ofdesiccant is greater than can be weighed on a balance of thissensitivity, two or more receptacles shall be used and weighedindividually. When product tests are made, a regular laboratorybalance and drying oven or other appropriate eq
20、uipment arerequired for making standard moisture determinations peculiarto the product.5.3 Receptacle for DesiccantA nonmoisture-absorptivereceptacle34 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
21、rest on the top rim ofthe receptacle to protect the desiccant from picking up moisturewhile being weighed. The size of the weighing receptacle orreceptacles 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 r
22、equire using two or more weighingreceptacles.5.4 Test ChamberA test room or cabinet provided withconditioned air that is continuously circulated around thespecimens under test. The conditions in the chamber shall besuch that no condensation occurs on the specimens exceptduring that portion of the cy
23、cle when the exposure is changedfrom a low temperature to a high temperature.6. Test Specimens6.1 Test specimens shall be representative of the containersbeing tested, and shall be closed and sealed in the normalmanner.6.2 The performance shall be based on tests of not less thantwo representative sp
24、ecimens of a given size and type ofcontainer.7. Procedure7.1 Locate the weighing receptacle or receptacles centrallywithin the test specimen, using a nonabsorptive support whenrequired. Place the selected quantity of the desiccant in thereceptacle sufficient to uniformly cover the area of the recep-
25、tacle to a depth of not less than12 in. (13 mm). Cover, and afterweighing, immediately transfer into the test specimen. Uncoverthe receptacle and close and seal the specimen in the normalmanner. The desiccant may require one or more replacementsif it becomes noticeably moist during the test.NOTE 1Wh
26、en the test is conducted to determine the water vaportransmission of the shipping container for research, development, manu-facturing control, specification acceptance, etc., a desiccant shall be usedas the water absorbing medium. When the test is used to determine thesuitability of the shipping con
27、tainer with respect to water vapor resistancefor a particular product, the product shall be used in lieu of the desiccant.7.2 Place the specimen inside the test room or cabinet in aposition where free access of the conditioned circulating air isprovided on all surfaces of the container according to
28、thefollowing:7.2.1 Constant Atmosphere MethodNormally surroundingconditions are 90 6 2 % relative humidity and a temperature of100 6 2F (37.7 6 1.1C).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. F
29、ollow immediately by3 weeks of exposure to the high temperature and humidity(normally 100F (37.8C) and 90 % relative humidity).7.3 Make successive weighings of the receptacle at suitableintervals and plot the mass gained against time using theseschedules:7.3.1 Constant MethodAccuracy of the test is
30、adverselyaffected by too frequent weighings. For highly permeablecontainers a minimum weighing frequency of 3 days isrecommended. For containers having a low rate of transmis-sion, a weighing frequency of biweekly to monthly is recom-mended.7.3.2 Cycle MethodMake successive weighings of thereceptacl
31、e 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 should be conducted asrapidly as possible, shall be as follows: Remove the specimenfrom the test chamber, open, remove the receptacle, and placethe c
32、over on the receptacle. Temporarily close the specimen toprevent the entrance of moisture from the surrounding atmo-sphere.Weigh the receptacle, open the specimen, and return thereceptacle. Uncover the receptacle, reclose the specimen, andreturn it without delay to the test room or cabinet. Continue
33、until a constant rate of gain is attained as indicated by at leastD 4279 95 (2009)2three successive points in a straight line. The slope of thisportion of the curve will furnish a measure of water vaportransmission.NOTE 2In instances where tests are made in which specific productsare used in place o
34、f the standard desiccant, a constant rate of gain may notbe attainable. Therefore, for product tests, the container is filled to itsnormal capacity and 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 roo
35、m for apredetermined period (usually one month), removed, and the averagemoisture content determined from a composite sample taken at the end ofthis period).For the Cycle Method the specimen shall be subjected to one exposurecycle for a predetermined period, removed, and the average moisturecontent
36、determined from a composite sample taken at the end of thisperiod.In either method the test can be continued by immediately closing andresealing, after which the specimen is returned without delay to the testroom or cabinet.METHOD BCONTAINERS NOT DESIGNED FORRECLOSING8. Apparatus8.1 The apparatus sh
37、all 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 it is notpracticable to weigh the entire container with the desiccantinside.9. Test Specimens9.1 Test specimens shall be representative of the conta
38、inersbeing tested, and shall be closed and sealed in the normalmanner. For containers that cannot be weighed to the accuracyprescribed in 5.2 with desiccant inside, an auxiliary openinglarge enough to permit inserting the desiccant receptacle shallbe cut in one face. A means of sealing the opening d
39、uring thetest shall be provided that will permit repeated opening andreclosing during the test. Closure of this handhole can beaccomplished with a piece of sheet metal, or other impervioussheeting somewhat larger than the opening, sealing it in placewith wax (Note 3), or forming an equally imperviou
40、s seal byother means.NOTE 3A satisfactory wax for this purpose consists of a mixture of60 % microcystalline wax and 40 % refined crystalline paraffin wax.10. Procedure10.1 For specimens that can be weighed accurately to therequirements prescribed in 5.2, place the selected quantity ofdesiccant or pr
41、oduct 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 make successiveweighings at suitable intervals until a constant rate of gain isestablished as described in 7.3.10.2 For specimens that are not practi
42、cable 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 regular closure is to remain sealed throughout the test.REPORT AND PRECISION11. Report11.1 The report shall include the following:11.1.1 Identification
43、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 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
44、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(61.1C) temperature is exceeded, the variation shall bespecified, and11.2.2 Water vapor transmission reported as grams of waterper 30 days for the contain
45、er 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 cycle 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 vap
46、or transmission rate calculation shall bemade for the period of constant rate of gain. If a product is usedinstead of a desiccant, the moisture content 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
47、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 percent.12.2 BiasThe procedure in this test method has no biasbecause the value is defined only in te
48、rms of this test method.13. Keywords13.1 constant rate of gain; cycle method; desiccant; reclos-able containers; water vapor permeabilityD 4279 95 (2009)3ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard.
49、Users of this standard are expressly advised that determination 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 or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will rece
