1、Designation: D 4279 95 (Reapproved 2003)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 (e) 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 ship
3、ping 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
4、more 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 va
5、por transmission may be determinedin accordance with Test Method D 895 or Test Method D 1251.1.5 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 prac
6、tices and determine the applica-bility of regulatory limitations prior to use.2. Referenced 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 Pe
7、rmeability of Pack-agesD 996 Terminology of Packaging and Distribution Environ-mentsD 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 Contai
8、ners and SystemsD 4169 Practice for Performance Testing of Shipping Con-tainers and SystemsD 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
9、 for the packaging anddistribution environments are found in Terminology D 996.3.2 Definitions 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 testmetho
10、d, the rate at which water is transmitted into the containerfrom the test atmosphere (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 tes
11、t method, the amount of watertransmitted into the container from the test atmosphere duringone cycle while a desiccant is sealed within.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 (1
12、7.8 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,1These t
13、est methods are under the jurisdiction of ASTM Committee D10 onPackaging and are the direct responsibility of Subcommittee D10.23 on Storage TestMethods.Current edition approved Sept. 10, 1995. Published November 1995. Originallypublished as D 4279 83. Last previous edition D 4279 83 (1995)e1.2For r
14、eferenced 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.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO
15、 Box C700, West Conshohocken, PA 19428-2959, United States.4.1.2 To 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 desic
16、cant 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 will pass aNo. 8 (2.36-mm) sieve and be free from fines that will pass aNo. 30 (600-m)
17、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 be usedinside the test specimen instead of the desiccant, in which casethe specimen shall
18、 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 or more receptacles shall be used and weighedindividually. When product tests are made, a
19、 regular laboratorybalance and drying oven or other appropriate equipment 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 co
20、ntainer 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 orreceptacles shall be such that the exposed area of desiccant isnot less than 10 % of the
21、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 around thespecimens under test. The conditions in the chamber shall besuch that no conden
22、sation 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 containersbeing tested, and shall be closed and sealed in the normalmanner.6.2 The perform
23、ance 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, using a nonabsorptive support whenrequired. Place the selected quantity of the desiccant in
24、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 close and seal the specimen in the normalmanner. The desiccant may require one or more r
25、eplacementsif 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, specification acceptance, etc., a desiccant shall be usedas the water absorbing medium. Whe
26、n 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 inside the test room or cabinet in aposition where free access of the conditioned circula
27、ting 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 1.1C).7.2.2 Cycle Atmosphere MethodPlace the specimen in thelow temperature test room or c
28、abinet (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 weighings of the receptacle at suitableintervals and plot the mass gained against time
29、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 having a low rate of transmis-sion, a weighing frequency of biweekly to monthly is recom-
30、mended.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 should be conducted asrapidly as possible, shall be as follows: Remove the specimen
31、from 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 the specimen, and return thereceptacle. Uncover the receptacle, reclose the specimen
32、, andreturn it without delay to the test room or cabinet. Continueuntil a constant rate of gain is attained as indicated by at leastthree 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 m
33、ade 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 the moisture content determined from a compositesample taken at the start of the test.For the Const
34、ant 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 period).For the Cycle Method the specimen shall be subjected to one exposurecycle for a predetermined
35、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 andD 4279 95 (2003)2resealing, after which the specimen is returned without delay to the testroom or cabinet.METHOD BCO
36、NTAINERS 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 it is notpracticable to weigh the entire container with the desiccantinside.9. Tes
37、t 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 desiccant inside, an auxiliary openinglarge enough to permit inserting the desiccant re
38、ceptacle 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 piece of sheet metal, or other impervioussheeting somewhat larger than the opening, sea
39、ling 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 wax4and 40% refined crystalline paraffin wax.10. Procedure10.1 For specimens that can be weighed accurately to therequirements
40、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 make successiveweighings at suitable intervals until a constant rate of gain isestabl
41、ished 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 regular closure is to remain sealed throughout the test.REPORT AND PRECISION11. Report11
42、.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 is used. When a desiccant is used, the mass and areaexposed shall be specified, and1
43、1.1.3 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(61.1C) temperature is exceeded, the variation shall bespecified, and11.2.2 Water vapor tr
44、ansmission 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 cycle at which the test was conducted, and11.3.2 Water vapor transmission reported as gram
45、s 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 content at the start andcompletion of each cycle shall be given, together with the netweight
46、 of contents, from which data the actual amount of waterpick up can be calculated.412. 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 th
47、is 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; reclos-able containers; water vapor permeabilityASTM International takes no position respecting the validity of any patent rights asserted in conn
48、ection with any item mentionedin this standard. 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 respons
49、ible 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 receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown
