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ASTM D2842-12
Standard Test Method for Water Absorption of Rigid Cellular Plastics
Automaticky přeložený název:
Standardní zkušební metoda pro nasákavost Pevné lehčených plastů
NORMA vydána dne 1.10.2012
Informace o normě:
Označení normy: ASTM D2842-12
Poznámka: NEPLATNÁ
Datum vydání normy: 1.10.2012
Kód zboží: NS-21669
Počet stran: 10
Přibližná hmotnost: 30 g (0.07 liber)
Země: Americká technická norma
Kategorie: Technické normy ASTM
Kategorie - podobné normy:
Anotace textu normy ASTM D2842-12 :
Keywords:
rigid cellular plastics, water absorption, ICS Number Code 83.100 (Cellular materials)
Doplňující informace
| Significance and Use | ||||||
|
5.1 The purpose of this test method is to provide a means for comparing relative water absorption tendencies between different cellular plastics. It is intended for use in specifications, product evaluation, and quality control. It is applicable to specific end-use design requirements only to the extent that the end-use conditions are similar to the immersion period (normally 96 h) and 5.1-cm [2-in.] head requirements of the test method. 5.2 This test method provides a
means for measuring absorption as a result of direct contact
exposure to free water. Results by this test method cannot be used
to compare the resistance of cellular plastics to water vapor
transmission and subsequent condensation within the cells. To
determine resistance to water vapor transmission, see Test Methods
E96.
5.3 Water absorption testing is subject to several important variables, which if not considered, prohibit sufficient agreement among testing laboratories. Development of this test method has taken into account the most serious of the possible sources of error. 5.4 The volume error associated with
surface cells opened during specimen preparation decreases as the
cell size decreases. This test method provides the option to ignore
this variable with cellular plastics that have an average cell
diameter of 0.03 cm or less. For cellular plastics having greater
than 0.03-cm average cell diameter and in all cases of dispute,
measurement of cell size shall be mandatory in determining the
specimen volume.
5.5 For most materials the size of the test specimens is small compared with the size of the products actually installed in the field. If the surface-to-volume ratios for the test specimens and the corresponding products are different, it is possible that the test results are misleading. 5.6 In most cases water retention is a secondary performance characteristic that has an influence on a primary characteristic, such as thermal performance, surface accumulation of moisture, localized collection of electrolytes, dimensional stability, etc. 5.7 Before proceeding with this test method, reference shall be made to the specification of the material being tested. Any test specimen preparation, conditioning, dimensions, or testing parameters covered in the materials specification, or both, shall take precedence over those mentioned in this test method. If there are no material specifications, then the default conditions in this standard shall apply. |
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| 1. Scope | ||||||
|
1.1 This test method covers the determination of the water absorption of rigid cellular plastics by measuring the change in buoyant force resulting from immersion under a 5.1-cm (2-in.) head of water for the specified immersion period of 96 h. 1.2 This test method describes two procedures that shall be used to measure the change in buoyant force. Procedure A shall be used for materials that either experience rapid water absorption or that show an increase in volume during the exposure period, or both. Materials that do not exhibit either of these characteristics shall be evaluated by Procedure B. 1.3 For specific applications, immersion periods varying from the normal 96-h test requirement shall be agreed upon between the manufacturer and the purchaser. 1.4 The values stated in SI units are to be regarded as the standard. |
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| 2. Referenced Documents | ||||||
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Podobné normy:
Historická
1.4.2008
Historická
1.9.2009
Historická
1.4.2011
Historická
1.9.2009
Historická
1.10.2012
Historická
1.12.2011
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