ASTM C1258 - 08(2013)

    Standard Test Method for Elevated Temperature and Humidity Resistance of Vapor Retarders for Insulation

    Active Standard ASTM C1258 | Developed by Subcommittee: C16.33

    Book of Standards Volume: 04.06


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    ASTM C1258

    Significance and Use

    5.1 On sub-ambient temperature systems, humid ambient conditions cause a vapor driving force toward the insulation which, if not retarded, is detrimental to the insulation's thermal resistance. Therefore a vapor retarder should resist degradation. Degradation in this test method is induced by elevated temperature and humidity conditions.

    1. Scope

    1.1 This test method covers the determination of the aging resistance of flexible low permeance vapor retarders for thermal insulation as classified in Specification C1136. Water vapor permeance measurement and visual inspection after exposure at elevated temperature and humidity are used to assess vapor retarder response.

    1.2 Typical vapor retarders applicable to this test method that are intended for indoor use include foil-scrim-kraft laminates, metallized polyester-scrim-kraft laminates, treated fabrics, treated papers, films, foils, or combinations of these materials that may comprise a vapor retarder material. This test method is not intended for assessment of the liquid-applied coatings, sealants, or mastics commonly used with insulation products.

    1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.

    1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.


    2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

    ASTM Standards

    C168 Terminology Relating to Thermal Insulation

    C1136 Specification for Flexible, Low Permeance Vapor Retarders for Thermal Insulation

    E96/E96M Test Methods for Water Vapor Transmission of Materials


    ICS Code

    ICS Number Code 91.100.50 (Binders. Sealing materials)

    UNSPSC Code

    UNSPSC Code 30141500(Thermal insulation)


    DOI: 10.1520/C1258

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