ASTM C1258-21a

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

SIGNIFICANCE AND USE
5.1 On systems operating at sub-ambient temperature, humid ambient conditions cause a vapor driving force toward the insulation. If not retarded, the driven moisture vapor is detrimental to the insulation's thermal resistance. A vapor retarder must resist degradation in order maintain its resistance to vapor passage. Degradation in this test method is induced by elevated temperature and humidity conditions.
SCOPE
1.1 This test method covers the determination of the resistance of flexible low permeance vapor retarders for thermal insulation as classified in Specification C1136 to elevated temperature and humidity. 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 evaluated in this test method are intended for indoor use and include foil-scrim-kraft laminates, metallized polyester-scrim-kraft laminates, treated fabrics, treated papers, films, foils, or combinations of these materials that 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Aug-2021
• ICS: 91.100.50 - Binders. Sealing materials
• Technical Committee: C16 - Thermal Insulation
• Drafting Committee: C16.33 - Insulation Finishes and Moisture

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: C1258 − 21a
Standard Test Method for
Elevated Temperature and Humidity Resistance of Vapor
1
Retarders for Insulation
This standard is issued under the fixed designation C1258; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope C1136 Specification for Flexible, Low Permeance Vapor
Retarders for Thermal Insulation
1.1 This test method covers the determination of the resis-
E96/E96M Test Methods for Water Vapor Transmission of
tance of flexible low permeance vapor retarders for thermal
Materials
insulation as classified in Specification C1136 to elevated
temperature and humidity. Water vapor permeance measure-
3. Terminology
ment and visual inspection after exposure at elevated tempera-
3.1 Terminology C168 shall be considered as applying to
ture and humidity are used to assess vapor retarder response.
the terms used in this specification.
1.2 Typical vapor retarders evaluated in this test method are
intended for indoor use and include foil-scrim-kraft laminates,
4. Summary of Test Method
metallized polyester-scrim-kraft laminates, treated fabrics,
4.1 The vapor retarders are exposed to elevated temperature
treated papers, films, foils, or combinations of these materials
and humidity at 120°F (49°C) and 95 % relative humidity for
that comprise a vapor retarder material. This test method is not
a period of 28 days, then visually inspected for corrosion (if
intended for assessment of the liquid-applied coatings,
applicable), delamination, and other degradation. Water vapor
sealants, or mastics commonly used with insulation products.
permeance in accordance with Test Methods E96/E96M is
1.3 The values stated in inch-pound units are to be regarded
measured after elevated temperature and humidity exposure.
as standard. The values given in parentheses are mathematical
5. Significance and Use
conversions to SI units that are provided for information only
and are not considered standard.
5.1 On systems operating at sub-ambient temperature, hu-
1.4 This standard does not purport to address all of the
mid ambient conditions cause a vapor driving force toward the
safety concerns, if any, associated with its use. It is the insulation. If not retarded, the driven moisture vapor is
responsibility of the user of this standard to establish appro-
detrimental to the insulation’s thermal resistance. A vapor
priate safety, health, and environmental practices and deter-
retarder must resist degradation in order maintain its resistance
mine the applicability of regulatory limitations prior to use.
to vapor passage. Degradation in this test method is induced by
1.5 This international standard was developed in accor-
elevated temperature and humidity conditions.
dance with internationally recognized principles on standard-
6. Apparatus
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
6.1 Environmental Chamber, capable of maintaining an
mendations issued by the World Trade Organization Technical
average of 120 6 2°F (49 6 1°C) and 95 6 2 % relative
Barriers to Trade (TBT) Committee.
humidity, using distilled or deionized water as the humidity
source. The chamber shall be of the air-circulating variety.
2. Referenced Documents
2 6.2 Lighted Box, with five opaque sides and one transparent
2.1 ASTM Standards:
glass or plastic viewing side, illuminated with an incandescent
C168 Terminology Relating to Thermal Insulation
lightbulb. The viewing area shall be slightly smaller than the
vapor retarder specimen so that holes or degradation caused by
1
This test method is under the jurisdiction ofASTM Committee C16 on Thermal
the testing conditions are readily visible.
Insulation and is the direct responsibility of Subcommittee C16.33 on Insulation
Finishes and Moisture.
6.3 Darkroom.
Current edition approved Sept. 1, 2021. Published September 2021. Originally
approved in 1994. Last previous edition approved in 2021 as C1258 – 21. DOI:
6.4 Cotton Gloves.
10.1520/C1258-21A.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 6.5 Frame/holder of non-reacting material.
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
6.6 Support of non-reacting material from which to suspend
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. specimens.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshoh
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: C1258 − 21 C1258 − 21a
Standard Test Method for
Elevated Temperature and Humidity Resistance of Vapor
1
Retarders for Insulation
This standard is issued under the fixed designation C1258; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method covers the determination of the resistance of flexible low permeance vapor retarders for thermal insulation
as classified in Specification C1136 to elevated temperature and humidity. 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 evaluated in this test method are intended for indoor use and include foil-scrim-kraft laminates,
metallized polyester-scrim-kraft laminates, treated fabrics, treated papers, films, foils, or combinations of these materials that
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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2
2.1 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
3. Terminology
3.1 Terminology C168 shall be considered as applying to the terms used in this specification.
1
This test method is under the jurisdiction of ASTM Committee C16 on Thermal Insulation and is the direct responsibility of Subcommittee C16.33 on Insulation Finishes
and Moisture.
Current edition approved March 1, 2021Sept. 1, 2021. Published April 2021September 2021. Originally approved in 1994. Last previous edition approved in 20192021
as C1258 – 19.C1258 – 21. DOI: 10.1520/C1258-21.10.1520/C1258-21A.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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C1258 − 21a
4. Summary of Test Method
4.1 The vapor retarders are exposed to elevated temperature and humidity at 120°F (49°C) and 95 % relative humidity for a period
of 28 days, then visually inspected for corrosion (if applicable), delamination, and other degradation. Water vapor permeance in
accordance with Test Methods E96/E96M is measured after elevated temperature and humidity exposure.
5. Significance and Use
5.1 On systems operating at sub-ambient temperature, humid ambient conditions cause a vapor driving force toward the insulation.
If not retarded, the driven moisture vapor is detrimental to the insulation’s thermal resistance. A vapor retarder must resist
degradation in order maintain its resistance to vapor passage. Degradation in this test method is induced by elevated temperature
and humidity conditions.
6. Apparatus
6.1 Environmental Chamber, capable of maintaining an average of 120 6 2°F (49 6 1°C) and 95 6 2 % relative humidity, using
distilled or deionized water as the humidity source. The chamber shall be of the air-circulating variety.
6.2 Lighted Box, with five opaque sides and one transparent glass or plastic viewing side, illuminated with an incandescent
lightbulb. The viewing area shall be
...