ASTM C1136-23

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

ABSTRACT
This specification covers vapor retarders for thermal insulation, specifically, flexible materials with permeance and surface burning characteristics. Vapor retarders are classified based on vapor retardance and strength properties: Types I, II, III, IV, V, and VI. The following test methods shall be performed: water vapor permeance; surface burning characteristics; tensile strength; dimensional stability; fungi resistance; thermal integrity of flexible water vapor retarders; burst strength of vapor retarders; permanence of flame retardancy; and elevated temperature and humidity resistance of vapor retarders for insulation.
SIGNIFICANCE AND USE
9.1 Entrapment of water in thermal insulation caused by condensation of water vapor that has penetrated into the insulation is detrimental to the thermal resistance of the insulation. For this reason, in certain installations where temperature and moisture conditions have the potential to create a vapor driving force toward the insulation, a deterrent to the passage of such vapor into the installed insulation needs to be provided. This is the primary function of the vapor retarder.  
9.2 In addition to the function stated in 9.1, a vapor retarder has the potential to provide physical protection and added strength to the insulation system.  
9.3 This specification is used to specify material by physical property requirements that address the above prerequisites. The designer of an insulation system, after determining the degree of protection needed for the insulation, can use this specification to specify the appropriate type of vapor retarder when one is required.
SCOPE
1.1 This specification covers vapor retarders for thermal insulation, specifically, flexible materials with permeance of 0.15 perm (8.63 ng·Pa–1 · s–1 · m–2) or lower and surface burning characteristics of 25 flame spread/50 smoke or lower. These materials are intended for use at surface temperatures of −20 to 150°F (−29 to 66°C). It does not cover mastics or barrier coatings applied in liquid form, nor materials intended for use as weather barriers.  
1.2 This is a material specification and does not imply that an installed system using these materials will provide the physical properties specified in Section 6.  
1.3 This specification provides physical requirements for vapor retarders. Practice C755 provides assistance in solving problems related to moisture vapor transmission through thermal insulation materials.  
1.4 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.  
1.5 The following precautionary caveat pertains to the test methods portion only, Section 10, of this specification: 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.  
1.6 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: 28-Feb-2023
• ICS: 91.100.60 - Thermal and sound insulating materials
• Technical Committee: C16 - Thermal Insulation
• Drafting Committee: C16.33 - Insulation Finishes and Moisture

Relations

• Refers: ASTM C168-24 - Standard Terminology Relating to Thermal Insulation
• Effective Date: 15-Apr-2024
• Refers: ASTM E96/E96M-24 - Standard Test Methods for Gravimetric Determination of Water Vapor Transmission Rate of Materials
• Effective Date: 01-Mar-2024
• Refers: ASTM E84-23d - Standard Test Method for Surface Burning Characteristics of Building Materials
• Effective Date: 01-Dec-2023
• Refers: ASTM E96/E96M-23 - Standard Test Methods for Gravimetric Determination of Water Vapor Transmission Rate of Materials
• Effective Date: 15-Nov-2023
• Refers: ASTM E84-23c - Standard Test Method for Surface Burning Characteristics of Building Materials
• Effective Date: 01-Sep-2023
• Refers: ASTM D1204-14(2020) - Standard Test Method for Linear Dimensional Changes of Nonrigid Thermoplastic Sheeting or Film at Elevated Temperature
• Effective Date: 01-Apr-2020
• Refers: ASTM C755-20 - Standard Practice for Selection of Water Vapor Retarders for Thermal Insulation
• Effective Date: 01-Mar-2020
• Refers: ASTM C755-19b - Standard Practice for Selection of Water Vapor Retarders for Thermal Insulation
• Effective Date: 15-Oct-2019
• Refers: ASTM C755-19a - Standard Practice for Selection of Water Vapor Retarders for Thermal Insulation
• Effective Date: 01-Sep-2019
• Refers: ASTM E84-19b - Standard Test Method for Surface Burning Characteristics of Building Materials
• Effective Date: 01-Jul-2019
• Refers: ASTM E84-19a - Standard Test Method for Surface Burning Characteristics of Building Materials
• Effective Date: 15-Apr-2019
• Refers: ASTM C755-19 - Standard Practice for Selection of Water Vapor Retarders for Thermal Insulation
• Effective Date: 15-Apr-2019
• Refers: ASTM C1878-19 - Standard Test Method for Surface Water Resistance of Vapor Retarders for Thermal Insulation
• Effective Date: 01-Apr-2019
• Refers: ASTM E84-19 - Standard Test Method for Surface Burning Characteristics of Building Materials
• Effective Date: 01-Mar-2019
• Refers: ASTM E84-18b - Standard Test Method for Surface Burning Characteristics of Building Materials
• Effective Date: 01-Oct-2018

Overview

ASTM C1136-23: Standard Specification for Flexible, Low Permeance Vapor Retarders for Thermal Insulation provides requirements for flexible vapor retarder materials used in thermal insulation systems. Developed by ASTM International, this specification ensures that vapor retarders offer reliable protection against water vapor transmission, enhancing the longevity and effectiveness of insulation by minimizing the risk of condensation and thermal degradation. The standard covers physical properties, classification, test methods, and product marking for a wide range of vapor retarders suitable for use at surface temperatures from -20°F to 150°F (-29°C to 66°C).

Key Topics

• Material Scope:
  Covers flexible vapor retarder materials with a permeance of 0.15 perm (8.63 ng·Pa–1·s–1·m–2) or lower, designed to meet strict limits on surface burning (flame spread ≤ 25, smoke ≤ 50). Excludes mastics, barrier coatings, and weather barriers.

• Classification:
  Vapor retarders are classified by vapor permeance and physical strength properties (Types I–VI).

• Physical Property Requirements:

  • Water vapor permeance
  • Surface burning characteristics
  • Tensile strength
  • Dimensional stability
  • Fungi resistance
  • Thermal integrity
  • Burst strength
  • Flame retardance permanence
  • Elevated temperature and humidity resistance
  • Water resistance for some types

• Testing and Certification:
  Physical properties are verified through standardized test methods, such as ASTM E96/E96M for permeance, ASTM E84 for burning characteristics, and ASTM D882/D828 for tensile strength. Certification of compliance may be required for procurement.

• Marking and Packaging:
  Specifies requirements for product labeling, including manufacturer identification, product designation, dimensions, lot number, and optional conformance statements.

Applications

ASTM C1136-compliant vapor retarders are critical in insulating systems where moisture control is vital. Typical applications include:

• Building Thermal Insulation:
  Used in walls, ceilings, attics, crawlspaces, and mechanical systems to prevent moisture ingress that could degrade insulation performance.

• Industrial Facilities:
  Protects process and mechanical insulation from water vapor, preserving thermal efficiency and system integrity in plants and refineries.

• HVAC Applications:
  Ensures ductwork insulation remains dry, reducing risk of mold and maintaining energy efficiency.

• Cold Storage, Food Processing, and Cleanrooms:
  Employs vapor retarders to safeguard insulation in environments with stringent humidity control requirements.

By maintaining vapor barrier integrity, systems designed with ASTM C1136 vapor retarders help prevent condensation, inhibit mold and fungal growth, and protect building materials.

Related Standards

• ASTM C168: Terminology Relating to Thermal Insulation
• ASTM C755: Practice for Selection of Water Vapor Retarders for Thermal Insulation
• ASTM E84: Test Method for Surface Burning Characteristics of Building Materials
• ASTM E96/E96M: Test Methods for Water Vapor Transmission Rate of Materials
• ASTM D882/D828: Test Methods for Tensile Properties of Plastic Sheeting and Paper
• ASTM C1263, C1338, C1258, C1878: Additional test methods for integrity, fungi resistance, elevated temperature/humidity resistance, and surface water resistance

ASTM C1136-23 supports industry best practices for moisture control in insulation, helping specifiers, contractors, and facility managers choose compliant materials for durable, high-performance insulation systems. For optimized protection and compliance, it is recommended to use this standard in conjunction with ASTM C755 and relevant test methods.

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: C1136 − 23
Standard Specification for
Flexible, Low Permeance Vapor Retarders for Thermal
Insulation
This standard is issued under the fixed designation C1136; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope 2. Referenced Documents
1.1 This specification covers vapor retarders for thermal
2.1 ASTM Standards:
insulation, specifically, flexible materials with permeance of
C168 Terminology Relating to Thermal Insulation
–1 –1 –2
0.15 perm (8.63 ng·Pa · s · m ) or lower and surface
C755 Practice for Selection of Water Vapor Retarders for
burning characteristics of 25 flame spread/50 smoke or lower.
Thermal Insulation
These materials are intended for use at surface temperatures
D774/D774M Test Method for Bursting Strength of Paper
of −20 to 150°F (−29 to 66°C). It does not cover mastics or 3
(Withdrawn 2010)
barrier coatings applied in liquid form, nor materials intended
C1258 Test Method for Elevated Temperature and Humidity
for use as weather barriers.
Resistance of Vapor Retarders for Insulation
1.2 This is a material specification and does not imply that
C1263 Test Method for Thermal Integrity of Flexible Water
an installed system using these materials will provide the
Vapor Retarders
physical properties specified in Section 6.
C1338 Test Method for Determining Fungi Resistance of
Insulation Materials and Facings
1.3 This specification provides physical requirements for
vapor retarders. Practice C755 provides assistance in solving C1878 Test Method for Surface Water Resistance of Vapor
problems related to moisture vapor transmission through ther- Retarders for Thermal Insulation
mal insulation materials. D828 Test Method for Tensile Properties of Paper and
Paperboard Using Constant-Rate-of-Elongation Apparatus
1.4 The values stated in inch-pound units are to be regarded
D882 Test Method for Tensile Properties of Thin Plastic
as standard. The values given in parentheses are mathematical
Sheeting
conversions to SI units that are provided for information only
D1204 Test Method for Linear Dimensional Changes of
and are not considered standard.
Nonrigid Thermoplastic Sheeting or Film at Elevated
1.5 The following precautionary caveat pertains to the test
Temperature
methods portion only, Section 10, of this specification: This
E84 Test Method for Surface Burning Characteristics of
standard does not purport to address all of the safety concerns,
Building Materials
if any, associated with its use. It is the responsibility of the user
E96/E96M Test Methods for Gravimetric Determination of
of this standard to establish appropriate safety, health, and
Water Vapor Transmission Rate of Materials
environmental practices and determine the applicability of
regulatory limitations prior to use.
2.2 TAPPI Standards:
1.6 This international standard was developed in accor-
T461 Flame Resistance of Treated Paper and Paperboard
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
3. Terminology
Development of International Standards, Guides and Recom-
3.1 Definitions—Definitions in Terminology C168 apply to
mendations issued by the World Trade Organization Technical
terms used in this specification.
Barriers to Trade (TBT) Committee.
1 2
This specification is under the jurisdiction of ASTM Committee C16 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Thermal Insulation and is the direct responsibility of Subcommittee C16.33 on contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Insulation Finishes and Moisture. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved March 1, 2023. Published March 2023. Originally the ASTM website.
approved in 1990. Last previous edition approved in 2021 as C1136 – 21. DOI: The last approved version of this historical standard is referenced on
10.1520/C1136-23. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1136 − 23
4. Classification 6.5 All type vapor retarders shall not sustain growth of fungi
when tested in accordance with 10.5.
4.1 Classification of vapor retarders, with the exception of
Type IX, is based on physical properties. 6.6 All type vapor retarders shall not crack or delaminate at
4.1.1 Type IX, in addition to physical property temperatures from −20 to 150°F (−29 to 66°C) when tested in
requirements, has specific structural requirements. accordance with 10.6.
4.2 Physical property requirements are listed in Table 1. 6.7 Minimum burst strength for a specific type vapor
retarder shall be as shown in Table 1 when tested in accordance
5. Materials and Manufacture
with 10.7.
5.1 Vapor retarders, with the exception of Type IX, are 6.8 Vapor retarders containing paper or paper products shall
constructed of various films, metallic foils, fabrics, papers and
not demonstrate an increase in char length of more than 20 %
reinforcements, alone or in combination as a lamination. when tested in accordance with 10.8.
5.2 Metallic foils, the most commonly used being aluminum
6.9 All type vapor retarders shall not corrode or delaminate,
of a minimum gauge, are the only materials expected to nor demonstrate, after exposure, a permeance greater than the
provide the impermeable component in a vapor retarder maximum allowable for the type being tested, when tested in
required for Type IX. accordance with 10.9.
5.2.1 Type IX vapor retarders must contain at a minimum
6.10 Maximum water weight per area absorbed by the
the following components in the structure:
service-exposed side of Type VII-X vapor retarders shall be as
5.2.2 One layer of metallic foil with a minimum thickness of
shown in Table 1 when tested for surface water resistance in
0.00095 in. (24.1μ) or
accordance with 10.10.
5.2.3 Multiple layers of metallic foil with a cumulative
minimum thickness of 0.0012 in. (30.5μ)
7. Dimensions, Mass, and Permissible Variations
5.2.4 A fully laminated, continuous protective substrate on
7.1 Dimensions for roll or sheeted materials shall be as
at least one side of the foil layers
specified by the purchaser.
5.3 Types VII-X vapor retarders contain water resistant
7.2 Tolerance for roll materials shall be 6 ⁄8 in. (63 mm) on
outer surfaces.
width and +5, −0 % on length.
6. Physical Properties
7.3 Tolerance for sheeted materials shall be 6 ⁄8 in. (63
mm) on length and width.
6.1 Maximum permeance for a specific type vapor retarder
shall be as shown in Table 1 when tested in accordance with
8. Workmanship, Finish, and Appearance
10.1. Values for permeance requirements are rounded to two
decimals. 8.1 There shall be no defects in materials or workmanship
that will affect the required performance of the vapor retarder.
6.2 All vapor retarders shall demonstrate a flame spread of
25 or less and smoke developed of 50 or less when testing the 8.2 There shall be no defects that adversely affect the
finish side (the side opposite that contacting the insulation) in
appearance of the vapor retarder.
accordance with 10.2.
8.3 There shall be no defects that would affect ability of user
6.3 Minimum tensile strength for a specific type vapor
to process material.
retarder shall be as shown in Table 1 when tested in accordance
with 10.3. 9. Significance and Use
6.4 Maximum dimensional change for a specific type vapor 9.1 Entrapment of water in thermal insulation caused by
retarder shall be as shown in Table 1, when tested in accor- condensation of water vapor that has penetrated into the
dance with 10.4. insulation is detrimental to the thermal resistance of the
TABLE 1 Physical Property Requirements
Physical Properties Type I Type II Type III Type IV Type V Type VI Type VII Type VIII Type IX Type X
Permeance, max 0.02 (1.15) 0.02 (1.15) 0.10 (5.75) 0.10 (5.75) 0.15 (8.63) 0.15 (8.63) 0.01 (0.58) 0.02 (1.15) 0.00 (0.00) 0.01 (0.58)
−1 −1 −2
Perms (ng·Pa · s · m )
Burst Strength, min 55 (380) 35 (240) 55 (380) 35 (240) 55 (380) 35 (240) 70 (483) 60 (414) 80 (552) 75 (518)
psi (kPa)
Tensile, Machine Direction 45 (7.9) 30 (5.3) 45 (7.9) 30 (5.3) 45 (7.9) 30 (5.3) 11 (1.9) 8 (1.4) 25 (4.4) 60 (10.5)
lb/in. width, min (N/mm width, min)
Tensile, Cross Direction 30 (5.3) 20 (3.5) 30 (5.3) 20 (3.5) 30 (5.3) 20 (3.5) 10 (1.7) 7 (1.2) 25 (4.4) 50 (8.8)
lb/in. width, min (N/mm width, min)
Dimensional Change, max 0.50 0.50 0.50 0.50 0.50 0.50 1 1 0.5 0.5
percent
Surface Water Resistance, n/a n/a n/a n/a n/a n/a 2.0 2.0 2.0 2.0
max. g/m
...

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: C1136 − 21 C1136 − 23
Standard Specification for
Flexible, Low Permeance Vapor Retarders for Thermal
Insulation
This standard is issued under the fixed designation C1136; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope
1.1 This specification covers vapor retarders for thermal insulation, specifically, flexible materials with permeance of 0.15 perm
–1 –1 –2
(8.63 ng·Pa · s · m ) or lower and surface burning characteristics of 25 flame spread/50 smoke or lower. These materials are
intended for use at surface temperatures of −20 to 150°F (−29 to 66°C). It does not cover mastics or barrier coatings applied in
liquid form, nor materials intended for use as weather barriers.
1.2 This is a material specification and does not imply that an installed system using these materials will provide the physical
properties specified in Section 6.
1.3 This specification provides physical requirements for vapor retarders. Practice C755 provides assistance in solving problems
related to moisture vapor transmission through thermal insulation materials.
1.4 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.
1.5 The following precautionary caveat pertains to the test methods portion only, Section 10, of this specification: 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.
1.6 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
2.1 ASTM Standards:
C168 Terminology Relating to Thermal Insulation
C755 Practice for Selection of Water Vapor Retarders for Thermal Insulation
D774/D774M Test Method for Bursting Strength of Paper (Withdrawn 2010)
This specification 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, 2021March 1, 2023. Published March 2021March 2023. Originally approved in 1990. Last previous edition approved in 20172021 as
C1136 – 17a.C1136 – 21. DOI: 10.1520/C1136-21.10.1520/C1136-23.
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.
The last approved version of this historical standard is referenced on www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1136 − 23
C1258 Test Method for Elevated Temperature and Humidity Resistance of Vapor Retarders for Insulation
C1263 Test Method for Thermal Integrity of Flexible Water Vapor Retarders
C1338 Test Method for Determining Fungi Resistance of Insulation Materials and Facings
C1878 Test Method for Surface Water Resistance of Vapor Retarders for Thermal Insulation
D828 Test Method for Tensile Properties of Paper and Paperboard Using Constant-Rate-of-Elongation Apparatus
D882 Test Method for Tensile Properties of Thin Plastic Sheeting
D1204 Test Method for Linear Dimensional Changes of Nonrigid Thermoplastic Sheeting or Film at Elevated Temperature
D3285 Test Method for Water Absorptiveness of Nonbibulous Paper and Paperboard (Cobb Test) (Withdrawn 2010)
E84 Test Method for Surface Burning Characteristics of Building Materials
E96/E96M Test Methods for Gravimetric Determination of Water Vapor Transmission Rate of Materials
2.2 TAPPI Standards:
T461 Flame Resistance of Treated Paper and Paperboard
3. Terminology
3.1 Definitions—Definitions in Terminology C168 apply to terms used in this specification.
4. Classification
4.1 Classification of vapor retarders, with the exception of Type IX, is based on physical properties.
4.1.1 Type IX, in addition to physical property requirements, has specific structural requirements.
4.2 Physical property requirements are listed in Table 1.
5. Materials and Manufacture
5.1 Vapor retarders, with the exception of Type IX, are constructed of various films, metallic foils, fabrics, papers and
reinforcements, alone or in combination as a lamination.
5.2 Metallic foils, the most commonly used being aluminum of a minimum gauge, are the only materials expected to provide the
impermeable component in a vapor retarder required for Type IX.
5.2.1 Type IX vapor retarders must contain at a minimum the following components in the structure:
5.2.2 One layer of metallic foil with a minimum thickness of 0.00095 in. (24.1μ) or
5.2.3 Multiple layers of metallic foil with a cumulative minimum thickness of 0.0012 in. (30.5μ)
5.2.4 A fully laminated, continuous protective substrate on at least one side of the foil layers
5.3 Types VII-X vapor retarders contain water resistant outer surfaces.
TABLE 1 Physical Property Requirements
Physical Properties Type I Type II Type III Type IV Type V Type VI Type VII Type VIII Type IX Type X
Permeance, max 0.02 (1.15) 0.02 (1.15) 0.10 (5.75) 0.10 (5.75) 0.15 (8.63) 0.15 (8.63) 0.01 (0.58) 0.02 (1.15) 0.00 (0.00) 0.01 (0.58)
−1 −1 −2
Perms (ng·Pa · s · m )
Burst Strength, min 55 (380) 35 (240) 55 (380) 35 (240) 55 (380) 35 (240) 70 (483) 60 (414) 80 (552) 75 (518)
psi (kPa)
Tensile, Machine Direction 45 (7.9) 30 (5.3) 45 (7.9) 30 (5.3) 45 (7.9) 30 (5.3) 11 (1.9) 8 (1.4) 25 (4.4) 60 (10.5)
lb/in. width, min (N/mm width, min)
Tensile, Cross Direction 30 (5.3) 20 (3.5) 30 (5.3) 20 (3.5) 30 (5.3) 20 (3.5) 10 (1.7) 7 (1.2) 25 (4.4) 50 (8.8)
lb/in. width, min (N/mm width, min)
Dimensional Change, max 0.50 0.50 0.50 0.50 0.50 0.50 1 1 0.5 0.5
percent
Surface Water Resistance, n/a n/a n/a n/a n/a n/a 2.0 2.0 2.0 2.0
max. g/m water absorption
C1136 − 23
6. Physical Properties
6.1 Maximum permeance for a specific type vapor retarder shall be as shown in Table 1 when tested in accordance with 10.1.
Values for permeance requirements are rounded to two decimals.
6.2 All vapor retarders shall demonstrate a flame spread of 25 or less and smoke developed of 50 or less when testing the finish
side (the side opposite that contacting the insulation) in accordance with 10.2.
6.3 Minimum tensile strength for a specific type vapor retarder shall be as shown in Table 1 when tested in accordance with 10.3.
6.4 Maximum dimensional change for a specific type vapor retarder shall be as shown in Table 1, when tested in accordance with
10.4.
6.5 All type vapor retarders shall not sustain growth of fungi when tested in accordance with 10.5.
6.6 All type vapor retarders shall not crack or delaminate at temperatures from −20 to 150°F (−29 to 66°C) when tested in
accordance with 10.6.
6.7 Minimum burst strength for a specific type vapor retarder shall be as shown in Table 1 when tested in accordance with 10.7.
6.8 Vapor retarders containing paper or paper products shall not demonstrate an increase in char length of more than 20 % when
tested in accordance with 10.8.
6.9 All type vapor retarders shall not corrode or delaminate, nor demonstrate, after exposure, a permeance greater than the
maximum allowable for the type being tested, when tested in accordance with 10.9.
6.10 Maximum water weight per area absorbed by the service-exposed side of Type VII-X vapor retarders shall be as shown in
Table 1 when tested for surface water resistance in accordance with 10.10.
7. Dimensions, Mass, and Permissible Variations
7.1 Dimensions for roll or sheeted materials shall be as specified by the purchaser.
7.2 Tolerance for roll materials shall be 6 ⁄8 in. (63 mm) on width and +5, −0 % on length.
7.3 Tolerance for sheeted materials shall be 6 ⁄8 in. (63 mm) on length and width.
8. Workmanship, Finish, and Appearance
8.1 There shall be no defects in materials or workmanship that will affect the required performance of the vapor retarder.
8.2 There shall be no defects that adversely affect the appearance of the vapor retarder.
8.3 There shall be no defects that would affect ability of user to process material.
9. Significance and Use
9.1 Entrapment of water in thermal insulati
...