ASTM C665-23

Standard Specification for Mineral-Fiber Blanket Thermal Insulation for Light Frame Construction and Manufactured Housing

ABSTRACT
This specification covers the composition and physical properties of mineral-fiber blanket insulation used to thermally or acoustically insulate ceilings, floors, and walls in light frame construction and manufactured housing. The requirements cover fibrous blankets and facings. Typical mineral-fiber thermal insulation is classified into the following types, classes, and categories: Type I; Type II (Class A, Class B, and Class C (Category 1 and Category 2)); and Type III (Class A, Class B, and Class C (Category 1 and Category 2)). The following test methods shall be performed: dimensions; thermal resistance; surface burning characteristics; critical radiant flux; water vapor permeance; water vapor sorption; odor emission; corrosiveness; and fungi resistance.
SIGNIFICANCE AND USE
11.1 This specification applies to products that are used in buildings. While products that comply with this specification are used in various constructions, they are adaptable primarily, but not exclusively, to wood frame construction.  
11.2 Since the property of thermal resistance for a specific thickness of blanket is only part of the total thermal performance of a building element such as a wall, ceiling, floor, and so forth, this specification states only general classifications for thermal resistance of the fibrous blanket itself. Facings that provide additional resistance to water-vapor transfer can affect system performance.
SCOPE
1.1 This specification covers the composition and physical properties of mineral-fiber blanket insulation used to thermally or acoustically insulate ceilings, floors, and walls in light frame construction and manufactured housing. The requirements cover fibrous blankets and facings. Values for water-vapor permeance of facings are suggested for information that will be helpful to designers and installers.  
1.2 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.  
1.3 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.  
1.4 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: 30-Apr-2023
• ICS: 27.220 - Heat recovery. Thermal insulation
• Technical Committee: C16 - Thermal Insulation
• Drafting Committee: C16.23 - Blanket and Loose Fill Insulation

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 C390-08(2024) - Standard Practice for Sampling and Acceptance of Thermal Insulation Lots
• 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 E970-23 - Standard Test Method for Critical Radiant Flux of Exposed Attic Floor Insulation Using a Radiant Heat Energy Source
• Effective Date: 01-Oct-2023
• Refers: ASTM E84-23c - Standard Test Method for Surface Burning Characteristics of Building Materials
• Effective Date: 01-Sep-2023
• Refers: ASTM B152/B152M-19 - Standard Specification for Copper Sheet, Strip, Plate, and Rolled Bar
• Effective Date: 01-Oct-2019
• Refers: ASTM C390-08(2019) - Standard Practice for Sampling and Acceptance of Thermal Insulation Lots
• Effective Date: 01-Sep-2019
• Refers: ASTM C1104/C1104M-19 - Standard Test Method for Determining the Water Vapor Sorption of Unfaced Mineral Fiber 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 C1617-19 - Standard Practice for Quantitative Accelerated Laboratory Evaluation of Extraction Solutions Containing Ions Leached from Thermal Insulation on Aqueous Corrosion of Metals
• Effective Date: 01-May-2019
• Refers: ASTM E84-19a - Standard Test Method for Surface Burning Characteristics of Building Materials
• Effective Date: 15-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 C665-23, developed by ASTM International, is the standard specification for mineral-fiber blanket thermal insulation used in light frame construction and manufactured housing. This standard establishes material composition, physical properties, and performance requirements for mineral-fiber insulation products designed to provide thermal and/or acoustic insulation in ceilings, floors, and walls. The document includes guidelines for both the fibrous blankets and their facings, ensuring reliable and safe application in residential and commercial building envelopes.

Key Topics

• Material Composition: Specifies that mineral-fiber insulation must be made from fibrous materials derived from rock, slag, or glass.
• Product Classification:
  • Type I: Blankets without facings
  • Type II: Blankets with non-reflective facings (multiple classes/categories for flame spread and vapor permeance)
  • Type III: Blankets with reflective facings (multiple classes/categories)
• Physical and Performance Requirements:
  • Thermal Resistance (R-value): Must meet stated R-values; R-value testing follows ASTM C177 or C518.
  • Surface Burning Characteristics: Blankets must display limited flame spread and smoke development when tested under ASTM E84.
  • Critical Radiant Flux: Minimum radiant flux required for specified applications, tested per ASTM E970.
  • Water Vapor Permeance/Sorption: Values for vapor permeance of facings and vapor sorption by insulation, following ASTM E96 and C1104.
  • Odor Emission: Insulation must not emit objectionable odors, as verified by professional panels per ASTM C1304.
  • Corrosiveness: Tested on steel, copper, and aluminum to ensure no detrimental corrosion effects, following procedures including ASTM C1617 and comparative control methods.
  • Fungi Resistance: Assessed per ASTM C1338 to ensure product does not promote fungal growth.
• Dimensional Tolerances and Workmanship: Defines limits for length, width, and thickness; requires materials free of defects and capable of installation to maintain performance.
• Product Marking and Packaging: Mandates clear labeling of R-value, thickness, and facing type, with additional requirements if flame spread ratings are not printed.

Applications

Mineral-fiber blanket thermal insulation in compliance with ASTM C665-23 is primarily used in:

• Light Frame Construction: Ideal for wood or steel stud wall assemblies, ceilings, and floor systems in new builds or renovations.
• Manufactured Housing: Commonly installed in residential modules, mobile homes, and prefabricated buildings.
• Acoustic and Thermal Barriers: Provides both sound attenuation and thermal performance in a single product.
• Versatile Installations: Suitable for both exposed and concealed spaces, depending on the class and type of facing, ensuring flexibility in design and installation.

This standard supports building professionals with essential guidelines for selecting, specifying, and installing mineral-fiber blankets to achieve energy efficiency, code compliance, and occupant comfort.

Related Standards

The performance and testing of mineral-fiber blanket insulation according to ASTM C665-23 often references other ASTM standards, including:

• ASTM C167: Thickness and Density Measurements
• ASTM C168: Thermal Insulation Terminology
• ASTM C177 & C518: Thermal Transmission Properties Testing
• ASTM C653: Thermal Resistance of Low-Density Blanket Insulation
• ASTM E84: Surface Burning Characteristics
• ASTM E96/E96M: Water Vapor Transmission Rate
• ASTM E970: Critical Radiant Flux for Floor Insulation
• ASTM C1104/C1104M: Water Vapor Sorption
• ASTM C1304: Odor Emission Assessment
• ASTM C1338: Fungi Resistance Testing
• ASTM B152/B152M: Copper Specifications for Corrosion Testing
• ASTM G1: Corrosion Specimen Preparation

These related standards ensure comprehensive quality control, product reliability, and safety for insulation used in diverse building projects.

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Keywords: mineral-fiber blanket, insulation, ASTM C665-23, light frame construction, manufactured housing, thermal insulation, acoustic insulation, thermal resistance, vapor retarder, building materials standards

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: C665 − 23
Standard Specification for
Mineral-Fiber Blanket Thermal Insulation for Light Frame
Construction and Manufactured Housing
This standard is issued under the fixed designation C665; 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 C177 Test Method for Steady-State Heat Flux Measure-
ments and Thermal Transmission Properties by Means of
1.1 This specification covers the composition and physical
the Guarded-Hot-Plate Apparatus
properties of mineral-fiber blanket insulation used to thermally
C390 Practice for Sampling and Acceptance of Thermal
or acoustically insulate ceilings, floors, and walls in light frame
Insulation Lots
construction and manufactured housing. The requirements
C518 Test Method for Steady-State Thermal Transmission
cover fibrous blankets and facings. Values for water-vapor
Properties by Means of the Heat Flow Meter Apparatus
permeance of facings are suggested for information that will be
C653 Guide for Determination of the Thermal Resistance of
helpful to designers and installers.
Low-Density Blanket-Type Mineral Fiber Insulation
1.2 The values stated in inch-pound units are to be regarded
C1104/C1104M Test Method for Determining the Water
as standard. The values given in parentheses are mathematical
Vapor Sorption of Unfaced Mineral Fiber Insulation
conversions to SI units that are provided for information only
C1304 Test Method for Assessing the Odor Emission of
and are not considered standard.
Thermal Insulation Materials
1.3 This standard does not purport to address all of the C1338 Test Method for Determining Fungi Resistance of
safety concerns, if any, associated with its use. It is the
Insulation Materials and Facings
responsibility of the user of this standard to establish appro- C1617 Practice for Quantitative Accelerated Laboratory
priate safety, health, and environmental practices and deter-
Evaluation of Extraction Solutions Containing Ions
mine the applicability of regulatory limitations prior to use. Leached from Thermal Insulation on Aqueous Corrosion
1.4 This international standard was developed in accor-
of Metals
dance with internationally recognized principles on standard- E84 Test Method for Surface Burning Characteristics of
ization established in the Decision on Principles for the Building Materials
Development of International Standards, Guides and Recom-
E96/E96M Test Methods for Gravimetric Determination of
mendations issued by the World Trade Organization Technical Water Vapor Transmission Rate of Materials
Barriers to Trade (TBT) Committee.
E970 Test Method for Critical Radiant Flux of Exposed Attic
Floor Insulation Using a Radiant Heat Energy Source
2. Referenced Documents
G1 Practice for Preparing, Cleaning, and Evaluating Corro-
sion Test Specimens
2.1 ASTM Standards:
B152/B152M Specification for Copper Sheet, Strip, Plate,
3. Terminology
and Rolled Bar
C167 Test Methods for Thickness and Density of Blanket or
3.1 Definitions—For definitions of terms used in this
Batt Thermal Insulations
specification, see Terminology C168.
C168 Terminology Relating to Thermal Insulation
4. Classification
This specification is under the jurisdiction of ASTM Committee C16 on
4.1 Typical mineral-fiber thermal insulation is classified into
Thermal Insulation and is the direct responsibility of Subcommittee C16.23 on
the following types, classes, and categories:
Blanket and Loose Fill Insulation.
4.1.1 Type I—Blankets without facings.
Current edition approved May 1, 2023. Published June 2023. Originally
4.1.2 Type II—Blankets with nonreflective facings.
approved in 1970. Last previous edition approved in 2017 as C665 – 17. DOI:
10.1520/C0665-23.
4.1.2.1 Class A—Facing with a flame spread index of 25 or
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
less.
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
(1) Category 1—Facing is a vapor retarder.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. (2) Category 2—Facing is not a vapor retarder.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C665 − 23
4.1.2.2 Class B—Facing with a flame propagation resis- 7. Physical Properties
2 2
tance; critical radiant flux of 0.12 W/cm (.11 Btu/ft ·s) or
7.1 Thermal Resistance—The standard thermal resistance
greater. 2 2
values in °F · h · ft /Btu (K · m /W) are: 4, 7, 11, 13, 19, 22,
(1) Category 1—Facing is a vapor retarder.
30, and 38 (0.7, 1.2, 1.9, 2.3, 3.3, 3.9, 5.3, and 6.7). R values
(2) Category 2—Facing is not a vapor retarder.
other than those listed shall be agreed upon between the
4.1.2.3 Class C—Facing not rated for flame propagation
supplier and the purchaser. The product must be produced to
resistance (for use in nonexposed applications only).
the label R value. The thermal resistance, R, for the average of
(1) Category 1—Facing is a vapor retarder.
any four randomly selected samples shall not be more than 5 %
(2) Category 2—Facing is not a vapor retarder.
below the listed R value when tested in accordance with 13.2,
4.1.3 Type III—Blankets with reflective facings:
nor shall any single specimen be more than 10 % below the
4.1.3.1 Class A—Facing with a flame spread index of 25 or
listed R value.
less.
7.2 Surface Burning Characteristics:
(1) Category 1—Facing is a vapor retarder.
7.2.1 Insulation blankets exclusive of facing, when tested in
(2) Category 2—Facing is not a vapor retarder.
accordance with Test Method E84, shall have a flame spread
4.1.3.2 Class B—Facing with a flame propagation resis-
2 2
index no greater than 25, and a smoke developed index no
tance; critical radiant flux of 0.12 W/cm (.11 Btu/ft ·s) or
greater than 50.
greater.
7.2.2 Insulation blankets with facings intended for exposed
(1) Category 1—Facing is a vapor retarder.
application, when tested in accordance with Test Method E84,
(2) Category 2—Facing is not a vapor retarder.
shall have a flame spread index no greater than 25, and a smoke
4.1.3.3 Class C—Facing not rated for flame propagation
developed index no greater than 50.
resistance (for use in nonexposed applications only).
(1) Category 1—Facing is a vapor retarder.
7.3 Critical Radiant Flux—Insulation blankets, when tested
(2) Category 2—Facing is not a vapor retarder.
in accordance with 13.4, shall have a critical radiant flux-flame
2 2
propagation resistance ≥0.12 W/cm (0.11 Btu/ft ·s). Blankets
4.2 Mechanically attached field installed facing shall be
with facing on both surfaces, shall be tested on the surface to
classified into Type/Class/Category as follows:
be left exposed and shall be marked on either surface.
(1) Type I insulation used in conjunction with a field
installed non-reflective facing having a 25 flame spread or less
7.4 Water-Vapor Permeance—When tested in accordance
on both sides is considered functionally equivalent to a Type
with 13.5, vapor retardant facings shall have a vapor per-
II/Class A/Category 1 insulation composite.
meance of no more than 1 perm
−11 −1 −1 –2
(2) Type I insulation used in conjunction with a field-
(5.7 × 10 kg·Pa ·s ·m ) and vapor-permeable facing shall
installed perforated, or vapor breathable, nonreflective facing
have a vapor permeance of no less than 5 perm
−10
−1 −1 −2
having a 25 flame spread or less on both sides is considered
(2.9 × 10 kg·Pa ·s ·m ).
functionally equivalent to Type II/Class A/Category 2 insula-
7.5 Water Vapor Sorption—The water vapor sorption of the
tion composite.
insulation without facing shall be not more than 5 % by weight,
(3) Type I insulation used in conjunction with a field-
when tested in accordance with 13.6.
installed reflective facing (reflective side exposed) having a 25
flame spread or less on both sides is considered equivalent to
7.6 Odor Emission—A detectable odor of strong objection-
a Type III/Class A/Category 1 insulation composite.
able nature recorded by more than two of the five panel
(4) Type I insulation used in conjunction with a field-
members shall constitute rejection of the material when tested
installed perforated, or vapor breathable, reflective facing
in accordance with 13.7.
(reflective side exposed) having a 25 flame spread or less on
7.7 Corrosiveness:
both sides is considered functionally equivalent to a Type
7.7.1 When tested in accordance with 13.8, the metal plates
III/Class A/Category 2 insulation composite.
in contact with the insulation shall show no corrosion greater
than that observed on the comparative plates in contact with
5. Ordering Information
sterile cotton.
5.1 For specific installations, thermal resistance, length,
7.7.2 Alternative test – Steel only—When tested in accor-
width, and facing suited to the intended use shall be specified
dance with 13.9, the mass loss corrosion rate of the unfaced
by the purchaser.
insulation extract shall not exceed that of the 5-ppm chloride
solution.
6. Materials and Manufacture
NOTE 1—The use of alternative metals such as copper and aluminum
6.1 Basic Material—The basic material shall be fibers made
have been evaluated using Practice C1617. The task group will continue
from mineral substances such as rock, slag, or glass processed
to investigate the potential for using Practice C1617 as an alternative to
from the molten state into a fibrous form.
7.7.1 for these metals.
NOTE 2—The pass/fail criteria established in section 7.7.2 is for
6.2 Manufacture—Insulation blankets shall consist of flex-
materials which claim compliance with Specification C665. The corrosion
ible units composed of felted, bonded, or unbonded fibers
procedure as detailed in 7.7.1 is referenced in multiple Mineral Fiber
formed into rolls or flat cut pieces (batts), with or without
material standards. The use of the alternative procedure and the establish-
various adhered facings, and with or without a means for
ment of pass/fail criteria using section 7.7.2 should be addressed by each
attachment of the blanket to applicable constructions. specific material standard.
C665 − 23
7.8 Fungi Resistance—When tested in accordance with they are presumed to be free of excessive tears, rips, holes, and
13.10, the insulation shall have growth no greater than that other defects that will adversely affect their performance.
observed on the white birch tongue depressor comparative
11. Significance and Use
item.
11.1 This specification applies to products that are used in
8. Other Requirements
buildings. While products that comply with this specification
are used in various constructions, they are adaptable primarily,
8.1 Qualification Requirements—The following require-
but not exclusively, to wood frame construction.
ments are generally used for purposes of initial material or
product qualification:
11.2 Since the property of thermal resistance for a specific
8.1.1 Thermal resistance,
thickness of blanket is only part of the total thermal perfor-
8.1.2 Surface burning characteristics,
mance of a building element such as a wall, ceiling, floor, and
8.1.3 Critical radiant flux,
so forth, this specification states only general classifications for
8.1.4 Water-vapor permeance,
thermal resistance of the fibrous blanket itself. Facings that
8.1.5 Water vapor sorption,
provide additional resistance to water-vapor transfer can affect
8.1.6 Odor emission,
system performance.
8.1.7 Corrosiveness, and
8.1.8 Fungi resistance. 12. Sampling
12.1 Sampling of the insulation shall be in accordance with
8.2 Inspection Requirements—The following requirements
Practice C390. Specific provision for sampling shall be agreed
are generally used for purposes of acceptance sampling of lots
upon between the purchaser and the supplier.
or shipments of qualified thermal insulation:
8.2.1 Dimensional tolerances, and
13. Test Methods
8.2.2 Workmanship.
13.1 Dimensions—Test in accordance with Test Methods
9. Dimensions
C167.
9.1 The material shall conform to the standard dimensions
13.2 Thermal Resistance:
and tolerances prescribed in Table 1.
13.2.1 Test in accordance with Test Method C177 or Test
Method C518 at 75 6 2°F (24 6 1°C) mean temperature. If
10. Workmanship and Finish
Test Method C518 is used, the manufacturer shall certify that
recent calibrations have been made.
10.1 Although all properties of the insulation blanket are not
presented in this specification, it is understood that the insula-
NOTE 3—See Guide C653. The thermal resistance is a function of mean
tion will essentially be free of defects that adversely affect
temperature. As an option, determine the thermal resistance at additional
thermal performance, such as local compressed areas, low
mean temperatures as agreed upon by the purchaser and the manufacturer.
density areas, tears and holes.
13.2.2 In case of question, determine referee test values in
accordance with Test Method C177, with resistances reported
10.2 Although the general properties of the facings and
at 75 6 2°F (24 6 1°C) mean temperature. The precision and
means for attachment are not included in this specification,
bias of the apparatus used for referee tests must be verified by
measuring the R-value of a standard reference material of light
A
density thermal insulation obtained from the National Institute
TABLE 1 Dimensions and Tolerances
of Standards and Technology. Determine thermal resistance at
Element Dimension Tolerance
the thickness marked on the product if its measured thickness
Length, in. cut pieces up to 96 in. (2 m) − ⁄2 in. (13 mm), excess
(mm) permitted
is equal to or greater than this value. Determine thermal
cut pieces up to 144 in. (4 m) −1.0 in. (25 mm), excess
resistance at actual thickness if less than the thickness marked
permitted
on the product. Always test at a thickness within the design
rolls over 144 in. (4 m) −0.5 %, excess permitted
1 1
Width, in. (mm) pieces and rolls up to 24 in. − ⁄4 in. (6 mm), + ⁄2 in. (13
accuracy limits of the test apparatus. For marked thicknesses
(0.6 m) mm)
appreciably greater than apparatus design, some materials can
1 1
rolls 24 to 144 in. (0.6 to − ⁄4 in. (6 mm), + ⁄2 in. (13
be split and both sections tested, but this procedure
...

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: C665 − 17 C665 − 23
Standard Specification for
Mineral-Fiber Blanket Thermal Insulation for Light Frame
Construction and Manufactured Housing
This standard is issued under the fixed designation C665; 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 the composition and physical properties of mineral-fiber blanket insulation used to thermally or
acoustically insulate ceilings, floors, and walls in light frame construction and manufactured housing. The requirements cover
fibrous blankets and facings. Values for water-vapor permeance of facings are suggested for information that will be helpful to
designers and installers.
1.2 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.
1.3 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 healthsafety, health, and environmental practices and determine
the applicability of regulatory limitations prior to use.
1.4 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:
B152/B152M Specification for Copper Sheet, Strip, Plate, and Rolled Bar
C167 Test Methods for Thickness and Density of Blanket or Batt Thermal Insulations
C168 Terminology Relating to Thermal Insulation
C177 Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the
Guarded-Hot-Plate Apparatus
C390 Practice for Sampling and Acceptance of Thermal Insulation Lots
C518 Test Method for Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus
C653 Guide for Determination of the Thermal Resistance of Low-Density Blanket-Type Mineral Fiber Insulation
C1104/C1104M Test Method for Determining the Water Vapor Sorption of Unfaced Mineral Fiber Insulation
C1304 Test Method for Assessing the Odor Emission of Thermal Insulation Materials
C1338 Test Method for Determining Fungi Resistance of Insulation Materials and Facings
This specification is under the jurisdiction of ASTM Committee C16 on Thermal Insulation and is the direct responsibility of Subcommittee C16.23 on Blanket and Loose
Fill Insulation.
Current edition approved Sept. 1, 2017May 1, 2023. Published September 2017June 2023. Originally approved in 1970. Last previous edition approved in 20122017 as
C665 – 12.C665 – 17. DOI: 10.1520/C0665-17.10.1520/C0665-23.
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.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C665 − 23
C1617 Practice for Quantitative Accelerated Laboratory Evaluation of Extraction Solutions Containing Ions Leached from
Thermal Insulation on Aqueous Corrosion of Metals
E84 Test Method for Surface Burning Characteristics of Building Materials
E96/E96M Test Methods for Gravimetric Determination of Water Vapor Transmission Rate of Materials
E970 Test Method for Critical Radiant Flux of Exposed Attic Floor Insulation Using a Radiant Heat Energy Source
G1 Practice for Preparing, Cleaning, and Evaluating Corrosion Test Specimens
3. Terminology
3.1 Definitions—For definitions of terms used in this specification, see Terminology C168.
4. Classification
4.1 Typical mineral-fiber thermal insulation is classified into the following types, classes, and categories:
4.1.1 Type I—Blankets without facings.
4.1.2 Type II—Blankets with nonreflective facings.
4.1.2.1 Class A—Facing with a flame spread index of 25 or less.
(1) Category 1—Facing is a vapor retarder.
(2) Category 2—Facing is not a vapor retarder.
2 2
4.1.2.2 Class B—Facing with a flame propagation resistance; critical radiant flux of 0.12 W/cm (.11 Btu/ft ·s) or greater.
(1) Category 1—Facing is a vapor retarder.
(2) Category 2—Facing is not a vapor retarder.
4.1.2.3 Class C—Facing not rated for flame propagation resistance (for use in nonexposed applications only).
(1) Category 1—Facing is a vapor retarder.
(2) Category 2—Facing is not a vapor retarder.
4.1.3 Type III—Blankets with reflective facings:
4.1.3.1 Class A—Facing with a flame spread index of 25 or less.
(1) Category 1—Facing is a vapor retarder.
(2) Category 2—Facing is not a vapor retarder.
2 2
4.1.3.2 Class B—Facing with a flame propagation resistance; critical radiant flux of 0.12 W/cm (.11 Btu/ft ·s) or greater.
(1) Category 1—Facing is a vapor retarder.
(2) Category 2—Facing is not a vapor retarder.
4.1.3.3 Class C—Facing not rated for flame propagation resistance (for use in nonexposed applications only).
(1) Category 1—Facing is a vapor retarder.
(2) Category 2—Facing is not a vapor retarder.
4.2 Mechanically attached field installed facing shall be classified into Type/Class/Category as follows:
(1) Type I insulation used in conjunction with a field installed non-reflective facing having a 25 flame spread or less on both
sides is considered functionally equivalent to a Type II/Class A/Category 1 insulation composite.
(2) Type I insulation used in conjunction with a field-installed perforated, or vapor breathable, nonreflective facing having a
25 flame spread or less on both sides is considered functionally equivalent to Type II/Class A/Category 2 insulation composite.
(3) Type I insulation used in conjunction with a field-installed reflective facing (reflective side exposed) having a 25 flame
spread or less on both sides is considered equivalent to a Type III/Class A/Category 1 insulation composite.
(4) Type I insulation used in conjunction with a field-installed perforated, or vapor breathable, reflective facing (reflective side
exposed) having a 25 flame spread or less on both sides is considered functionally equivalent to a Type III/Class A/Category 2
insulation composite.
C665 − 23
5. Ordering Information
5.1 For specific installations, thermal resistance, length, width, and facing suited to the intended use shall be specified by the
purchaser.
6. Materials and Manufacture
6.1 Basic Material—The basic material shall be fibers made from mineral substances such as rock, slag, or glass processed from
the molten state into a fibrous form.
6.2 Manufacture—Insulation blankets shall consist of flexible units composed of felted, bonded, or unbonded fibers formed into
rolls or flat cut pieces (batts), with or without various adhered facings, and with or without a means for attachment of the blanket
to applicable constructions.
7. Physical Properties
2 2
7.1 Thermal Resistance—The standard thermal resistance values in °F · h · ft /Btu (K · m /W) are: 4, 7, 11, 13, 19, 22, 30, and
38 (0.7, 1.2, 1.9, 2.3, 3.3, 3.9, 5.3, and 6.7). R values other than those listed shall be agreed upon between the supplier and the
purchaser. The product must be produced to the label R value. The thermal resistance, R, for the average of any four randomly
selected samples shall not be more than 5 % below the listed R value when tested in accordance with 13.2, nor shall any single
specimen be more than 10 % below the listed R value.
7.2 Surface Burning Characteristics:
7.2.1 Insulation blankets exclusive of facing, when tested in accordance with Test Method E84, shall have a flame spread index
no greater than 25, and a smoke developed index no greater than 50.
7.2.2 Insulation blankets with facings intended for exposed application, when tested in accordance with Test Method E84, shall
have a flame spread index no greater than 25, and a smoke developed index no greater than 50.
7.3 Critical Radiant Flux—Insulation blankets, when tested in accordance with 13.4, shall have a critical radiant flux-flame
2 2
propagation resistance ≥0.12 W/cm (0.11 Btu/ft ·s). Blankets with facing on both surfaces, shall be tested on the surface to be left
exposed and shall be marked on either surface.
7.4 Water-Vapor Permeance—When tested in accordance with 13.5, vapor retardant facings shall have a vapor permeance of no
more than 1 perm
−11 −1 −1 –2 −10
(5.7 × 10 kg·Pa ·s ·m ) and vapor-permeable facing shall have a vapor permeance of no less than 5 perm (2.9 × 10 kg·Pa
−1 −2
−1·s ·m ).
7.5 Water Vapor Sorption—The water vapor sorption of the insulation without facing shall be not more than 5 % by weight, when
tested in accordance with 13.6.
7.6 Odor Emission—A detectable odor of strong objectionable nature recorded by more than two of the five panel members shall
constitute rejection of the material when tested in accordance with 13.7.
7.7 Corrosiveness:
7.7.1 When tested in accordance with 13.8, the metal plates in contact with the insulation shall show no corrosion greater than
that observed on the comparative plates in contact with sterile cotton.
7.7.2 Alternative test – Steel only—When tested in accordance with 13.9, the mass loss corrosion rate of the unfaced insulation
extract shall not exceed that of the 5-ppm chloride solution.
NOTE 1—The use of alternative metals such as copper and aluminum have been evaluated using Practice C1617. The task group will continue to
investigate the potential for using Practice C1617 as an alternative to 7.7.1 for these metals.
C665 − 23
NOTE 2—The pass/fail criteria established in section 7.7.2 is for materials which claim compliance with Specification C665. The corrosion procedure as
detailed in 7.7.1 is referenced in multiple Mineral Fiber material standards. The use of the alternative procedure and the establishment of pass/fail criteria
using section 7.7.2 should be addressed by each specific material standard.
7.8 Fungi Resistance—When tested in accordance with 13.10, the insulation shall have growth no greater than that observed on
the white birch tongue depressor comparative item.
8. Other Requirements
8.1 Qualification Requirements—The following requirements are generally used for purposes of initial material or product
qualification:
8.1.1 Thermal resistance,
8.1.2 Surface burning characteristics,
8.1.3 Critical radiant flux,
8.1.4 Water-vapor permeance,
8.1.5 Water vapor sorption,
8.1.6 Odor emission,
8.1.7 Corrosiveness, and
8.1.8 Fungi resistance.
8.2 Inspection Requirements—The following requirements are generally used for purposes of acceptance sampling of lots or
shipments of qualified thermal insulation:
8.2.1 Dimensional tolerances, and
8.2.2 Workmanship.
9. Dimensions
9.1 The material shall conform to the standard dimensions and tolerances prescribed in Table 1.
10. Workmanship and Finish
10.1 Although all properties of the insulation blanket are not presented in this specification, it is understood that the insulation will
essentially be free of defects that adversely affect thermal performance, such as local compressed areas, low density areas, tears
and holes.
10.2 Although the general properties of the facings and means for attachment are not included in this specification, they are
presumed to be free of excessive tears, rips, holes, and other defects that will adversely affect their performance.
11. Significance and Use
11.1 This specification applies to products that are used in buildings. While products that comply with this specification are used
in various constructions, they are adaptable primarily, but not exclusively, to wood frame construction.
11.2 Since the property of thermal resistance for a specific thickness of blanket is only part of the total thermal performance of
a building element such as a wall, ceiling, floor, and so forth, this specification states only general classifications for thermal
resistance of the fibrous blanket itself. Facings that provide additional resistance to water-vapor transfer can affect system
performance.
C665 − 23
A
TABLE 1 Dimensions and Tolerances
Element Dimension Tolerance
Length, in. cut pieces up to 96 in. (2 m) − ⁄2 in. (13 mm), excess
(mm) permitted
cut pieces up to 144 in. (4 m) −1.0 in. (25 mm), excess
permitted
rolls over 144 in. (4 m) −0.5 %, excess permitted
1 1
Width, in. (mm) pieces and rolls up to 24 in. − ⁄4 in. (6 mm), + ⁄2 in. (13
(0.6 m) mm)
1 1
rolls 24 to 144 in. (0.6 to − ⁄4 in. (6 mm), + ⁄2 in. (13
4 m) mm)
Thickness as required for thermal resist- consistent with tolerances of
B C
ance thermal resistance
A
All sizes listed are not always available from all manufacturers. For sizes other
than those listed, consult manufacturers.
B
Thicknesses of the various mineral fiber insulations available can differ to provide
rated thermal resistance. Products are generally available in a range of thick-
nesses from 3 to 12 in. (75 to 305 mm). Thickness required to attain a rated
performance shall not exceed that of the cavity into which the material shall be
installed.
C
Blanket insulation manufactured to provide a designated thermal resistance are
produced by varying one or more of the factors of density, thickness, or fiber
characteristics. Therefore, blankets having the same designated thermal resis-
tance but different manufacturing sources may vary in one or more of these
factors.
12. Sampling
12.1 Sampling of the insulation shall be in accordance with Practice C390. Specific provision for sampling shall be agreed upon
between the purchaser and the supplier.
13. Test Methods
13.1 Dimensions—Test in accordance with Test Methods C167.
13.2 Thermal Resistance:
13.2.1 Test in accordance with Test Method C177 or Test Method C518 at 75 6 2°F (24 6 1°C) mean temperature. If Test Method
C518 is used, the manufacturer shall certify that recent calibrations have been made.
NOTE 3—See Guide C653. The thermal resistance is a
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