ASTM E2231-21

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: E2231 − 19 E2231 − 21 An American National Standard
Standard Practice for
Specimen Preparation and Mounting of Pipe and Duct
Insulation Materials to Assess Surface Burning
Characteristics
This standard is issued under the fixed designation E2231; 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 practice describes procedures for specimen preparation and mounting when testing pipe and duct insulation materials to
assess flame spread and smoke development as surface burning characteristics using Test Method E84.
1.2 If the pipe or duct insulation materials to be tested are reflective insulation materials (see 3.2.10 and 3.2.11), the materials shall
be tested using the procedures for specimen preparation and mounting described in Practice E2599 and not the procedures
described in 6.1 through 6.6.
1.3 Testing is conducted with Test Method E84.
1.4 This practice does not provide pass/fail criteria that can be used as a regulatory tool.
1.5 Use the values stated in inch-pound units as the standard, in referee decisions. The values in the SI system of units are given
in parentheses, for information only; see IEEE/ASTM SI-10 for further details.
1.6 This fire standard cannot be used to provide quantitative measures.
1.7 Fire testing of products and materials is inherently hazardous, and adequate safeguards for personnel and property shall be
employed in conducting these tests. Fire testing involves hazardous materials, operations, and equipment. This standard gives
instructions on specimen preparation and mounting, but the fire-test-response method is given in Test Method E84. See also Section
8.
1.8 The text of this standard references notes and footnotes which provide explanatory material. These notes and footnotes
(excluding those in tables and figures) shall not be considered requirements of the standard.
1.9 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.
1.10 This fire standard cannot be used to provide quantitative measures.
This practice is under the jurisdiction of ASTM Committee E05 on Fire Standards and is the direct responsibility of Subcommittee E05.22 on Surface Burning.
Current edition approved Dec. 15, 2019Dec. 15, 2021. Published January 2020January 2022. Originally approved in 2002. Last previous edition approved in 20182019
as E2231-18.-19. DOI: 10.1520/E2231-19.10.1520/E2231-21.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2231 − 21
1.10 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
C1186 Specification for Flat Fiber-Cement Sheets
C1224 Specification for Reflective Insulation for Building Applications
C1396/C1396M Specification for Gypsum Board
E84 Test Method for Surface Burning Characteristics of Building Materials
E176 Terminology of Fire Standards
E2599 Practice for Specimen Preparation and Mounting of Reflective Insulation, Radiant Barrier and Vinyl Stretch Ceiling
Materials for Building Applications to Assess Surface Burning Characteristics
IEEE/ASTM SI-10 International System of Units (SI) The Modernized Metric System
2.2 UL Standards:
UL 181 Standard for Safety for Factory-Made Air Ducts and Connectors
3. Terminology
3.1 Definitions—For definitions of terms used in this practice refer to the terminology contained in Terminology E176.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 composite, n—as related to a pipe or duct insulation, see duct insulation system or pipe insulation system.
3.2.2 duct, n—as related to heating ventilating, air conditioning or exhaust systems, a passageway made of sheet metal or other
suitable material used for conveying air or other gases.
3.2.3 duct insulation system, n—as related to fire testing, system intended to insulate and cover, continuously for an extended
length, the outside surface of a duct; the system shall have an insulation core, with or without a covering or vapor retarder facing
which includes longitudinal closure systems (if used) and perhaps other duct insulation supplementary materials such as adhesives,
fasteners, or tapes (if used).
3.2.3.1 Discussion—
Duct system components, including tapes, sealants, and fitting covers, that do not cover the duct continuously for an extended
length, but which are associated with the duct insulation system are considered separately (see duct insulation supplementary
materials). An extended length is not intended to imply a length of 25 ft, 25 ft, but a length of at least 3 ft.3 ft.
3.2.4 duct insulation supplementary materials, n—as related to fire testing, components, including tapes and sealants used for
transverse joints as well as fitting covers that are intermittently spaced, as needed, within the duct insulation system, as well as
adhesives used to bond the insulation to the duct substrate and that do not cover the duct continuously for an extended length.
3.2.5 duct lining, n—material such as an insulation, coating or film, including adhesive, used to line the inside surface of a duct.
3.2.6 insulation blanket, n—a relatively flat and flexible insulation in coherent sheet form furnished in units of substantial area.
3.2.7 pipe, n—as related to heating, ventilating, or air conditioning systems, a cylindrical conduit for the conveyance of liquids
or semi-solids.
3.2.8 pipe insulation system, n—as related to fire testing, system intended to insulate and cover, continuously for an extended
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from Underwriters Laboratories (UL), Corporate Progress, 333 Pfingsten Rd., Northbrook, IL 60062.
This definition is similar to the definition of “blanket insulation” in Terminology C168 from committee C16 on Thermal Insulation.
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length, the outside surface of a pipe; the system shall have an insulation core, with or without a covering or vapor retarder facing
which includes longitudinal closure systems (if used) and perhaps other pipe insulation supplementary materials such as adhesives,
fasteners, or tapes (if used).
3.2.8.1 Discussion—
Pipe system components, including tapes, sealants, and fitting covers, that do not cover the pipe continuously for an extended
length, but which are associated with the pipe insulation system are considered separately (see pipe insulation supplementary
materials). An extended length is not intended to imply a length of 25 ft, but a length of at least 3 ft.
3.2.9 pipe insulation supplementary materials, n—as related to fire testing, components, including tapes and sealants used for
transverse joints as well as fitting covers that are intermittently spaced, as needed, within the pipe insulation system, as well as
adhesives used to bond the insulation to the pipe substrate and that do not cover the pipe continuously for an extended length.
3.2.10 reflective insulation, n—thermal insulation consisting of one or more low emittance surfaces bounding one or more
enclosed air spaces.
3.2.10.1 Discussion—
Reflective insulation materials are defined in Specification C1224.
3.2.11 reflective plastic core insulation, n—an insulation material packaged in rolls, that is less than 0.5 in. (12.7 mm) thick, with
at least one exterior low emittance surface (0.1 or less) and a core material containing voids or cells.
3.2.11.1 Discussion—
Reflective plastic core insulation materials are one specific type of reflective insulation materials.
3.2.12 self-supporting specimen, n—a specimen that remains in place by its own structural characteristics both before and during
the fire test.
4. Summary of Practice
4.1 This practice describes procedures for specimen preparation and mounting when testing pipe and duct insulation materials to
assess flame spread and smoke development as surface burning characteristics using Test Method E84.
4.2 Pipe or duct insulation systems (or composites related to pipe or duct insulation) consist of an insulation core, with or without
a jacket, and with or without an adhesive. Pipe or duct insulation systems shall be tested in accordance with the specimen
preparation and mounting procedures described in this practice, using Test Method E84.
4.3 Supplementary materials for pipe or duct insulation systems, including tapes, joint sealants, and fitting covers, that are
intermittently spaced, shall be tested for flame spread and smoke development as single-component systems, using Test Method
E84.
5. Significance and Use
5.1 Pipe and duct insulation systems are often evaluated with Test Method E84 to comply with building or mechanical code
requirements. This practice describes, in detail, specimen preparation and mounting procedures for single-component pipe or duct
insulation systems and for multi-component pipe or duct insulation systems.
5.2 The material, system, composite, or assembly tested shall be representative of the completed insulation system used in actual
field installations, in terms of the components, including their respective thicknesses.
5.3 Pipe and duct insulation systems consist of a variety of materials and constructions.
5.4 Some testing laboratories have developed a number of protocols for testing pipe or duct insulation systems which utilize one
generic type of materials, all of them with an insulation core and a jacket. Those protocols are the origin of this practice, which
makes them generic, to reduce material bias in the standard; they have resulted in the procedures presented in 6.1. The procedures
presented in 6.2 – 6.5 address other types of pipe or duct insulation systems.
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5.5 This practice addresses specimen preparation and mounting of systems of the types described in 5.5.1 – 5.5.3 and testing of
supplementary materials as described in 5.6.
5.5.1 Multi-component systems containing an insulation core and a jacket, with or without adhesive between insulation core and
jacket, not intended to be bonded to a pipe or duct substrate. Specimen preparation and mounting for such systems is described
in 6.1 if they are self-supporting and in 6.2 if they are not self-supporting.
5.5.2 Single component systems, not intended to be bonded to a pipe or duct substrate. Specimen preparation and mounting for
such systems is described in 6.3 if they are self-supporting and in 6.4 if they are not self-supporting.
5.5.3 Systems intended to be bonded to a pipe or duct substrate. Specimen preparation and mounting for such systems is described
in 6.5.
5.5.4 Reflective insulation materials (see 3.2.10 and 3.2.11) intended to be used as pipe or duct insulation materials and installed
with an air gap shall be tested using the procedures for specimen preparation and mounting procedures described in Practice E2599.
Reflective insulation materials intended to be used as pipe or duct insulation materials and installed without an air gap shall be
tested using the specimen preparation and mounting procedures described in Section 6 of this practice.
5.5.5 Specimen preparation and mounting procedures for systems not described in this practice shall be added as the information
becomes available.
5.6 Supplementary Materials:
5.6.1 It is recognized that supplementary materials for pipe or duct insulation systems are normally able to generate heat, flame
or smoke. Thus, the fire safety of the entire system depends, at least to some extent, on the fire performance of supplementary
materials. Consequently, the fire-test-response characteristics of all supplementary materials shall be assessed to obtain a full
assessment of the fire-test-response of the pipe or duct insulation system. See Appendix X1.
5.6.2 Supplementary materials are often present intermittently spaced, and not for an extended length, in a pipe or duct insulation
system. Thus, it is not always possible to suitably test them in conjunction with a pipe or duct insulation system.
5.6.3 Testing of Supplementary Materials—Supplementary materials that have not been fully tested in conjunction with the pipe
or duct insulation system, in accordance with Section 6, shall be tested for flame spread and smoke development as
single-component systems, in accordance with Test Method E84.
5.7 The limitations for this procedure are those associated with Test Method E84.
6. Specimen Preparation and Mounting
6.1 Self-supporting multi-component systems, not intended to be bonded to a pipe or duct substrate:
6.1.1 Hollow cylindrical insulation core inside a jacket, with a longitudinal joint system, to be used without adhesive between
jacket and insulation core:
6.1.1.1 In this construction, the insulation board specimens, 20 to 24 in. (510 to 610 mm) 20 in. to 24 in. (510 mm to 610 mm)
by the appropriate length, shall be produced in a flat cross-section with the jacket (facing) with a seam created at the approximate
longitudinal centerline using the same method of closure used in actual field installations. The jacket (facing) shall be mechanically
attached to the insulation core using 0.5 in. (13 mm) 0.5 in. (13 mm) divergent point steel flared staples. The staples shall be
applied, around the perimeter of the board, at 6 6 3 in. (152 6 76 mm) 6 in. 6 3 in. (152 mm 6 76 mm) on center spacing, as
well as adjacent to and along both sides of the longitudinal seam, at approximately 1 in. 1 in. from the seam (see Fig. 1).
6.1.1.2 Mount the specimens on the ledges of the Test Method E84 furnace without using an auxiliary support mechanism.
The specimen preparation and mounting procedures in 6.1, including potentially slitting the facing or jacket, mirror those used by Underwriters Laboratories, and
described in their documents “BRER GuideInfo—Pipe and Equipment Coverings—[Building Materials] (Surface Burning Characteristics)” and “BIYR GuideInfo—
Acoustical Materials—[Building Materials] (Surface Burning Characteristics).” Similar concepts are also used in the testing of Factory-made Air Ducts and Air Connectors
by Test Method E84 in UL 181.
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FIG. 1 Insulation and Jacket with No Adhesive (see 6.1.1.1)
6.1.2 Hollow cylindrical insulation core inside a jacket, with a full coat adhesive attaching the jacket to the insulation core:
6.1.2.1 In this construction, the insulation board specimens, 2020 in. to 24 in. (510(510 mm to 610 mm) by the appropriate length,
shall be produced in a flat cross-section with the jacket (facing) adhered to one side of the insulation core (see Fig. 2).
6.1.2.2 Each test shall be conducted using a factory or field joint along the longitudinal centerline of the test specimen, with a
longitudinal seam created in the approximate centerline using the same method of closure used in actual field installations.
6.1.2.3 It shall be permitted to represent the field joint by introducing a longitudinal slit cut along the longitudinal centerline of
the specimen jacket and applying the manufacturer’s recommended field closure system (if applicable).
6.1.2.4 For each test, mount the specimens on the ledges of the Test Method E84 furnace without using an auxiliary support
mechanism.
6.1.3 Hollow cylindrical insulation core inside a jacket, with longitudinal adhesive beads or stripes in a stitch pattern attaching
the jacket to the insulation core:
6.1.3.1 In this construction, the insulation board specimens, 2020 in. to 24 in. (510(510 mm to 610 mm) by the appropriate length,
shall be produced in a flat cross-section with the jacket (facing) laminated to one side of the insulation core. The adhesive bead
or stripe spacing shall be the same as used in the actual field installation. Divergent point steel flared staples, 0.5 in. (13 mm) 0.5 in.
(13 mm) in size, shall be applied, around the perimeter of the board, at 6 6 3 in. (152 6 76 mm) 6 in. 6 3 in. (152 mm 6 76 mm)
on center spacing, as well as adjacent to and along both sides of the longitudinal seam, at approximately 1 in. from the seam (see
Fig. 3).
6.1.3.2 For each test, mount the specimens on the ledges of the Test Method E84 furnace without using an auxiliary support
mechanism.
6.1.4 Insulation core board with a jacket laminated to the insulation:
6.1.4.1 In this system the resulting longitudinal seam shall be closed with either an adhesive tape or a vapor retarder lap adhesive.
In this construction, the insulation board specimens, 2020 in. to 24 in. (510(510 mm to 610 mm) by the appropriate length, shall
be produced in a flat cross-section with the jacket (facing) laminated to one side of the insulation core (see Fig. 2).
6.1.4.2 Each test shall be conducted using a factory or field joint along the longitudinal centerline of the test specimen, with a
longitudinal seam created in the approximate centerline using the same method of closure used in actual field installations.
This testing is intended to investigate the contribution of all combustibles to the flame spread and smoke developed by the system to be used in the actual fiel
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