ASTM C591-20

Standard Specification for Unfaced Preformed Rigid Cellular Polyisocyanurate Thermal Insulation

ABSTRACT
This specification covers the types, physical properties, and dimensions of unfaced, preformed rigid cellular polyurethane modified polyisocyanurate plastic material intended for use as thermal insulation on surfaces. This insulation can be classified into six types according to its compressive resistance: Types I, IV, II, III, V, and VI. Also this insulation can be classified as Grades 1 and 2 according to its service temperature range. The thermal insulation is produced by the polymerization of polymeric polyisocyanates in the presence of polyhydroxyl compounds, catalysts, cell stabilizers, and blowing agents. Different test methods shall be performed in order to determine the thermal insulation's following properties: density, compressive resistance, apparent thermal conductivity, hot-surface performance, water absorption, water vapor permeability, dimensional stability, closed-cell content, surface bearing characteristics, tensile strength, and leachable chloride, fluoride, silicate, and sodium ions.
SCOPE
1.1 This specification covers the types, physical properties, and dimensions of unfaced, preformed rigid cellular polyisocyanurate plastic material intended for use as thermal insulation on surfaces from –297°F (–183°C) to 300°F (149°C). For specific applications, the actual temperature limits shall be agreed upon by the manufacturer and purchaser.  
1.2 This specification only covers “polyurethane modified polyisocyanurate” thermal insulation which is commonly referred to as “polyisocyanurate” thermal insulation. This standard does not encompass all polyurethane modified materials. Polyurethane modified polyisocyanurate and other polyurethane materials are similar, but the materials will perform differently under some service conditions.  
1.3 This standard is designed as a material specification, not a design document. Physical property requirements vary by application and temperature. At temperatures below –70°F (–51°C) the physical properties of the polyisocyanurate insulation at the service temperature are of particular importance. Below –70°F (–51°C) the manufacturer and the purchaser must agree on what additional cold temperature performance properties are required to determine if the material can function adequately for the particular application.  
1.4 This standard addresses requirements of unfaced preformed rigid cellular polyisocyanurate thermal insulation manufactured using blowing agents with an ozone depletion potential of 0 (ODP 0).  
1.5 Except 6.2 and 8.2 – 8.4, which are related to the size and shape of fabricated parts, and 16.1, which is related to the storage of fabricated parts, the requirements in this standard specification apply to the polyisocyanurate insulation in the form of buns supplied by the insulation manufacturer.  
1.6 When adopted by an authority having jurisdiction, codes that address fire properties in many applications regulate the use of the thermal insulation materials covered by this specification. Fire properties are controlled by job, project, or other specifications where codes or government regulations do not apply.  
1.7 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.  
1.8 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.  
1.9 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: Historical
• Publication Date: 14-May-2020
• ICS: 83.100 - Cellular materials
• ICS: 91.100.60 - Thermal and sound insulating materials
• Technical Committee: C16 - Thermal Insulation
• Drafting Committee: C16.22 - Organic and Nonhomogeneous Inorganic Thermal Insulations

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:C591 −20
Standard Specification for
Unfaced Preformed Rigid Cellular Polyisocyanurate Thermal
1
Insulation
This standard is issued under the fixed designation C591; 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 1.6 Whenadoptedbyanauthorityhavingjurisdiction,codes
that address fire properties in many applications regulate the
1.1 This specification covers the types, physical properties,
use of the thermal insulation materials covered by this speci-
and dimensions of unfaced, preformed rigid cellular polyiso-
fication. Fire properties are controlled by job, project, or other
cyanurate plastic material intended for use as thermal insula-
specifications where codes or government regulations do not
tion on surfaces from –297°F (–183°C) to 300°F (149°C). For
apply.
specific applications, the actual temperature limits shall be
1.7 The values stated in inch-pound units are to be regarded
agreed upon by the manufacturer and purchaser.
as standard. The values given in parentheses are mathematical
1.2 This specification only covers “polyurethane modified
conversions to SI units that are provided for information only
polyisocyanurate” thermal insulation which is commonly re-
and are not considered standard.
ferred to as “polyisocyanurate” thermal insulation. This stan-
1.8 This standard does not purport to address all of the
dard does not encompass all polyurethane modified materials.
safety concerns, if any, associated with its use. It is the
Polyurethane modified polyisocyanurate and other polyure-
responsibility of the user of this standard to establish appro-
thane materials are similar, but the materials will perform
priate safety, health, and environmental practices and deter-
differently under some service conditions.
mine the applicability of regulatory limitations prior to use.
1.3 This standard is designed as a material specification, not
1.9 This international standard was developed in accor-
a design document. Physical property requirements vary by
dance with internationally recognized principles on standard-
application and temperature. At temperatures below –70°F
ization established in the Decision on Principles for the
(–51°C) the physical properties of the polyisocyanurate insu-
Development of International Standards, Guides and Recom-
lation at the service temperature are of particular importance.
mendations issued by the World Trade Organization Technical
Below–70°F(–51°C)themanufacturerandthepurchasermust
Barriers to Trade (TBT) Committee.
agree on what additional cold temperature performance prop-
erties are required to determine if the material can function 2. Referenced Documents
adequately for the particular application. 2
2.1 ASTM Standards:
C165 Test Method for Measuring Compressive Properties of
1.4 This standard addresses requirements of unfaced pre-
Thermal Insulations
formed rigid cellular polyisocyanurate thermal insulation
C168 Terminology Relating to Thermal Insulation
manufactured using blowing agents with an ozone depletion
C177 Test Method for Steady-State Heat Flux Measure-
potential of 0 (ODP 0).
ments and Thermal Transmission Properties by Means of
6.2 and 8.2 – 8.4, which are related to the size
1.5 Except
the Guarded-Hot-Plate Apparatus
and shape of fabricated parts, and 16.1, which is related to the
C272/C272M Test Method for Water Absorption of Core
storage of fabricated parts, the requirements in this standard
Materials for Sandwich Constructions
specification apply to the polyisocyanurate insulation in the
C303 Test Method for Dimensions and Density of Pre-
form of buns supplied by the insulation manufacturer.
formed Block and Board–Type Thermal Insulation
C335/C335M Test Method for Steady-State Heat Transfer
Properties of Pipe Insulation
1
This specification is under the jurisdiction of ASTM Committee C16 on
Thermal Insulation and is the direct responsibility of Subcommittee C16.22 on
2
Organic and Nonhomogeneous Inorganic Thermal Insulations. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved May 15, 2020. Published June 2020. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1966. Last previous edition approved in 2019 as C591 – 19a. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/C0591-20. 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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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: C591 − 19a C591 − 20
Standard Specification for
Unfaced Preformed Rigid Cellular Polyisocyanurate Thermal
1
Insulation
This standard is issued under the fixed designation C591; 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 types, physical properties, and dimensions of unfaced, preformed rigid cellular polyisocya-
nurate plastic material intended for use as thermal insulation on surfaces from –297°F (–183°C) to 300°F (149°C). For specific
applications, the actual temperature limits shall be agreed upon by the manufacturer and purchaser.
1.2 This specification only covers “polyurethane modified polyisocyanurate” thermal insulation which is commonly referred to
as “polyisocyanurate” thermal insulation. This standard does not encompass all polyurethane modified materials. Polyurethane
modified polyisocyanurate and other polyurethane materials are similar, but the materials will perform differently under some
service conditions.
1.3 This standard is designed as a material specification, not a design document. Physical property requirements vary by
application and temperature. At temperatures below –70°F (–51°C) the physical properties of the polyisocyanurate insulation at
the service temperature are of particular importance. Below –70°F (–51°C) the manufacturer and the purchaser must agree on what
additional cold temperature performance properties are required to determine if the material can function adequately for the
particular application.
1.4 This standard addresses requirements of unfaced preformed rigid cellular polyisocyanurate thermal insulation manufactured
using blowing agents with an ozone depletion potential of 0 (ODP 0).
1.5 Except 6.2 and 8.2 – 8.4, which are related to the size and shape of fabricated parts, and 16.1, which is related to the storage
of fabricated parts, the requirements in this standard specification apply to the polyisocyanurate insulation in the form of buns
supplied by the insulation manufacturer.
1.6 When adopted by an authority having jurisdiction, codes that address fire properties in many applications regulate the use
of the thermal insulation materials covered by this specification. Fire properties are controlled by job, project, or other
specifications where codes or government regulations do not apply.
1.7 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.
1.8 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.
1.9 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:
C165 Test Method for Measuring Compressive Properties of Thermal Insulations
1
This specification is under the jurisdiction of ASTM Committee C16 on Thermal Insulation and is the direct responsibility of Subcommittee C16.22 on Organic and
Nonhomogeneous Inorganic Thermal Insulations.
Current edition approved Nov. 1, 2019May 15, 2020. Published November 2019June 2020. Originally approved in 1966. Last previous edition approved in 2019 as
C591 – 19.C591 – 19a. DOI: 10.1520/C0591-19A.10.1520/C0591-20.
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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C591 − 20
C168 Terminology Relating to Thermal Insulation
C177 Test Method f
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