ASTM C591-08

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 (150°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 Tables in the Annex A1 address requirements of unfaced preformed rigid cellular polyisocyanurate thermal insulation manufactured with HCFC blowing agent.  
1.5 The use of thermal insulation material covered by this specification may be regulated by building codes that address fire performance.
1.6 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.
1.7 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 health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 31-May-2008
• ICS: 91.100.60 - Thermal and sound insulating materials
• Technical Committee: C16 - Thermal Insulation
• Drafting Committee: C16.22 - Organic and Nonhomogeneous Inorganic Thermal Insulations

Relations

• Replaces: ASTM C591-07 - Standard Specification for Unfaced Preformed Rigid Cellular Polyisocyanurate Thermal Insulation
• Effective Date: 01-Jun-2008
• Replaced By: ASTM C591-08a - Standard Specification for Unfaced Preformed Rigid Cellular Polyisocyanurate Thermal Insulation
• Effective Date: 01-Dec-2008
• Referred By: ASTM D1079-20 - Standard Terminology Relating to Roofing and Waterproofing
• Effective Date: 01-Jun-2008
• Referred By: ASTM C1774-13(2019) - Standard Guide for Thermal Performance Testing of Cryogenic Insulation Systems
• Effective Date: 01-Jun-2008
• Referred By: ASTM D7793-21 - Standard Specification for Insulated Vinyl Siding
• Effective Date: 01-Jun-2008
• Referred By: ASTM C1696-20 - Standard Guide for Industrial Thermal Insulation Systems
• Effective Date: 01-Jun-2008
• Referred By: ASTM C1303/C1303M-22 - Standard Test Method for Predicting Long-Term Thermal Resistance of Closed-Cell Foam Insulation
• Effective Date: 01-Jun-2008

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: C 591 – 08
Standard Specification for
Unfaced Preformed Rigid Cellular Polyisocyanurate
1
Thermal 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.Anumber 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 Department of Defense.
1. Scope priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
1.1 This specification covers the types, physical properties,
and dimensions of unfaced, preformed rigid cellular polyiso-
2. Referenced Documents
cyanurate plastic material intended for use as thermal insula-
2
2.1 ASTM Standards:
tiononsurfacesfrom−297°F(−183°C)to300°F(150°C).For
C165 Test Method for Measuring Compressive Properties
specific applications, the actual temperature limits shall be
of Thermal Insulations
agreed upon by the manufacturer and purchaser.
C168 Terminology Relating to Thermal Insulation
1.2 This specification only covers “polyurethane modified
C177 Test Method for Steady-State Heat Flux Measure-
polyisocyanurate” thermal insulation which is commonly re-
ments and Thermal Transmission Properties by Means of
ferred to as “polyisocyanurate” thermal insulation. This stan-
the Guarded-Hot-Plate Apparatus
dard does not encompass all polyurethane modified materials.
C203 Test Methods for Breaking Load and Flexural Prop-
Polyurethane modified polyisocyanurate and other polyure-
erties of Block-Type Thermal Insulation
thane materials are similar, but the materials will perform
C272 Test Method for WaterAbsorption of Core Materials
differently under some service conditions.
for Structural Sandwich Constructions
1.3 Thisstandardisdesignedasamaterialspecification,not
C303 Test Method for Dimensions and Density of Pre-
a design document. Physical property requirements vary by
formed Block and Board−Type Thermal Insulation
application and temperature. At temperatures below -70°F
C335 Test Method for Steady-State Heat Transfer Proper-
(-51°C) the physical properties of the polyisocyanurate insu-
ties of Pipe Insulation
lation at the service temperature are of particular importance.
C390 Practice for Sampling and Acceptance of Thermal
Below -70°F (-51°C) the manufacturer and the purchaser
Insulation Lots
must agree on what additional cold temperature performance
C411 Test Method for Hot-Surface Performance of High-
propertiesarerequiredtodetermineifthematerialcanfunction
Temperature Thermal Insulation
adequately for the particular application.
C518 Test Method for Steady-State Thermal Transmission
1.4 TablesintheAnnexA1addressrequirementsofunfaced
Properties by Means of the Heat Flow Meter Apparatus
preformed rigid cellular polyisocyanurate thermal insulation
C550 Test Method for MeasuringTrueness and Squareness
manufactured with HCFC blowing agent.
of Rigid Block and Board Thermal Insulation
1.5 The use of thermal insulation material covered by this
C585 Practice for Inner and Outer Diameters of Rigid
specification may be regulated by building codes that address
Thermal Insulation for Nominal Sizes of Pipe and Tubing
fire performance.
(NPS System)
1.6 The values stated in inch-pound units are to be regarded
C871 Test Methods for Chemical Analysis of Thermal
as standard. The values given in parentheses are mathematical
Insulation Materials for Leachable Chloride, Fluoride,
conversions to SI units that are provided for information only
Silicate, and Sodium Ions
and are not considered standard.
C 1045 Practice for Calculating Thermal Transmission
1.7 This standard does not purport to address all of the
Properties Under Steady-State Conditions
safety concerns, if any, associated with its use. It is the
C1058 Practice for Selecting Temperatures for Evaluating
responsibility of the user of this standard to establish appro-
and Reporting Thermal Properties of Thermal Insulation
1
This specification is under the jurisdiction of ASTM Committee C16 on
2
Thermal Insulation and is the direct responsibility of Subcommittee C16.22 on
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Organic and Nonhomogeneous Inorganic Thermal Insulations.
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Current edition approved June 1, 2008. Published June 2008. Originally
Standards volume information, refer to the standard’s Document Summary page on
approved in 1966. Last previous edition approved in 2007 as C591–07.
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 anASTM standard and is intended only to provide the user of anASTM 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:C591–07 Designation: C 591 – 08
Standard Specification for
Unfaced Preformed Rigid Cellular Polyisocyanurate
1
Thermal 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.Anumber 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 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 (150°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
theservicetemperatureareofparticularimportance.Below-70°F(-51°C),(-51°C)themanufacturerandthepurchasermustagree
on what additional cold temperature performance properties, may beproperties are required to determine if the material can
function adequately for the particular application.
1.4 Tables in the Annex A1 address requirements of unfaced preformed rigid cellular polyisocyanurate thermal insulation
manufactured with HCFC blowing agent.
1.5 The use of thermal insulation material covered by this specification may be regulated by building codes that address fire
performance.
1.6The values stated in inch-pound units are to be regarded as the standard.The values given in parentheses are for information
only and may be approximate.
1.6 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.
1.7 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 health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2
2.1 ASTM Standards:
C165 Test Method for Measuring Compressive Properties of 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
C203 Test Methods for Breaking Load and Flexural Properties of Block-Type Thermal Insulation
C272 Test Method for Water Absorption of Core Materials for Structural Sandwich Constructions
C303 Test Method for Dimensions and Density of Preformed Block and BoardType Thermal Insulation
C335 Test Method for Steady-State Heat Transfer Properties of Pipe Insulation
C390 Practice for Sampling and Acceptance of Thermal Insulation Lots
C411 Test Method for Hot-Surface Performance of High-Temperature Thermal Insulation
C518 Test Method for Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus
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 June 1, 2007.2008. Published June 2007.2008. Originally approved in 1966. Last previous edition approved in 20052007 as C591–057.
2
ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,[e-mail] 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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C591–08
C550 Test Method for Measuring
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