ISO 18959:2025

Thermal insulation products — Rigid nano-microporous insulation for industrial applications — Specification

This document specifies the requirements for factory-made rigid nano-microporous insulation, which are used for the thermal insulation of industrial applications on surface at temperatures from 100 °C to 1 150 °C. This document specifies insulation that exhibits thermal insulating performance through nano-sized pore composite material comprising a blend of inorganic powder, fibres and opacifiers. The products are delivered as board or pipe section type. This document describes product characteristics and includes procedures for testing, evaluation of conformity, marking and labelling. This document does not specify the required level of a given property to be achieved by a product to demonstrate fitness for purpose in a particular application. The levels required for a given application are to be found in regulations or non-conflicting standards.

Produits isolants thermiques — Isolation nano-microporeuse rigide pour applications industrielles — Spécifications

General Information

• Status: Published
• Publication Date: 31-Aug-2025
• ICS: 91.100.60 - Thermal and sound insulating materials
• Technical Committee: ISO/TC 163/SC 3 - Thermal insulation products, components and systems
• Drafting Committee: ISO/TC 163/SC 3 - Thermal insulation products, components and systems
• Current Stage: 6060 - International Standard published
• Start Date: 01-Sep-2025
• Due Date: 10-Nov-2025
• Completion Date: 01-Sep-2025

Standards Content (Sample)

International
Standard
ISO 18959
First edition
Thermal insulation products —
2025-09
Rigid nano-microporous insulation
for industrial applications —
Specification
Produits isolants thermiques — Isolation nano-microporeuse
rigide pour applications industrielles — Spécifications
Reference number
© ISO 2025
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms, definitions, symbols and abbreviated terms . 1
3.1 Terms and definitions .2
3.2 Symbols and units .2
3.3 Abbreviated terms .2
3.3.1 Abbreviated terms for general usage.2
3.3.2 Abbreviated terms for declared properties .2
4 Requirements . 3
4.1 General .3
4.2 Classification .3
4.3 Permanent linear change .3
4.4 Thermal conductivity .3
4.5 Linear dimensions .3
4.6 Squareness .4
4.7 Flatness .4
4.8 Pipe section linearity .4
4.9 Density .4
4.10 Compressive stress at 10 % deformation .4
4.11 Corrosiveness to steel .4
5 Test methods . 5
5.1 Sampling .5
5.2 Conditioning.5
5.3 Testing .5
5.3.1 General .5
5.3.2 Thermal conductivity .5
6 Designation code . . 6
7 Evaluation of conformity . . 6
8 Marking and labelling . 6
Annex A (normative) Factory production control . 8
Bibliography . 9

iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 163, Thermal performance and energy use in
the built environment, Subcommittee SC 3, Thermal insulation products, components and systems.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
International Standard ISO 18959:2025(en)
Thermal insulation products — Rigid nano-microporous
insulation for industrial applications — Specification
1 Scope
This document specifies the requirements for factory-made rigid nano-microporous insulation, which
are used for the thermal insulation of industrial applications on surface at temperatures from 100 °C to
1 150 °C. This document specifies insulation that exhibits thermal insulating performance through nano-
sized pore composite material comprising a blend of inorganic powder, fibres and opacifiers. The products
are delivered as board or pipe section type.
This document describes product characteristics and includes procedures for testing, evaluation of
conformity, marking and labelling.
This document does not specify the required level of a given property to be achieved by a product to
demonstrate fitness for purpose in a particular application. The levels required for a given application are to
be found in regulations or non-conflicting standards.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 8302, Thermal insulation — Determination of steady-state thermal resistance and related properties —
Guarded hot plate apparatus
ISO 8497, Thermal insulation — Determination of steady-state thermal transmission properties of thermal
insulation for circular pipes
ISO 9229, Thermal insulation — Vocabulary
ISO 12624, Thermal insulating products for building equipment and industrial installations — Determination of
trace quantities of water-soluble chloride, fluoride, silicate, sodium ions and pH
ISO 13787, Thermal insulation products for building equipment and industrial installations — Determination of
declared thermal conductivity
ISO 29465, Thermal insulating products for building applications — Determination of length and width
ISO 29466, Thermal insulating products for building applications — Determination of thickness
ISO 29469:2022, Thermal insulating products for building applications — Determination of compression
behaviour
ISO 29470, Thermal insulating products for building applications — Determination of the apparent density
3 Terms, definitions, symbols and abbreviated terms
For the purposes of this document, the terms and definitions given in ISO 9229 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp

— IEC Electropedia: available at https:// www .electropedia .org/
3.1 Terms and definitions
3.1.1
inorganic powder
base ingredient of microporous thermal insulation such as fumed silica composed of SiO or fumed Al O
2 2 3
3.1.2
nano-microporous
composite material that comes in the form of fibre reinforced inorganic powder containing nano-micropores
3.1.3
rigid nano-microporous
type of nano-microporous thermal insulation formed as board or pipe section
3.2 Symbols and units
Symbol Quantity Unit
l length mm
b width mm
t thickness mm
λ thermal conductivity W/(m·K)
declared thermal conductivity as determined by ISO 13787, and
λ W/(m·K)
D
expressed with three significant digits
S deviation from squareness of boards on length mm
b
S deviation from squareness of boards on thickness mm
d
S deviation from squareness for pipe sections mm
p
S deviation from flatness mm
max
S deviation from linearity mm
lin
ρ apparent density kg/m
a
ρ nominal density kg/m
D
3.3 Abbreviated terms
3.3.1 Abbreviated terms for general usage
Abbreviated term Meaning
RMI rigid nano-microporous insulation
ITT initial type test
FPC factory production control
3.3.2 Abbreviated terms for declared properties
Abbreviated term Declared property
CS(10\Y) declared level for compressive stress at 10 % deformation
Cl declared level for chloride content
T declared level for thickness
...

FINAL DRAFT
International
Standard
ISO/FDIS 18959
ISO/TC 163/SC 3
Thermal insulation products —
Secretariat: SCC
Rigid nano-microporous insulation
Voting begins on:
for industrial applications —
2025-05-30
Specification
Voting terminates on:
2025-07-25
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
ISO/FDIS 18959:2025(en) © ISO 2025

FINAL DRAFT
ISO/FDIS 18959:2025(en)
International
Standard
ISO/FDIS 18959
ISO/TC 163/SC 3
Thermal insulation products —
Secretariat: SCC
Rigid nano-microporous insulation
Voting begins on:
for industrial applications —
Specification
Voting terminates on:
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
© ISO 2025
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland Reference number
ISO/FDIS 18959:2025(en) © ISO 2025

ii
ISO/FDIS 18959:2025(en)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms, definitions, symbols and abbreviated terms . 1
3.1 Terms and definitions .2
3.2 Symbols and units .2
3.3 Abbreviated terms .2
3.3.1 Abbreviated terms for general usage.2
3.3.2 Abbreviated terms for declared properties .2
4 Requirements . 3
4.1 General .3
4.2 Classification .3
4.3 Permanent linear change .3
4.4 Thermal conductivity .3
4.5 Linear dimensions .3
4.6 Squareness .4
4.7 Flatness .4
4.8 Pipe section linearity .4
4.9 Density .4
4.10 Compressive stress at 10 % deformation .4
4.11 Corrosiveness to steel .4
5 Test methods . 5
5.1 Sampling .5
5.2 Conditioning.5
5.3 Testing .5
5.3.1 General .5
5.3.2 Thermal conductivity .5
6 Designation code . . 6
7 Evaluation of conformity . . 6
8 Marking and labelling . 6
Annex A (normative) Factory production control . 8
Bibliography . 9

iii
ISO/FDIS 18959:2025(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 163, Thermal performance and energy use in
the built environment, Subcommittee SC 3, Thermal insulation products, components and systems.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
FINAL DRAFT International Standard ISO/FDIS 18959:2025(en)
Thermal insulation products — Rigid nano-microporous
insulation for industrial applications — Specification
1 Scope
This document specifies the requirements for factory-made rigid nano-microporous insulation, which are
used for the thermal insulation of industrial applications on surface at temperatures from 100 °C up to
1 150 °C. This document specifies insulation that exhibits thermal insulating performance through nano-
sized pore composite material comprising a blend of inorganic powder, fibres and opacifiers. The products
are delivered as board or pipe section type.
This document describes product characteristics and includes procedures for testing, evaluation of
conformity, marking and labelling.
This document does not specify the required level of a given property to be achieved by a product to
demonstrate fitness for purpose in a particular application. The levels required for a given application are to
be found in regulations or non-conflicting standards.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 8302, Thermal insulation — Determination of steady-state thermal resistance and related properties —
Guarded hot plate apparatus
ISO 8497, Thermal insulation — Determination of steady-state thermal transmission properties of thermal
insulation for circular pipes
ISO 9229, Thermal insulation — Vocabulary
ISO 12624, Thermal insulating products for building equipment and industrial installations — Determination of
trace quantities of water-soluble chloride, fluoride, silicate, sodium ions and pH
ISO 13787, Thermal insulation products for building equipment and industrial installations — Determination of
declared thermal conductivity
ISO 29465, Thermal insulating products for building applications — Determination of length and width
ISO 29466, Thermal insulating products for building applications — Determination of thickness
ISO 29469:2022, Thermal insulating products for building applications — Determination of compression
behaviour
ISO 29470, Thermal insulating products for building applications — Determination of the apparent density
3 Terms, definitions, symbols and abbreviated terms
For the purposes of this document, the terms and definitions given in ISO 9229 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp

ISO/FDIS 18959:2025(en)
— IEC Electropedia: available at https:// www .electropedia .org/
3.1 Terms and definitions
3.1.1
inorganic powder
base ingredien
...

ISO/FDIS 18959:2024(en)
ISO/TC 163/SC 3
Secretariat: SCC
Date: 2025-03-0205-15
Thermal insulation products — Rigid nano-microporous insulation
for industrial applications — Specification
FDIS stage
ISO/FDIS 18959:2025(en)
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication
may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying,
or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO
at the address below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
Fax: + 41 22 749 09 47
E-mail: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
ISO/FDIS 18959:2025(en)
Contents
iii
ISO/FDIS 18959:2025(en)
Contents
Foreword . v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions, symbols and abbreviated terms . 1
4 Requirements . 3
5 Test methods . 5
6 Designation code . 6
7 Evaluation of conformity . 6
8 Marking and labelling . 7
Annex A (normative) Factory production control . 8
Bibliography . 9

iv
ISO/FDIS 18959:2025(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of
ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 163, Thermal performance and energy use in the
built environment, Subcommittee SC 3, Thermal insulation products, components and systems.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
v
ISO/FDIS 18959:2025(en)
Thermal insulation products — Rigid nano-microporous insulation
for industrial applications — Specification
1 Scope
This document specifies the requirements for factory-made rigid nano-microporous insulation, which are
used for the thermal insulation of industrial applications on surface at temperatures from 100 °C up to
11501 150 °C. This document specifies insulation that exhibits thermal insulating performance through nano-
sized pore composite material comprising a blend of inorganic powder, fibres and opacifiers. The products are
delivered as board or pipe section type.
This document describes product characteristics and includes procedures for testing, evaluation of
conformity, marking and labelling.
This document does not specify the required level of a given property to be achieved by a product to
demonstrate fitness for purpose in a particular application. The levels required for a given application are to
be found in regulations or non-conflicting standards.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 8302, Thermal insulation — Determination of steady-state thermal resistance and related properties —
Guarded hot plate apparatus
ISO 8497, Thermal insulation — Determination of steady-state thermal transmission properties of thermal
insulation for circular pipes
ISO 9229, Thermal insulation — Vocabulary
ISO 12624, Thermal insulating products for building equipment and industrial installations — Determination of
trace quantities of water-soluble chloride, fluoride, silicate, sodium ions and pH
ISO 13787, Thermal insulation products for building equipment and industrial installations — Determination of
declared thermal conductivity
ISO 29465, Thermal insulating products for building applications — Determination of length and width
ISO 29466, Thermal insulating products for building applications — Determination of thickness
ISO 29469:2022, Thermal insulating products for building applications — Determination of compression
behaviour
ISO 29470, Thermal insulating products for building applications — Determination of the apparent density
3 Terms, definitions, symbols and abbreviated terms
For the purposes of this document, the terms and definitions given in ISO 9229 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— — ISO Online browsing platform: available at https://www.iso.org/obp
ISO/FDIS 18959:2025(en)
— — IEC Electropedia: available at https://www.electropedia.org/
3.1 Terms and definitions
3.1.1 3.1.1
inorganic powder
base ingredient of microporous thermal insulation such as fumed silica composed of SiO or fumed Al O
2 2 3
3.1.2 3.1.2
nano-microporous
composite material that comes in the form of fibre reinforced inorganic powder containing nano-micropores
3.1.3 3.1.3
rigid nano-microporous
type of nano-microporous thermal insulation formed as board or pipe section
3.2 Symbols and units
Symbol Quantity Unit
l length mm
b width mm
t thickness mm
λ thermal conductivity W/(m·K)
declared thermal conductivity as determined by ISO 13787, and
λD W/(m·K)
expressed with three significant digits
Sb deviation from squareness of boards on length mm
Sd deviation from squareness of boards on thickness mm
S deviation from squareness for pipe sections mm
p
S deviation from flatness mm
max
Slin deviation from linearity mm
ρD apparent density kg/m
ρ nominal density kg/m
a
3.3 Abbreviated terms
3.3.1 Abbreviated terms for general usage
Abbreviated term Meaning
RMI rigid nano-microporous insulation
ITT initial type test
FPC factory production control
3.3.2 Abbreviated terms for declared properties
Abbreviated term Declared property
CS(10\Y) declared level for compressive stress at 10 % deformation
Cl declared level for chloride content
ISO/FDIS 18959:2025(en)
Abbreviated term Declared property
T declared level for thickness
4 Requirements
4.1 General
Product properties shall be assessed in accordance with Clause 4Clause 4. .
The test methods for determination of each property are given in Table 4Table 4,, which als
...