ISO 18959:2025

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
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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

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Foreword
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in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
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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 o
...