ISO 20394:2007

INTERNATIONAL ISO
STANDARD 20394
First edition
2007-06-15

Thermal-insulating materials —
Determination of freeze-thaw resistance
Matériaux d'isolation thermique — Détermination de la résistance au
gel-dégel




Reference number
ISO 20394:2007(E)
©
ISO 2007

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ISO 20394:2007(E)
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ISO 20394:2007(E)
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
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International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 20394 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 10, Cellular plastics.

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INTERNATIONAL STANDARD ISO 20394:2007(E)

Thermal-insulating materials — Determination of freeze-thaw
resistance
1 Scope
This International Standard specifies the equipment and procedures for determining the effect, on the
mechanical properties and moisture content of a product, of the successive cycling of the product from dry
conditions at −20 °C to wet conditions (water) at +20 °C. It is applicable to thermal-insulation products.
The method is intended to simulate freeze-thaw effects on thermal-insulation products which are frequently
exposed to water and low-temperature conditions, e.g. inverted roofs and unprotected ground insulation.
This test method is not recommended for all thermal-insulation products. It will normally be clear from the
product standard if this International Standard is applicable to a particular product.
2 Normative references
The following referenced documents are indispensable for the application 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 2896, Rigid cellular plastics — Determination of water absorption
ISO 20392, Rigid cellular plastics — Determination of long-term compressive creep
ISO 20393, Rigid cellular plastics — Determination of long-term water absorption by diffusion
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
freeze-thaw resistance
ability of a product to withstand repeated wetting followed by freezing conditions, this ability being quantified in
terms of the water absorption and the change in compression behaviour
4 Principle
The freeze-thaw resistance is determined as the change in the amount of water absorbed and the change in
compression strength or stress of a test specimen which is subjected to 300 successive cycles from dry
conditions at −20 °C to wet conditions (water) at +20 °C. The freezing takes place in air, the thawing in water.
The freeze-thaw exposure is carried out in conjunction with one of the following long-term water absorption
tests:
a) water absorption by diffusion as specified in ISO 20393;
b) water absorption by total immersion as specified in ISO 2896.
The water absorption test to be used will be indicated in the relevant product standard.
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ISO 20394:2007(E)
5 Apparatus
5.1 Cold chamber, at a constant temperature of (−20 ± 2) °C.
5.2 Water tank, with a constant water temperature of (20 ± 2) °C, equipped with a device for holding the
test specimen in position.
NOTE Normally, no accelerated thermal-exchange facilities, e.g. fan assistance in the cold chamber or turbulent
water circulation in the water tank, are provided.
5.3 Balance, which permits reading to 0,1 g.
5.4 Compression-testing machine, including measuring devices, as specified in ISO 20392.
6 Test specimens
6.1 General
The test specimens used for this method (set A) shall be the same test specimens which have been used for
the determination of long-term water absorption by diffusion in accordance with ISO 20393 or by total
immersion in accordance with ISO 2896.
6.2 Dimensions
The thickness of the test specimens shall be the original product thickness.
The test specimens for set A shall be square, with squarely cut edges, having sides of length (500 ± 1) mm or
(200 ± 1) mm, depending on the water absorption method chosen.
6.3 Number
The number of test specimens in set A will depend on the sizes of the two sets of specimens for the
compression test (sets B1 and B2) which are prepared from set A.
The number of test specimens in each of sets B1 and B2 for the compression test, and their dimensions, shall
be as specified in the relevant product standard or another international technical specification. In the absence
of such a specification, the number of specimens and their dimensions shall be as def
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