ISO 23327:2021

INTERNATIONAL ISO
STANDARD 23327
First edition
2021-09
Hygrothermal performance of
building materials and products —
Determination of moisture
adsorption/desorption properties
in response to periodic temperature
variation
Performance hygrothermique des matériaux et produits pour le
bâtiment — Détermination des propriétés d'adsorption/désorption de
l'humidité en réponse à une fluctuation périodique de la température
Reference number
©
ISO 2021
© ISO 2021
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ii © ISO 2021 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Specimen . 1
5 Test apparatus . 2
5.1 General . 2
5.2 Sealed box . . 2
5.3 Box or chamber with thermostat . 4
5.4 Thermometer . 4
5.5 Hygrometer . 4
6 Curing and thermal insulation of specimen . 4
6.1 Damp-proofing of specimen . 4
6.2 Curing of specimen . 5
6.3 Thermal insulation of specimen . 5
7 Test method . 6
7.1 Cleaning inside the sealed box . 6
7.2 Initial relative humidity inside the sealed box . 6
7.3 Installation of specimen . 6
7.4 Placement of sealed box . 6
7.5 Temperature conditions . 7
7.6 Measurement . 7
8 Water vapour leakage from sealed box . 7
8.1 Calibration of sealed box for vapour leakage. 7
8.2 Calculation of calibration value . 8
8.3 Tolerance calibration value . 8
9 Calculation of results . 8
9.1 Temperature and humidity in sealed box . 8
9.2 Moisture-adsorption/desorption amount . 9
10 Test report .10
Annex A (informative) Temperature conditions of box or chamber with thermostat .11
Foreword
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iv © ISO 2021 – All rights reserved

INTERNATIONAL STANDARD ISO 23327:2021(E)
Hygrothermal performance of building materials and
products — Determination of moisture adsorption/
desorption properties in response to periodic temperature
variation
1 Scope
This document specifies the test method of moisture-adsorption/desorption efficiency (or capacity)
of building materials, when there are changes in temperature in sealed boxes containing building
materials.
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 9346, Hygrothermal performance of buildings and building materials — Physical quantities for mass
transfer — Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 9346 and the following apply.
ISO and IEC maintain terminological 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
moisture-adsorption/desorption amount
amount of moisture which is adsorbed in or desorbed from materials in a moisture-adsorption/
desorption process, calculated as:
mm=⋅VA/
mv=−()ΣΣv / θθ−
()
4 Specimen
A specimen shall be extracted from the test product. The size, the thickness, and the number of sheets
shall be as follows.
a) Size: the standard size of the specimen shall be 100 mm x 100 mm.
b) Thickness: the thickness shall, as a rule, be the thickness of the product. However, the upper limit of
thickness is 20 mm.
c) The number of sheets: the number of sheets shall, as a rule, be one for each test condition.
5 Test apparatus
5.1 General
A test apparatus shall be principally comprised of a sealed box, a box or chamber with thermostat, a
thermometer and a hygrometer, and be constructed as given in Figure 1.
Dimension in millimetres
Key
1 chamber
2 sealed box
3 specimen
4 thermal insulation
5 thermom
...