ISO 16533:2014

INTERNATIONAL ISO
STANDARD 16533
First edition
2014-07-01
Textiles — Measurement of
exothermic and endothermic
properties of textiles under humidity
change
Textiles — Mesurage des propriétés exothermiques et endothermiques
de textiles sous conditions d’humidité changeantes
Reference number
©
ISO 2014
© ISO 2014
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ii © ISO 2014 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and units . 2
5 Principle . 2
6 Apparatus . 2
7 Reagent . 4
8 Preparation of the humidity control material . 4
9 Test procedure . 5
9.1 Preparation of test specimen . 5
9.2 Preparation of apparatus . 5
9.3 Test specimen mounting . 5
9.4 Measurement of exothermic and endothermic properties . 6
10 Test report . 8
Annex A (informative) Example of hygroscopic and exothermic property test .9
Annex B (informative) Example of hygroemissive and endothermic property test .10
Annex C (informative) Example of practical humidity measurement .11
Bibliography .13
Foreword
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The committee responsible for this document is ISO/TC 38, Textiles.
iv © ISO 2014 – All rights reserved

Introduction
The thermal properties of textile materials contribute to a wearer’s physiological comfort, product’s
durability, etc. Hence, there are many kinds of products with specific thermal performances and various
test methods that have been developed and standardized. However, these tests should be conducted in
a certain humidity. The method for thermal properties in elevated or reduced humidity has not been
standardized.
All materials generate heat when absorbing moisture and absorb heat when releasing moisture. The
heat of absorption varies according to the material, for example, the heat of absorption in wool fibre is
much bigger than that in common synthetic fibre. Recently, with this property, some heat-generating
textiles have been developed and applied to various products, such as outdoor wear, sportswear, inner
wear, special working wear, and healthcare wear. Therefore, the test for the hygroscopic and exothermic
properties of textiles is needed for both producers and customers. Despite these needs, accurate and
reliable information about hygroscopic and exothermic properties of textiles cannot be offered because
of the absence of a standard test method.
The exothermic and endothermic properties of textiles under changing conditions of environmental
humidity can be measured with this test method and apparatus proposed in this International Standard.
INTERNATIONAL STANDARD ISO 16533:2014(E)
Textiles — Measurement of exothermic and endothermic
properties of textiles under humidity change
1 Scope
This International Standard specifies a method for the measurement of exothermic and endothermic
properties by moisture absorption and desorption in sheet-like textiles, e.g. fabrics, knit or nonwovens
for clothing, bedding, upholstery, and similar textile products.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 3696:1987, Water for analytical laboratory use — Specification and test methods
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
exothermic property
property of material whereby it releases heat to the surroundings
3.2
endothermic property
property of material whereby it absorbs heat from the surroundings
3.3
hygroscopic and exothermic property
property of material whereby it generates heat by absorbing moisture and releases the generated heat
to its surroundings where relative humidity changes from low to high over time
3.4
hygroemissive and endothermic property
property of material whereby it loses heat and cools down by releasing moisture through evaporation
to its surroundings where relative humidity changes from high to low over time
4 Symbols and units
T is the ambient temperature in a temperature and humidity controlled chamber, in degrees Celsius.
A
RH is the ambient relative humidity in a temperature and humidity controlled chamber, in per cent.
A
RH is the relative humidity in the first constant humidity container, starting humidity, in per cent.
RH is the relative humidity in the second constant humidity container, target humidity, in per cent.
T is the peak temperature, determined using a temperature sensor with or without the test specimen
peak
mounted on the sensor probe in the second constant humidity container during the hygroscopic and
exothermic property tes
...