ISO/FDIS 11092

ISO/DISFDIS 11092
ISO/TC 38
Secretariat: JISCSAC
Date: 2025-12-192026-02-17
Textiles — Physiological effects — Measurement of thermal and
water-vapour resistance under steady-state conditions (sweating
guarded-hotplate test)
Textiles — Effets physiologiques — Mesurage de la résistance thermique et de la résistance à la vapeur d'eau en
régime stationnaire (essai de la plaque chaude gardée transpirante)
DISFDIS stage
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ISO/DISFDIS 11092:20252026(en)
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Published in Switzerland
ii
ISO/DISFDIS 11092:20252026(en)
Contents
Foreword . iv
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols, abbreviated terms and units . 2
5 Principle . 3
6 Apparatus . 4
7 Test specimens . 8
7.1 Materials ≤ 5 mm thick . 8
7.2 Materials > 5 mm thick . 9
8 Test procedure . 11
8.1 Determination of apparatus constants . 11
8.2 Assembly of test specimens on the measuring unit . 12
8.3 Measurement of thermal resistance, R . 13
ct
8.4 Measurement of water-vapour resistance, R . 13
et
9 Precision of results . 14
9.1 Repeatability . 14
9.2 Reproducibility . 14
10 Test report . 14
Annex A (normative) Mounting procedure for test specimens containing loose filling materials
or having uneven thickness . 15
Annex B (normative) Determination of correction terms for heating power . 16
Annex C (normative) Test specimen assembly for materials prone to swelling . 17
Bibliography . 20

iii
ISO/DISFDIS 11092:20252026(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/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
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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 TC38, Textiles, in collaboration with the European
Committee for Standardization (CEN) Technical Committee CEN/TC 248, Textiles and textile products, in
accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
This third edition edition cancels and replaces the second edition (ISO11092ISO 11092:2014), which has been
technically revised.
The main changes are as follows:
— — the Normative references clause (2(Clause 2)) has been added and subsequent clauses have been
renumbered;
— — in 8.1.3.18.1.3.1,, the water supplied to the measuring plate has been changed to Grade 3 water in
accordance with ISO 3696;
— — in 9.19.1 and 9.29.2,, the thermal resistance values have been changed to standard notation;
— — in 9.19.1,, the precision is no longer only applicable to foams;
— — in 9.2 9.2, the reproducibility of the water vapour resistance values has been updated based on the
results from the interlaboratory test in 2025;
— Annex C— Annex C is has been made normative;
— — a Bibliography has been added.
iv
ISO/DISFDIS 11092:20252026(en)
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/DISFDIS 11092:20252026(en)
Introduction
This document is the first of a number of standard test methods in the field of clothing comfort.
The physical properties of textile materials which contribute to physiological comfort involve a complex
combination of heat and mass transfer. Each can occur separately or simultaneously. They are time-
dependent, and can be considered in steady-state or transient conditions.
Error! Reference source not found.Thermal resistance is the net result of the combination of radiant,
conductive and convective heat transfer, and its value depends on the contribution of each to the total heat
transfer. Although it is an intrinsic property of the textile material, its measured value can change through the
conditions of test due to the interaction of parameters, such as radiant heat transfer with the surroundings.
Several methods exist which can be used to measure heat and moisture properties of textiles, each of which is
specific to one or the other and relies on certain assumptions for its interpretation.
The sweating guarded-hotplate (often referred to as the “skin model”) described in this document is intended
to simulate the heat and mass transfer processes which occur next to human skin. Measurements involving
one or both processes can be carried out either separately or simultaneously using a variety of environmental
conditions, involving combinations of temperature, relative humidity, air speed, and in the liquid or gaseous
phase. Hence transport properties measured with this apparatus can be made to simulate different wear and
environmental situations in both transient and steady-states. In this document only steady-state conditions
are selected.
vi
ISO/DISFDIS 11092:20252026(en)
Textiles — Physiological effects — Measurement of thermal and
water-vapour resistance under steady-state conditions (sweating
guarded-hotplate test)
1 Scope
This document specifies methods for the measurement of the Error! Reference source not found.thermal
resistance and Error! Reference source not found. water-vapour resistance, under steady-state conditions,
of e.g. fabrics, films, coatings, foams and leather, including multilayer assemblies, for use in clothing, quilts,
sleeping bags, upholstery and similar textile or textile-like products.
The application of this measurement technique is restricted to a maximum thermal resistance and water-
vapour resistance which depend on the dimensions and construction of the apparatus used (e.g. 2 m ·K/W
and 700 m ·Pa/W respectively, for the minimum specifications of the equipment referred to in this document).
The test conditions used in this document are not intended to represent specific comfort situations, and
performance specifications in relation to physiological comfort are not stated.
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.
EN ISO 3696, Water for analytical laboratory use -— Specification and test methods (ISO 3696:1987)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminologicalterminology databases for use in standardization at the following
addresses:
— ISO Online browsing platform: available at http://www.iso.org/obp
— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at http://www.iso.org/obp
3.1
thermal resistance
R
ct
temperature difference between the two faces of a material divided by the resultant heat flux per unit area in
the direction of the gradient
Note 1 to entry: It is a quantity specific to textile materials or composites which determines the dry heat flux across a
given area in response to a steady applied temperature gradient. The dry heat flux can consist of one or more conductive,
convective and radiant components.
Note 2 to entry: Thermal resistance is expressed in square metres kelvin per watt.
ISO/DISFDIS 11092:20252026(en)
3.2
water-vapour resistance
R
et
water-vapour partial pressure difference between the two faces of a material divided by the resultant
evaporative heat flux per unit area in the direction of the gradient
Note 1 to entry: It is a quantity specific to textile materials or composites which determines the “latent” evaporative heat
flux across a given area in response to a steady applied water-vapour partial pressure gradient. The evaporative heat flux
can consist of both diffusive and convective components.
Note 2 to entry: Water-vapour resistance is expressed in square metres pascal per watt.
3.3
water-vapour permeability index
i
mt
ratio of thermal and water-vapour resistances in accordance with 0Formula (1)::
𝑅
ct
𝑖 =𝑆× (1)
mt
𝑅
et
where
S equals 60 Pa/K
Note 1 to entry: The water-vapour permeability index is dimensionless, and has values between 0 and 1. A value of 0
implies that the material is water-vapour impermeable, that is, it has infinite water-vapour resistance, and a material
with a value of 1 has both the thermal resistance and water-vapour resistance of an air layer of the same thickness.
3.4
water-vapour permeability
W
d
characteristic of a textile material or composite depending on water-vapour resistance (3.2) and temperature
in accordance with 0Formula (2)::
1 1
𝑊 = (2)
d
𝑅 ×∅𝑇 𝑅 ×𝜙𝑇
et m et m
where
ϕT is the latent heat of vaporization of water at the temperature T of the measuring unit, equals, for example, 0,672
m m
W·h/g at T = 35 °C
m
Note 1 to entry: Water-vapour permeability is expressed in grams per square metre hour pascal.
4 Symbols, abbreviated terms and units
0Table 1 shows the symbols and abbreviations that are used in this document.
Table 1 — Symbols, abbreviated terms and units
Symbols and abbreviated terms ExplanationDescription Unit
A area of the measuring unit m²
b thickness of thermal guard m
d thickness of test specimen m
i Error! Reference source not dimensionless
mt
found.water-vapour permeability
index
ISO/DISFDIS 11092:20252026(en)
Symbols and abbreviated terms ExplanationDescription Unit
H heating power supplied to the W
measuring unit
l Lengthlength m
pa water-vapour partial pressure of the Pa
air in the test enclosure at
temperature, T
a
p the saturation water-vapour partial Pa
m
pressure at the surface of the
measuring unit at temperature, Tm
Rct thermal resistance m²·K/W
R apparatus constant for the m²·K/W
ct0
measurement of thermal resistance,
Rct
Ret water-vapour resistance, m²·Pa/W
R apparatus constant for the m²·Pa/W
et0
measurement of water vapour
resistance, Ret
R.H. relative humidity %
Sv standard deviation of air speed v, m/s
T air temperature in the test enclosure °C
a
T temperature of the measuring unit °C
m
Ts temperature of the thermal guard, °C
va speed of air above the surface of the m/s
test specimen
Wd Error! Reference source not g/(m²·h· Pa)
found.water-vapour permeability
α slope of the correction line for the dimensionless
calculation of ΔH
c
β slope of the correction line for the dimensionless
calculation of ΔH
e
ΔHc correction term for heating power dimensionless
for the measurement of thermal
resistance, R
ct
ΔH correction term for heating power dimensionless
e
for the measurement of water-
vapour resistance, Ret
ϕTm latent heat of vaporization of water Wh/g
at the temperature, Tm,
5 Principle
The test specimen is placed on an electrically heated plate with conditioned air ducted to flow across and
parallel to its upper surface as specified in this document.
For the determination of thermal resistance, the heat flux through the test specimen is measured after steady-
state conditions have been reached.
ISO/DISFDIS 11092:20252026(en)
The technique described in this document enables the thermal resistance, R of a material to be determined
ct
by subtracting the thermal resistance of the boundary air layer above the surface of the test apparatus from
that of a test specimen plus boundary air layer, both measured under the same conditions.
For the determination of water-vapour resistance, an electrically heated porous plate is covered by a water-
vapour permeable but liquid-water impermeable membrane. Water fed to the heated plate evaporates and
passes through the membrane as vapour, so that no liquid water contacts the test specimen. With the test
specimen placed on the membrane, the heat flux required to maintain a constant temperature at the plate is a
measure of the rate of water evaporation, and from this the water-vapour resistance of the test specimen is
determined.
The technique described in this document enables the water-vapour resistance, R of a material to be
et
determined by subtracting the water-vapour resistance of the boundary air layer above the surface of the test
apparatus from that of a test specimen plus boundary air layer, both measured under the same conditions.
6 Apparatus
6.1 Measuring unit, with temperature and water supply control, consisting of a metal plate approximately
3 mm thick with a minimum area of 0,04 m (e.g. a square with each side 200 mm in length, l) fixed to a
conductive metal block containing an electrical heating element [see 0Figure 1, items, keys (1) and (6)]. For
the measurement of water-vapour resistance, the metal plate (1) shall be porous. It is surrounded by a thermal
guard [see itemkey (8) of 0Figure 2]] which is in turn located within an opening in a measuring table (11).
The coefficient of radiant emissivity of the plate surface (1) shall be greater than 0,35, measured at 20 °C
between the wavelengths 8 µm to 14 µm, with the primary beam perpendicular to the plate surface and the
reflection hemispherical.
Channels are machined into the face of the heating element block (6) where it contacts the porous plate to
enable water to be fed from a dosing device (5).
The position of the measuring unit with respect to the measuring table shall be adjustable, so that the upper
surface of test specimens placed on it can be made coplanar with the measuring table.
Heat losses from the wiring to the measuring unit or to its temperature measuring device should be minimized,
e.g. by leading as much wiring as possible along the inner face of the thermal guard (8).
The temperature controller (3), including the temperature sensor of the measuring unit (2), shall maintain the
temperature T of the measuring unit (7) constant to within ±0,1 K. The heating power H shall be measurable
m
by means of a suitable device (4) to within ±2 % over the whole of its usable range.
Water is supplied to the surface of the porous metal plate (1) by a dosing device (5) such as a motor-driven
burette. The dosing device is activated by a switch which senses when the level of water in the plate falls more
than approximately 1,0 mm below the plate surface, in order to maintain a constant rate of evaporation. The
level switch is mechanically connected to the measuring unit.
Before entering the measuring unit, the water shall be preheated to the temperature of the measuring unit.
This can be achieved by passing it through tubes in the thermal guard before it enters the measuring unit.
ISO/DISFDIS 11092:20252026(en)

Key
ISO/DISFDIS 11092:20252026(en)
1 metal plate
2 temperature sensor
3 temperature controller
4 heating-power measuring device
5 water-dosing device
6 metal block with heating element
a
Set value of T
m
l length of the metal plate
Figure 1 — Measuring unit with temperature and water supply control

ISO/DISFDIS 11092:20252026(en)

Key
7 measuring unit according to 6.1
8 thermal guard
9 temperature controller
ISO/DISFDIS 11092:20252026(en
...