SIST EN ISO 9920:2008

SLOVENSKI STANDARD
SIST EN ISO 9920:2008
01-marec-2008
1DGRPHãþD
SIST EN ISO 9920:2004
(UJRQRPLMDWRSORWQHJDRNROMD2FHQLWHYWRSORWQHL]RODWLYQRVWLLQRGSRUQRVWL
REODþLOSURWLYRGQLSDUL,62
Ergonomics of the thermal environment - Estimation of thermal insulation and water
vapour resistance of a clothing ensemble (ISO 9920:2007)
Ergonomie der thermischen Umgebung - Abschätzung der Wärmeisolation und des
Verdunstungswiderstandes einer Bekleidungskombination (ISO 9920:2007)
Ergonomie des ambiances thermiques - Détermination de l'isolement thermique et de la
résistance a l'évaporation d'une tenue vestimentaire (ISO 9920:2007)
Ta slovenski standard je istoveten z: EN ISO 9920:2007
ICS:
13.180 Ergonomija Ergonomics
61.020 2EODþLOD Clothes
SIST EN ISO 9920:2008 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 9920:2008

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SIST EN ISO 9920:2008
EUROPEAN STANDARD
EN ISO 9920
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2007
ICS 13.180 Supersedes EN ISO 9920:2003
English Version
Ergonomics of the thermal environment - Estimation of thermal
insulation and water vapour resistance of a clothing ensemble
(ISO 9920:2007)
Ergonomie des ambiances thermiques - Détermination de Ergonomie der thermischen Umgebung - Abschätzung der
l'isolement thermique et de la résistance à l'évaporation Wärmeisolation und des Verdunstungswiderstandes einer
d'une tenue vestimentaire (ISO 9920:2007) Bekleidungskombination (ISO 9920:2007)
This European Standard was approved by CEN on 13 April 2007.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2007 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 9920:2007: E
worldwide for CEN national Members.

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SIST EN ISO 9920:2008

EN ISO 9920:2007 (E)





Foreword


This document (EN ISO 9920:2007) has been prepared by Technical Committee ISO/TC 159
"Ergonomics" in collaboration with Technical Committee CEN/TC 122 "Ergonomics", the
secretariat of which is held by DIN.

This European Standard shall be given the status of a national standard, either by publication of
an identical text or by endorsement, at the latest by December 2007, and conflicting national
standards shall be withdrawn at the latest by December 2007.

This document supersedes EN ISO 9920:2003.

According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium,
Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United
Kingdom.


Endorsement notice

The text of ISO 9920:2007 has been approved by CEN as EN ISO 9920:2007 without any
modifications.

2

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SIST EN ISO 9920:2008

INTERNATIONAL ISO
STANDARD 9920
Second edition
2007-06-01

Ergonomics of the thermal
environment — Estimation of thermal
insulation and water vapour resistance of
a clothing ensemble
Ergonomie des ambiances thermiques — Détermination de l'isolement
thermique et de la résistance à l'évaporation d'une tenue vestimentaire




Reference number
ISO 9920:2007(E)
©
ISO 2007

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SIST EN ISO 9920:2008
ISO 9920:2007(E)
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ii © ISO 2007 – All rights reserved

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SIST EN ISO 9920:2008
ISO 9920:2007(E)
Contents Page
Foreword. v
Introduction . vi
1 Scope . 1
2 Terms and definitions. 1
3 Application of this International Standard . 5
4 Estimation of thermal insulation of clothing ensemble based on tables and with values
measured on a standing thermal manikin.7
4.1 General. 7
4.2 Insulation values of complete ensembles. 8
4.3 Ensemble thermal insulation values based on individual garments . 8
4.4 Complete ensemble insulation corrected for small differences in composition . 8
4.5 Calculation of thermal insulation for clothing ensembles . 9
4.6 Calculation of thermal insulation for individual garments. 9
5 Estimation of clothing area factor. 10
6 Estimation of surface (or boundary) air layer insulation. 10
7 Estimation of water vapour resistance. 12
7.1 General. 12
7.2 Estimation of vapour resistance of clothing ensembles based on tables with values
measured on standing thermal manikin. 12
7.3 Estimation of vapour resistance of clothing ensemble based on its relation with dry heat
resistance . 12
8 Influence of body movement and air movement on the thermal insulation and vapour
resistance of a clothing ensemble . 13
8.1 General. 13
8.2 Correction of clothing insulation . 13
8.3 Correction of clothing vapour resistance .18
8.4 Activities other than walking . 20
8.5 Relative air velocity . 20
9 Other factors influencing clothing insulation. 22
9.1 General. 22
9.2 Posture. 22
9.3 Effect of seats . 22
9.4 Effect of pressure . 22
9.5 Wetting. 22
9.6 Washing . 22
Annex A (normative) Thermal insulation values for clothing ensembles . 23
Annex B (normative) Thermal insulation values for individual garments. 45
Annex C (normative) Vapour permeability index values for clothing ensembles. 72
Annex D (informative) Measurement of thermal insulation and water vapour resistance of clothing
ensembles on a thermal manikin . 87
Annex E (informative) Measurement of thermal insulation and water vapour resistance of a
clothing ensemble on human subjects . 93
Annex F (informative) Different expressions for the thermal insulation of clothing. 95
Annex G (informative) Estimation of the heat exchanges for reflective clothing. 97
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SIST EN ISO 9920:2008
ISO 9920:2007(E)
Annex H (informative) Guidance on the determination of the covered body surface area. 99
Bibliography . 101

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SIST EN ISO 9920:2008
ISO 9920:2007(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
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.
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 9920 was prepared by Technical Committee ISO/TC 159, Ergonomics, Subcommittee SC 5, Ergonomics
of the physical environment.
This second edition cancels and replaces the first edition (ISO 9920:1995), which has been technically revised.
It includes major changes to the sections on clothing vapour resistance as well as those dealing with the
effects of air movement and body motion on clothing insulation and vapour resistance.
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SIST EN ISO 9920:2008
ISO 9920:2007(E)
Introduction
This International Standard is one of a series of International Standards intended for use in the study of
thermal environments. It is a basic document for evaluation of the thermal characteristics of a clothing
ensemble (thermal insulation and water vapour resistance). It is necessary to know these values when
evaluating the thermal stress or degree of comfort provided by the physical environment according to
standardized methods. The thermal characteristics determined in this International Standard are values for
steady-state conditions. Properties like “buffering”, adsorption of water and similar are not dealt with.
The emphasis in this International Standard is on the estimation of the thermal characteristics. The heat and
vapour resistance may also be measured directly, and this is discussed in the annexes.
This International Standard does not deal with the local thermal insulation on different body parts, nor the
discomfort due to a non-uniform distribution of the clothing on the body.
Man’s thermal balance in neutral, cold and warm environments is influenced by the clothing worn. For
evaluating the thermal stress on human beings in the cold (IREQ, see ISO/TR 11079, insulation index),
neutral environments (PMV-PPD, see ISO 7730, indices) and the heat (predicted heat strain, see ISO 7933,
index), it is necessary to know the thermal characteristics of the clothing ensemble, i.e. the thermal insulation
and the water vapour resistance.

vi © ISO 2007 – All rights reserved

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SIST EN ISO 9920:2008
INTERNATIONAL STANDARD ISO 9920:2007(E)

Ergonomics of the thermal environment — Estimation of
thermal insulation and water vapour resistance of a clothing
ensemble
1 Scope
This International Standard specifies methods for estimating the thermal characteristics (resistance to dry heat
loss and evaporative heat loss) in steady-state conditions for a clothing ensemble based on values for known
garments, ensembles and textiles. It examines the influence of body movement and air penetration on the
thermal insulation and water vapour resistance.
This International Standard does not
⎯ deal with other effects of clothing, such as adsorption of water, buffering or tactile comfort,
⎯ take into account the influence of rain and snow on the thermal characteristics,
⎯ consider special protective clothing (water-cooled suits, ventilated suits, heated clothing), or
⎯ deal with the separate insulation on different parts of the body and discomfort due to the asymmetry of a
clothing ensemble.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
2.1
thermal insulation
I
2 −1
resistance to dry heat loss between two surfaces, expressed in square metres Kelvin per watt (m ⋅ K ⋅ W )
NOTE 1 In this International Standard it is considered as the equivalent uniform thermal resistance, or thermal
insulation, on a human body. This is the clothing heat resistance (thermal insulation) that, when uniformly covering the
whole body surface (including hands, face, etc.), would result in the same heat loss as the actual, possibly non-uniform,
clothing heat resistance. This heat resistance is the quotient of the temperature gradient between the surfaces (the driving
force) over the dry heat loss per unit of body surface area (the flux):
temperature gradient
I= (1)
heat loss per unit of body surfacearea
For the human body, this resistance can be divided into specific layers, as illustrated in Figure 1 (see also Annex F).
NOTE 2 Because of the special definition of thermal insulation in this International Standard, it is usually expressed
in clo, the unit of thermal insulation of clothing. Although it can be converted into SI units in similar fashion to the thermal
2 −1
insulation of, for example, textile samples [symbol: R ; 1 clo = 0,155 (m ⋅ K ⋅ W )], the meaning is not the same.
ct
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SIST EN ISO 9920:2008
ISO 9920:2007(E)
2.1.1
total insulation
I
T
thermal insulation from the body surface to the environment (including all clothing, enclosed air layers and
boundary air layer) under reference conditions, static
See Figure 1.
NOTE Based on Equation (1), it is expressed as:
tt−
sk o
I = (2)
T
H
where
t is the mean skin surface temperature, in degrees Celsius;
sk
t is the operative temperature, in degrees Celsius (in most cases equal to the air temperature, t );
o a
H is the dry heat loss per square metre of skin, in watts per square metre.
2.1.2
basic insulation
intrinsic insulation
I
cl
thermal insulation from the skin surface to the outer clothing surface (including enclosed air layers) under
reference conditions, static
See Figure 1.
NOTE Based on Equation (1), it is expressed as:
tt−
sk cl
I = (3)
cl
H
where t is the mean outer clothing surface temperature, in degrees Celsius.
cl
2.1.3
air insulation
I
a
thermal insulation of the boundary (surface) air layer around the outer clothing or, when nude, around the skin
surface
See Figure 1.
NOTE 1 Based on Equation (1), it is expressed as
tt−
cl o
I = (4)
a
H
NOTE 2 The dry heat loss is composed of radiant and convective heat loss (see Annex G). These heat transfers
through the clothing layers are not considered separately in this International Standard; for the air layer, they can be
considered separately. The alternative representation is then:
1
I = (5)
a
hh+
cr
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SIST EN ISO 9920:2008
ISO 9920:2007(E)
where
−2 −1
h is the convective heat transfer coefficient, in watts per square metre Kelvin (W ⋅ m ⋅ K );
c
−2 −1
h is the radiative heat transfer coefficient, in watts per square metre Kelvin (W ⋅ m ⋅ K ).
r
−1
NOTE 3 Such values are defined for standardized conditions (static body, wind still, i.e. speed < 0,2 m ⋅ s ). When air
movement is present, or when the body moves, this will affect the insulation (typically lowering it), in which case, it is
referred to as resultant or dynamic heat resistance.

Key
1 surface (or boundary) air layer
2 enclosed air layer
3 clothing
4 body
Figure 1 — Schematic representation of total, basic and air insulations
2.1.4
clothing area factor
f
cl
ratio of the outer surface area of the clothed body to the surface area of the nude body
NOTE 1 The outer surface area of a clothed person, A , is greater than the surface area of a nude body, A . Their
cl Du
ratio is therefore larger than 1:
A
cl
f = (6)
cl
A
Du
NOTE 2 Basic and air insulation do not simply add up to total insulation. This is explained by the difference in surface
area between the outer clothing surface and the skin surface. Owing to this higher surface area, the insulative effect for
the body of the air insulation is reduced the thicker the clothing (the larger the outer clothing surface area):
I
a
II=+ (7)
Tcl
f
cl
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SIST EN ISO 9920:2008
ISO 9920:2007(E)
2.1.5
resultant total insulation
dynamic total insulation
I
T,r
actual thermal insulation from the body surface to the environment (including all clothing, enclosed air layers
and boundary air layers) under given environmental conditions and activities
NOTE It is the total insulation (I ) value in actual situations (as opposed to reference conditions), including the effects
T
of movements and wind. Values for Ι given in this International Standard and in most of the literature are obtained on a
T
thermal manikin which remains static in a low wind condition, and such values need to be corrected for wind and
movement effects.
2.1.6
resultant basic insulation
dynamic basic insulation
I
cl,r
actual thermal insulation from the body surface to the outer clothing surface (including enclosed air layers)
under given environmental conditions and activities
NOTE It is the basic (intrinsic) insulation (I ) value in actual situations (as opposed to reference conditions), including
cl
the effects of movements and wind.
2.1.7
effective insulation
I
clu
increase in insulation provided to a thermal manikin by a single garment compared to the nude manikin
insulation
NOTE For insulation of individual garments, the term effective thermal insulation is used (I ). The effective thermal
clu
insulation of individual garments making up the ensemble (see Table B.2) is determined on a manikin wearing only that
single garment as:
tt−
sk o
I =−II= −I (8)
clu T a a
H
where
2 −1
I is the total thermal insulation of the garment, in square metres Kelvin per watt (m ⋅ K ⋅ W ) or in clo;
T
t is the operative temperature, in degrees Celsius (equal to the air temperature, t , for most measuring conditions
o a
in climatic chambers).
2.2
water vapour resistance
evaporative resistance
R
e
resistance to water vapour transfer between two surfaces, expressed in square metres kilopascal per watt
NOTE 1 In this International Standard it is considered as the equivalent uniform vapour resistance. This is the
resistance that, when uniformly covering the whole body surface (including hands, face, etc.), would result in the same
heat loss through evaporation as the actual, possibly non-uniform, vapour resistance. This resistance is the quotient of the
vapour pressure gradient between the surfaces (the driving force) over the evaporative heat loss per unit of body surface
area:
vapour pressure gradient
R = (9)
e
evaporative heat loss per unit of body surface area
NOTE 2 Similarly to heat resistance, it is divided into specific layers.
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SIST EN ISO 9920:2008
ISO 9920:2007(E)
2.2.1
total water vapour resistance
R
e,T
vapour resistance from the body surface to the environment (including all clothing, enclosed air layers and
boundary air layers) under reference conditions, static
2.2.2
basic water vapour resistance
R
e,cl
vapour resistance from the body surface to the outer clothing surface (including enclosed air layers) under
reference conditions, static
2.2.3
air water vapour resistance
R
e,a
vapour resistance of the boundary (surface) air layer around the outer clothing or, when nude, around the skin
surface
NOTE In analogy to heat resistance:
R
e,a
RR=+ (10)
e,T e,cl
f
cl
2.2.4
resultant total water vapour resistance
dynamic total water vapour resistance
R
e,T,r
vapour resistance from the body surface to the environment (including all clothing, enclosed air layers and
boundary air layers) under given environmental conditions and activities
NOTE 1 It is the total water vapour resistance (R ) value in actual situations (as opposed to reference conditions),
e,T
including the effects of movements and wind.
−1
NOTE 2 Values of R are defined for standardized conditions (static body, wind still, i.e. speed < 0,2 m ⋅ s ). When air
e,T
movement is present, or when the body moves, this will affect the vapour resistance (typically lowering it), in which case it
is referred to as the resultant or dynamic total water vapour resistance.
2.2.5
resultant basic water vapour resistance
dynamic basic water vapour resistance
R
e,cl,r
vapour resistance from the body surface to the outer clothing surface (including enclosed air layers) under
given environmental conditions and activities
NOTE 1 It is the basic water vapour resistance (R ) value in actual situations (as opposed to reference conditions),
e,cl
including the effects of movements and wind.
−1
NOTE 2 Values of R are defined for standardized conditions (static body, wind still, i.e. speed < 0,2 m ⋅ s ). When
e,cl
air movement is present, or when the body moves, this will affect the vapour resistance (typically lowering it), in which
case it is referred to as the resultant or dynamic basic water vapour resistance.
3 Application of this International Standard
Where possible, the insulation and vapour resistance values of a clothing ensemble should be measured
using equipment such as thermal (wetted or sweating) manikins, or by performing experiments involving
human subjects. Test procedures for the measurement of heat and vapour resistance are outlined in
Annexes D and E. However, given the cost and the need for specialized equipment, actual measurement will
most likely be beyond the reach of most users of this International Standard. In that case, the insulation and
vapour resistance shall be estimated using the methods specified in the following clauses and Annexes A, B
and C.
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SIST EN ISO 9920:2008
ISO 9920:2007(E)
For guidance, the stepwise approach is schematically represented in the flowcharts of Figure 2, for the
determination of heat resistance, and Figure 3, for the determination of vapour resistance. The various options
are described.

Figure 2 — Determining clothing insulation
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SIST EN ISO 9920:2008
ISO 9920:2007(E)

Figure 3 — Determining clothing vapour resistance
4 Estimation of thermal insulation of clothing ensemble based on tables and with
values measured on a standing thermal manikin
4.1 General
Tables in this International Standard provide data on the insulation of complete clothing ensembles, as well as
insulation values for individual garments that can be added to create complete ensembles. It is advisable to
use the tables of complete ensembles to match the actual ensemble, as this will provide a more accurate
value for clothing insulation than the summation of individual garments. Interpolation between the thermal
insulation of two ensembles may be used and, when an ensemble is found similar to the actual ensemble,
small corrections may also be made by adding or subtracting individual garment insulations to achieve the
best estimate of the insulation of the actual ensemble. Finally, corrections for movement and air velocity shall
be applied.
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SIST EN ISO 9920:2008
ISO 9920:2007(E)
4.2 Insulation values of complete ensembles
In Annex A, I and I values are listed for a selection of clothing ensembles. All of the values were measured
T cl
−1
on a static, standing, thermal manikin in low air movement (< 0,2 m ⋅ s ). In Table A.1, a short description of
the clothing ensembles is given. Tables A.2 to A.10 present more extended lists that can be used for finding a
clothing ensemble that is comparable with the actual clothing ensemble; f values are also given. The total
cl
clothing mass, where this is given, is based on garments that fit a standard person (European male size 52)
and does not include shoes. A number following the listing in the tables of individual garments making up most
of the ensembles refers to Annex B, where a more detailed description of the individual garment is presented,
including fig
...