Ergonomics of the thermal environment - Estimation of thermal insulation and water vapour resistance of a clothing ensemble (ISO 9920:2007, Corrected version 2008-11-01)

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.

Ergnomie der thermischen Umgebung - Abschätzung der Wärmeisolation und des Verdunstungswiderstandes einer Bekleidungskombination (ISO 9920:2007, Korrigierte Fassung 2008-11-01)

Diese Internationale Norm legt Verfahren zur Abschätzung der thermischen Kennwerte (Widerstand gegen den Verlust an trockener Wärme und Verdunstungswiderstand) unter stationären Prüfbedingungen für eine Bekleidungskombination fest, die sich auf Werten für bekannte Kleidungsstücke, Bekleidungskombinationen und Textilien begründet. Sie behandelt den Einfluss von Körperbewegungen und des Luftdurchganges durch die Kleidung auf die Wärmeisolation und den Verdunstungswiderstand.
Diese Internationale Norm behandelt nicht
   andere Wirkungen der Bekleidung wie Wasseraufnahme, Pufferwirkung und Tragekomfort,
   den Einfluss von Regen und Schnee auf die thermischen Kennwerte,
   spezielle Schutzkleidung (wasser­ oder luftgekühlte Anzüge, beheizte Kleidung) und
die örtliche Wärmeisolation an verschiedenen Körperteilen und die Unbehaglichkeit infolge der Asymmetrie der Bekleidungskombination.

Ergonomie des ambiances thermiques - Détermination de l'isolement thermique et de la résistance à l'évaporation d'une tenue vestimentaire (ISO 9920:2007, Version corrigé 2008-11-01)

L'ISO 9920:2007 spécifie des méthodes pour la détermination des caractéristiques thermiques d'une tenue vestimentaire, dans des conditions d'équilibre, à partir des valeurs de pièces vestimentaires, de tenues et de textiles connus. L'influence des mouvements du corps et de la pénétration de l'air sur l'isolement thermique et sur la résistance à l'évaporation est examinée.
L'ISO 9920:2007 ne traite pas des autres effets des pièces vestimentaires, tels que l'adsorption d'eau, l'effet tampon, le confort au toucher, ne tient pas compte de l'influence de la pluie et de la neige sur les caractéristiques thermiques, n'est pas applicable aux tenues de protection spéciales (tenues refroidies par eau, tenues ventilées, vêtements chauffants), et ne traite pas d'isolements thermiques distincts sur différentes parties du corps, ni de l'inconfort dû à l'asymétrie d'une tenue vestimentaire.

Ergonomija toplotnega okolja - Ocenitev toplotne izolativnosti in odpornosti oblačil proti vodni pari (ISO 9920:2007, popravljena različica 2008-11-01)

Ta mednarodni standard določa metode za ocenitev toplotnih lastnosti (odpornost proti izgubi suhe toplote in izgubi toplote preko izhlapevanja) v ustaljenih pogojih za oblačila, osnovana na vrednostnih za že znane obleke, komplete in tekstilije. Preučuje vplive telesnega gibanja in prodor zraka na toplotno izolacijo in odpornosti proti vlagi.

General Information

Status
Published
Publication Date
16-May-2010
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
06-Apr-2010
Due Date
11-Jun-2010
Completion Date
17-May-2010

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SLOVENSKI STANDARD
SIST EN ISO 9920:2010
01-junij-2010
Nadomešča:
SIST EN ISO 9920:2008
Ergonomija toplotnega okolja - Ocenitev toplotne izolativnosti in odpornosti
oblačil proti vodni pari (ISO 9920:2007, popravljena različica 2008-11-01)

Ergonomics of the thermal environment - Estimation of thermal insulation and water

vapour resistance of a clothing ensemble (ISO 9920:2007, Corrected version 2008-11-

01)
Ergnomie der thermischen Umgebung - Abschätzung der Wärmeisolation und des

Verdunstungswiderstandes einer Bekleidungskombination (ISO 9920:2007, Korrigierte

Fassung 2008-11-01)

Ergonomie des ambiances thermiques - Détermination de l'isolement thermique et de la

résistance à l'évaporation d'une tenue vestimentaire (ISO 9920:2007, Version corrigé

2008-11-01)
Ta slovenski standard je istoveten z: EN ISO 9920:2009
ICS:
13.180 Ergonomija Ergonomics
61.020 Oblačila Clothes
SIST EN ISO 9920:2010 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN ISO 9920:2010
---------------------- Page: 2 ----------------------
SIST EN ISO 9920:2010
EUROPEAN STANDARD
EN ISO 9920
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2009
ICS 13.180; 61.020 Supersedes EN ISO 9920:2007
English Version
Ergonomics of the thermal environment - Estimation of thermal
insulation and water vapour resistance of a clothing ensemble
(ISO 9920:2007, Corrected version 2008-11-01)

Ergonomie des ambiances thermiques - Détermination de Ergnomie 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, Version corrigé Bekleidungskombination (ISO 9920:2007, Korrigierte

2008-11-01) Fassung 2008-11-01)
This European Standard was approved by CEN on 16 May 2009.

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: Avenue Marnix 17, B-1000 Brussels

© 2009 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 9920:2009: E

worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST EN ISO 9920:2010
EN ISO 9920:2009 (E)
Contents Page

Foreword ..............................................................................................................................................................3

---------------------- Page: 4 ----------------------
SIST EN ISO 9920:2010
EN ISO 9920:2009 (E)
Foreword

The text of ISO 9920:2007, corrected version 2008-11-01 has been prepared by Technical Committee

ISO/TC 159 “Ergonomics” of the International Organization for Standardization (ISO) and has been taken over

as EN ISO 9920:2009 by 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 2009, and conflicting national standards shall be withdrawn

at the latest by December 2009.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent

rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.

This document supersedes EN ISO 9920:2007.

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 the United Kingdom.
Endorsement notice

The text of ISO 9920:2007, corrected version 2008-11-01 has been approved by CEN as a EN ISO 9920:2009

without any modification.
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SIST EN ISO 9920:2010
---------------------- Page: 6 ----------------------
SIST EN ISO 9920:2010
INTERNATIONAL ISO
STANDARD 9920
Second edition
2007-06-01
Corrected version
2008-11-01
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
---------------------- Page: 7 ----------------------
SIST EN ISO 9920:2010
ISO 9920:2007(E)
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COPYRIGHT PROTECTED DOCUMENT
© ISO 2007

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,

electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or

ISO's member body in the country of the requester.
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Web www.iso.org
Published in Switzerland
ii © ISO 2007 – All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 9920:2010
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.................................................. 46

Annex C (normative) Vapour permeability index values for clothing ensembles..................................... 73

Annex D (informative) Measurement of thermal insulation and water vapour resistance of clothing

ensembles on a thermal manikin ...................................................................................................... 88

Annex E (informative) Measurement of thermal insulation and water vapour resistance of a

clothing ensemble on human subjects ............................................................................................ 94

Annex F (informative) Different expressions for the thermal insulation of clothing................................. 96

Annex G (informative) Estimation of the heat exchanges for reflective clothing...................................... 98

© ISO 2007 – All rights reserved iii
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SIST EN ISO 9920:2010
ISO 9920:2007(E)

Annex H (informative) Guidance on the determination of the covered body surface area..................... 100

Bibliography ................................................................................................................................................... 102

iv © ISO 2007 – All rights reserved
---------------------- Page: 10 ----------------------
SIST EN ISO 9920:2010
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.

This corrected version of ISO 9920:2007 incorporates the following corrections.
⎯ A value and a symbol missing from Equation (38) have been reinstated.

⎯ In Equation (15), the multiplication symbol has been substituted for an (incorrect) asterisk.

⎯ In Figure A.1, traditional Korean garments erroneously captioned “China” and “Sokchina” have been

corrected to read Chima and Sokchima.

⎯ In Equation (F.8), the subscript of the second representation of “I ” has been changed to I .

cl cli

⎯ In the description of symbol H given with Equation (F.1), the minus sign missing from the superscript

attached to the unit W⋅m has been inserted.

⎯ “Mean skin temperature”, given as the description for t with Equation (G.6), has been corrected to

“mean outer clothing surface temperature”.

⎯ In a number of instances, “weight” has been changed to the accepted ISO term, mass.

⎯ Values in Table A.2, No. 134 for I and I have been corrected.
cl T

⎯ Introductory text similar to that present in the first edition has been reinstated in Annex A, and a new

introductory text has been added to Annex C.
⎯ Some minor editorial corrections and additions have been made.
© ISO 2007 – All rights reserved v
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SIST EN ISO 9920:2010
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
---------------------- Page: 12 ----------------------
SIST EN ISO 9920:2010
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
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.

© ISO 2007 – All rights reserved 1
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SIST EN ISO 9920:2010
ISO 9920:2007(E)
2.1.1
total insulation

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)
where
t is the mean skin surface temperature, in degrees Celsius;

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

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)
where t is the mean outer clothing surface temperature, in degrees Celsius.
2.1.3
air insulation

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)

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:
I = (5)
hh+
2 © ISO 2007 – All rights reserved
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SIST EN ISO 9920:2010
ISO 9920:2007(E)
where
−2 −1

h is the convective heat transfer coefficient, in watts per square metre Kelvin (W ⋅ m ⋅ K );

−2 −1

h is the radiative heat transfer coefficient, in watts per square metre Kelvin (W ⋅ m ⋅ K ).

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

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:
f = (6)

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):

II=+ (7)
Tcl
© ISO 2007 – All rights reserved 3
---------------------- Page: 15 ----------------------
SIST EN ISO 9920:2010
ISO 9920:2007(E)
2.1.5
resultant total insulation
dynamic total insulation
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

of movements and wind. Values for Ι given in this International Standard and in most of the literature are obtained on a

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
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

the effects of movements and wind.
2.1.7
effective insulation
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
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 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

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)
evaporative heat loss per unit of body surface area
NOTE 2 Similarly to heat resistance, it is divided into specific layers.
4 © ISO 2007 – All rights reserved
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SIST EN ISO 9920:2010
ISO 9920:2007(E)
2.2.1
total water vapour resistance
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
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
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:
e,a
RR=+ (10)
e,T e,cl
2.2.4
resultant total water vapour resistance
dynamic total water vapour resistance
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.

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
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.

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.
© ISO 2007 – All rights reserved 5
---------------------- Page: 17 ----------------------
SIST EN ISO 9920:2010
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 clot
...

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SIST EN ISO 9920:2010
01-junij-2010
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Ergonomics of the thermal environment - Estimation of thermal insulation and water

vapour resistance of a clothing ensemble (ISO 9920:2007, Corrected version 2008-11-

01)
Ergnomie der thermischen Umgebung - Abschätzung der Wärmeisolation und des

Verdunstungswiderstandes einer Bekleidungskombination (ISO 9920:2007, Korrigierte

Fassung 2008-11-01)

Ergonomie des ambiances thermiques - Détermination de l'isolement thermique et de la

résistance à l'évaporation d'une tenue vestimentaire (ISO 9920:2007, Version corrigé

2008-11-01)
Ta slovenski standard je istoveten z: EN ISO 9920:2009
ICS:
13.180 Ergonomija Ergonomics
61.020 2EODþLOD Clothes
SIST EN ISO 9920:2010 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 9920:2010
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SIST EN ISO 9920:2010
EUROPEAN STANDARD
EN ISO 9920
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2009
ICS 13.180; 61.020 Supersedes EN ISO 9920:2007
English Version
Ergonomics of the thermal environment - Estimation of thermal
insulation and water vapour resistance of a clothing ensemble
(ISO 9920:2007, Corrected version 2008-11-01)

Ergonomie des ambiances thermiques - Détermination de Ergnomie 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, Version corrigé Bekleidungskombination (ISO 9920:2007, Korrigierte

2008-11-01) Fassung 2008-11-01)
This European Standard was approved by CEN on 16 May 2009.

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: Avenue Marnix 17, B-1000 Brussels

© 2009 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 9920:2009: E

worldwide for CEN national Members.
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SIST EN ISO 9920:2010
EN ISO 9920:2009 (E)
Contents Page

Foreword ..............................................................................................................................................................3

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SIST EN ISO 9920:2010
EN ISO 9920:2009 (E)
Foreword

The text of ISO 9920:2007, corrected version 2008-11-01 has been prepared by Technical Committee

ISO/TC 159 “Ergonomics” of the International Organization for Standardization (ISO) and has been taken over

as EN ISO 9920:2009 by 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 2009, and conflicting national standards shall be withdrawn

at the latest by December 2009.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent

rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.

This document supersedes EN ISO 9920:2007.

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 the United Kingdom.
Endorsement notice

The text of ISO 9920:2007, corrected version 2008-11-01 has been approved by CEN as a EN ISO 9920:2009

without any modification.
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SIST EN ISO 9920:2010
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SIST EN ISO 9920:2010
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 9920:2010
ISO 9920:2007(E)
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© ISO 2007

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,

electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or

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ii © ISO 2007 – All rights reserved
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SIST EN ISO 9920:2010
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

© ISO 2007 – All rights reserved iii
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SIST EN ISO 9920:2010
ISO 9920:2007(E)

Annex H (informative) Guidance on the determination of the covered body surface area....................... 99

Bibliography ................................................................................................................................................... 101

iv © ISO 2007 – All rights reserved
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SIST EN ISO 9920:2010
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.

© ISO 2007 – All rights reserved v
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SIST EN ISO 9920:2010
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 9920:2010
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
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.

© ISO 2007 – All rights reserved 1
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SIST EN ISO 9920:2010
ISO 9920:2007(E)
2.1.1
total insulation

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)
where
t is the mean skin surface temperature, in degrees Celsius;

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

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)
where t is the mean outer clothing surface temperature, in degrees Celsius.
2.1.3
air insulation

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)

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:
I = (5)
hh+
2 © ISO 2007 – All rights reserved
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SIST EN ISO 9920:2010
ISO 9920:2007(E)
where
−2 −1

h is the convective heat transfer coefficient, in watts per square metre Kelvin (W ⋅ m ⋅ K );

−2 −1

h is the radiative heat transfer coefficient, in watts per square metre Kelvin (W ⋅ m ⋅ K ).

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

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:
f = (6)

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):

II=+ (7)
Tcl
© ISO 2007 – All rights reserved 3
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SIST EN ISO 9920:2010
ISO 9920:2007(E)
2.1.5
resultant total insulation
dynamic total insulation
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

of movements and wind. Values for Ι given in this International Standard and in most of the literature are obtained on a

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
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

the effects of movements and wind.
2.1.7
effective insulation
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
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 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

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)
evaporative heat loss per unit of body surface area
NOTE 2 Similarly to heat resistance, it is divided into specific layers.
4 © ISO 2007 – All rights reserved
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SIST EN ISO 9920:2010
ISO 9920:2007(E)
2.2.1
total water vapour resistance
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
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
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:
e,a
RR=+ (10)
e,T e,cl
2.2.4
resultant total water vapour resistance
dynamic total water vapour resistance
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.

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
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.

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.
© ISO 2007 – All rights reserved 5
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SIST EN ISO 9920:2010
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
6 © ISO 2007 – All rights reserved
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SIST EN ISO 9920:2010
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.
© ISO 2007 – All rights reserved 7
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...

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