ISO 9920:2007
(Main)Ergonomics of the thermal environment — Estimation of thermal insulation and water vapour resistance of a clothing ensemble
Ergonomics of the thermal environment — Estimation of thermal insulation and water vapour resistance of a clothing ensemble
ISO 9920:2007 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. It 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.
Ergonomie des ambiances thermiques — Détermination de l'isolement thermique et de la résistance à l'évaporation d'une tenue vestimentaire
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.
General Information
Relations
Buy Standard
Standards Content (Sample)
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: 1 ----------------------
ISO 9920:2007(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
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.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2007 – All rights reserved
---------------------- Page: 2 ----------------------
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
---------------------- Page: 3 ----------------------
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: 4 ----------------------
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
−2
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
cl
“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
---------------------- Page: 5 ----------------------
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: 6 ----------------------
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
© ISO 2007 – All rights reserved 1
---------------------- Page: 7 ----------------------
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
2 © ISO 2007 – All rights reserved
---------------------- Page: 8 ----------------------
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
© ISO 2007 – All rights reserved 3
---------------------- Page: 9 ----------------------
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.
4 © ISO 2007 – All rights reserved
---------------------- Page: 10 ----------------------
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.
© ISO 2007 – All rights reserved 5
---------------------- Page: 11 ----------------------
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
---------------------- Page: 12 ----------------------
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
---------------------- Page: 13 ----------------------
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 figures.
Annex A can also be used to select clothing for a workplace when the required insulation is known.
4.3 Ensemble thermal insulation values based on individual garments
Instead of using the ensembles in Annex A, the insulation for an ensemble, I , expressed in clo, may also be
cl
estimated, based on a summation of the insulation of individual garments using the following empirical
[31], [36]
equation :
I=+0,161 0,835 I (11)
cl ∑ clu
expressed in clo.
[32], [37]
Or, with slightly reduced accuracy :
I = I (12)
cl ∑ clu
expressed in square metres Kelvin per watt, or clo, and where I is the effective thermal insulation of the
clu
individual garments making up the ensemble, in values of either square metres Kelvin per watt or clo.
Such values are listed in Annex B.
The design of the various garments in Annex B is indicated by a type number, referring to drawings showing a
person dressed in various garment designs (Figures B.1 to B.14).
In some cases, the fabrics used are also listed. The type of material, however, has a limited influence on the
thermal insulation. Instead, the insulation is mainly influenced by the thickness (indicated in Annex B) and the
body surface area covered (indicated on the drawings).
It should be noted that the summations presented in Equations (11) and (12) are based on data with rather
uniform insulation distributions over the body. Such summations should not be used for extreme situations
(e.g. three layers on lower body and only a thin layer on upper body). The accuracy of the summation was
acceptable when actually measured data for the respective garments were used. When the separate
garments’ insulations were obtained from the tables, the accuracy of the summation was limited. Hence, it is
preferable to work with values of full ensembles (see Annex A).
The application range for which these relationships [Equations (11) and (12)] were tested is between 0,2 clo
and 1,6 clo.
4.4 Complete ensemble insulation corrected for small differences in composition
The accuracy of the summation of individual garments (4.3) is much less than that of matching the actual
ensemble with an ensemble taken from Annex A (4.2). Hence, when an exact match of the actual ensemble
with those of the tables of Annex A is not possible, but similar ensembles can be found, it is best to take the
similar ensemble insulation value and correct this for the difference in ensemble composition. For example, if
the actual ensemble has a different type of sweater, the ensemble insulation may be corrected for the
difference in insulation between the actual sweater and that of the sweater in the ensemble description of
8 © ISO 2007 – All rights reserved
---------------------- Page: 14 ----------------------
ISO 9920:2007(E)
Annex A. For this purpose, the effective insulations of both clothing items are compared and the difference
used for adjustment of the ensemble value:
I =+II0,835×∆ (13)
cl,a cl,A clu
2 −1
with the result expressed in clo or in m⋅K⋅W , and where I is the basic insulation of the actual ensemble,
cl,a
I is the basic insulation of the ensemble according to Annex A, and ∆I is the correction for the difference
cl,A clu
in individual garments (negative for subtracting a garment or when replacing with a less insulative garment).
This can be the difference between two garments of the same type (replacing one sweater
...
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
---------------------- Page: 1 ----------------------
ISO 9920:2007(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
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.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2007 – All rights reserved
---------------------- Page: 2 ----------------------
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
---------------------- Page: 3 ----------------------
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
---------------------- Page: 4 ----------------------
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
---------------------- Page: 5 ----------------------
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: 6 ----------------------
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
© ISO 2007 – All rights reserved 1
---------------------- Page: 7 ----------------------
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
2 © ISO 2007 – All rights reserved
---------------------- Page: 8 ----------------------
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
© ISO 2007 – All rights reserved 3
---------------------- Page: 9 ----------------------
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.
4 © ISO 2007 – All rights reserved
---------------------- Page: 10 ----------------------
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.
© ISO 2007 – All rights reserved 5
---------------------- Page: 11 ----------------------
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
---------------------- Page: 12 ----------------------
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
---------------------- Page: 13 ----------------------
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 figures.
Annex A can also be used to select clothing for a workplace when the required insulation is known.
4.3 Ensemble thermal insulation values based on individual garments
Instead of using the ensembles in Annex A, the insulation for an ensemble, I , expressed in clo, may also be
cl
estimated, based on a summation of the insulation of individual garments using the following empirical
[31], [36]
equation :
I=+0,161 0,835 I (11)
cl ∑ clu
expressed in clo.
[32], [37]
Or, with slightly reduced accuracy :
I = I (12)
cl ∑ clu
expressed in square metres Kelvin per watt, or clo, and where I is the effective thermal insulation of the
clu
individual garments making up the ensemble, in values of either square metres Kelvin per watt or clo.
Such values are listed in Annex B.
The design of the various garments in Annex B is indicated by a type number, referring to drawings showing a
person dressed in various garment designs (Figures B.1 to B.14).
In some cases, the fabrics used are also listed. The type of material, however, has a limited influence on the
thermal insulation. Instead, the insulation is mainly influenced by the thickness (indicated in Annex B) and the
body surface area covered (indicated on the drawings).
It should be noted that the summations presented in Equations (11) and (12) are based on data with rather
uniform insulation distributions over the body. Such summations should not be used for extreme situations
(e.g. three layers on lower body and only a thin layer on upper body). The accuracy of the summation was
acceptable when actually measured data for the respective garments were used. When the separate
garments’ insulations were obtained from the tables, the accuracy of the summation was limited. Hence, it is
preferable to work with values of full ensembles (see Annex A).
The application range for which these relationships [Equations (11) and (12)] were tested is between 0,2 clo
and 1,6 clo.
4.4 Complete ensemble insulation corrected for small differences in composition
The accuracy of the summation of individual garments (4.3) is much less than that of matching the actual
ensemble with an ensemble taken from Annex A (4.2). Hence, when an exact match of the actual ensemble
with those of the tables of Annex A is not possible, but similar ensembles can be found, it is best to take the
similar ensemble insulation value and correct this for the difference in ensemble composition. For example, if
the actual ensemble has a different type of sweater, the ensemble insulation may be corrected for the
difference in insulation between the actual sweater and that of the sweater in the ensemble description of
8 © ISO 2007 – All rights reserved
---------------------- Page: 14 ----------------------
ISO 9920:2007(E)
Annex A. For this purpose, the effective insulations of both clothing items are compared and the difference
used for adjustment of the ensemble value:
I =+II0,835×∆ (13)
cl,a cl,A clu
2 −1
with the result expressed in clo or in m⋅k⋅w , and where I is the basic insulation of the actual ensemble,
cl,a
I is the basic insulation of the ensemble according to Annex A, and ∆I is the correction for the difference
c l , A clu
in individual garments (negative for subtracting a garment or when replacing with a less insulative garment).
This can be the difference between two garments of the same type (replacing one sweater by another), or the
effective insulation of an extra garment, or a negative value in the case where the actual ensemble contains
one garment less. The I values are taken from Annex B.
clu
Corrections should be kept to a minimum, and interpolation between two relevant ensembles is preferred. In
adding and removing garments, it should be considered how the insulation is distributed. Adding a thin layer to
an already covered part of a cold weather ensemble will have minimal impact, compared with the large impact
of adding a thin layer to a nude part in such an ensemble.
4.5 Calculation of thermal insulation for clothing ensembles
As an alternative to the selection of an ensemble from the tables, it is also possible to determine the clothing
[32], [37]
insulation of an ensemble using the following empirically determined relationship :
Im=+0,919 0,255×− 0,008 74×A − 0,005 10×A (14)
cl COV,0 COV,1
where
I is the intrinsic clothing insulation, in clo;
cl
m is the clothing weight (without shoes), in kilograms;
A is the body surface area not covered by clothing, as a percentage of total body surface area;
COV,0
A is the body surface area covered by a single clothing layer, as a
...
NORME ISO
INTERNATIONALE 9920
Deuxième édition
2007-06-01
Ergonomie des ambiances thermiques —
Détermination de l'isolement thermique et
de la résistance à l'évaporation d'une
tenue vestimentaire
Ergonomics of the thermal environment — Estimation of thermal
insulation and water vapour resistance of a clothing ensemble
Numéro de référence
ISO 9920:2007(F)
©
ISO 2007
---------------------- Page: 1 ----------------------
ISO 9920:2007(F)
PDF – Exonération de responsabilité
Le présent fichier PDF peut contenir des polices de caractères intégrées. Conformément aux conditions de licence d'Adobe, ce fichier
peut être imprimé ou visualisé, mais ne doit pas être modifié à moins que l'ordinateur employé à cet effet ne bénéficie d'une licence
autorisant l'utilisation de ces polices et que celles-ci y soient installées. Lors du téléchargement de ce fichier, les parties concernées
acceptent de fait la responsabilité de ne pas enfreindre les conditions de licence d'Adobe. Le Secrétariat central de l'ISO décline toute
responsabilité en la matière.
Adobe est une marque déposée d'Adobe Systems Incorporated.
Les détails relatifs aux produits logiciels utilisés pour la création du présent fichier PDF sont disponibles dans la rubrique General Info
du fichier; les paramètres de création PDF ont été optimisés pour l'impression. Toutes les mesures ont été prises pour garantir
l'exploitation de ce fichier par les comités membres de l'ISO. Dans le cas peu probable où surviendrait un problème d'utilisation,
veuillez en informer le Secrétariat central à l'adresse donnée ci-dessous.
DOCUMENT PROTÉGÉ PAR COPYRIGHT
© ISO 2007
Droits de reproduction réservés. Sauf prescription différente, aucune partie de cette publication ne peut être reproduite ni utilisée sous
quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie et les microfilms, sans l'accord écrit
de l'ISO à l'adresse ci-après ou du comité membre de l'ISO dans le pays du demandeur.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax. + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Version française parue en 2008
Publié en Suisse
ii © ISO 2007 – Tous droits réservés
---------------------- Page: 2 ----------------------
ISO 9920:2007(F)
Sommaire Page
Avant-propos. v
Introduction . vi
1 Domaine d'application. 1
2 Termes et définitions. 1
3 Application de logigrammes décrivant la manière d'utiliser la présente Norme
internationale . 6
4 Estimation de l'isolement thermique d'une tenue vestimentaire à partir de tableaux de
valeurs mesurées sur un mannequin thermique debout. 7
4.1 Généralités . 7
4.2 Valeurs d'isolement thermique des tenues complètes. 8
4.3 Valeurs d'isolement thermique des tenues complètes basées sur les pièces
vestimentaires. 8
4.4 Correction de l'isolement thermique de tenues vestimentaires complètes pour de faibles
différences de composition . 9
4.5 Calcul de l'isolement thermique des tenues vestimentaires . 9
4.6 Calcul de l'isolement thermique des pièces vestimentaires. 10
5 Estimation du facteur de surface du vêtement. 10
6 Estimation de l'isolement thermique de la couche d'air (ou limite) superficielle . 11
7 Estimation de la résistance à l'évaporation .12
7.1 Généralités . 12
7.2 Estimation de la résistance au transfert de vapeur d'une tenue vestimentaire à partir de
tableaux de valeurs mesurées sur un mannequin thermique debout. 12
7.3 Estimation de la résistance au transfert de vapeur d'une tenue vestimentaire sur la base
de sa relation avec la résistance au transfert de chaleur sèche . 12
8 Influence du mouvement du corps et de l'air sur l'isolement thermique et sur la résistance
au transfert de vapeur d'une tenue vestimentaire. 13
8.1 Généralités . 13
8.2 Correction de l'isolement thermique du vêtement. 14
8.3 Correction de la résistance au transfert de vapeur d'un vêtement . 19
8.4 Activités autres que la marche. 21
8.5 Vitesse relative de l'air . 21
9 Autres facteurs d'influence de l'isolement thermique du vêtement. 23
9.1 Généralités . 23
9.2 Posture. 23
9.3 Effet du siège . 23
9.4 Effet de la pression. 23
9.5 Vêtement mouillé . 23
9.6 Lavage. 23
Annexe A (normative) Valeurs de l'isolement thermique des tenues vestimentaires . 24
Annexe B (normative) Valeurs de l'isolement thermique des pièces vestimentaires. 51
Annexe C (normative) Valeurs de l'indice de perméabilité à la vapeur des tenues vestimentaires. 79
Annexe D (informative) Mesurage de l'isolement thermique et de la résistance au transfert de
vapeur des vêtements sur un mannequin thermique . 95
Annexe E (informative) Mesurage de l'isolement thermique et de la résistance au transfert de
vapeur d'une tenue vestimentaire sur des sujets humains . 102
© ISO 2007 – Tous droits réservés iii
---------------------- Page: 3 ----------------------
ISO 9920:2007(F)
Annexe F (informative) Différentes expressions de l'isolement thermique d'un vêtement. 104
Annexe G (informative) Détermination des échanges de chaleur pour des vêtements
réfléchissants . 106
Annexe H (informative) Lignes directrices pour déterminer la surface du corps recouverte . 108
Bibliographie . 110
iv © ISO 2007 – Tous droits réservés
---------------------- Page: 4 ----------------------
ISO 9920:2007(F)
Avant-propos
L'ISO (Organisation internationale de normalisation) est une fédération mondiale d'organismes nationaux de
normalisation (comités membres de l'ISO). L'élaboration des Normes internationales est en général confiée
aux comités techniques de l'ISO. Chaque comité membre intéressé par une étude a le droit de faire partie du
comité technique créé à cet effet. Les organisations internationales, gouvernementales et non
gouvernementales, en liaison avec l'ISO participent également aux travaux. L'ISO collabore étroitement avec
la Commission électrotechnique internationale (CEI) en ce qui concerne la normalisation électrotechnique.
Les Normes internationales sont rédigées conformément aux règles données dans les Directives ISO/CEI,
Partie 2.
La tâche principale des comités techniques est d'élaborer les Normes internationales. Les projets de Normes
internationales adoptés par les comités techniques sont soumis aux comités membres pour vote. Leur
publication comme Normes internationales requiert l'approbation de 75 % au moins des comités membres
votants.
L'attention est appelée sur le fait que certains des éléments du présent document peuvent faire l'objet de
droits de propriété intellectuelle ou de droits analogues. L'ISO ne saurait être tenue pour responsable de ne
pas avoir identifié de tels droits de propriété et averti de leur existence.
L'ISO 9920 a été élaborée par le comité technique ISO/TC 159, Ergonomie, sous-comité SC 4, Ergonomie de
l'environnement physique.
Cette deuxième édition annule et remplace la première édition (ISO 9920:1995), qui a fait l'objet d'une
révision technique. Les principales modifications apportées concernent les sections relatives à la résistance à
l'évaporation des vêtements et aux effets des mouvements de l'air et du corps sur l'isolement thermique et la
résistance à l'évaporation des vêtements.
La présente version française de l'ISO 9920 correspond à la version anglaise publiée le 2007-06-01 et
corrigée le 2008-11-01.
© ISO 2007 – Tous droits réservés v
---------------------- Page: 5 ----------------------
ISO 9920:2007(F)
Introduction
La présente Norme internationale fait partie d'une série de Normes internationales consacrées à l'étude des
ambiances thermiques. Elle constitue un document de référence pour l'évaluation des caractéristiques
thermiques d'une tenue vestimentaire (isolement thermique et résistance à l'évaporation). Il est nécessaire de
connaître ces valeurs lors de l'évaluation de la contrainte thermique ou du niveau de confort apportés par
l'environnement physique selon les méthodes normalisées. Les caractéristiques thermiques déterminées au
moyen de la présente Norme internationale sont des valeurs correspondant à des conditions d'équilibre. Les
phénomènes tels que l'effet tampon, l'adsorption d'eau, etc. n'y sont pas traités.
La présente Norme internationale est centrée sur l'estimation des caractéristiques thermiques. La résistance
aux transferts de chaleur et de vapeur peut également faire l'objet d'une mesure directe, exposée dans les
annexes.
La présente Norme internationale ne traite pas de l'isolement thermique local sur différentes parties du corps,
ni de l'inconfort dû à une répartition non uniforme du vêtement sur le corps.
Le bilan thermique de l'homme dans des ambiances neutre, froide ou chaude est influencé par les vêtements
qu'il porte. Pour évaluer la contrainte thermique exercée sur l'homme dans une ambiance froide [indice de
l'isolement requis des vêtements – IREQ (voir l'ISO/TR 11079)], neutre [indices PMV-PPD (voir l'ISO 7730)] et
chaude [indice d'astreinte thermique prévisible – PHS (voir l'ISO 7933)], il est nécessaire de connaître les
caractéristiques thermiques de la tenue vestimentaire, à savoir l'isolement thermique et la résistance à
l'évaporation.
vi © ISO 2007 – Tous droits réservés
---------------------- Page: 6 ----------------------
NORME INTERNATIONALE ISO 9920:2007(F)
Ergonomie des ambiances thermiques — Détermination de
l'isolement thermique et de la résistance à l'évaporation d'une
tenue vestimentaire
1 Domaine d'application
La présente Norme internationale spécifie des méthodes pour la détermination des caractéristiques
thermiques (résistance aux pertes de chaleur sèche et aux pertes de chaleur par évaporation) 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.
La présente Norme internationale:
⎯ 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);
⎯ ne traite pas d'isolements thermiques distincts sur différentes parties du corps, ni de l'inconfort dû à
l'asymétrie d'une tenue vestimentaire.
2 Termes et définitions
Pour les besoins du présent document, les termes et définitions suivants s'appliquent.
2.1
isolement thermique
I
résistance au transfert de chaleur sèche entre deux surfaces, exprimée en mètres carrés kelvin par watt
2 −1
(m⋅K⋅W )
NOTE 1 Pour les besoins de la présente Norme internationale, elle est définie comme la résistance thermique
uniforme équivalente, ou isolement thermique, sur le corps humain. Il s'agit de la résistance thermique d'un vêtement
(isolement thermique) qui, recouvrant de manière uniforme toute la surface du corps (y compris les mains, le visage, etc.),
entraînerait les mêmes pertes de chaleur que la tenue réelle, éventuellement non uniforme. Cette résistance est égale au
quotient du gradient de température entre les surfaces (force motrice) par la perte de chaleur sèche par unité de surface
cutanée (l'écoulement):
gradient de température
I= (1)
perte de chaleur par unité de surface corporelle
Pour le corps humain, cette résistance peut être divisée en couches spécifiques, comme illustré à la Figure 1 (voir
également Annexe F).
© ISO 2007 – Tous droits réservés 1
---------------------- Page: 7 ----------------------
ISO 9920:2007(F)
NOTE 2 Du fait de la définition particulière de l'isolement thermique dans la présente Norme internationale, ce dernier
est généralement exprimé en «clo», l'unité de l'isolement thermique d'un vêtement. Bien que cette unité puisse être
convertie en unités SI semblables à celles de l'isolement thermique, par exemple d'échantillons textiles (symbole: R ;
ct
2 −1
1 clo = 0,155 m ·°K·W ), la signification est différente.
2.1.1
isolement thermique total
I
T
isolement thermique existant entre la surface corporelle et l'ambiance (comprenant l'ensemble des vêtements,
les couches d'air emprisonnées et la couche limite d'air), dans des conditions de référence statiques
Voir Figure 1.
NOTE Sur la base de l'Équation (1), il est exprimé comme suit:
tt−
sk o
I = (2)
T
H
où
t est la température surfacique cutanée moyenne, en degrés Celsius;
sk
t est la température opérative, en degrés Celsius (dans la plupart des cas, égale à la température de l'air t );
o a
H est la perte de chaleur sèche par mètre carré de surface cutanée, en watts par mètre carré.
2.1.2
isolement thermique de base
isolement thermique intrinsèque
I
cl
isolement thermique existant entre la surface corporelle et la surface extérieure du vêtement (y compris les
couches d'air emprisonnées), dans des conditions de référence statiques
Voir Figure 1.
NOTE Sur la base de l'Équation (1), il est exprimé comme suit:
tt−
sk cl
I = (3)
cl
H
où t est la température moyenne de la surface extérieure du vêtement, en degrés Celsius.
cl
2.1.3
isolement thermique dû à l'air
I
a
isolement thermique de la couche limite d'air à la périphérie de la surface extérieure du vêtement ou, lorsque
le corps est nu, de la peau
Voir Figure 1.
NOTE 1 Sur la base de l'Équation (1), il est exprimé comme suit:
tt−
cl o
I = (4)
a
H
NOTE 2 La perte de chaleur sèche comprend la perte de chaleur par rayonnement et la perte de chaleur par
convection (voir l'Annexe G). Dans le cadre de la présente Norme internationale, ces modes de transfert de chaleur à
travers les couches vestimentaires ne sont pas distingués. Ils peuvent cependant l'être au niveau de la couche d'air. La
représentation alternative de I est alors:
a
1
I = (5)
a
hh+
cr
2 © ISO 2007 – Tous droits réservés
---------------------- Page: 8 ----------------------
ISO 9920:2007(F)
où
−2 −1
h est le coefficient de transfert de chaleur par convection, en watts par mètre carré par kelvin (W·m ·K );
c
−2 −1
h est le coefficient de transfert de chaleur par rayonnement, en watts par mètre carré par kelvin (W·m ·K );
r
NOTE 3 Ces valeurs sont définies pour des conditions normalisées (corps statique, vent calme, c'est-à-dire avec une
−1
vitesse d'air < 0,2 m·s ). Tout mouvement de l'air ou du corps affecte la résistance thermique (il la réduit généralement).
On parlera, dans ce cas, de résistance thermique résultante ou dynamique.
Légende
1 couche d'air de surface
2 couche d'air emprisonnée
3 vêtement
4 corps
Figure 1 — Représentation schématique de l'isolement thermique total,
de l'isolement thermique de base et de l'isolement thermique dû à l'air
2.1.4
facteur de surface du vêtement
f
cl
rapport de la surface extérieure du corps vêtu à la surface du corps nu
NOTE 1 La surface extérieure du corps vêtu, A , est supérieure à la surface du corps nu, A . Leur rapport est par
cl Du
conséquent plus grand que 1.
A
cl
f = (6)
cl
A
Du
NOTE 2 L'isolement de base et l'isolement dû à l'air ne viennent pas s'ajouter simplement pour donner l'isolement total.
Cela est dû à la différence de surface (aire) entre la surface extérieure du vêtement et celle de la peau, la première étant
plus grande que la seconde. Cette plus grande surface entraîne une réduction de l'effet isolant pour le corps de
l'isolement thermique de l'air (plus le vêtement est épais, plus la surface extérieure du vêtement est grande):
I
a
II=+ (7)
Tcl
f
cl
© ISO 2007 – Tous droits réservés 3
---------------------- Page: 9 ----------------------
ISO 9920:2007(F)
2.1.5
isolement thermique total résultant
isolement thermique total dynamique
I
T,r
isolement thermique existant entre la surface corporelle et l'ambiance (comprenant l'ensemble des vêtements,
les couches d'air emprisonnées et la couche limite d'air), pour des conditions d'ambiance et d'activité données
NOTE C'est la valeur d'isolement thermique total en situations réelles (contrairement aux conditions de référence)
comprenant les effets des mouvements et du vent. Les valeurs de Ι énumérées dans la présente Norme internationale et
T
dans la plupart de la documentation technique correspondante sont obtenues sur un mannequin thermique statique dans
des conditions de vent faible. Ces valeurs doivent être corrigées pour les effets du vent et des mouvements.
2.1.6
isolement thermique de base résultant
isolement thermique de base dynamique
I
cl,r
isolement thermique existant entre la surface corporelle et la surface extérieure du vêtement (comprenant les
couches d'air emprisonnées), pour des conditions d'ambiance et d'activité données
NOTE Il s'agit de la valeur d'isolement de base (intrinsèque) (I ) en situations réelles (contrairement aux conditions
cl
de référence) comprenant les effets des mouvements et du vent.
2.1.7
isolement thermique effectif
Ι
clu
augmentation de l'isolement thermique mesurée sur un mannequin thermique portant une pièce vestimentaire
comparée à la valeur d'isolement thermique sur mannequin nu
NOTE Le terme isolement thermique effectif (Ι ) est utilisé pour l'isolement thermique des pièces vestimentaires
clu
individuelles. L'isolement thermique effectif des pièces vestimentaires individuelles composant la tenue (voir Tableau B.2)
est déterminé sur un mannequin thermique portant uniquement la pièce vestimentaire considérée, de la manière suivante:
tt−
sk o
I =−II= −I (8)
clu T a a
H
où
2 −1
Ι est l'isolement thermique total de la pièce vestimentaire, en mètres carrés kelvin par watt (m ⋅K ⋅ W ) ou en
T
clo;
t est la température opérative, en degrés Celsius (pour la plupart des conditions de mesure dans des chambres
o
climatiques, elle est égale à la température de l'air t ).
a
2.2
résistance à l'évaporation
résistance évaporatoire
R
e
résistance au transfert de vapeur d'eau entre deux surfaces, exprimée en mètres carrés kilopascals par watt
NOTE 1 Pour les besoins de la présente Norme internationale, elle est définie comme la résistance uniforme
équivalente au transfert de vapeur. Il s'agit de la résistance évaporatoire d'un vêtement qui, recouvrant de manière
uniforme toute la surface du corps (y compris les mains, le visage, etc.), entraînerait les mêmes pertes de chaleur par
évaporation que la tenue réelle, éventuellement non uniforme. Cette résistance est égale au quotient du gradient de
pression de vapeur entre les surfaces (force motrice) par la perte de chaleur par évaporation par unité de surface cutanée
gradient de pression de vapeur
R = (9)
e
perte de chaleur par évaporation par unité de surface corporelle
NOTE 2 De la même manière que la résistance à la chaleur sèche, elle est divisée en couches spécifiques:
4 © ISO 2007 – Tous droits réservés
---------------------- Page: 10 ----------------------
ISO 9920:2007(F)
2.2.1
résistance totale à l'évaporation
R
e,T
résistance au transfert de vapeur existant entre la surface corporelle et l'ambiance (comprenant l'ensemble
des vêtements, les couches d'air emprisonnées et la couche limite d'air), dans des conditions de référence
statiques
2.2.2
résistance de base à l'évaporation
résistance intrinsèque à l'évaporation
R
e,cl
résistance au transfert de vapeur entre la surface corporelle et la surface extérieure du vêtement (y compris
les couches d'air emprisonnées), dans des conditions de référence statiques
2.2.3
résistance à l'évaporation due à l'air
R
e,a
résistance au transfert de vapeur due à la couche limite d'air à la périphérie de la surface extérieure du
vêtement ou, lorsque le corps est nu, de la peau
NOTE Par analogie à la résistance thermique:
R
e,a
RR=+ (10)
e,T e,cl
f
cl
2.2.4
résistance totale à l'évaporation résultante
résistance totale à l'évaporation dynamique
R
e,T,r
résistance au transfert de vapeur existant entre la surface corporelle et l'ambiance (comprenant l'ensemble
des vêtements, les couches d'air emprisonnées et la couche limite d'air), pour des conditions d'ambiance et
d'activité données
NOTE 1 Il s'agit de la valeur de la résistance totale à l'évaporation en situations réelles (R ) (contrairement aux
e,T
conditions de référence) comprenant les effets des mouvements et du vent.
NOTE 2 Les valeurs de R sont définies pour des conditions normalisées (corps statique, vent calme, c'est-à-dire
e,T
−1
avec une vitesse d'air < 0,2 m·s ). Tout mouvement de l'air ou du corps affecte la résistance à l'évaporation (il la réduit
généralement). On parlera, dans ce cas, de résistance totale à l'évaporation résultante ou dynamique.
2.2.5
résistance de base à l'évaporation résultante
résistance de base à l'évaporation dynamique
R
e,cl,r
résistance au transfert de vapeur existant entre la surface corporelle et la surface extérieure du vêtement (y
compris les couches d'air emprisonnées) pour des conditions d'ambiance et d'activité données
NOTE 1 Il s'agit de la valeur de la résistance de base à l'évaporation (R ) en situations réelles (contrairement aux
e,cl
conditions de référence) comprenant les effets des mouvements et du vent.
NOTE 2 Les valeurs de R sont définies pour des conditions normalisées (corps statique, vent calme, c'est-à-dire
e,cl
−1
avec une vitesse d'air < 0,2 m·s ). Tout mouvement de l'air ou du corps affecte la résistance à l'évaporation (il la réduit
généralement). On parlera, dans ce cas, de résistance de base à l'évaporation résultante ou dynamique.
© ISO 2007 – Tous droits réservés 5
---------------------- Page: 11 ----------------------
ISO 9920:2007(F)
3 Application de logigrammes décrivant la manière d'utiliser la présente Norme
internationale
Dans la mesure du possible, il convient de mesurer les valeurs d'isolement et de résistance à l'évaporation en
utilisant des équipements tels que des mannequins thermiques (mouillés ou transpirants) ou en effectuant des
expérimentations avec des sujets humains. Les méthodes d'essai pour la mesure des résistances thermique
et à l'évaporation des vêtements sont décrites dans les Annexes D et E. Cependant, en raison du coût et des
équipements spécialisés à utiliser, cette méthode réelle de mesure n'est pas à la portée de la plupart des
utilisateurs de la présente Norme internationale. Dans ce cas, l'isolement thermique et la résistance au
transfert de vapeur doivent être mesurés en utilisant les méthodes décrites dans les articles qui suivent et les
Annexes A, B et C.
Afin d'illustrer la démarche progressive, deux organigrammes sont respectivement fournis à la Figure 2, pour
la détermination de la résistance thermique et à la Figure 3 pour la détermination de la résistance au transfert
de vapeur. Les diverses options correspondantes sont décrites.
Figure 2 — Logigramme pour la détermination de l'isolement thermique du vêtement
6 © ISO 2007 – Tous droits réservés
---------------------- Page: 12 ----------------------
ISO 9920:2007(F)
Figure 3 — Logigramme pour la détermination de la résistance du vêtement au transfert de vapeur
4 Estimation de l'isolement thermique d'une tenue vestimentaire à partir
de tableaux de valeurs mesurées sur un mannequin thermique debout
4.1 Généralités
Le présent article fournit des tableaux de données concernant l'isolement de tenues vestimentaires complètes,
ainsi que des tableaux de valeurs d'isolement thermique pour des pièces vestimentaires pouvant être
ajoutées afin de reconstituer des tenues complètes. Il est recommandé d'utiliser les tableaux relatifs aux
tenues complètes pour identifier la tenue réelle, cette méthode fournissant une valeur de l'isolement
thermique du vêtement plus précise que l'addition de pièces vestimentaires. Une interpolation entre les
valeurs d'isolement thermique de deux tenues est possible, et lorsqu'une tenue se révèle proche de la tenue
réelle, de légères corrections peuvent également être apportées en ajoutant ou en retirant les isolements
thermiques de pièces vestimentaires afin d'obtenir une meilleure estimation de l'isolement de la tenue réelle.
En dernier lieu, des corrections pour la vitesse de l'air et des mouvements doivent être appliquées.
© ISO 2007 – Tous droits réservés 7
---------------------- Page: 13 ----------------------
ISO 9920:2007(F)
4.2 Valeurs d'isolement thermique des tenues complètes
L'Annexe A donne les valeurs de I et I pour un ensemble de tenues vestimentaires. Toutes ces valeurs ont
T cl
été mesurées sur un mannequin thermique statique, en position debout, avec de faibles mouvements d'air
−1
(< 0,2 m·s ). Le Tableau A.1 donne une brève description des tenues vestimentaires. Les Tableaux A.2
à A.10 contiennent une liste plus détaillée pouvant servir à identifier une tenue vestimentaire comparable à la
tenue vestimentaire réelle. Ces tableaux donnent également les différentes valeurs de f . La masse totale de
cl
la tenue, lorsqu'elle est indiquée, est basée sur des pièces vestimentaires convenant à un sujet standard
(taille européenne 52 pour homme), chaussures non comprises. Les pièces vestimentaires constituant la
plupart des tenues sont identifiées par un numéro, qui renvoie à l'Annexe B dans laquelle figure une
description plus détaillée de ces différentes pièces, y compris des dessins.
L'Annexe A peut également être utilisée pour choisir un vêtement pour un poste de travail donné, lorsque
l'isolement thermique requis est connu.
4.3 Valeurs d'isolement thermique des tenues complètes basées
sur les pièces vestimentaires
Au lieu d'utiliser les tenues décrites dans l'Annexe A, l'isolement thermique d'une tenue, I (en clo), peut
cl
également être estimé en agrégeant les isolements thermiques des pièces vestimentaires, à l'aide de
[31], [36]
l'équation empirique suivante :
I=+0,161 0,835 I (11)
cl ∑ clu
exprimé en clo.
[32], [37]
Ou bien, avec une précision sensiblement réduite :
I = I (12)
cl clu
∑
exprimé en mètres carrés kelvin par watt ou en clo, et où I est l'isolement thermique effectif des pièces
clu
vestimentaires composant la tenue, en mètres carrés kelvin par watt ou en clo.
Ces valeurs sont données dans l'Annexe B.
La forme des différentes piè
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.