EN ISO 9886:2004

SLOVENSKI STANDARD
01-september-2004
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SIST EN ISO 9886:2002
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Ergonomics - Evaluation of thermal strain by physiological measurements (ISO
9886:2004)
Ergonomie - Ermittlung der thermischen Beanspruchung durch physiologische
Messungen (ISO 9886:2004)
Ergonomie - Evaluation de l'astreinte thermique par mesures physiologiques (ISO
9886:2004)
Ta slovenski standard je istoveten z: EN ISO 9886:2004
ICS:
13.180 Ergonomija Ergonomics
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 9886
NORME EUROPÉENNE
EUROPÄISCHE NORM
February 2004
ICS 13.180 Supersedes EN ISO 9886:2001
English version
Ergonomics - Evaluation of thermal strain by physiological
measurements (ISO 9886:2004)
Ergonomie - Evaluation de l'astreinte thermique par Ergonomie - Ermittlung der thermischen Beanspruchung
mesures physiologiques (ISO 9886:2004) durch physiologische Messungen (ISO 9886:2004)
This European Standard was approved by CEN on 19 February 2004.
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 Central Secretariat 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 Central Secretariat has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
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© 2004 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 9886:2004: E
worldwide for CEN national Members.

CORRECTED  2004-02-25
Foreword
This document (EN ISO 9886:2004) has been prepared by Technical Committee ISO/TC 159
"Ergonomics" in collaboration with Technical Committee CEN/TC 122 "Ergonomics", the
secretariat of which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of
an identical text or by endorsement, at the latest by August 2004, and conflicting national
standards shall be withdrawn at the latest by August 2004.
This document supersedes EN ISO 9886:2001.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary,
Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
Endorsement notice
The text of ISO 9886:2004 has been approved by CEN as EN ISO 9886:2004 without any
modifications.
INTERNATIONAL ISO
STANDARD 9886
Second edition
2004-02-15
Ergonomics — Evaluation of thermal
strain by physiological measurements
Ergonomie — Évaluation de l'astreinte thermique par mesures
physiologiques
Reference number
ISO 9886:2004(E)
©
ISO 2004
ISO 9886:2004(E)
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ii © ISO 2004 – All rights reserved

ISO 9886:2004(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Normative references. 1
3 Symbols and abbreviated terms. 2
4 Measurement of body core temperature (t ) . 3
cr
4.1 General. 3
4.2 Measurement techniques for indicators of body core temperature . 4
5 Measurement of body skin temperature (t ). 6
sk
5.1 General. 6
5.2 Principle of the method . 7
5.3 Interpretation. 7
6 Assessment of thermal strain on the basis of heart rate (HR) . 7
6.1 General. 7
6.2 Principle of the method . 7
6.3 Interpretation. 8
7 Assessment of physiological strain on the basis of body-mass loss (∆m ) due to
sw
sweating. 8
7.1 Principle of the method . 8
7.2 Interpretation. 8
Annex A (informative) Comparison between the physiological methods of evaluation of thermal
strain. 9
Annex B (informative) Measuring techniques . 12
Annex C (informative) Limit values of the physiological parameters of thermal strain. 18
Bibliography . 21

ISO 9886:2004(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 9886 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 9886:1992), which has been technically revised.

iv © ISO 2004 – All rights reserved

ISO 9886:2004(E)
Introduction
This document is part of a series of standards concerned with the assessment of thermal stress and strain.
This series of International Standards aims in particular at
a) establishing specifications for the methods of measuring physical parameters characterising thermal
environments;
b) establishing methods for assessing thermal stress in cold, moderate and hot environments.
The analysis methods described by these latter standards allow the prediction of the average physiological
response of subjects exposed to a thermal environment. Some of these methods are not applicable under
exceptional climatic circumstances, when the characteristics of the exposed subjects differ greatly from the
average or when special means of protection are used.
In these cases, or for the sake of research, it may be useful or even necessary to measure directly the
physiological strain experienced by the subject.
This International Standard gives a series of specifications concerning the methods of measurement and
interpretation of the physiological parameters considered as reflecting the response of the human organism
placed in a hot or cold environment.

INTERNATIONAL STANDARD ISO 9886:2004(E)

Ergonomics — Evaluation of thermal strain by physiological
measurements
1 Scope
This International Standard describes methods for measuring and interpreting the following physiological
parameters:
 body core temperature;
 skin temperatures;
 heart rate;
 body-mass loss.
The choice of variables to be measured and techniques to be used is at the discretion of those responsible for
the health of the employees. These persons will have to take into account not only the nature of the thermal
conditions, but also the degree of acceptance of these techniques by the employees concerned.
It should be emphasised that direct measurements on the individual can only be carried out on two conditions.
a) If the person has been fully informed about the discomfort and the potential risks associated with the
measurement technique and gives free consent to such measurements.
b) If the measurements present no risk for the person which is unacceptable in view of general or specific
codes of ethics.
In order to simplify this choice, Annex A presents a comparison of the different methods concerning their field
of application, their technical complexity, the discomfort and the risks that they might involve.
This standard defines the conditions which are to be met in order to ensure the accuracy of the data gathered
from the different methods. The measurement methods are described in Annex B. Limit values are proposed
in Annex C (informative).
This standard is not concerned with experimental conditions for which investigators may develop alternative
methods intended to improve knowledge in this area. It is however recommended, when conducting such
studies in the laboratory, to use the methods described below as references, so that results may be compared.
Before using the evaluations methods described in this International Standard, the user is required to follow
the ethics and legal rules in force in his country or institution. Accordingly, ethical committees will be consulted
and rules concerning free written consent, freedom of participation, confidentiality, etc. will be strictly followed.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 7933, Ergonomics of the thermal environment — Analytical determination and interpretation of heat stress
using calculation of the predicted heat strain
ISO 9886:2004(E)
3 Symbols and abbreviated terms
A body surface area calculated from the Du Bois formula (m )
Du
−1
HR heart rate (beats⋅min )
−1
HR average heart rate (beats⋅min ) of the subject at rest while sitting under neutral conditions
−1
HR heart rate (beats⋅min ) during a break in work after heart rate components due to static exertion
r
and dynamic muscular work have disappeared
−1
HR limit of heart rate (beats⋅min )
L
−1
∆HR increase in heart rate (beats⋅min ) linked with work metabolism
M
−1
∆HR increase in heart rate (beats⋅min ) linked with static exertion
s
−1
∆HR increase in heart rate (beats⋅min ) connected with the thermal strain experienced by the subject
T
−1
∆HR increase in heart rate (beats⋅min ) due to psychological factors
N
−1
∆HR residual component in heart rate (beats⋅min ) connected with rhythm of breathing, circadian rhythm,
ε
etc.
I thermal clothing insulation (clo)
cl
k weighting coefficient for a point measurement
i
∆m body mass variation
M average metabolic rate (W/m )
∆m mass variation due to variation of clothing or to sweat accumulation in the clothing
clo
∆m gross body-mass loss
g
∆m mass loss due to the mass difference between carbon dioxide and oxygen
o
∆m mass loss due to evaporation in the respiratory tract
res
∆m mass variation of the body due to intake (food) and excretions (stools) of solids
sol
∆m mass loss due to sweat loss during the time interval
sw
∆m mass variation of the body due to intake and excretion (urine) of water
wat
p partial water vapour pressure in the air (kPa)
a
R respiratory quotient (dimensionless)
∆t time interval (min)
t intra-abdominal temperature (°C)
ab
t auditory canal temperature (°C)
ac
2 © ISO 2004 – All rights reserved

ISO 9886:2004(E)
t body core temperature (°C)
cr
t oesophageal temperature (°C)
es
t oral temperature (°C)
or
t rectal temperature (°C)
re
t skin temperature (°C)
sk
t local skin temperature at point i (°C)
ski
t tympanic temperature (°C)
ty
t urine temperature (°C)
ur
4 Measurement of body core temperature (t )
cr
4.1 General
The “core” refers to all the tissues located at a sufficient depth not to be affected by a temperature gradient
through surface tissue. Temperature differences are, however, possible within the core depending on local
metabolisms, on the concentration of vascular networks and on local variations in blood flow. The core
temperature is thus not a unique concept and measurable as such. This temperature may be approximated by
the measurement of temperature at different points of the body:
 oesophagus: oesophageal temperature (t );
es
 rectum: rectal temperature (t );
re
 gastro-intestinal tract: intra-abdominal temperature (t );
ab
 mouth: oral temperature (t );
or
 tympanum: tympanic temperature (t );
ty
 auditory canal: auditory canal temperature (t );
ac
 urine temperature (t ).
ur
The order of presentation of these different techniques has been adopted only for the clarity of the
presentation.
Depending on the technique used, the temperature measured can reflect
 the mean temperature of the body mass, or
 the temperature of the blood irrigating the brain and therefore influencing the thermoregulation centres in
the hypothalamus. This temperature is usually considered for assessing the thermal strain sustained by a
subject.
ISO 9886:2004(E)
4.2 Measurement techniques for indicators of body core temperature
4.2.1 Oesophageal temperature (t )
es
4.2.1.1 Principle of the method
The temperature transducer is introduced in the lower part of the oesophagus, which is in contact over a
length of 50 mm to 70 mm with the front of the left auricle and with the rear surface of the descending aorta. In
this position, the temperature transducer registers variations in arterial blood temperature with a very short
reaction time.
The upper part of the oesophagus presses against the trachea and the measurement of temperature at that
level is affected by breathing. On the contrary, if the transducer is placed too low, it records gastric
temperature.
The temperature of the saliva swallowed by the subject also influences the transducer. The oesophageal
temperature is therefore not given by the mean value of the recorded temperatures but by the peak values.
This is particularly true in cold environments, where the saliva can be chilled.
4.2.1.2 Interpretation
Of all the indirect measurements of t mentioned in 4.2.1.1, t is the one which most accurately reflects
cr es
temperature variations in the blood leaving the heart, and in all probability, the temperature of the blood
irrigating the thermoregulation centres in the hypothalamus.
4.2.2 Rectal temperature (t )
re
4.2.2.1 Principle of the method
A temperature transducer is inserted in the rectum; this being surrounded by a large mass of abdominal
tissues with low thermal conductivity, the rectal temperature is independent of ambient conditions.
4.2.2.2 Interpretation
When the subject is resting, the rectal temperature is the highest of the body temperatures. When the subject
is working, on the contrary, t is directly affected by the production of heat from the local muscles: with an
re
equal expenditure of energy per unit of time, t is higher when work is performed with the legs than when it is
re
carried out exclusively with the arms.
t essentially gives an indication of the mean temperature of body core mass. It may only be considered as
re
an indicator of blood temperature and therefore of the temperature of the thermoregulation centres when heat
storage is slow and when work is performed using the whole body.
When heat storage is low and work is essentially performed with the legs, the measurement of t leads to a
re
slight overestimation of the temperature of the thermoregulation centres.
On the contrary, in the case of rapid storage, during intense thermal stress of short duration, t rises at a
re
slower rate than the temperature of the thermoregulation centres, continues to rise after the exposure has
stopped and finally decreases progressively. Rising speed and lag time depend on the exposure and recovery
conditions. In these cases, t is inappropriate for estimating the strain sustained by a subject.
re
4 © ISO 2004 – All rights reserved

ISO 9886:2004(E)
4.2.3 Intra-abdominal temperature (t )
ab
4.2.3.1 Principle of the method
The subject swallows a temperature transducer. During its transit through the intestinal tract, the temperature
recorded will vary according to whether it is located in an area close to large arterial vessels or to organs with
high local metabolism or, on the contrary, near the abdominal walls.
4.2.3.2 Interpretation
When the transducer is located in the stomach or the duodenum, temperature variations are similar to those of
t and the difference between the two temperatures is very small. As the transducer progresses inside the
es
intestine, the characteristics of the temperature come closer to those of t . Therefore, the interpretation will
re
depend on the time elapsed since the swallowing of the transducer and on the speed of the gastro-intestinal
transit for the given subject.
In the present state of knowledge, t seems to be independent of ambient climatic conditions, except for
ab
strong radiant heat impinging on the abdomen.
4.2.4 Oral temperature (t )
or
4.2.4.1 Principle of the method
The transducer is placed underneath the tongue, and is therefore in close contact with the deep arterial
branches of the lingual artery. It will then provide a satisfactory measurement of the temperature of the blood
influencing the thermoregulation centres.
The temperature measured nevertheless depends on the external conditions. When the mouth is open,
thermal exchanges by convection and evaporation on the surface of the buccal mucus membrane contribute
to a reduction in the temperature of the buccal cavity. Even when the mouth is closed, the temperature may
be significantly lowered as a function of a reduction in the cutaneous temperature of the face, or raised if the
face is exposed to strong radiant heat.
4.2.4.2 Interpretation
When the measurement conditions are met, t is very similar to t . With the subject resting and in
or es
environments in which air temperature is greater than 40 °C, t may overestimate t by 0,25 °C to 0,4 °C.
or es
With the subject working, the concordance between t and t is only established for muscular effort levels not
or es
exceeding 35 % of the maximal aerobic power of the subject.
4.2.5 Tympanic temperature (t )
ty
4.2.5.1 Principle of the method
This method aims at measuring the temperature of the tympanic membrane whose vascularisation is provided
in part by the internal carotid artery, which also supplies the hypothalamus. As the thermal inertia of the
eardrum is very low, due to its low mass and high vascularity, its temperature reflects the variations in arterial
blood temperature, which influence the centres of thermoregulation.
However, as the tympanic membrane is also vascularised by the external carotid artery, its temperature is
influenced by the local thermal exchanges existing in the area vascularised by this artery. As the contact of a
sensor with the tympanic membrane or the surrounding areas is painful, either a thermal transducer is placed
as close as possible to the membrane or its temperature is measured using an infrared (IR) surface-
temperature measurement device which is focussed on the membrane. However, in practice the infrared
method often encounters significant problems (see B.1.6).
ISO 9886:2004(E)
4.2.5.2 Interpretation
t varies in a similar fashion to t during rapid variations in the thermal content of the core, whether these are
ty es
of metabolic origin or caused by the environment. The observed difference between these two temperatures
or between t and t is, however, influenced by local heat exchanges around the ear and the cutaneous
ty re
surface of the head.
4.2.6 Auditory canal temperature (t )
ac
4.2.6.1 Principle of the method
The transducer is, in this case, located against the walls of the auditory meatus immediately adjacent to the
tympanum. These are vascularised by the external carotid artery and their temperature is affected both by the
arterial blood temperature at the heart and by the cutaneous blood flow around the ear and adjacent parts of
the head. A temperature gradient is thus observed between the tympanum and the external orifice of the
auditory meatus. Insulating the ear adequately from the external climate may reduce this gradient.
4.2.6.2 Interpretation
The interpretation principles are very similar to those presented for the tympanic temperature. The auditory
canal temperature therefore presents, as t , variations parallel to those of t .
ty es
However, the positive deviations in hot environments or the negative ones in cold climates from t are
es
systematically greater than for t . Therefore, t may rather be considered as an indicator of the combined
ty ac
temperatures of the core and of the skin, than of an indicator of the core temperature only.
This measuring site is accepted by some as a necessary compromise between the precision of the estimation
and the practicability for the subject and the observer.
4.2.7 Urine temperature (t )
ur
4.2.7.1 Principle of the method
The bladder and its content may be considered as being part of the core of the body. Therefore, the
measurement of the urine temperature during its discharge can provide information concerning t . The
cr
measurement is done by means of a temperature transducer inserted in a collecting device. By definition, the
measurement possibilities are dependent on the quantity of urine available in the bladder.
4.2.7.2 Interpretation
Urine temperature varies approximately as t , except that the time constant is somewhat greater. Considering
re
the actual value, t is systematically lower by 0,2 °C to 0,5 °C than t .
ur re
5 Measurement of skin temperature (t )
sk
5.1 General
Skin temperature varies widely over the surface of the body and especially when the ambient conditions are
cold. For this reason, a distinction should be made between
 the local skin temperature (t ) measured at a specific point of the body surface, and
sk
 the mean skin temperature (t ) on the entire surface of the body, which cannot be easily measured
sk
directly but can be estimated by weighting an ensemble of local skin temperatures according to the area
they characterise.
6 © ISO 2004 – All rights reserved

ISO 9886:2004(E)
By itself, t does not make it possible to evaluate the thermal physiological strain. It constitutes, however, an
sk
important criterion for the appraisal of thermal comfort.
5.2 Principle of the method
For a nude subject, the temperature at a given point of the body surface may be measured from a distance by
means of an infrared radiation transducer. This technique gives the mean temperature of the area, small or
large, of the skin, which is intercepted by the transducer. Otherwise, the temperature is measured by contact
with a temperature transducer fixed on the skin.
5.3 Interpretation
Skin temperature is influenced by
 the thermal exchanges by conduction, convection, radiation and evaporation at the surface of the skin,
and
 the variations of skin blood flow and of the temperature of the arterial blood reaching the particular part of
the body.
In dry environments, skin temperature responds, with a time constant of about 3 min, to variations of ambient
air temperature, radiation and air velocity.
The number of measuring points should be determined as a function of the degree of precision which is
wanted, the ambient conditions, the technical requirements and the degree of annoyance tolerated by the
subject.
As temperatures at the surface of the body are very heterogeneous in ambient conditions close to thermal
neutrality and in cold environments, weighting schemes with many measur
...