SIST EN ISO 7730:2006
(Main)Ergonomics of the thermal environment - Analytical determination and interpretation of thermal comfort using calculation of the PMV and PPD indices and local thermal comfort criteria (ISO 7730:2005)
Ergonomics of the thermal environment - Analytical determination and interpretation of thermal comfort using calculation of the PMV and PPD indices and local thermal comfort criteria (ISO 7730:2005)
The purpose of this International Standard is a) to present a method for predicting the thermal sensation and the degree of discomfort (thermal dissatisfaction) of people exposed to moderate thermal environments, and b) to specify acceptable thermal environmental conditions for comfort.
Ergonomie der thermischen Umgebung - Analytische Bestimmung und Interpretation der thermischen Behaglichkeit durch Berechnung des PMV- und des PPD-Indexes und Kriterien der lokalen thermischen Behaglichkeit (ISO 7730:2005)
Diese Internationale Norm enthält Verfahren, anhand deren das allgemeine menschliche Wärmeempfinden und der Grad der Unbehaglichkeit (thermischen Unzufriedenheit) von Menschen vorausgesagt werden können, die einem gemäßigten Umgebungsklima ausgesetzt sind. Sie ermöglicht die analytische Bestimmung und Interpretation der thermischen Behaglichkeit durch die Berechnung von PMV (predicted mean vote) und PPD (predicted percentage of dissatisfied) und der örtlichen Kriterien für thermische Behaglichkeit, indem sie die Umgebungsbedingungen, die für den allgemeinen thermischen Komfort sowie die lokale Unbehaglichkeit als akzeptabel betrachtet werden, beschreibt. Die Internationale Norm gilt für gesunde Männer und Frauen, die einem Innenraumklima ausgesetzt sind, durch das ein Gefühl thermischer Behaglichkeit erreicht werden soll, oder in dem es zu moderaten Abweichungen vom Zustand der Behaglichkeit kommt, in der Gestaltung neuer Umgebungen oder der Anpassung existierender. Obwohl diese Norm für die Arbeitsumgebung erstellt wurde, kann sie aber auch für jede andere Art der Umgebung angewendet werden. Für Personen mit besonderen Anforderungen wie solche mit physikalischen Einschränkungen sollte ISO/TS 14415:2005, 4.2 angewendet werden. In nicht klimatisierten Räumen können ethnische und national geografische Abweichungen auftreten.
Ergonomie des ambiances thermiques - Détermination analytique et interprétation du confort thermique par le calcul des indices PMV et PPD et par des criteres de confort thermique local (ISO 7730:2005)
L'ISO 7730:2005 présente des méthodes de prévision de la sensation thermique générale et du degré d'inconfort (insatisfaction thermique) général des personnes exposées à des ambiances thermiques modérées. Elle permet de déterminer analytiquement et d'interpréter le confort thermique, par le calcul des indices PMV (vote moyen prévisible) et PPD (pourcentage prévisible d'insatisfaits) et par des critères de confort thermique local, donnant les conditions des ambiances thermiques considérées acceptables du point de vue du confort thermique général et les conditions représentant les inconforts locaux.
Ergonomija toplotnega okolja - Analitično ugotavljanje in interpretacija toplotnega ugodja z izračunom PMV in PPD vrednosti ter merili za lokalno toplotno ugodje (ISO 7730:2005)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 7730:2006
01-marec-2006
1DGRPHãþD
SIST EN ISO 7730:2001
(UJRQRPLMDWRSORWQHJDRNROMD$QDOLWLþQRXJRWDYOMDQMHLQLQWHUSUHWDFLMDWRSORWQHJD
XJRGMD]L]UDþXQRP309LQ33'YUHGQRVWLWHUPHULOL]DORNDOQRWRSORWQRXJRGMH
,62
Ergonomics of the thermal environment - Analytical determination and interpretation of
thermal comfort using calculation of the PMV and PPD indices and local thermal comfort
criteria (ISO 7730:2005)
Ergonomie der thermischen Umgebung - Analytische Bestimmung und Interpretation der
thermischen Behaglichkeit durch Berechnung des PMV- und des PPD-Indexes und
Kriterien der lokalen thermischen Behaglichkeit (ISO 7730:2005)
Ergonomie des ambiances thermiques - Détermination analytique et interprétation du
confort thermique par le calcul des indices PMV et PPD et par des criteres de confort
thermique local (ISO 7730:2005)
Ta slovenski standard je istoveten z: EN ISO 7730:2005
ICS:
13.180 Ergonomija Ergonomics
SIST EN ISO 7730:2006 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 7730:2006
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SIST EN ISO 7730:2006
EUROPEAN STANDARD
EN ISO 7730
NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2005
ICS 13.180 Supersedes EN ISO 7730:1995
English Version
Ergonomics of the thermal environment - Analytical
determination and interpretation of thermal comfort using
calculation of the PMV and PPD indices and local thermal
comfort criteria (ISO 7730:2005)
Ergonomie des ambiances thermiques - Détermination Ergonomie der thermischen Umgebung - Analytische
analytique et interprétation du confort thermique par le Bestimmung und Interpretation der thermischen
calcul des indices PMV et PPD et par des critères de Behaglichkeit durch Berechnung des PMV- und des PPD-
confort thermique local (ISO 7730:2005) Indexes und Kriterien der lokalen thermischen
Behaglichkeit (ISO 7730:2005)
This European Standard was approved by CEN on 21 October 2005.
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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COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 7730:2005: E
worldwide for CEN national Members.
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SIST EN ISO 7730:2006
EN ISO 7730:2005 (E)
Foreword
This document (EN ISO 7730:2005) 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 May 2006, and conflicting national standards
shall be withdrawn at the latest by May 2006.
This document supersedes EN ISO 7730:1995.
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 7730:2005 has been approved by CEN as EN ISO 7730:2005 without any
modifications.
2
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SIST EN ISO 7730:2006
INTERNATIONAL ISO
STANDARD 7730
Third edition
2005-11-15
Ergonomics of the thermal
environment — Analytical determination
and interpretation of thermal comfort
using calculation of the PMV and PPD
indices and local thermal comfort criteria
Ergonomie des ambiances thermiques — Détermination analytique et
interprétation du confort thermique par le calcul des indices PMV et
PPD et par des critères de confort thermique local
Reference number
ISO 7730:2005(E)
©
ISO 2005
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SIST EN ISO 7730:2006
ISO 7730:2005(E)
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ii © ISO 2005 – All rights reserved
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SIST EN ISO 7730:2006
ISO 7730:2005(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 1
4 Predicted mean vote (PMV) . 2
5 Predicted percentage dissatisfied (PPD). 4
6 Local thermal discomfort. 6
7 Acceptable thermal environments for comfort. 10
8 Non-steady-state thermal environments. 11
9 Long-term evaluation of the general thermal comfort conditions. 11
10 Adaptation . 12
Annex A (informative) Examples of thermal comfort requirements for different categories of
environment and types of space. 13
Annex B (informative) Metabolic rates of different activities. 18
Annex C (informative) Estimation of thermal insulation of clothing ensembles. 19
Annex D (normative) Computer program for calculating PMV and PPD. 23
Annex E (normative) Tables for determination of predicted mean vote (PMV) . 26
Annex F (informative) Humidity . 44
Annex G (informative) Air velocity. 45
Annex H (informative) Long-term evaluation of the general thermal comfort conditions. 47
Bibliography . 49
© ISO 2005 – All rights reserved iii
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SIST EN ISO 7730:2006
ISO 7730:2005(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 7730 was prepared by Technical Committee ISO/TC 159, Ergonomics, Subcommittee SC 5, Ergonomics
of the physical environment.
This third edition cancels and replaces the second edition (ISO 7730:1994), which has been technically
revised. A method for long term evaluation has been added, as well as information on local thermal discomfort,
non-steady-state conditions and adaptation, and an annex stating how thermal comfort requirements can be
expressed in different categories.
iv © ISO 2005 – All rights reserved
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SIST EN ISO 7730:2006
ISO 7730:2005(E)
Introduction
This International Standard covering the evaluation of moderate thermal environments was developed in
1)
parallel with the revised ASHRAE standard 55 and is one of a series of ISO documents specifying methods
for the measurement and evaluation of the moderate and extreme thermal environments to which human
beings are exposed (ISO 7243, ISO 7933 and ISO/TR 11079, all three dealing with extreme environmental
conditions, are others in the series).
A human being's thermal sensation is mainly related to the thermal balance of his or her body as a whole.
This balance is influenced by physical activity and clothing, as well as the environmental parameters: air
temperature, mean radiant temperature, air velocity and air humidity. When these factors have been
estimated or measured, the thermal sensation for the body as a whole can be predicted by calculating the
predicted mean vote (PMV). See Clause 4.
The predicted percentage dissatisfied (PPD) index provides information on thermal discomfort or thermal
dissatisfaction by predicting the percentage of people likely to feel too warm or too cool in a given environment.
The PPD can be obtained from the PMV. See Clause 5.
Thermal discomfort can also be caused by unwanted local cooling or heating of the body. The most common
local discomfort factors are radiant temperature asymmetry (cold or warm surfaces), draught (defined as a
local cooling of the body caused by air movement), vertical air temperature difference, and cold or warm floors.
Clause 6 specifies how to predict the percentage dissatisfied owing to local discomfort parameters.
Dissatisfaction can be caused by hot or cold discomfort for the body as a whole. Comfort limits can in this
case be expressed by the PMV and PPD indices. But thermal dissatisfaction can also be caused by local
thermal discomfort parameters. Clause 7 deals with acceptable thermal environments for comfort.
Clauses 6 and 7 are based mainly on steady-state conditions. Means of evaluating non-steady-state
conditions such as transients (temperature steps), cycling temperatures or temperature ramps are presented
in Clause 8. The thermal environments in buildings or at workplaces will change over time and it might not
always be possible to keep conditions within recommended limits. A method for long-term evaluation of
thermal comfort is given in Clause 9.
Clause 10 gives recommendations on how to take into account the adaptation of people when evaluating and
designing buildings and systems.
1) American Society of Heating, Refrigerating and Air-conditioning Engineers.
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SIST EN ISO 7730:2006
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SIST EN ISO 7730:2006
INTERNATIONAL STANDARD ISO 7730:2005(E)
Ergonomics of the thermal environment — Analytical
determination and interpretation of thermal comfort using
calculation of the PMV and PPD indices and local thermal
comfort criteria
1 Scope
This International Standard presents methods for predicting the general thermal sensation and degree of
discomfort (thermal dissatisfaction) of people exposed to moderate thermal environments. It enables the
analytical determination and interpretation of thermal comfort using calculation of PMV (predicted mean vote)
and PPD (predicted percentage of dissatisfied) and local thermal comfort criteria, giving the environmental
conditions considered acceptable for general thermal comfort as well as those representing local discomfort. It
is applicable to healthy men and women exposed to indoor environments where thermal comfort is desirable,
but where moderate deviations from thermal comfort occur, in the design of new environments or the
assessment of existing ones. Although developed specifically for the work environment, it is applicable to
other kinds of environment as well. It is intended to be used with reference to ISO/TS 14415:2005, 4.2, when
considering persons with special requirements, such as those with physical disabilities. Ethnic, national or
geographical differences need also to be taken into account when considering non-conditioned spaces.
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 13731, Ergonomics of the thermal environment — Vocabulary and symbols
ISO/TS 13732-2, Ergonomics of the thermal environment — Methods for the assessment of human responses
to contact with surfaces — Part 2: Human contact with surfaces at moderate temperature
ISO/TS 14415:2005, Ergonomics of the thermal environment — Application of International Standards to
people with special requirements
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 13731 and the following apply.
3.1
temperature cycle
variable temperature with a given amplitude and frequency
3.2
drift temperature
passive monotonic, steady, non-cyclic change in the operative temperature of an enclosed space
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SIST EN ISO 7730:2006
ISO 7730:2005(E)
3.3
ramp temperature
actively controlled monotonic, steady, non-cyclic change in the operative temperature of an enclosed space
3.4
operative temperature
t
o
uniform temperature of an imaginary black enclosure in which an occupant would exchange the same amount
of heat by radiation and convection as in the actual non-uniform environment
3.5
transient temperature
sudden change in the thermal conditions due to step change in temperature, humidity, activity or clothing
3.6
draught
unwanted local cooling of the body caused by air movement
4 Predicted mean vote (PMV)
4.1 Determination
The PMV is an index that predicts the mean value of the votes of a large group of persons on the 7-point
thermal sensation scale (see Table 1), based on the heat balance of the human body. Thermal balance is
obtained when the internal heat production in the body is equal to the loss of heat to the environment. In a
moderate environment, the human thermoregulatory system will automatically attempt to modify skin
temperature and sweat secretion to maintain heat balance.
Table 1 — Seven-point thermal sensation scale
+ 3 Hot
+ 2 Warm
+ 1 Slightly warm
0 Neutral
− 1 Slightly cool
−2 Cool
− 3 Cold
2 © ISO 2005 – All rights reserved
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SIST EN ISO 7730:2006
ISO 7730:2005(E)
Calculate the PMV using Equations (1) to (4):
PMV=⋅0,303 exp(−0,036⋅M )+ 0,028⋅
⎡⎤
⎣⎦
⎧ ⎫
−3
⎡ ⎤⎡ ⎤
MW−− 3,05⋅10⋅ 5 733− 6,99⋅M−−W p− 0,42⋅ M−−W 58,15
() () ()
⎪ a ⎪
⎣ ⎦⎣ ⎦
⎪ ⎪
⎪ ⎪
−5
−1,7⋅10 ⋅⋅Mp5 867− − 0,0014⋅⋅M 34−t (1)
() ( )
⎨ ⎬
aa
⎪ ⎪
44
−8
⎡⎤
⎪ ⎪
−⋅3,96 10⋅ft⋅()+ 273−()t+ 273 −f⋅h⋅(t−t)
cl cl r cl c cl a
⎢⎥
⎪ ⎪
⎣⎦
⎩ ⎭
44
−8⎡⎤
tM=−35,7 0,028⋅ −W−I⋅ 3,96⋅10⋅f⋅t+ 273−t+ 273+f⋅h⋅t−t (2)
() ()() ( )
cl cl cl cl r cl c cl a
{}
⎢⎥
⎣⎦
0,25 0,25
⎧
2,38⋅−tt for 2,38⋅−tt > 12,1⋅v
cl a cl a ar
⎪
h = (3)
⎨
c
0,25
⎪
12,1⋅⋅vtfor 2,38−t<12,1⋅v
ar cl a ar
⎩
2
⎧
1,00+⋅1,290llfor u 0,078 m K/W
⎪ cl cl
f = (4)
⎨
cl
2
1,05+>0,645llfor 0,078 m⋅K/W
⎪
⎩ cl cl
where
2
M is the metabolic rate, in watts per square metre (W/m );
2
W is the effective mechanical power, in watts per square metre (W/m );
2
I is the clothing insulation, in square metres kelvin per watt (m ⋅ K/W);
cl
f is the clothing surface area factor;
cl
t is the air temperature, in degrees Celsius (°C);
a
t is the mean radiant temperature, in degrees Celsius (°C);
r
v is the relative air velocity, in metres per second (m/s);
ar
p is the water vapour partial pressure, in pascals (Pa);
a
2
h is the convective heat transfer coefficient, in watts per square metre kelvin [W/(m ⋅ K)];
c
t is the clothing surface temperature, in degrees Celsius (°C).
cl
2 2
NOTE 1 metabolic unit = 1 met = 58,2 W/m ; 1 clothing unit = 1 clo = 0,155 m ⋅ °C/W.
PMV may be calculated for different combinations of metabolic rate, clothing insulation, air temperature, mean
radiant temperature, air velocity and air humidity (see ISO 7726). The equations for t and h may be solved
cl c
by iteration.
The PMV index is derived for steady-state conditions but can be applied with good approximation during minor
fluctuations of one or more of the variables, provided that time-weighted averages of the variables during the
previous 1 h period are applied.
The index should be used only for values of PMV between −2 and +2, and when the six main parameters are
within the following intervals:
2 2
M 46 W/m to 232 W/m (0,8 met to 4 met);
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SIST EN ISO 7730:2006
ISO 7730:2005(E)
2 2
I 0 m ⋅ K/W to 0,310 m ⋅ K/W (0 clo to 2 clo);
cl
t 10 °C to 30 °C;
a
t 10 °C to 40 °C;
r
v 0 m/s to 1 m/s;
ar
p 0 Pa to 2 700 Pa.
a
NOTE In respect of v , during light, mainly sedentary, activity, a mean velocity within this range can be felt as a
ar
draught.
Estimate the metabolic rate using ISO 8996 or Annex B, taking into account the type of work. For varying
metabolic rates, a time-weighted average should be estimated during the previous 1 h period. Estimate the
thermal resistance of clothing and chair using ISO 9920 or Annex C, taking into account the time of year.
Determine the PMV in one of the following ways.
a) From Equation (1) using a digital computer. A BASIC program is given in Annex D for this purpose. For
verification of other computer programs, Annex D provides example output.
b) Directly from Annex E, where tables of PMV values are given for different combinations of activity,
clothing, operative temperature and relative velocity.
c) By direct measurement, using an integrating sensor (equivalent and operative temperatures).
The PMV values given in Annex E apply for a relative humidity of 50 %. The influence of humidity on thermal
sensation is small at moderate temperatures close to comfort and may usually be disregarded when
determining the PMV value (see Annex F).
4.2 Applications
The PMV can be used to check whether a given thermal environment complies with comfort criteria (see
Clause 7 and Annex A), and to establish requirements for different levels of acceptability.
By setting PMV = 0, an equation is established which predicts combinations of activity, clothing and
environmental parameters which on average will provide a thermally neutral sensation.
5 Predicted percentage dissatisfied (PPD)
The PMV predicts the mean value of the thermal votes of a large group of people exposed to the same
environment. But individual votes are scattered around this mean value and it is useful to be able to predict
the number of people likely to feel uncomfortably warm or cool.
The PPD is an index that establishes a quantitative prediction of the percentage of thermally dissatisfied
people who feel too cool or too warm. For the purposes of this International Standard, thermally dissatisfied
people are those who will vote hot, warm, cool or cold on the 7-point thermal sensation scale given in Table 1.
With the PMV value determined, calculate the PPD using Equation (5), see Figure 1:
42
PPD=−100 95⋅ exp(−0,033 53⋅PMV− 0,217 9⋅PMV ) (5)
4 © ISO 2005 – All rights reserved
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SIST EN ISO 7730:2006
ISO 7730:2005(E)
Key
PMV predicted mean vote
PPD predicted percentage dissatisfied, %
Figure 1 — PPD as function of PMV
The PPD predicts the number of thermally dissatisfied persons among a large group of people. The rest of the
group will feel thermally neutral, slightly warm or slightly cool. The predicted distribution of votes is given in
Table 2.
Table 2 — Distribution of individual thermal sensation votes for different values of mean vote
a
PMV PPD Persons predicted to vote
%
0 −1, 0 or +1 −2, −1, 0, +1 or +2
+2 75 5 25 70
+1 25 30 75 95
+0,5 10 55 90 98
0 5 60 95 100
−0,5 10 55 90 98
−1 25 30 75 95
−2 75 5 25 70
a
Based on experiments involving 1 300 subjects.
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SIST EN ISO 7730:2006
ISO 7730:2005(E)
6 Local thermal discomfort
6.1 General
The PMV and PPD express warm and cold discomfort for the body as a whole. But thermal dissatisfaction can
also be caused by unwanted cooling or heating of one particular part of the body. This is known as local
discomfort. The most common cause of local discomfort is draught (6.2). But local discomfort can also be
caused by an abnormally high vertical temperature difference between the head and ankles (6.3), by too warm
or too cool a floor (6.4), or by too high a radiant temperature asymmetry (6.5). Annex A provides examples of
local and overall thermal comfort requirements for different categories of environment and types of space.
It is mainly people at light sedentary activity who are sensitive to local discomfort. These will have a thermal
sensation for the whole body close to neutral. At higher levels of activity, people are less thermally sensitive
and consequently the risk of local discomfort is lower.
6.2 Draught
The discomfort due to draught may be expressed as the percentage of people predicted to be bothered by
draught. Calculate the draught rate (DR) using Equation (6) (model of draught):
0,62
DR=−34 t v− 0,05 0,37⋅v⋅Tu+ 3,14 (6)
() a,l a,l
()()
a,l
For v < 0,05 m/s: use v = 0,05 m/s
a,l a,l
For DR > 100 %: use DR = 100 %
where
t is the local air temperature, in degrees Celsius, 20 °C to 26 °C;
a,l
v is the local mean air velocity, in metres per second, < 0,5 m/s;
a,l
Tu is the local turbulence intensity, in percent, 10 % to 60 % (if unknown, 40 % may be used).
The model applies to people at light, mainly sedentary activity with a thermal sensation for the whole body
close to neutral and for prediction of draught at the neck. At the level of arms and feet, the model could
overestimate the predicted draught rate. The sensation of draught is lower at activities higher than sedentary
(> 1,2 met) and for people feeling warmer than neutral. Additional information on the effect of air velocity can
be found in Annex G.
6.3 Vertical air temperature difference
A high vertical air temperature difference between head and ankles can cause discomfort. Figure 2 shows the
percentage dissatisfied (PD) as a function of the vertical air temperature difference between head and ankles.
The figure applies when the temperature increases upwards. People are less sensitive under decreasing
temperatures. Determine the PD using Equation (7):
100
(7)
PD=
1+−exp(5,76 0,856⋅∆t )
a,v
Equation (7), derived from the original data using logistic regression analysis, should only be used at
∆t < 8 °C.
a,v
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SIST EN ISO 7730:2006
ISO 7730:2005(E)
Key
PD percentage dissatisfied, %
∆t vertical air temperature difference between head and feet, °C
a,v
Figure 2 — Local discomfort caused by vertical air temperature difference
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SIST EN ISO 7730:2006
ISO 7730:2005(E)
6.4 Warm and cool floors
If the floor is too warm or too cool, the occupants could feel uncomfortable owing to thermal sensation of their
feet. For people wearing light indoor shoes, it is the temperature of the floor rather than the material of the
floor covering which is important for comfort. Figure 3 shows the percentage dissatisfied as a function of the
floor temperature, based on studies with standing and/or sedentary people.
Key
PD percentage dissatisfied, %
t floor temperature, °C
f
Figure 3 — Local thermal discomfort caused by warm or cold floors
For people sitting or lying on the floor, similar values may be used. Determine the PD using Equation (8),
derived from the original data using non-linear regression analysis:
2
PD=−100 94⋅ exp(−1,387+ 0,118⋅t− 0,002 5⋅t ) (8)
ff
For longer occupancy the results are not valid for electrically heated floors.
NOTE By electrical heating, a certain heat input is provided independent of the surface temperature. A water-based
heating system will not produce temperatures higher than the water temperature.
For spaces that people occupy with bare feet, see ISO/TS 13732-2.
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SIST EN ISO 7730:2006
ISO 7730:2005(E)
6.5 Radiant asymmetry
Radiant asymmetry (∆t ) can also cause discomfort. People are most sensitive to radiant asymmetry caused
pr
by warm ceilings or cool walls (windows). Figure 4 shows the percentage dissatisfied as a function of the
radiant temperature asymmetry caused by a warm ceiling, a cool wall, a cool ceiling or by a warm wall. For
horizontal radiant asymmetry, Figure 4 applies from side-to-side (left/right or right/left) asymmetry, the curves
providing a conservative estimate of the discomfort: no other positions of the body in relation to the surfaces
(e.g. front/back) cause higher asymmetry discomfort. Determine the PD using Equations (9) to (12), as
applicable.
a) Warm ceiling
100
PD=− 5,5 (9)
1+−exp(2,84 0,174⋅∆t )
pr
∆t < 23 °C
pr
b) Cool wall
100
PD= (10)
1+−exp(6,61 0,345⋅∆t )
pr
∆t < 15 °C
pr
c) Cool ceiling
100
PD= (11)
1e+−xp(9,93 0,50⋅∆t )
pr
∆t < 15 °C
pr
d) Warm wall
100
PD=− 3,5 (12)
1+−exp(3,72 0,052⋅∆t )
pr
∆t < 35 °C
pr
Equations (9) to (12) were derived from the original data using logistic regression analysis, and should not be
used beyond the ranges shown above. Those for a) (warm ceiling) and for d) (warm wall) have been adjusted
to a
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