oSIST prEN ISO 7730:2023

SLOVENSKI STANDARD
oSIST prEN ISO 7730:2023
01-maj-2023
Nadomešča:
SIST EN ISO 7730:2006
Ergonomija toplotnega okolja - Analitično ugotavljanje in interpretacija toplotnega
ugodja z izračunom PMV in PPD vrednosti ter merili za lokalno toplotno ugodje
(ISO/DIS 7730:2023)
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/DIS 7730:2023)
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/DIS 7730:2023)
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 (ISO/DIS 7730:2023)
Ta slovenski standard je istoveten z: prEN ISO 7730
ICS:
13.180 Ergonomija Ergonomics
oSIST prEN ISO 7730:2023 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN ISO 7730:2023

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oSIST prEN ISO 7730:2023
DRAFT INTERNATIONAL STANDARD
ISO/DIS 7730
ISO/TC 159/SC 5 Secretariat: BSI
Voting begins on: Voting terminates on:
2023-03-22 2023-06-14
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
ICS: 13.180
This document is circulated as received from the committee secretariat.
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
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NATIONAL REGULATIONS.
ISO/DIS 7730:2023(E)
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PROVIDE SUPPORTING DOCUMENTATION. © ISO 2023

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oSIST prEN ISO 7730:2023
ISO/DIS 7730:2023(E)
DRAFT INTERNATIONAL STANDARD
ISO/DIS 7730
ISO/TC 159/SC 5 Secretariat: BSI
Voting begins on: Voting terminates on:

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
ICS: 13.180
This document is circulated as received from the committee secretariat.
COPYRIGHT PROTECTED DOCUMENT
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
© ISO 2023
ISO/CEN PARALLEL PROCESSING
THEREFORE SUBJECT TO CHANGE AND MAY
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Reference number
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NATIONAL REGULATIONS.
Website: www.iso.org ISO/DIS 7730:2023(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
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RIGHTS OF WHICH THEY ARE AWARE AND TO
ii
  © ISO 2023 – All rights reserved
PROVIDE SUPPORTING DOCUMENTATION. © ISO 2023

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oSIST prEN ISO 7730:2023
ISO/DIS 7730:2023(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Whole body thermal comfort Predicted mean vote (PMV) . 2
4.1 Determination . 2
4.2 Applications. 4
5 Predicted percentage dissatisfied (PPD) . 4
6 Local thermal comfort . 5
6.1 General . 5
6.2 Draught . 6
6.3 Vertical air temperature difference . 6
6.4 Warm and cool floors . 7
6.5 Radiant temperature asymmetry . 8
7 Thermal environments for comfort . 9
8 Non-steady-state thermal environments .10
8.1 General . 10
8.2 Temperature cycles . 10
8.3 Temperature drifts or ramps . . 10
8.4 Transients . 10
Annex A (informative) Examples of thermal comfort requirements for different
categoriesof environment and types of space .11
Annex B (informative) Metabolic rates of different activities .16
Annex C (informative) Estimation of thermal insulation of clothing ensembles .17
Annex D (normative) Computer program for calculating PMV and PPD .21
Annex E (informative) Graphics for determination of predicted mean vote (PMV) .25
Annex F (informative) Humidity .28
Annex G (informative) Air velocity .29
Bibliography .31
iii
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oSIST prEN ISO 7730:2023
ISO/DIS 7730:2023(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 fourth edition cancels and replaces the third edition (ISO 7730:2005), which has been technically
revised. Parts of the standard (long term evaluations, adaptation and diversity) has been moved to the
technical guideline DTRxxxxx. The mistakes in the calculation program has been corrected. The tables
for predicting PMV has been deleted, as most people today will use a calculation program.
iv
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oSIST prEN ISO 7730:2023
ISO/DIS 7730:2023(E)
Introduction
This International Standard covering the evaluation of moderate thermal environments 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 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 index for thermal comfort, PMV (Predicted Mean Vote)
can be calculated. See Clause 4.
The predicted percentage dissatisfied (PPD) index provides information on thermal discomfort or
thermal dissatisfaction expressed as 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.
This standard is supposed to be used together with the technical guideline DTRxxxxx: Guidance for
design, control and evaluation of moderate indoor thermal environment
v
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oSIST prEN ISO 7730:2023

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oSIST prEN ISO 7730:2023
DRAFT INTERNATIONAL STANDARD ISO/DIS 7730:2023(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 defines a standardised method to evaluate the general thermal comfort of
people in a space and the degree of discomfort (thermal dissatisfaction) of people exposed to moderate
thermal environments. It defines 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 28803, when considering persons
with special requirements, such as those with physical disabilities. Ethnic, national or geographical
differences need also to be taken into account especially when considering non-conditioned spaces.
Guidance is given in clause 8 and 10 in the guideline ISO DTR XXXXX
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 7726, Ergonomics of the thermal environment — Instruments for measuring physical quantities
ISO 8996, Ergonomics of the thermal environment — Determination of metabolic rate
ISO 9920, Ergonomics of the thermal environment — Estimation of thermal insulation and water vapour
resistance of a clothing ensemble
ISO 10551, Ergonomics of the physical environment — Subjective judgement scales for assessing physical
environments
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 28803, Ergonomics of the physical 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
1
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oSIST prEN ISO 7730:2023
ISO/DIS 7730:2023(E)
3.2
drift temperature
passive monotonic, steady, non-cyclic change in the operative temperature of an enclosed space
3.3
ramp temperature
actively controlled monotonic, steady, non-cyclic change in the operative temperature of an enclosed
space
3.4
operative temperature
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 Whole body thermal comfort 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
Calculate the PMV using Equations (1) to (4):
PMVM=−[,0 303··exp( 0,)036 +0,]028 .
−3
 
()MW− −⋅3,05 105⋅−[]733 69,,90⋅−()MW −pM−⋅42 []()−W −58,15
a
 
 
−5
−1,771⋅⋅05Mp⋅−867 −⋅0,00143Mt⋅−4 (1)
() ()
 
aa
 
44
−8
 
 
−⋅39, 610 ⋅⋅ft(()+273 −+()tf273 −⋅ht⋅−()t
cl cl rclc cl a
   
4 44
−8
 
tM=−35,70,028⋅−WI−⋅ 39, 61⋅⋅0 ft⋅+273 −+t 273 +⋅fh ⋅−tt (2)
() () () ()
{}
cl cl cl cl r cl ccla
 
2
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oSIST prEN ISO 7730:2023
ISO/DIS 7730:2023(E)
02,,50 25

23,,81⋅−tt for 2,38⋅−tt >⋅21 v
 cl acla ar
h = (3)

c
02, 5

12,1⋅ v for 22,38⋅−tt <⋅12,1 v

ar cl aar
2

10,,01+⋅290llformu0,078 K/W
cl cl

f = (4)

cl
2
10,,50+>645llfor 00, 778mK⋅ /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
cl c
may be solved 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);
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
ar
as a 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.
3
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oSIST prEN ISO 7730:2023
ISO/DIS 7730:2023(E)
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) From Annex E, where graphics 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 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 categories 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-index is defined in relation to 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 index related to 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,,03353⋅−PMVP0 2179⋅ MV ) (5)
4
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oSIST prEN ISO 7730:2023
ISO/DIS 7730:2023(E)
Key
PMV predicted mean vote
PPD predicted percentage dissatisfied, %
Figure 1 — PPD as function of PMV
The PPD is related to 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 relation between PMV
and PPD distributionis 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.
6 Local thermal comfort
6.1 General
The PMV and PPD are indices related to warm and cold discomfort for the body as a whole. But thermal
dissatisfaction can also be caused by unwanted cold or warm sensation of a 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
5
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oSIST prEN ISO 7730:2023
ISO/DIS 7730:2023(E)
and ankles (6.3), by too warm or too cool a floor (6.4), or by 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):
06, 2
DR=−34 tv −00,,50 37⋅⋅vTu+31, 4 (6)
()
()a,la(),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
PD= (7)
15+−exp( ,,76 0 856⋅Δt )
a,v
Equation (7), derived from the original data using logistic regression analysis, should only be used at
Δt < 8 °C.
a,v
6
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oSIST prEN ISO 7730:2023
ISO/DIS 7730:2023(E)
Key
PD percentage dissatisfied, %
Δt vertical air temperature difference between head and feet, °C
a,v
Figure 2 — Local discomfort caused by vertical air temperature difference
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.
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oSIST prEN ISO 7730:2023
ISO/DIS 7730:2023(E)
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 tt−⋅0,)0025 (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.
6.5 Radiant temperature asymmetry
Radiant temperature asymmetry (Δt ) can also cause discomfort. People are most sensitive to
pr
radiant asymmetry caused 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:
...