ISO 17772-1:2017

Energy performance of buildings - Indoor environmental quality - Part 1: Indoor environmental input parameters for the design and assessment of energy performance of buildings

ISO 17772-1:2017 specifies requirements for indoor environmental parameters for thermal environment, indoor air quality, lighting and acoustics and specifies how to establish these parameters for building system design and energy performance calculations. It includes design criteria for the local thermal discomfort factors, draught, radiant temperature asymmetry, vertical air temperature differences and floor surface temperature. ISO 17772-1:2017 is applicable where the criteria for indoor environment are set by human occupancy and where the production or process does not have a major impact on indoor environment. It also specifies occupancy schedules to be used in standard energy calculations and how different categories of criteria for the indoor environment can be used. The criteria in ISO 17772-1:2017can also be used in national calculation methods. ISO 17772-1:2017 sets criteria for the indoor environment based on existing standards and reports (listed in Clause 2 and the Bibliography). The document does not specify design methods, but gives input parameters to the design of building envelope, heating, cooling, ventilation and lighting.

Performance énergétique des bâtiments — Qualité de l'environnement intérieur — Partie 1: Paramètres d'entrée de l'environnement intérieur pour la conception et l'évaluation de la performance énergétique des bâtiments

General Information

• Status: Published
• Publication Date: 20-Jun-2017
• ICS: 91.120.10 - Thermal insulation of buildings
• Technical Committee: ISO/TC 163 - Thermal performance and energy use in the built environment
• Drafting Committee: ISO/TC 163/WG 4 - Joint ISO/TC 163 - ISO/TC 205 WG: Energy performance of buildings using holistic approach
• Parallel Committee: ISO/TC 205 - Building environment design
• Current Stage: 9092 - International Standard to be revised
• Start Date: 05-Sep-2025
• Completion Date: 13-Dec-2025

Overview

ISO 17772-1:2017 - Energy performance of buildings: Indoor environmental quality (Part 1) defines the input parameters for assessing and designing building energy performance with respect to the indoor environmental quality (IEQ). Rather than prescribing design methods, this standard specifies the thermal environment, indoor air quality (IAQ), lighting and acoustics parameters and how to establish them for building system sizing and energy calculations. It is applicable where indoor environment criteria are driven by human occupancy (not dominated by industrial processes) and is intended for use in energy simulations, national calculation methods and monitoring.

Why it matters: IEQ choices (ventilation rates, temperature setpoints, lighting levels, noise limits) strongly influence building energy use, occupant comfort, health and productivity. ISO 17772-1:2017 provides a consistent set of input parameters to balance energy performance with occupant needs.

Key Topics and Requirements

• Thermal environment: Input parameters for heating and cooling seasons, treatment of naturally ventilated and mechanically cooled buildings, and local thermal discomfort factors such as draught, radiant temperature asymmetry, vertical air temperature differences and floor surface temperature.
• Indoor air quality (IAQ) and ventilation rates: Methods to establish ventilation design values, guidance for residential and non-residential buildings, filtration/air cleaning and criteria for low/very-low polluting buildings.
• Lighting: Criteria and input parameters for energy calculations and design for both residential and non-residential spaces.
• Acoustics (noise): Indoor system noise criteria for different spaces and their use in energy-related assessments.
• Occupant schedules and usage profiles: Standard occupancy schedules for seasonal, monthly and hourly energy calculations (see Annexes G, N, O).
• Humidity and monitoring: Parameters for humidity control and recommendations for monitoring and display of IEQ variables.
• Annexes: Normative and informative annexes provide recommended criteria (Annex A), IAQ basis (Annex B/I), pollutant criteria (Annex F/M), examples for lighting and noise, and sample occupant schedules.

Practical Applications and Users

Who should use ISO 17772-1:2017:

• HVAC and building services engineers for system sizing and commissioning input
• Energy modelers and simulation analysts who need standardized IEQ inputs
• Architects and façade designers to set envelope and thermal comfort targets
• Sustainability consultants and building certifiers using national or EU EPB frameworks
• Facility managers and building operators for monitoring and performance evaluation Practical uses include establishing simulation inputs, setting design criteria that align occupant comfort with energy targets, defining ventilation strategies, and informing national calculation methods.

Related Standards

• ISO 52000-1 (energy performance of buildings - EPB framework)
• ISO 7730 (thermal comfort standards referenced for basis)
• WHO health-based indoor air guidance (referenced in Annex M) ISO 17772-1:2017 complements existing thermal comfort, ventilation and EPB standards by providing consistent IEQ input parameters for energy performance calculations.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 17772-1
First edition
2017-06
Energy performance of buildings —
Indoor environmental quality —
Part 1:
Indoor environmental input
parameters for the design and
assessment of energy performance of
buildings
Performance énergétique des bâtiments — Qualité de
l’environnement intérieur —
Partie 1: Paramètres d’entrée de l’environnement intérieur pour
la conception et l’évaluation de la performance énergétique des
bâtiments
Reference number
©
ISO 2017
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO 2017 – All rights reserved

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviations . 5
4.1 Symbols . 5
4.2 Abbreviations . 6
5 Interactions with other standards . 6
6 Design input parameters for design of buildings and sizing of heating, cooling,
ventilation and lighting systems . 6
6.1 General . 6
6.2 Thermal environment . 7
6.2.1 Heated and/or mechanically cooled buildings . 7
6.2.2 Buildings without mechanical cooling . 7
6.2.3 Increased air velocity . 8
6.3 Design for indoor air quality (ventilation rates). 8
6.3.1 General. 8
6.3.2 Methods . 9
6.3.3 Non-residential buildings .11
6.3.4 Residential buildings .11
6.3.5 Access to operable windows .12
6.3.6 Filtration and air cleaning .12
6.4 Humidity .12
6.5 Lighting .12
6.5.1 General.12
6.5.2 Non-residential buildings .13
6.5.3 Residential buildings .13
6.6 Noise .13
7 Indoor environment parameters for energy calculation .14
7.1 General .14
7.2 Thermal environment .14
7.2.1 Seasonal and monthly calculations .14
7.2.2 Hourly calculations .14
7.3 Indoor air quality and ventilation .14
7.3.1 General.14
7.4 Humidity .15
7.5 Lighting .15
7.5.1 Non-residential buildings .15
7.5.2 Residential buildings .15
Annex A (normative) Recommended criteria for the thermal environment .16
Annex B (normative) Basis for the criteria for indoor air quality and ventilation rates .22
Annex C (normative) How to define low and very low polluting buildings .27
Annex D (normative) Examples of criteria for lighting .28
Annex E (normative) Indoor system noise criteria of some spaces and buildings.29
Annex F (normative) Criteria for substances in indoor air .30
Annex G (normative) Occupant schedules for energy calculations .31
Annex H (informative) Default criteria for the thermal environment .32
Annex I (informative) Basis for the criteria for indoor air quality and ventilation rates .38
Annex J (informative) Example on how to define low and very low polluting buildings .44
Annex K (informative) Examples of criteria for lighting .45
Annex L (informative) Indoor system noise criteria of some spaces and buildings .46
Annex M (informative) WHO health-based criteria for indoor air .47
Annex N (informative) Occupants schedules for energy calculations .48
Annex O (informative) Occupants schedules for energy calculations .50
Bibliography .58
iv © ISO 2017 – All rights reserved

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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2. www .iso .org/ directives
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received. www .iso .org/ patents
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO’s adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see the following
URL: http:// www .iso .org/ iso/ foreword .html
This document was prepared by Technical Committee ISO/TC 163, Thermal performance and energy use
in the built environment.
A list of all the parts in the ISO 17772 series can be found on the ISO website.
Introduction
Energy consumption of buildings depends significantly on the criteria used for the indoor environment
(heating, cooling, ventilation and lighting) and building (including systems) design and operation.
Indoor environment also affects health, productivity and comfort of the occupants. Recent studies
have shown that costs of poor indoor environment for the employer, the building owner and for society,
as a whole are often considerable higher than the cost of the energy used in the same building. It has
also been shown that good indoor environmental quality can improve overall work and learning
performance and reduce absenteeism. In addition uncomfortable occupants are likely to take actions
to make themselves comfortable which may have energy implications. There is therefore a need for
specifying criteria for the indoor environment for design and energy calculations for buildings and
building service systems.
There exist other national and International Standards, and technical reports, which specify criteria for
[2]
thermal comfort (ISO 7730 ). These documents do specify different types and categories of criteria,
which may have a significant influence on the energy demand. For the thermal environment criteria
for the heating season (cold/winter) and cooling season (warm/summer) are listed. These criteria are,
however, mainly for dimensioning of building, heating, cooling and ventilation systems. They may not
be used directly for energy calculations and year-round evaluation of the indoor thermal environment.
Studies have shown that occupant expectations in natural ventilated buildings may differ from
conditioned buildings, which will be part of this document.
This document specifies how design criteria can be established and used for dimensioning of systems.
It defines how to establish and define the main parameters to be used as input for building energy
calculation and long term evaluation of the indoor environment. Finally this document identifies
parameters to be used for monitoring and displaying of the indoor environment
Different categories of criteria may be used depending on type of building, type of occupants, type
of climate and national differences. This document specifies several different categories of indoor
environment which could be selected for the space to be conditioned. These different categories are
intended to be used for design and may also be used to give an overall, yearly evaluation of the indoor
environment by evaluating the percentage of time in each category. The designer may also select other
categories using the principles from this document.
Table 1 shows the relative position of this document within the set of EPB standards in the context of
[15]
the modular structure as set out in ISO 52000-1 .
NOTE 1 In ISO/TR 52000-2 the same table can be found, with, for each module, the numbers of the relevant
EPB standards and accompanying technical reports that are published or in preparation.
NOTE 2 The modules represent EPB standards, although one EPB standard can cover more than one module
and one module can be covered by more than one EPB standard, for instance a simplified and a detailed method
respectively. See also Clause 2 and Tables A.1 and H.1.
vi © ISO 2017 – All rights reserved

Table 1 — Position of this document within the EN EPB set of standards according to
ISO 52001-1
Building
Overarching Technical Building Systems
(as such)
Building
Humid- Domes- PV,
Descrip- Descrip- Descrip- Heat- Cool- Ventila- Dehumidifi- Light- automa-
ifi tic hot wind,
tions tions tions ing ing tion cation ing tion and
cation water .
control
sub1 M1 sub1 M2 sub1 M3 M4 M5 M6 M7 M8 M9 M10 M11
1 General 1 General 1 General
Common
terms and
Building
definitions;
2 2 energy 2 Needs
symbols,
needs
units and
subscripts
(Free)
Indoor Maximum
Applica-
3 3 conditions 3 load and
tions
without power
systems
Ways to Ways to Ways to
express express express
4 energy 4 energy 4 energy
perfor- perfor- perfor-
mance mance mance
Building
Heat
functions Emission
transfer by
5 and build- 5 5 and con-
transmis-
ing bound- trol
sion
aries
Building Heat
occupan- transfer by Distribu-
6 cy and 6 infiltra- 6 tion and
operating tion and control
conditions ventilation
Aggre-
gation of
Storage
energy Internal
7 7 7 and con-
services heat gains
trol
and energy
carriers
Building Genera-
Solar heat
8 partition- 8 8 tion and
gains
ing control
Load
Calculated Building
dispatch-
energy dynamics
9 9 9 ing and
perfor- (thermal
operating
mance mass)
conditions
Measured Measured Measured
energy energy energy
10 10 10
perfor- perfor- perfor-
mance mance mance
11 Inspection 11 Inspection 11 Inspection
Table 1 (continued)
Building
Overarching Technical Building Systems
(as such)
Building
Humid- Domes- PV,
Descrip- Descrip- Descrip- Heat- Cool- Ventila- Dehumidifi- Light- automa-
ifi tic hot wind,
tions tions tions ing ing tion cation ing tion and
cation water .
control
Ways to
express
12  12 BMS
indoor
comfort
Outdoor
envi-
ronment
conditions
Economic
calculation
viii © ISO 2017 – All rights reserved

INTERNATIONAL STANDARD ISO 17772-1:2017(E)
Energy performance of buildings — Indoor environmental
quality —
Part 1:
Indoor environmental input parameters for the design and
assessment of energy performance of buildings
1 Scope
This document specifies requirements for indoor environmental parameters for thermal environment,
indoor air quality, lighting and acoustics and specifies how to establish these parameters for building
system design and energy performance calculations.
It includes design criteria for the local thermal discomfort factors, draught, radiant temperature
asymmetry, vertical air temperature differences and floor surface temperature.
This document is applicable where the criteria for indoor environment are set by human occupancy and
where the production or process does not have a major impact on indoor environment.
It also specifies occupancy schedules to be used in standard energy calculations and how different
categories of criteria for the indoor environment can be used.
The criteria in this document can also be used in national calculation methods. This document sets
criteria for the indoor environment based on existing standards and reports (listed in Clause 2 and the
Bibliography).
The document does not specify design methods, but gives input parameters to the design of building
envelope, heating, cooling, ventilation and lighting.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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
IEC 60050-845, International electrotechnical vocabulary — Chapter 845: Lighting
EN 16798-3, Ventilation of non-residential buildings — Performance requirements for ventilation and
room-conditioning systems
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 13731 and IEC 60050-845,
and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at http:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
EPB standard
[19]
standard that complies with the requirements given in ISO 52000-1, CEN/TS 16628 and
[20]
CEN/TS 16629
Note 1 to entry: These three basic EPB documents were developed under a mandate given to CEN by the European
Commission and the European Free Trade Association (Mandate M/480,), and support essential requirements of
EU Directive 2010/31/EU on the energy performance of buildings (EPBD). Several EPB standards and related
documents are developed or revised under the same mandate.
[SOURCE: ISO 52000-1:2017, 3.5.14]
3.2
adaptation, thermal
physiological, psychological or behavioural adjustment of building occupants to the interior thermal
environment in order to avoid or to limit thermal discomfort
Note 1 to entry: In naturally ventilated buildings these are often in response to changes in indoor environment
induced by outdoor weather conditions.
3.3
adaptation
perceived air quality
sensory adaptation to perceived air quality (odour), which occurs during the first 15 min exposure to
bio effluents
3.4
airing
intentional opening of windows, doors, vents, etc. for increasing the ventilation in a room
3.5
breathing zone
part of the occupied zone at the head level of the occupants
Note 1 to entry: Head level is 1,7 m standing, 1,1 m seated and 0,2 m for children on the floor
Note 2 to entry: For a definition of occupied zone see EN 16798–3.
3.6
building, very low-polluting
building where predominantly very low-emitting materials and furniture are used, activities with
emission of pollutants are prohibited and no previous emitting sources (like tobacco smoke, from
cleaning) were present
Note 1 to entry: Default criteria are listed in Annex H.
3.7
building, low-polluting
building where predominantly low emitting materials are used and materials and activities with
emission of pollutants are limited
Note 1 to entry: Note to entry: Default criteria are listed in in Annex H.
3.8
building, non low-polluting
building where no effort has been done to select low-emitting materials and where activities with
emission of pollutants are not limited or prohibited
Note 1 to entry: Default criteria are listed in Annex H. Previous emissions (like tobacco smoke) can have taken place.
2 © ISO 2017 – All rights reserved

3.9
cooling season
part of the year (usually summer) during which cooling is needed to keep the indoor temperature
within specified levels, at least part of the day and in part of the rooms
Note 1 to entry: The length of the cooling season differs substantially from country to country and from region
to region.
3.10
daylight factor
ratio of the illuminance at a point on a given plane due to the light received directly or indirectly from
a sky of assumed or known luminance distribution, to the illuminance on a horizontal plane due to an
unobstructed hemisphere of this sky, excluding the contribution of direct sunlight to both illuminances
3.11
demand controlled ventilation
ventilation system where airflow rates are controlled automatically according to measured needs at
room level
3.12
dehumidification
process of removing water vapour from air
3.13
outdoor temperature, daily mean
average of the hourly mean outdoor air temperature for one calendar day (24 h)
3.14
outdoor temperature
running mean
Θ
ed
exponentially weighted running mean of the daily mean outdoor air temperature
3.15
heating season
part of the year during which heating is needed to keep the indoor temperature within specified levels,
at least part of the day and in part of the rooms
Note 1 to entry: The length of the heating season differs substantially from country to country and from region
to region.
3.16
humidification
process of adding water vapour to air to increase humidity
3.17
mechanical cooling
cooling of the indoor environment by mechanical means used to provide cooling of supply air
Note 1 to entry: This includes fan coil units, cooled surfaces, etc.
Note 2 to entry: Opening of windows during night and day time or mechanical supply of cold outdoor air is not
regarded as mechanical cooling.
3.18
mechanical ventilation
ventilation system where air is supplied or extracted from the building or both by a fan using air
terminal devices, ducts and roof/wall devices
3.19
natural ventilation
ventilation provided by thermal, wind, or diffusion effects through doors, windows, or other intentional
devices in the building designed for ventilation
Note 1 to entry: Natural ventilation systems can be either manually or automatically controlled.
3.20
occupied hours
hours when the majority of the building or part of the building being considered is in its intended use
3.21
operative temperature
uniform temperature of an imaginary black enclosure in which an occupant would exchange the same
amount of heat by radiation plus convection as in the actual non-uniform environment
[1] [13]
Note 1 to entry: Further information is given in ISO 7726 and EN 16798-2 .
3.22
optimal operative temperature
operative temperature that satisfies the greatest percentage of occupants at a given clothing and
activity level in the current thermal environment
3.23
room conditioning system
system installed and used to keep comfortable conditions in a room within a defined range
Note 1 to entry: Air conditioning, chilled beams and radiant, surface heating and cooling systems are included.
3.24
ventilation
process of providing outdoor air by natural or mechanical means to a space or building
3.25
ventilation rate
magnitude of outdoor air flow to a room or building through the ventilation system or device
3.26
ventilation system
combination of appliances or building components designed to supply indoor spaces with outdoor air
and/or to extract polluted indoor air
Note 1 to entry: A ventilation system can refer to mechanical, natural and hybrid ventilation systems.
Note 2 to entry: The ventilation system can consist of mechanical components (e.g. combination of air handling
unit, ducts and terminal units). A ventilation system can also refer to natural ventilation systems making use of
temperature differences and wind with facade grills in combination with mechanical exhaust (e.g. in corridors,
toilets etc.). A combination of mechanical and natural ventilation is possible (hybrid systems).
3.27
design ventilation airflow rate
ventilation rate that the ventilation system is able to provide in design conditions (including boost,
weather and loads)
4 © ISO 2017 – All rights reserved

4 Symbols and abbreviations
4.1 Symbols
For the purposes of this document, the symbols given in ISO 52000-1:2017, Annex C and the
following apply.
Symbol Quantity Unit
θ indoor operative temperature °C
o
θ outdoor temperature °C
e
Θ running mean outdoor air temperature °C
m
Θ operative temperature, design and energy calculations °C
o
Θ running mean outdoor temperature °C
rm-i
Θ daily mean outdoor temperature °C
ed-i
v air speed (average / maximum) m/s
a
Θ floor surface temperature °C
f
ΔCO concentration ppm
ΔΘ radiant temperature asymmetry K
pr
ΔΘ vertical air temperature difference K
a
α constant for running mean calculations
q total ventilation rate l/s
tot
q ventilation rate for building materials l/s(m )
B
q ventilation rate for persons l/s (per person)
p
q total ventilation rate in occupied zone l/s(m ), l/s(person)
tot,oz
n number of persons
q ventilation rate required for dilution of pollutant L/s
h
G generation of a pollutant µg/s
h
C guideline value of a pollutant µg/L
h
C guideline value of the substance µg /m
h,i
C supply concentration of a pollutant at air intake µg/L
h,o
ε ventilation effectiveness -
v
A floor area m
L A-weighed sound pressure level dB(A)
p,A
L equivalent continuous sound pressure level dB(A)
eq, nT,A
D daylight factor
DC daylight quotient of the calculated area j
a,j
E average maintained illuminance lx
m
M activity level met
l assumed clothing level winter/summer clo
cl
4.2 Abbreviations
For the purposes of this document, the abbreviations given in ISO 52000-1:2017, Annex C and the
following apply.
Abbreviation Term
ACH
DR draught rate, %
DSNA daylight quotient sunscreen not
activated
IEQ indoor environmental quality
IEQ indoor environmental quality category
cat
for design
LPB low polluting building class
1–3
PD percentage dissatisfied for local;
thermal discomfort
PMV predicted mean vote
PPD predicted percentage of dissatisfied, %
RH relative humidity
WHO World Health Organization
5 Interactions with other standards
The present document provides default indoor environmental criteria for the design of buildings, room
conditioning systems and lighting systems (see Clause 6). The thermal criteria (PMV or design indoor
temperature in winter, design indoor temperature in summer) shall be used as bases for the definition
of input for heating load calculations and cooling load calculations, sizing of equipment and energy
calculations. Ventilation rates shall be used for design, sizing and energy calculations for ventilation
systems. Lighting levels shall be used for design of lighting system including the use of day lighting. The
present document shall provide default values for the indoor environment (like temperature, ventilation
rate, illuminance) as input to the calculation of the energy demand (building energy demand), when the
space is occupied (see Clause 7).
NOTE The categories are related to the level of expectations the occupants might have. A normal level would
be “Medium”. A higher level might be selected for occupants with special needs (children, elderly, handicapped,
etc.). A lower level does not provide any health risk but might decrease comfort.
6 Design input parameters for design of buildings and sizing of heating, cooling,
ventilation and lighting systems
6.1 General
For design of buildings and sizing of technical building systems for heating, cooling, ventilation and
lighting parameters and criteria shall be specified and documented. The criteria given in this clause
shall be used as input values for sizing of the systems as well as for design of buildings.
The present document specifies, in informative annexes, default input values for use in cases where no
national regulation is available. The default criteria are given for several categories. Design criteria for
the indoor environment shall be documented together with the premises for use of the spaces.
Default input values are given for each of the different categories of indoor environmental quality. A
short description of the categories is shown in Table 2.
6 © ISO 2017 – All rights reserved

Table 2 — Categories of indoor environmental quality
Category Level of expectation
IEQ High
I
IEQ Medium
II
IEQ Moderate
III
IEQ Low
IV
NOTE The categories are related to the level of expectations the occupants might have. A normal level would
be “Medium”. A higher level might be selected for occupants with special needs (children, elderly, handicapped,
etc.). A lower level will not provide any health risk but might decrease comfort.
6.2 Thermal environment
6.2.1 Heated and/or mechanically cooled buildings
For establishing design criteria the following procedure shall be used.
Criteria for the thermal environment in heated and/or mechanical cooled buildings shall be based on
the thermal comfort indices PMV-PPD, with assumed typical levels of activity and typical values of
thermal insulation for clothing (winter and summer). Based on the selected criteria a corresponding
design operative temperature interval shall be established. The values for dimensioning of cooling
systems shall be the upper values of the comfort range during cooling season (summer) and values for
dimensioning of the heating system shall be the lower values of the comfort range.
The design criteria in this section shall be used for both design of buildings (dimensioning of windows,
solar shading, building mass etc.) and HVAC systems.
Selection of the category is building, zone or room specific, and the needs of special occupant groups
such as elderly people (low metabolic rate and impaired control of body temperature) shall be
considered. For this group of people it is recommended to use category I requirements.
For buildings and spaces were the mechanical cooling capacity is not adequate to meet the required
temperature categories, the design documents shall state that fact.
NOTE 1 Some default examples of recommended design indoor operative temperatures for heating and
[14]
cooling, derived according to this principle, are presented in Table H.2 and in ISO/TR 17772-2 .
NOTE 2 Instead of using operative temperature as the design criterion the PMV-PPD index can be used
directly. In this way the effect of increased air velocity and effect of dynamic clothing insulation can be taken into
account.
NOTE 3 Using one of the default methods described in ISO/TR 17772-2, it can be described how often the
conditions are out of the required range.
6.2.1.1 Local thermal discomfort
Criteria for local thermal discomfort such as draught, radiant temperature asymmetry, vertical air
temperature differences and floor surface temperatures shall also be taken into account when designing
buildings and HVAC systems. Table H.3 presents the most important local thermal discomfort criteria
at three category levels.
NOTE 1 For more background information see ISO/TR 17772-2.
6.2.2 Buildings without mechanical cooling
For the dimensioning of the heating system the same criteria as for mechanically, cooled and heated
buildings shall be used (see 6.1.1).
In buildings without mechanical cooling, the criteria for the thermal environment shall be specified
using the method described in 6.1.1 or using the adapted method that takes into account adaptation
effects. This adaptive method only applies for occupants with sedentary activities without strict
clothing policies where thermal conditions are regulated primarily by the occupants through opening
and closing of elements in the building envelop (e.g. windows, ventilation flaps, roof lights, etc.). This
method applies to office buildings and other buildings of similar type used mainly for human occupancy
with mainly sedentary activities, where there is easy access to operable windows and occupants can
freely adapt their clothing to the indoor and/or outdoor thermal conditions.
NOTE 1 The field studies behind the method were conducted in office buildings but the method can also apply
in other spaces with similar individual possibilities for adaptation, e.g. in residential buildings.
NOTE 2 Default criteria for the indoor operative temperature in buildings without mechanical cooling systems
are presented in H.2.
The upper limits shall be used to design buildings and passive thermal controls (e.g. orientation of
glazing and solar shading, thermal building capacity, size and adjustability of operable windows etc.) to
avoid overheating.
For buildings and spaces were the building design and the natural ventilation system is not adequate to
meet the required temperature categories the design documents shall state that fact.
NOTE 3 Using one of the methods described in ISO/TR 17772-2, it can be described how often the conditions
are out of the required range.
6.2.3 Increased air velocity
It shall be evaluated if increased air velocity (with or without personal control) can improve thermal
comfort.
NOTE Under summer comfort conditions with indoor operative temperatures >25 °C increased air velocity
can be used to reduce the adverse effects of increased air temperatures according to H.3.
6.3 Design for indoor air quality (ventilation rates)
6.3.1 General
Indoor air quality shall be controlled by the following means: source control, ventilation, and possible
filtration and/or air cleaning.
Design ventilation airflow rates intended for sizing of the ventilation system shall be specified.
NOTE 1 Default ventilation airflow rates are presented in Annex B.
NOTE 2 During normal operation of the ventilation system, the ventilation flow rates can be different from the
design ventilation flow rates.
6.3.1.1 Source control
The control of emission of non-human pollutants shall be the primary strategy for maintaining
acceptable air quality.
NOTE 1 Once the main sources of pollutants are identified they can be eliminated or decreased by ventilation.
NOTE 2 The choice of building materials, surface preparation, maintenance and furniture has an impact on
the non-human pollutant emission in rooms, spaces and buildings. The classification of this is shown in Annex C.
6.3.1.2 Ventilation
The design ventilation air flow rates shall be used for designing any type of ventilation system, including
mechanical, natural and hybrid ventilation systems.
8 © ISO 2017 – All rights reserved

The design requirements for the ventilation air flow rates shall take into account the pollutant emissions
rates left after source control with material selection, local exhaust and other means.
6.3.1.3 Time periods used for determining air flow rates
The methods described in Clause 6 assume that pollutants emissions are constant in each time period
considered and lead to a constant ventilation air flow rate for each time period.
If occupation and pollutant loads vary in time, the designer shall specify the time periods considered
for the calculation of the design ventilation air flow rates. These shall describe at least the assumed
periods of occupancy and of non-occupancy.
NOTE Ventilation is also needed during non-occupied hours of the building to avoid accumulation of
pollutant in indoor air or on surfaces, or ventilation can be started before occupancy (see ISO/TR 17772-2).
Annex N includes default occupant schedules.
6.3.1.4 Building damage
Building damage shall be evaluated if the required ventilation rate for indoor air quality is high enough
to avoid damaging condensation on surfaces, in the materials or in the structure. If not a higher
ventilation rate shall be used as design value.
6.3.1.5 Design documentation
The design documentation shall state:
— which design method and if applicable which IEQ is used for design;
cat
— which pollutant sources have been identified and processes used to eliminate or decrease those
sources;
— which method has been used to derive the specified design ventilation airflow rates and the applied
occupancy schedules;
— design flow rates and the control range of ventilation in l/s per m and l/s per occupant.
NOTE Default occupant schedules are given in Annex N.
6.3.2 Methods
6.3.2.1 General
Design parameters for indoor air quality shall be derived using one or more of the following methods:
— Method 1: Method based on perceived air quality;
— Method 2: Method using limit values for substance concentration;
— Method 3: Method based on predefined ventilation air flow rates.
NOTE Within each method, the designer can choose between different categories of indoor environmental
quality and define which low pollutant building category, LPB , Annex C or Annex J is used.
1–3
6.3.2.2 Method 1 based on perceived air quality
The dilution required for reducing the health risk from a specific air pollutant shall be evaluated
separately from the ventilation rates required to obtain a desired perceived air quality level
(see Table 4). The highest of these ventilation rate values shall be used for design. If critical sources
are identified for health, it shall be checked that they remain below the health threshold values (see
6.3.2.3).
The total ventilation rate for the breathing zone is found by combining the ventilation for people and
building calculated from Formula (1):
qn=⋅qA+⋅q (1)
totp R B
where
q is the total ventilation rate for the breathing zone, l/s;
tot
n is the design value for the number of the persons in the room;
q is the ventilation rate for occupancy per person, l/(s·person);
p
A is the floor area, m ;
R
q is the ventilation rate for emissions from building, l/(s·m ).
B
The perceived air quality levels are defined by default for non-adapted persons in non-residential and
adapted persons in residential buildings. In non-residential buildings, assuming adapted persons shall
be justified.
NOTE See Annex B for default values. The methods described in ISO/TR 17772-2 can be used in special cases
where adapted persons are considered. The resulting ventilation rates are assumed to be independent of seasons.
6.3.2.3 Method 2 using criteria for individual substances
The design ventilation rate required to dilute an individual substance shall be calculated
using Formula (2):
G
h
Q =⋅ (2)
h
CC- ε
h,ih,o v
where
Q is the ventilation rate required for dilution, in m /s;
h
G is the generation rate of the substance, in µg/s;
h
C is the guideline value of the substance, in µg/m ;
h,i
C is the concentration of the substance of the supply air, in µg/m ;
h,o
ε is the ventilation effectiveness.
v
NOTE 1 Default values for C can be found in Annex B (for CO ) and Annex F (other substances). Default
h,i 2
values for ε (complete mixing is 1) can be found in EN 16798–3. C and C can also be expressed as ppm 10
v h,i h,o
(V/V). In this case the pollution load G needs to be expressed as l/s.
h
Formula (2) applies to steady-state conditions and the method requires that the supply air substance
concentration is lower than the indoor concentration.
To calculate the design ventilation air flow rate from Formula (2), the most critical or relevant pollutant
(or group of pollutants) shall be identified and the pollution load in the space shall be estimated.
When this method is used it is required that CO representing the pollutant emission from people
(bio effluents) shall be used as one of the substances.
Values depending on the category of indoor air are defined for CO in Annex B. Threshold values for
other sources are listed in Annex F. Emission rates and outdoor concentrations for the substances
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considered shall be defined based on material testing or certification (see Annex J) and local ambient
air quality values.
NOTE 2 ISO/TR 17772-2 shows examples of pollutants generation and concentration (e.g. for CO or water
vapour, together with sample calculations) as well as calculations for non-steady-state.
6.3.2.4 Method 3 based on pre-defined ventilation air flow rates
This is a method to determine c
...