CEN/TR 16798-2:2019

SLOVENSKI STANDARD
01-julij-2019
Energijske lastnosti stavb - Prezračevanje stavb - 2. del: Razlaga in utemeljitev EN
16798-1 - Vstopni podatki notranjega okolja za projektiranje in ocenjevanje
energijskih lastnosti stavb glede kakovosti notranjega zraka, toplotnega okolja,
razsvetljave in akustike - Modul M1-6
Energy performance of buildings - Ventilation for buildings - Part 2: Interpretation of the
requirements in EN 16798-1 - Indoor environmental input parameters for design and
assessment of energy performance of buildings addressing indoor air quality, thermal
environment, lighting and acoustics - Module M1-6
Energetische Bewertung von Gebäuden - Lüftung von Gebäuden - Teil 2: Interpretation
der Anforderungen der EN 16798-1 - Eingangsparameter für das Innenraumklima zur
Auslegung und Bewertung der Energieeffizienz von Gebäuden bezüglich
Raumluftqualität, Temperatur, Licht und Akustik - Module M1-6
Performance énergétique des bâtiments - Ventilation des bâtiments - Partie 2:
Interprétation des exigences de l’EN 16798-1 - Données d'entrées d'ambiance intérieure
pour la conception et l'évaluation de la performance énergétique des bâtiments couvrant
la qualité de l'air intérieur, l'ambiance thermique, l'éclairage et l'acoustique - Module M1-
Ta slovenski standard je istoveten z: CEN/TR 16798-2:2019
ICS:
91.120.10 Toplotna izolacija stavb Thermal insulation of
buildings
91.140.30 Prezračevalni in klimatski Ventilation and air-
sistemi conditioning systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

CEN/TR 16798-2
TECHNICAL REPORT
RAPPORT TECHNIQUE
May 2019
TECHNISCHER BERICHT
ICS 91.120.10; 91.140.01
English Version
Energy performance of buildings - Ventilation for buildings
- Part 2: Interpretation of the requirements in EN 16798-1
- Indoor environmental input parameters for design and
assessment of energy performance of buildings addressing
indoor air quality, thermal environment, lighting and
acoustics (Module M1-6)
Performance énergétique des bâtiments - Ventilation Energetische Bewertung von Gebäuden - Lüftung von
des bâtiments - Partie 2 : Interprétation des exigences Gebäuden - Teil 2: Interpretation der Anforderungen
de l'EN 16798-1 - Données d'entrées d'ambiance der EN 16798-1 - Eingangsparameter für das
intérieure pour la conception et l'évaluation de la Innenraumklima zur Auslegung und Bewertung der
performance énergétique des bâtiments couvrant la Energieeffizienz von Gebäuden bezüglich
qualité de l'air intérieur, l'ambiance thermique, Raumluftqualität, Temperatur, Licht und Akustik
l'éclairage et l'acoustique (Module M1-6) (Module M1-6)

This Technical Report was approved by CEN on 8 February 2019. It has been drawn up by the Technical Committee CEN/TC 156.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 16798-2:2019 E
worldwide for CEN national Members.

Contents Page
European foreword . 5
Introduction . 9
1 Scope . 10
2 Normative references . 10
3 Terms and definitions . 11
4 Symbols and abbreviations . 11
4.1 Symbols . 11
4.2 Abbreviations . 12
5 Interactions with other standards and use of categories . 12
6 How to establish design input criteria for dimensioning of buildings, heating,
cooling, ventilation and lighting systems . 13
6.1 Introduction . 13
6.2 Thermal environment . 14
6.2.1 General . 14
6.2.2 Mechanically heated and/or cooled buildings . 14
6.2.3 Buildings without mechanical cooling . 15
6.2.4 Increased air velocity . 17
6.3 Design for indoor air quality (ventilation rates) . 17
6.3.1 General . 17
6.3.2 Methods . 18
6.3.3 Non-residential buildings . 19
6.3.4 Residential buildings . 19
6.3.5 Access to operable windows . 20
6.3.6 Filtration and air cleaning . 20
6.4 Humidity . 21
6.5 Lighting . 21
6.5.1 General . 21
6.5.2 Non-residential buildings . 21
6.5.3 Residential buildings . 21
6.6 Noise. 22
7 Indoor environment parameters for energy calculation. 22
7.1 General . 22
7.2 Thermal environment . 22
7.2.1 General . 22
7.2.2 Seasonal and monthly calculations . 22
7.2.3 Hourly calculations or dynamic building simulation . 22
7.3 Indoor air quality and ventilation . 23
7.3.1 Generals . 23
7.3.2 Non-residential buildings . 23
7.3.3 Residential buildings . 23
7.4 Humidity . 23
7.5 Lighting . 23
8 Evaluation of the indoor environment and long term indicators . 23
8.1 General . 23
8.2 Design indicators . 23
8.3 Calculated indicators of indoor environment . 24
8.3.1 General . 24
8.3.2 Simple indicator . 24
8.3.3 Hourly criteria . 24
8.3.4 Degree hours criteria . 24
8.3.5 Overall thermal comfort criteria (weighted PMV criteria) . 24
8.4 Measured indicators . 24
8.4.1 General . 24
8.4.2 Thermal environment . 24
8.4.3 Indoor air quality and ventilation . 25
8.4.4 Lighting . 25
8.4.5 Noise. 25
8.5 Subjective evaluations . 26
9 Inspections and measurement of the indoor environment in existing
buildings . 26
9.1 General . 26
9.2 Measurements . 26
9.2.1 General . 26
9.2.2 Thermal environment . 26
9.2.3 Indoor air quality . 27
9.2.4 Indoor light quality measurements based on illuminance . 28
10 Classification and certification of the indoor environment . 28
10.1 General . 28
10.2 Detailed classification and certification . 28
10.3 Recommended overall evaluation of the indoor environment and
certification . 28
Annex A (informative) Information about national annexes . 29
Annex B (informative) Default criteria for the indoor environment . 30
B.1 General . 30
B.2 Default criteria for the thermal environment . 30
B.2.1 Default categories for design of mechanically heated and cooled building. 30
B.2.2 Default acceptable indoor temperatures for design of buildings without
mechanical cooling systems . 33
B.2.3 Increased air velocity . 34
B.2.4 Recommended indoor temperatures for energy calculations . 34
B.3 Basis for the criteria for indoor air quality and ventilation rates . 35
B.3.1 Default design ventilation air flow rates for non-residential buildings . 35
B.3.2 Default design ventilation air flow rates for residential buildings . 41
B.3.3 Recommended criteria for dimensioning of humidification and de-
humidification . 53
B.4 Example on how to define low and very low polluting buildings . 53
B.5 Examples of criteria for lighting . 57
B.6 Indoor system noise criteria of some spaces and buildings . 58
B.6.1 Noise from continuous sources . 58
B.6.2 Noise from service equipment in buildings . 59
Annex C (informative) Occupants schedules for energy calculations . 61
Annex D (informative) Long term evaluation of the general thermal comfort
conditions . 68
Annex E (informative) Recommended criteria for acceptable deviations . 71
E.1 Indoor Environmental Quality Category . 71

E.2 Length of deviation . 71
Annex F (informative) Methodologies for subjective evaluations. 75
Annex G (informative) Examples of classification and certification of the indoor
environment . 77
G.1 General . 77
G.2 The design criteria used . 77
G.3 Whole year computer simulations of the indoor environment and energy
performance . 77
G.4 Long term measurement of selected parameters for the indoor
environment . 78
G.5 Subjective responses from occupants . 78
Annex H (informative) Recommended criteria for personalized systems . 79
Annex I (informative) Recommended methods for substitute ventilation air by air
cleaning . 81
Annex J (informative) WHO criteria for health in the indoor environment . 84
Bibliography . 85
European foreword
This document (CEN/TR 16798-2:2019) has been prepared by Technical Committee CEN/TC 156
“Ventilation for buildings”, the secretariat of which is held by BSI.
Attention is drawn to the possibility that some of the elements of this document may be the
subject of patent rights. CEN shall not be held responsible for identifying any or all such patent
rights.
This document is part of the set of standards and accompanying Technical Reports on the energy
performance of buildings and has been prepared under the Mandate M 480 given to CEN by the
European Commission and the European Free Trade Association,
see Bibliographical Reference [35]).
Directive 2010/31/EU recasting the Directive 2002/91/EC on energy performance of buildings
(EPBD, [36]) promotes the improvement of the energy performance of buildings within the
European Union, taking into account all types of energy uses (heating, lighting, cooling, air
conditioning, ventilation) and outdoor climatic and local conditions, as well as indoor climate
requirements and cost effectiveness (Article 1).
The directive requires Member States to adopt measures and tools to achieve the prudent and
rational use of energy resources. In order to achieve those goals, the EPBD requires increasing
energy efficiency and the enhanced use of renewable energies in both new and existing buildings.
One tool for this is the application by Member States of minimum requirements on the energy
performance of new buildings and for existing buildings that are subject to major renovation, as
well as for minimum performance requirements for the building envelope if energy-relevant
parts are replaced or retrofitted. Other tools are energy certification of buildings, inspection of
boilers and air-conditioning systems.
The use of European standards increases the accessibility, transparency and objectivity of the
energy performance assessment in the Member States facilitating the comparison of best
practices and supporting the internal market for construction products. The use of EPB-standards
for calculating energy performance, as well as for energy performance certification and the
inspection of heating systems and boilers, ventilation and air-conditioning systems will reduce
costs compared to developing different standards at national level.
The first mandate to CEN to develop a set of CEN EPBD standards (M/343, [34]), to support the
first edition of the EPBD ([33]) resulted in the successful publication of all EPBD related CEN
standards in 2007-2008.
The Mandate M/480 was issued to review the Mandate M/343 as the recast of the EPBD raised
the need to revisit the standards and reformulate and add standards so that they become on the
one hand unambiguous and compatible, and on the other hand a clear and explicit overview of
the choices, boundary conditions and input data that need to be defined at national or regional
level. Such national or regional choices remain necessary, due to differences in climate, culture
and building tradition, policy and legal frameworks. Consequently, the set of CEN-EPBD standards
published in 2007-2008 had to be improved and expanded on the basis of the recast of the EPBD.
The EPB standards are flexible enough to allow for necessary national and regional differentiation
and facilitate Member States implementation and the setting of requirements by the Member
States.
Further target groups are users of the voluntary common European Union certification scheme
for the energy performance of non-residential buildings (EPBD art.11.9) and any other regional
(e.g. Pan European) parties wanting to motivate their assumptions by classifying the building
energy performance for a dedicated building stock.
For the convenience of Standards users CEN/TC 156, together with responsible Working Group
Conveners, have prepared a simple table below relating, where appropriate, the relationship
between the ‘EPBD’ and ‘recast EPBD’ standard numbers prepared by Technical Committee
CEN/TC 156 “Ventilation for buildings”.
Recast EPBD
EPBD EN Number Title
EN Number
Energy performance of buildings – Ventilation for
buildings - Part 1: Indoor environmental input
parameters for design and assessment of energy
performance of buildings addressing indoor air
EN 15251 EN 16798–1
quality, thermal environment, lighting and
acoustics (Module M1-6)
(revision of EN 15251)
Energy performance of buildings – Ventilation for
buildings - Part 2: Interpretation of the
requirements in EN 16798-1 - Indoor
CEN/TR 16798– environmental input parameters for design and
N/A
2 assessment of energy performance of buildings
addressing indoor air quality, thermal
environment, lighting and acoustics (Module M1-
6)
Energy performance of buildings – Ventilation for
buildings - Part 3: For non-residential buildings –
Performance requirements for ventilation and
EN 13779 EN 16798–3
room-conditioning systems (Modules M5-1, M5-
4)
(revision of EN 13779)
Energy performance of buildings – Ventilation for
buildings - Part 4: Interpretation of the
CEN/TR 16798– requirements in EN 16798-3 - For non-
N/A
4 residential buildings – Performance
requirements for ventilation and room-
conditioning systems(Modules M5-1, M5-4)
Energy performance of buildings — Ventilation
for buildings – Part 5-1: Calculation methods for
energy requirements of ventilation and air
conditioning systems (Modules M5-6, M5-8, M6-5,
EN 15241 EN 16798–5–1
M6-8, M7-5, M7-8) — Method 1: Distribution and
generation
(revision of EN 15241)
Recast EPBD
EPBD EN Number Title
EN Number
Energy performance of buildings – Ventilation for
buildings - Part 5-2: Calculation methods for
energy requirements of ventilation systems
EN 15241 EN 16798–5–2
(Modules M5-6, M5-8, M6-5, M6-8, M7-5, M7-8) -
Method 2: Distribution and generation
(revision of EN 15241)
Energy performance of buildings - Ventilation for
buildings – Part 6: Interpretation of the
CEN/TR 16798– requirements in EN 16798-5-1 and EN 16798-5-2
N/A
6 – Calculation methods for energy requirements of
ventilation and air conditioning systems
(Modules M5-6, M5-8, M 6-5, M6-8 , M7-5, M7-8)
Energy performance of buildings - Ventilation for
buildings - Part 7: Calculation methods for the
determination of air flow rates in buildings
EN 15242 EN 16798–7
including infiltration (Modules M5-5)
(revision of EN 15242)
Energy performance of buildings – Ventilation for
buildings – Part 8: Interpretation of the
CEN/TR 16798–
N/A requirements in EN 16798-7 – Calculation
methods for the determination of air flow rates in
buildings including infiltration – (Modules M5-5)
Energy performance of buildings – Ventilation for
buildings - Part 9: Calculation methods for energy
requirements of cooling systems (Modules M4-1,
EN 15243 EN 16798–9
M4-4, M4-9) – General
(revision of EN 15243)
Energy performance of buildings – Ventilation for
buildings – Part 10: Interpretation of the
CEN/TR 16798–
N/A requirements in EN 16798-9 – Calculation
methods for energy requirements of cooling
systems (Module M4-1,M4-4, M4-9) – General
Energy performance of buildings – Ventilation for
N/A EN 16798–13 buildings - Part 13: - Calculation of cooling
systems (Module M4-8) – Generation
Energy performance of buildings – Ventilation for
CEN/TR 16798– buildings - Part 14: Interpretation of the
N/A
14 requirements in EN 16798-13 – Calculation of
cooling systems (Module M4-8) – Generation
Recast EPBD
EPBD EN Number Title
EN Number
Energy performance of buildings – Ventilation for
N/A EN 16798–15 buildings – Part 15: Calculation of cooling systems
(Module M4-7) – Storage
Energy performance of buildings – Ventilation for
CEN/TR 16798– buildings – Part 16: Interpretation of the
N/A
16 requirements in EN 16798-15 – Calculation of
cooling systems (Module M4-7) – Storage
Energy performance of buildings – Ventilation for
EN 15239 and buildings - Part 17: Guidelines for inspection of
EN 16798–17
EN 15240 ventilation and air- conditioning systems (Module
M4-11, M5-11, M6-11, M7-11)
Energy performance of buildings – Ventilation for
buildings – Part 18: Interpretation of the
CEN/TR 16798–
N/A requirements in EN 16798-17 – Guidelines for
inspection of ventilation and air-conditioning
systems (Module M4-11, M5-11, M6-11, M7-11)
Introduction
This document is a guide to EN 16798-1 and can help the user in application of the standard and
give additional background information. Besides this document describes and recommends
additional topics related to the evaluation of the indoor environmental quality and new
possibilities to improve the indoor environmental quality and reduce energy use of buildings like
personalized systems, air cleaning technologies, consideration of adapted persons, etc.
This document explains how design criteria can be established and used for dimensioning of
systems. It explains 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. This document
also describes how gas phase air cleaning in the future can improve the indoor air quality and
partly substitute for outside air. Finally it will identify parameters to be used for monitoring and
displaying of the indoor environment. Different categories of criteria can be used depending on
type of building, type of occupants, type of climate and national differences. The report explains
how these different categories of indoor environment can be individually selected as national
criteria, be used in project agreement for design criteria and for displaying the yearly building
performance in relation to indoor environmental quality. The designer can also define other
categories using the principles from EN 16798-1 and this document.
1 Scope
This document deals with the indoor environmental parameters for thermal environment, indoor
air quality, lighting and acoustic. The document explains how to use EN 16798-1 for specifying
indoor environmental input parameters for building system design and energy performance
calculations. The document specifies methods for long term evaluation of the indoor environment
obtained as a result of calculations or measurements. The document specifies criteria for
measurements which can be used if required to measure compliance by inspection. The
Document identifies parameters to be used by monitoring and displaying the indoor environment
in existing buildings. 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. The document explains how different categories of criteria for the indoor
environment can be used.
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.
NOTE The references in EN 16798–1 are also applicable in this document. Additional references are
listed in the Bibliography.
EN 12193, Light and lighting — Sports lighting
EN 12464-1:2011, Light and lighting — Lighting of work places — Part 1: Indoor work places
EN 12464-2, Light and lighting — Lighting of work places — Part 2: Outdoor work places
EN 12665, Light and lighting — Basic terms and criteria for specifying lighting requirements
EN 12792, Ventilation for buildings — Symbols, terminology and graphical symbols
EN 16798-1:2019, Energy performance of buildings — Part 1: Indoor environmental input
parameters for design and assessment of energy performance of buildings addressing indoor air
quality, thermal environment, lighting and acoustics — Module M1-6
EN 16798-3, Energy performance of buildings — Part 3: Ventilation for non-residential
buildings — Performance requirements for ventilation and room-conditioning systems
EN ISO 10052, Acoustics — Field measurements of airborne and impact sound insulation and of
service equipment sound — Survey method (ISO 10052)
EN ISO 16032, Acoustics — Measurement of sound pressure level from service equipment in
buildings — Engineering method (ISO 16032)
EN ISO 13731, Ergonomics of the thermal environment — Vocabulary and symbols (ISO 13731)
EN ISO 52000-1:2017, Energy performance of buildings — Overarching EPB assessment — Part 1:
General framework and procedures (ISO/FDIS 52000-1:2017)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 16798-1, EN 12792,
EN ISO 13731, EN 12464 (all parts), EN 12665 and EN ISO 52000-1 apply.
4 Symbols and abbreviations
4.1 Symbols
For the purposes of this Report, the symbols given in EN ISO 52000-1:2016, Clause 4 and Annex C
and the specific symbols listed in Table 1 apply.
Table 1 — Symbols and units
Symbol Quantity Unit
θ indoor operative temperature °C
o
θ outdoor temperature °C
e
Θ running mean outdoor air temperature °C
m
Θ daily mean outdoor temperature °C
ed-i
Θ operative temperature, design and energy °C
o
calculations
Θ running mean outdoor temperature °C
rm-i
v air speed (average/maximum) m/s
a
Θ floor surface temperature °C
f
Δ CO Concentration difference ppm
Δ Θ radiant temperature asymmetry K
pr
Δ Θ 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
n number of persons
q ventilation rate required for dilution of L/s
h
pollutant
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 µg/L
h,o
intake
ε ventilation effectiveness -
v
Symbol Quantity Unit
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
a,j
E average maintained illuminance lx
m
M activity level met
I assumed clothing level winter/summer clo
cl
4.2 Abbreviations
Table 2 — Abbreviations
Abbreviation Term
ACH air changes per hour
DR draught rate, %
DSNA daylight quotient sunscreen not
activated
IEQ indoor environmental quality
IEQ indoor environmental quality
cat
category 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 and use of categories
The present document interacts mainly with EN 16798-1 and indirectly with the standards that
interact with EN 16798-1.
The document explains how the indoor environmental criteria in EN 16798-1 can be used for the
design of building and HVAC systems. The thermal criteria (design indoor temperature in winter,
design indoor temperature in summer) are used as input for heating and cooling load calculations
and sizing of the installed systems. Ventilation rates are used for sizing ventilation systems, and
lighting levels for design of lighting system including the use of day lighting. The design values for
sizing the building services are needed to avoid possible negative effect of indoor environment
and to give advice in respect of improvement of the energy efficiency of existing buildings as well
as of the heating and cooling of buildings.
This document explains how values for the indoor environment (temperature, ventilation,
lighting) are used as input to the calculation of the energy demand (building energy demand).
Output from measured indoor environmental parameters in existing buildings (temperature, CO ,
ventilation rates, illumination levels) will enable the evaluation of overall annual performance
and can be used to display the indoor environmental factors together with data for the energy
performance.
Output from room temperature calculations and yearly dynamic building simulations will enable
evaluation of the annual performance of buildings at the design stage.
The document describes methods for measurement of the indoor environment and for treating
measured data related to the inspection of HVAC systems.
The document will provide a method for categorization of indoor environment (Clause 10). This
method can be used to integrate complex indoor environment information to simple classification
for a possible indoor environment certificate.
6 How to establish design input criteria for dimensioning of buildings,
heating, cooling, ventilation and lighting systems
6.1 Introduction
Recommended input values are given for each of the different categories as shown in Table 3.
These categories can be used in different ways. First and foremost they can be used to establish
different levels of criteria for the design of buildings and building services. Different countries can
standardize one category for design. The consultant and client of a building project can use the
categories to agree on a specific design level. The intention is not that a building should be
operated strictly in one class the whole year round. Instead the categories can be used to describe
the yearly indoor environmental performance of a building by showing the distribution of the
parameters in the different categories. It can then, on the national level or in a design/operation
contract, be specified how much of the time the categories can be exceeded. This is shown in this
report with some examples.
Table 3 — Categories of indoor environmental quality
Category Level of Explanation
expectation
IEQ High Should be selected for occupants with
I
special needs (children, elderly, persons
with disabilities).
IEQ Medium The normal level used for design and
II
operation.
IEQ Moderate Will still provide an acceptable
III
environment. Some risk of reduced
performance of the occupants.
IEQ Low Should only be used for a short time of
IV
the year or in spaces with very short
time of occupancy.
Even if a building is designed for category III it can still be operated a greater part of the year in
category I or II. When the outdoor conditions are less severe (warmer in winter, colder in
summer) than the design day, the capacity of the heating/cooling system will be large enough to
keep the indoor environment within a more narrow range.
It can be argued that selecting a higher category can increase the energy consumption. The energy
requirement is however regulated by national building codes and cannot be exceeded. The
challenge is then for the designer/operator of the building to obtain a high level of indoor
environmental quality within the required energy criteria.
For design of buildings and dimensioning of room conditioning systems the thermal comfort
criteria (minimum room operative temperature in winter, maximum room operative
temperature in summer) will be used as input for heating load and cooling load calculations. The
design ventilation rates that are used for sizing the equipment, are also used for energy
calculations. The criteria are used as input values for the sizing and dimensioning of the systems
as well as for design of buildings (facades, orientation, solar shading, etc.). Using a higher category
will result in systems with a higher capacity; but depending on how the system is operated the
energy use is not necessarily higher. In the design a design external temperature for heating and
a design day (including solar load) for cooling will normally be used.
To protect the designer/installer against complaint for not meeting the design intend, it is very
important that the basis for design (boundary conditions, occupant density, etc.) are documented
in the design documents. This will avoid discussions when these boundary conditions are
changed during the lifetime of the building and the performance criteria cannot be met.
6.2 Thermal environment
6.2.1 General
Field studies in office buildings have shown that people’s expectations regarding the thermal
environment can be different for buildings with installed mechanical cooling and buildings where
the occupants only have the possibility to open windows to influence the thermal environment.
Therefore the design criteria are different for the two types of office buildings: mechanical heated
and cooled buildings and buildings without mechanical cooling (see definition in EN 16798-1).
The decision on which approach to use is taken by the client together with his consultant. It is
possible for the consultant to show the difference between the two methods (acceptable indoor
temperatures, energy use, etc.)
6.2.2 Mechanically heated and/or cooled buildings
6.2.2.1 General
Criteria for the thermal environment in heated and/or cooled buildings, in EN 16798-1 are based
on the thermal comfort indices PMV-PPD (Predicted Mean Vote - Predicted Percentage of
Dissatisfied) with assumed typical levels of activity and typical values of thermal insulation for
clothing (winter and summer) as described in detail in EN ISO 7730. Assuming different criteria
for the PPD, different categories of the indoor environment are established. The PMV-PPD index
takes into account the influence of all six thermal parameters (clothing, activity, air temperature,
mean radiant temperature, air velocity and humidity) and can be directly used as criteria.
With a specified combination of activity and clothing, an assumed 50 % relative humidity and low
air velocities (<0,1 m/s) the criteria can also be expressed as operative temperature as shown in
B.2.1. For other air velocities and humidities the corresponding operative temperature will be
different. Some examples of recommended design indoor operative temperatures for heating and
cooling, derived according to this principle, are presented in B.2, Table B.2. This presents design
values for the indoor operative temperature in buildings that have active heating systems in
operation during winter season and active cooling systems during summer season, assumed
clothing level for winter (1,0 clo) and summer (0,5 clo) and activity level (sedentary, 1,2 met).
Note that the operative temperature limits should be adjusted when clothing levels and/or
activity levels are different from the values mentioned in the table.
In some types of room there can be mixed type of occupants (sedentary-standing/walking) with
different type of clothing (visitor to department store in outdoor clothing and shop assistance in
indoor clothing). In these cases a compromise should be found for the design criteria and the
boundary conditions and this should be documented in the design documents and agreed by the
client.
The temperatures in Table B.2 are operative temperatures (EN ISO 7726) with design loads at the
design weather conditions which are specified nationally according to EN ISO 15927-4 and
EN ISO 15927-5.
In most cases the average room air temperature can be used as defining the design indoor
temperature, but if temperatures of large room surfaces differ significantly from the air
temperature (windows in winter and summer) or in situations where building occupants are
often exposed to direct sun, the operative temperature should be used. Further information on
clothing and activity can be found in EN ISO 9920 and EN ISO 8996. The value of design
temperature can vary from the values shown, to take account of e.g. local custom (clothing) or a
desire for energy saving so long as the within-day variation from the design temperature is within
the given range, and the occupants are given time and opportunity to adapt to the modified design
temperature.
The design criteria in this section are both for design of buildings (dimensioning of windows,
solar shading, building mass, etc.) and for design of HVAC systems.
6.2.2.2 Local thermal discomfort
Criteria for local thermal discomfort (see EN 16798-1) such as draught, radiant temperature
asymmetry, vertical air temperature differences and floor surface temperatures will also have an
influence on the design of buildings and systems, and should be taken account of.
6.2.2.3 Personalized systems
Individual preferences regarding the indoor environment can be very different. Therefore there
is an increasing interest in using personalized systems for providing thermal comfort at
individual work places. With personalized systems it can be possible to satisfy all occupants.
Recommended criteria for these types of systems are included in Annex H.
6.2.3 Buildings without mechanical cooling
During the summer season and during the between-seasons (spring and autumn) the so-called
adaptive criteria (upper and lower temperature limits that change with the running mean outside
temperature) can be applied (see the category I, II and III upper and lower limits in B.2.2,
Figure B.1 in EN 16798-1:2019). During the winter season, the same temperature limits should
be applied as presented for buildings with mechanical cooling systems.
The adaptive criteria are based on data for office buildings, but could possibly be used for other
buildings of similar type used m
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