SIST EN ISO 11855-1:2021
(Main)Building environment design - Embedded radiant heating and cooling systems - Part 1: Definitions, symbols, and comfort criteria (ISO 11855-1:2021)
Building environment design - Embedded radiant heating and cooling systems - Part 1: Definitions, symbols, and comfort criteria (ISO 11855-1:2021)
This document specifies the basic definitions, symbols, and comfort criteria for embedded radiant
heating and cooling systems.
Umweltgerechte Gebäudeplanung - Flächenintegrierte Strahlheizungs- und -kühlsysteme - Teil 1: Begriffe, Symbole und Komfortkriterien (ISO 11855-1:2021)
Dieses Dokument legt grundlegende Definitionen, Symbole und Komfortkriterien für flächenintegrierte Strahlungsheiz- und kühlsysteme fest.
Conception de l'environnement des bâtiments - Systèmes intégrés de chauffage et de refroidissement par rayonnement - Partie 1: Définitions, symboles et critères de confort (ISO 11855-1:2021)
Načrtovanje notranjega okolja v stavbah - Vgrajeni sevalni ogrevalni in hladilni sistemi - 1. del: Definicije, simboli in merila za ugodje (ISO 11855-1:2021)
General Information
RELATIONS
Standards Content (sample)
SLOVENSKI STANDARD
SIST EN ISO 11855-1:2021
01-november-2021
Nadomešča:
SIST EN ISO 11855-1:2015
Načrtovanje notranjega okolja v stavbah - Vgrajeni sevalni ogrevalni in hladilni
sistemi - 1. del: Definicije, simboli in merila za ugodje (ISO 11855-1:2021)
Building environment design - Embedded radiant heating and cooling systems - Part 1:
Definitions, symbols, and comfort criteria (ISO 11855-1:2021)Umweltgerechte Gebäudeplanung - Flächenintegrierte Strahlheizungs- und -
kühlsysteme - Teil 1: Begriffe, Symbole und Komfortkriterien (ISO 11855-1:2021)
Conception de l'environnement des bâtiments - Systèmes intégrés de chauffage et de
refroidissement par rayonnement - Partie 1: Définitions, symboles et critères de confort
(ISO 11855-1:2021)Ta slovenski standard je istoveten z: EN ISO 11855-1:2021
ICS:
91.140.10 Sistemi centralnega Central heating systems
ogrevanja
91.140.30 Prezračevalni in klimatski Ventilation and air-
sistemi conditioning systems
SIST EN ISO 11855-1:2021 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 11855-1:2021
EN ISO 11855-1
EUROPEAN STANDARD
NORME EUROPÉENNE
August 2021
EUROPÄISCHE NORM
ICS 91.040.01 Supersedes EN ISO 11855-1:2015
English Version
Building environment design - Embedded radiant heating
and cooling systems - Part 1: Definitions, symbols, and
comfort criteria (ISO 11855-1:2021)
Conception de l'environnement des bâtiments - Umweltgerechte Gebäudeplanung - Flächenintegrierte
Systèmes intégrés de chauffage et de refroidissement Strahlheizungs- und -kühlsysteme - Teil 1: Begriffe,
par rayonnement - Partie 1: Définitions, symboles et Symbole und Komfortkriterien (ISO 11855-1:2021)
critères de confort (ISO 11855-1:2021)This European Standard was approved by CEN on 29 July 2021.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, 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
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 11855-1:2021 E
worldwide for CEN national Members.---------------------- Page: 3 ----------------------
SIST EN ISO 11855-1:2021
EN ISO 11855-1:2021 (E)
Contents Page
European foreword ....................................................................................................................................................... 3
---------------------- Page: 4 ----------------------SIST EN ISO 11855-1:2021
EN ISO 11855-1:2021 (E)
European foreword
This document (EN ISO 11855-1:2021) has been prepared by Technical Committee ISO/TC 205
"Building environment design" in collaboration with Technical Committee CEN/TC 228 “Heating
systems and water based cooling systems in buildings” the secretariat of which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by February 2022, and conflicting national standards
shall be withdrawn at the latest by February 2022.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 supersedes EN ISO 11855-1:2015.Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN websites.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.Endorsement notice
The text of ISO 11855-1:2021 has been approved by CEN as EN ISO 11855-1:2021 without any
modification.---------------------- Page: 5 ----------------------
SIST EN ISO 11855-1:2021
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SIST EN ISO 11855-1:2021
INTERNATIONAL ISO
STANDARD 11855-1
Second edition
2021-08
Building environment design —
Embedded radiant heating and cooling
systems —
Part 1:
Definitions, symbols, and comfort
criteria
Conception de l'environnement des bâtiments — Systèmes intégrés de
chauffage et de refroidissement par rayonnement —
Partie 1: Définitions, symboles et critères de confort
Reference number
ISO 11855-1:2021(E)
ISO 2021
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SIST EN ISO 11855-1:2021
ISO 11855-1:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
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SIST EN ISO 11855-1:2021
ISO 11855-1:2021(E)
Contents Page
Foreword ........................................................................................................................................................................................................................................iv
Introduction ..................................................................................................................................................................................................................................v
1 Scope ................................................................................................................................................................................................................................. 1
2 Normative references ...................................................................................................................................................................................... 1
3 Terms and definitions ..................................................................................................................................................................................... 1
4 Symbols and abbreviated terms ........................................................................................................................................................11
5 Comfort criteria ..................................................................................................................................................................................................16
5.1 General ........................................................................................................................................................................................................16
5.2 General thermal comfort .............................................................................................................................................................16
5.2.1 Operative temperature ............................................................................................................................................17
5.2.2 PMV (predicted mean vote) and PPD (predicted percentage of dissatisfied) .........17
5.3 Local thermal discomfort ............................................................................................................................................................18
5.3.1 Surface temperature limit .....................................................................................................................................18
5.3.2 Radiant temperature asymmetry ...................................................................................................................19
5.3.3 Vertical air temperature difference ..............................................................................................................19
5.4 Acoustical comfort ............................................................................................................................................................................20
5.4.1 Water velocity and noise ........................................................................................................................................20
5.4.2 Acoustical comfort in water-based heating and cooling systems .......................................20
5.4.3 Acoustical comfort in thermally active building systems (TABS) .......................................21
Annex A (informative) Floor surface temperature for thermal comfort ......................................................................22
Annex B (informative) Draught ...............................................................................................................................................................................25
Bibliography .............................................................................................................................................................................................................................26
© ISO 2021 – All rights reserved iii---------------------- Page: 9 ----------------------
SIST EN ISO 11855-1:2021
ISO 11855-1:2021(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.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 (see 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 (see 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 of 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 www .iso .org/
iso/ foreword .html.This document was prepared by Technical Committee ISO/TC 205, Building environment design, in
collaboration with the European Committee for Standardization (CEN) Technical Committee CEN/
TC 228, Heating systems and water based cooling systems in buildings, in accordance with the Agreement
on technical cooperation between ISO and CEN (Vienna Agreement).This second edition cancels and replaces the first edition (ISO 11855-1:2012), which has been technically
revised.The main changes compared to the previous edition are as follows:
— only references cited normatively were kept in Clause 2, the others were moved to Bibliography;
— in Clause 3, self-explanatory terms were removed, two similar terms representing the same concept
were unified into one term, and one term explaining two concepts were divided into two terms each
having one concept;— editorial changes were performed.
A list of all parts in the ISO 11855 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.iv © ISO 2021 – All rights reserved
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SIST EN ISO 11855-1:2021
ISO 11855-1:2021(E)
Introduction
The radiant heating and cooling system consists of heat emitting/absorbing, heat supply, distribution,
and control systems. The ISO 11855 series deals with the embedded surface heating and cooling system
that directly controls heat exchange within the space. It does not include the system equipment itself,
such as heat source, distribution system and controller.The ISO 11855 series addresses an embedded system that is integrated with the building structure.
Therefore, the panel system with open air gap, which is not integrated with the building structure, is
not covered by this series.The ISO 11855 series is applicable to water-based embedded surface heating and cooling systems
in buildings. The ISO 11855 series is applied to systems using not only water but also other fluids or
electricity as a heating or cooling medium. The ISO 11855 series is not applicable for testing of systems.
The methods do not apply to heated or chilled ceiling panels or beams.The object of the ISO 11855 series is to provide criteria to effectively design embedded systems. To do
this, it presents comfort criteria for the space served by embedded systems, heat output calculation,
dimensioning, dynamic analysis, installation, control method of embedded systems, and input
parameters for the energy calculations.The ISO 11855 series consists of the following parts, under the general title Building environment
design — Embedded radiant heating and cooling systems:— Part 1: Definitions, symbols, and comfort criteria
— Part 2: Determination of the design heating and cooling capacity
— Part 3: Design and dimensioning
— Part 4: Dimensioning and calculation of the dynamic heating and cooling capacity of Thermo Active
Building Systems (TABS)— Part 5: Installation
— Part 6: Control
— Part 7: Input parameters for the energy calculation
ISO 11855-1, this document, specifies the comfort criteria which should be considered in designing
embedded radiant heating and cooling systems, since the main objective of the radiant heating and
cooling system is to satisfy thermal comfort of the occupants. ISO 11855-2 provides steady-state
calculation methods for determination of the heating and cooling capacity. ISO 11855-3 specifies design
and dimensioning methods of radiant heating and cooling systems to ensure the heating and cooling
capacity. ISO 11855-4 provides a dimensioning and calculation method to design Thermo Active
Building Systems (TABS) for energy saving purposes, since radiant heating and cooling systems can
reduce energy consumption and heat source size by using renewable energy. ISO 11855-5 addresses the
installation process for the system to operate as intended. ISO 11855-6 shows a proper control method
of the radiant heating and cooling systems to ensure the maximum performance which was intended
in the design stage when the system is actually being operated in a building. ISO 11855-7 presents a
calculation method for input parameters to ISO 52031.© ISO 2021 – All rights reserved v
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SIST EN ISO 11855-1:2021
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SIST EN ISO 11855-1:2021
INTERNATIONAL STANDARD ISO 11855-1:2021(E)
Building environment design — Embedded radiant heating
and cooling systems —
Part 1:
Definitions, symbols, and comfort criteria
1 Scope
This document specifies the basic definitions, symbols, and comfort criteria for embedded radiant
heating and cooling systems.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 11855-5:2021, Building environment design —Embedded radiant heating and cooling systems — Part 5:
Installation3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp— IEC Electropedia: available at https:// www .electropedia .org/
3.1
additional thermal resistance
thermal resistance representing layers added to the building structure and acting mostly as thermal
resistances because of their own low thermal inertiaEXAMPLE Carpets, moquette, and suspended ceilings.
3.2
average specific thermal capacity of the internal walls
thermal capacity related to one square metre of the internal walls
Note 1 to entry: Since internal walls are shared with other rooms, then just half of the total specific thermal
capacity of the wall shall be taken into account, since the second half is influenced by the opposite rooms that are
considered to be at the same thermal conditions as the one under consideration.3.3
average surface temperature
s,m
average value of all surface temperatures in the occupied or peripheral area (3.62)
© ISO 2021 – All rights reserved 1---------------------- Page: 13 ----------------------
SIST EN ISO 11855-1:2021
ISO 11855-1:2021(E)
3.4
basic characteristic curve
curve reflecting the relationship between the heat flux (3.31) and the mean surface temperature
difference (3.47)Note 1 to entry: This depends on the heating or cooling and the surface (floor, wall or ceiling) but not on the type
of embedded system.3.5
calculation time step
length of time considered for the calculation
Note 1 to entry: This is typically assumed to equal 3 600 s.
3.6
circuit
section of system connected to a distributor (3.25) which can be independently switched and controlled
3.7circuit total thermal resistance
thermal resistance representing the circuit (3.6) as a whole, determining a straight connection between
the water inlet temperature and the mean temperature at the pipe level (3.63)Note 1 to entry: It includes the water flow thermal resistance (3.92), the convection thermal resistance at the pipe
inner side (3.10), the pipe thickness thermal resistance (3.66), and the pipe level thermal resistance (3.64).
3.8clothing insulation
resistance of a uniform layer of insulation covering the entire body that has the same effect on sensible
heat flow as the actual clothing under standardized (static, wind-still) conditions
Note 1 to entry: The definition of clothing insulation also includes the uncovered parts of the body, e.g. the head. It
is specified as the intrinsic insulation from the skin to the clothing surface, not including the resistance provided
2 2by the air layer around the clothed body, and is expressed in the clo unit or in m K/W; 1 clo = 0,155 m K/W.
3.9conductive region of the slab
region of the slab (3.75) that includes the pipes with thermal conductivities of the layers higher than
0,8 W/(m·K)Note 1 to entry: Due to the subdivision of the slab into an upper slab and a lower slab, the conductive region is
also subdivided into an upper conductive region and a lower conductive region.3.10
convection thermal resistance at the pipe inner side
thermal resistance associated to the convection heat transfer taking place between the water flowing
in the pipe and the pipe inner side, thus connecting the mean water temperature along the circuit (3.6)
with the mean temperature of the pipe inner side3.11
convective heating and cooling system
system that directly conditions the air in the room for the purpose of heating and cooling
3.12convective peak load
maximum cooling load to be extracted by a virtual convective system used to keep comfort conditions
in the room3.13
design cooling capacity
H,c
thermal output by a cooling surface at design conditions
2 © ISO 2021 – All rights reserved
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SIST EN ISO 11855-1:2021
ISO 11855-1:2021(E)
3.14
design cooling load
N,c
required thermal output necessary to achieve the specified design conditions in outside summer design
conditions3.15
design sensible cooling load
required sensible thermal output necessary to achieve the specified design conditions in outside
summer design conditions3.16
design supply temperature of heating medium
V,des
value of flow water temperature with the thermal resistance of the chosen floor covering, at maximum
value of heat flux qmax
Note 1 to entry: The flow and the supply temperature are the same throughout the EN 1264 series.
Note 2 to entry: For the radiant cooling system, the design supply temperature of cooling medium applies instead
of design supply temperature of heating medium.3.17
design heat flux
des
heat flow divided by the heating or cooling surface, taking into account the surface temperature
required to reach the design thermal capacity of a surface heated or cooled space, Q , reduced by the
thermal capacity of any supplementary heating or cooling equipment, if applicable
3.18design heating capacity
H,h
thermal output from a heating surface (3.33) at design conditions
3.19
design heating load
N,h
required thermal output necessary to achieve the specified design conditions in outside winter design
conditionsNote 1 to entry: When calculating the value of the design heat load, the heat flow from embedded heating systems
into neighbouring rooms is not taken into account.3.20
design heating medium differential temperature
H,des
temperature difference of heating medium at design heat flux (3.17)
3.21
design cooling medium differential temperature
C,des
temperature difference of cooling medium at design heat flux (3.17)
3.22
design heating medium differential supply temperature
V,des
temperature difference between the design supply medium temperature and indoor temperature at
design heat flux (3.17)© ISO 2021 – All rights reserved 3
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SIST EN ISO 11855-1:2021
ISO 11855-1:2021(E)
3.23
design heating medium flow rate
mass flow rate in a circuit (3.6) which is needed to achieve the design heat flux (3.17)
Note 1 to entry: The design cooling medium flow rate is similar with the only difference being that it has an
embedded radiant cooling system.3.24
design indoor temperature
operative temperature (3.58) at the centre of the conditioned space used for calculation of the design
load and capacityNote 1 to entry: The operative temperature is considered relevant for thermal comfort assessment and heat loss
calculations. This value of internal temperature is used for the calculation method.
3.25distributor
common connection point for several circuits (3.6)
3.26
draught
unwanted local cooling of a body caused by movement of air and related to temperature
3.27electric heating system
several panel systems that convert electrical energy to heat, raising the temperature of conditioned
indoor surfaces and the indoor airNote 1 to entry: The electric heating system can be applied to floor, walls and ceiling.
3.28embedded surface heating and cooling system
system consisting of circuits (3.6) of pipes embedded in floor, wall or ceiling construction, distributors
(3.25) and control equipment3.29
equivalent heat transmission coefficient
coefficient describing the relationship between the heat flux (3.31) from the surface and the heating
medium differential temperature (3.36)Note 1 to entry: For the radiant cooling system, the cooling medium differential temperature applies instead of
heating medium differential temperature.3.30
family of characteristic curves
curves denoting the system-specific relationship between the heat flux (q) (3.31) and the required
heating medium differential temperature (ΔθH) (3.36) for conduction resistance of various floor
coverings3.31
heat flux
heat flow between the space and surface divided by the heated or cooled surface
Note 1 to entry: For heating it is a positive value and for cooling it is a negative value.
4 © ISO 2021 – All rights reserved---------------------- Page: 16 ----------------------
SIST EN ISO 11855-1:2021
ISO 11855-1:2021(E)
3.32
heat transfer coefficient
combined convective and radiative heat transfer coefficient between the heated or cooled surface and
the space operative temperature (3.58) [design indoor temperature (3.24)]3.33
heating surface
surface (floor, wall, ceiling) covered by the embedded surface heating system between the pipes at the
outer edges of the system with the addition of a strip at each edge of width equal to half the pipe spacing
(3.65), but not exceeding 0,15 mNote 1 to entry: The cooling surface is similar with the only difference being that it has an embedded surface
cooling system.3.34
heating surface area
area of surface (floor, wall, ceiling) covered by the embedded surface heating system between the pipes
at the outer edges of the system with the addition of a strip at each edge of width equal to half the pipe
spacing (3.65), but not exceeding 0,15 mNote 1 to entry: The same concept of cooling surface area applies to the embedded cooling system.
3.35heating capacity for circuit
heat exchange between a pipe circuit (3.6) and the conditioned room
Note 1 to entry: The same concept of cooling capacity for circuit applies to the embedded cooling system.
3.36heating medium differential temperature
logarithmically determined average difference between the temperature of the heating medium (3.83)
and the design indoor temperature (3.24)Note 1 to entry: The same concept of cooling medium differential temperature applies to the embedded cooling
system.3.37
internal convective heat gain
convective contributions by internal heat gains acting in the room
Note 1 to entry: Mainly due to people or electrical equipment.
3.38
internal radiant heat gain
radiant contributions by internal heat gains acting in the room
Note 1 to entry: This is mainly due to people or electrical equipment.
3.39
internal thermal resistance of the slab conductive region
total thermal resistance connecting the pipe level (3.63) with the middle points of the upper conductive
region and lower conductive region of the slab (3.9)3.40
limit curve
curve in the field of characteristic curves showing the pattern of the limit heat flux (3.41) depending on
the heating medium differential temperature (3.36) and the floor covering© ISO 2021 – All rights reserved 5
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SIST EN ISO 11855-1:2021
ISO 11855-1:2021(E)
3.41
limit heat flux
heat flux (3.31) at which the maximum (3.45) or minimum permissible surface temperature (3.49) is
achieved3.42
limit heating medium temperature difference
H,G
intersection of the system characteristic curve with the limit curve (3.40)
3.43
maximum cooling power
maximum thermal power of the cooling equipment, referring only to the room under consideration
3.44maximum design heat flux
max
required design heat flux (3.17) in the room in order to design supply medium temperature
3.45maximum permissible surface temperature
S,max
maximum temperature permissible for physiological reasons or for the physical building, for calculation
of the limit curves (3.40), which may occur at a point on the surface (floor, wall, ceiling) in the occupied
or peripheral area (3.62) depending on the particular usage at a temperature drop (σ) (3.82) of the
heating medium equal to 03.46
mean radiant temperature
uniform surface temperature of an imaginary black enclosure in which an occupant would exchange
the same amount of radiant heat as in the actual non-uniform enclosure...
SLOVENSKI STANDARD
oSIST prEN ISO 11855-1:2020
01-maj-2020
Načrtovanje okolja v stavbah - Vgrajeni hladilni in ogrevalni sistemi - 1. del:
Definicije, simboli in merila za ugodje (ISO/DIS 11855-1:2020)
Building environment design - Embedded radiant heating and cooling systems - Part 1:
Definitions, symbols, and comfort criteria (ISO/DIS 11855-1:2020)Umweltgerechte Gebäudeplanung - Flächenintegrierte Strahlheizungs- und -
kühlsysteme - Teil 1: Begriffe, Symbole und Komfortkriterien (ISO/DIS 11855-1:2020)
Conception de l'environnement des bâtiments - Systèmes intégrés de chauffage et de
refroidissement par rayonnement - Partie 1: Définitions, symboles et critères de confort
(ISO/DIS 11855-1:2020)Ta slovenski standard je istoveten z: prEN ISO 11855-1
ICS:
91.140.10 Sistemi centralnega Central heating systems
ogrevanja
91.140.30 Prezračevalni in klimatski Ventilation and air-
sistemi conditioning systems
oSIST prEN ISO 11855-1:2020 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------oSIST prEN ISO 11855-1:2020
---------------------- Page: 2 ----------------------
oSIST prEN ISO 11855-1:2020
DRAFT INTERNATIONAL STANDARD
ISO/DIS 11855-1
ISO/TC 205 Secretariat: ANSI
Voting begins on: Voting terminates on:
2020-03-16 2020-06-08
Building environment design — Embedded radiant heating
and cooling systems —
Part 1:
Definitions, symbols, and comfort criteria
Conception de l'environnement des bâtiments — Systèmes intégrés de chauffage et de refroidissement par
rayonnement —Partie 1: Définitions, symboles et critères de confort
ICS: 91.040.01
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 11855-1:2020(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION. ISO 2020
---------------------- Page: 3 ----------------------
oSIST prEN ISO 11855-1:2020
ISO/DIS 11855-1:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
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oSIST prEN ISO 11855-1:2020
ISO/DIS 11855-1:2020(E)
Contents Page
Foreword ........................................................................................................................................................................................................................................iv
Introduction ..................................................................................................................................................................................................................................v
1 Scope ................................................................................................................................................................................................................................. 1
2 Normative references ...................................................................................................................................................................................... 1
3 Terms and definitions ..................................................................................................................................................................................... 1
4 Symbols and abbreviations ....................................................................................................................................................................10
5 Comfort criteria ..................................................................................................................................................................................................15
5.1 General thermal comfort .............................................................................................................................................................16
5.1.1 Operative temperature ............................................................................................................................................16
5.1.2 PMV (predicted mean vote)/PPD (predicted percentage of dissatisfied) ...................17
5.2 Local thermal discomfort ............................................................................................................................................................17
5.2.1 Surface temperature limit .....................................................................................................................................17
5.2.2 Radiant temperature asymmetry ...................................................................................................................18
5.2.3 Vertical air temperature difference ..............................................................................................................19
5.3 Acoustical comfort ............................................................................................................................................................................19
5.3.1 Water velocity and noise ........................................................................................................................................19
5.3.2 Acoustical comfort in water based heating and cooling systems .......................................20
5.3.3 Acoustical comfort in Thermally Active Building Systems (TABS) ....................................20
Annex A (informative) Floor surface temperature for thermal comfort ......................................................................21
Annex B (informative) Draught ...............................................................................................................................................................................24
Bibliography .............................................................................................................................................................................................................................25
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oSIST prEN ISO 11855-1:2020
ISO/DIS 11855-1:2020(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 11855-1 was prepared by Technical Committee ISO/TC 205, Building environment design.
ISO 11855 consists of the following parts, under the general title Building environment design —
Design, dimensioning, installation, control and input parameters for the energy calculation of embedded
radiant heating and cooling systems:— Part 1: Definitions, symbols, and comfort criteria
— Part 2: Determination of the design and heating and cooling capacity
— Part 3: Design and dimensioning
— Part 4: Dimensioning and calculation of the dynamic heating and cooling capacity of Thermo Active
Building Systems (TABS)— Part 5: Installation
— Part 6: Control
— Part 7: Input parameters for the energy calculation
Part 1 specifies the comfort criteria which should be considered in designing embedded radiant heating
and cooling systems, since the main objective of the radiant heating and cooling system is to satisfy
thermal comfort of the occupants. Part 2 provides steady-state calculation methods for determination
of the heating and cooling capacity. Part 3 specifies design and dimensioning methods of radiant
heating and cooling systems to ensure the heating and cooling capacity. Part 4 provides a dimensioning
and calculation method to design Thermo Active Building Systems (TABS) for energy-saving purposes,
since radiant heating and cooling systems can reduce energy consumption and heat source size by using
renewable energy. Part 5 addresses the installation process for the system to operate as intended. Part
6 shows a proper control method of the radiant heating and cooling systems to ensure the maximum
performance which was intended in the design stage when the system is actually being operated in a
building. Part 7 presents a calculation method for input parameters to ISO 52031.
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oSIST prEN ISO 11855-1:2020
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Introduction
The radiant heating and cooling system consists of heat emitting/absorbing, heat supply, distribution,
and control systems. The ISO 11855 series deals with the embedded surface heating and cooling system
that directly controls heat exchange within the space. It does not include the system equipment itself,
such as heat source, distribution system and controller.The ISO 11855 series addresses an embedded system that is integrated with the building structure.
Therefore, the panel system with open air gap, which is not integrated with the building structure, is
not covered by this series.The ISO 11855 series shall be applied to systems using not only water but also other fluids or electricity
as a heating or cooling medium.The object of the ISO 11855 series is to provide criteria to effectively design embedded systems. To do
this, it presents comfort criteria for the space served by embedded systems, heat output calculation,
dimensioning, dynamic analysis, installation, control method of embedded systems, and input
parameters for the energy calculations.© ISO 2020 – All rights reserved v
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oSIST prEN ISO 11855-1:2020
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oSIST prEN ISO 11855-1:2020
DRAFT INTERNATIONAL STANDARD ISO/DIS 11855-1:2020(E)
Building environment design — Embedded radiant heating
and cooling systems —
Part 1:
Definitions, symbols, and comfort criteria
1 Scope
This part of ISO 11855 specifies the basic definitions, symbols, and comfort criteria for embedded
radiant heating and cooling systems.The ISO 11855 series is applicable to water based embedded surface heating and cooling systems in
residential, commercial and industrial buildings. The methods apply to systems integrated into the
wall, floor or ceiling construction without any open air gaps. It does not apply to panel systems with
open air gaps which are not integrated into the building structure.The ISO 11855 series also applies, as appropriate, to the use of fluids other than water as a heating or
cooling medium. The ISO 11855 series is not applicable for testing of systems. The methods do not apply
to heated or chilled ceiling panels or beams.2 Normative references
ISO 7726:1998, Ergonomics of the thermal environment — Instruments for measuring physical quantities
ISO 7730:2005, Ergonomics of the thermal environment — Analytical determination and interpretation of
thermal comfort using calculation of the PMV and PPD indices and local thermal comfort criteria
ISO 13731:2001, Ergonomics of the thermal environment — Vocabulary and symbols3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
additional thermal resistance
thermal resistance representing layers added to the building structure and acting mostly as thermal
resistances because of their own low thermal inertiaEXAMPLE Carpets, moquette, and suspended ceilings.
3.2
average specific thermal capacity of the internal walls
thermal capacity related to one square metre of the internal walls
Note 1 to entry: Since internal walls are shared with other rooms, then just half of the total specific thermal
capacity of the wall must be taken into account, since the second half is influenced by the opposite rooms that are
considered to be at the same thermal conditions as the one under consideration.3.3
average surface temperature
s,m
average value of all surface temperatures in the occupied or peripheral area
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3.4
basic characteristic curve
curve or formula reflecting the relationship between the heat flux and the mean surface temperature
differenceNote 1 to entry: This depends on heating/cooling and surface (floor/wall/ceiling) but not on the type of
embedded system.3.5
calculation time step
length of time considered for the calculation of the temperatures and heat flows in the room and slab
Note 1 to entry: This is typically assumed to equal 3 600 s.3.6
circuit
section of system connected to a distributor which can be independently switched and controlled
3.7circuit total thermal resistance
thermal resistance representing the circuit as a whole, determining a straight connection between the
water inlet temperature and the mean temperature at the pipe levelNote 1 to entry: It includes the water flow thermal resistance, the convection thermal resistance at the pipe inner
side, the pipe thickness thermal resistance, and the pipe level thermal resistance.
3.8clothing insulation
basic clothing insulation that is the resistance of a uniform layer of insulation covering the entire body
that has the same effect on sensible heat flow as the actual clothing under standardized (static, wind-
still) conditionsNote 1 to entry: The definition of clothing insulation also includes the uncovered parts of the body, e.g. the head. It
is described as the intrinsic insulation from the skin to the clothing surface, not including the resistance provided
2 2by the air layer around the clothed body, and is expressed in the clo unit or in m K/W; 1 clo = 0,155 m K/W.
3.9conductive region of the slab
region of the slab that includes the pipes with thermal conductivities of the layers higher than 0,8 W/(m·K)
Note 1 to entry: Due to the subdivision of the slab into an upper slab and a lower slab, the conductive region is
also subdivided into an upper conductive region and a lower conductive region.3.10
convection thermal resistance at the pipe inner side
thermal resistance associated to the convection heat transfer taking place between the water flowing
in the pipe and the pipe inner side, thus connecting the mean water temperature along the circuit with
the mean temperature of the pipe inner side3.11
convective heating and cooling system
system that directly conditions the air in the room for the purpose of heating and cooling
3.12convective peak load
maximum cooling load to be extracted by a virtual convective system used to keep comfort conditions
in the room3.13
daily average temperature of the conductive region of the slab
average temperature of the conductive region of the slab during the day
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3.14
design cooling capacity
H,c
thermal output by a cooling surface at design conditions
3.15
design cooling load
N,c
required thermal output necessary to achieve the specified design conditions in outside summer design
conditions3.16
design sensible cooling load
required sensible thermal output necessary to achieve the specified design conditions in outside
summer design conditions3.17
design dew point
Dp,des
dew point determined for the design
3.18
design supply temperature of heating/cooling medium
V,des
value of flow water temperature with the thermal resistance of the chosen floor covering, at maximum
value of heat flux qmax
Note 1 to entry: The flow and the supply temperature are the same throughout the EN 1264 series.
3.19design heat flux
des
heat flow divided by the heating or cooling surface, taking into account the surface temperature
required to reach the design thermal capacity of a surface heated or cooled space, Q , reduced by the
thermal capacity of any supplementary heating or cooling equipment, if applicable
3.20design heating capacity
H,h
thermal output from a heating surface at design conditions
3.21
design heating load
N,h
required thermal output necessary to achieve the specified design conditions in outside winter design
conditionsNote 1 to entry: When calculating the value of the design heat load, the heat flow from embedded heating systems
into neighbouring rooms is not taken into account.3.22
design heating/cooling medium differential temperature
Δθ /Δθ
H,des C,des
temperature difference at design heat flux
3.23
design heating medium differential supply temperature
V,des
temperature difference between the design supply medium temperature and indoor temperature at
design heat flux© ISO 2020 – All rights reserved 3
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3.24
design heating/cooling medium flow rate
mass flow rate in a circuit which is needed to achieve the design heat flux
3.25
design indoor temperature
operative temperature at the centre of the conditioned space used for calculation of the design load and
capacityNote 1 to entry: The operative temperature is considered relevant for thermal comfort assessment and heat loss
calculations. This value of internal temperature is used for the calculation method.
3.26distributor
common connection point for several circuits
3.27
draught
unwanted local cooling of a body caused by movement of air and related to temperature
3.28electric floor (wall, ceiling) heating system
several panel systems that convert electrical energy to heat, raising the temperature of conditioned
indoor surfaces and the indoor air3.29
embedded surface heating and cooling system
system consisting of circuits of pipes embedded in floor, wall or ceiling construction, distributors and
control equipments3.30
equivalent heat transmission coefficient
coefficient describing the relationship between the heat flux from the surface and the heating/cooling
medium differential temperature3.31
family of characteristic curves
curves denoting the system-specific relationship between the heat flux, q, and the required heating
medium differential temperature Δθ for conduction resistance of various floor coverings
3.32heat flux
heat flow between the space and surface divided by the heated/cooled surface
Note 1 to entry: For heating it is a positive value and for cooling it is a negative value.
3.33heat transfer coefficient
combined convective and radiative heat transfer coefficient between the heated or cooled surface and
the space operative temperature (design indoor temperature)3.34
heating or cooling surface
surface (floor, wall, ceiling) covered by the embedded surface heating/cooling system between the
pipes at the outer edges of the system with the addition of a strip at each edge of width equal to half the
pipe spacing, but not exceeding 0,15 m4 © ISO 2020 – All rights reserved
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3.35
heating or cooling surface area
area of surface (floor, wall, ceiling) covered by the embedded surface heating/cooling system between
the pipes at the outer edges of the system with the addition of a strip at each edge of width equal to half
the pipe spacing, but not exceeding 0,15 m3.36
heating/cooling capacity for circuit
heat exchange between a pipe circuit and the conditioned room
3.37
heating/cooling medium differential temperature
logarithmically determined average difference between the temperature of the heating/cooling
medium and the design indoor temperature3.38
internal convective heat gains
convective contributions by internal heat gains acting in the room
Note 1 to entry: Mainly due to people or electrical equipment.
3.39
internal radiant heat gains
radiant contributions by internal heat gains acting in the room
Note 1 to entry: Mainly due to people or electrical equipment.
3.40
internal thermal resistance of the slab conductive region
total thermal resistance connecting the pipe level with the middle points of the upper conductive region
and lower conductive region of the slab3.41
limit curves
curves in the field of characteristic curves showing the pattern of the limit heat flux depending on the
heating medium differential temperature and the floor covering3.42
limit heat flux
heat flux at which the maximum or minimum permissible surface temperature is achieved
3.43limit heating medium temperature difference
H,G
intersection of the system characteristic curve with the limit curve
3.44
maximum cooling power
maximum thermal power of the cooling equipment, referring only to the room under consideration
3.45maximum permissible surface temperature
max
required design heat flux in the room in order to design supply medium temperature
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3.46
maximum operative temperature allowed for comfort conditions
maximum operative temperature allowed in the room according to comfort requirements in cooling
conditions3.47
maximum operative temperature drift allowed for comfort conditions
maximum drift in operative temperature allowed in the room according to comfort requirements
3.48maximum permissible surface temperature
S,max
maximum temperature permissible for physiological reasons or for the physical building, for calculation
of the limit curves, which may occur at a point on the surface (floor, wall, ceiling) in the occupied or
peripheral area depending on the particular usage at a temperature drop σ of the heating medium
equal to 03.49
mean radiant temperature
uniform surface temperature of an imaginary black enclosure in which an occupant would exchange
the same amount of radiant heat as in the actual non-uniform enclosure3.50
mean surface temperature difference
difference between the average surface temperature θ and the design indoor temperature θ
S,m iNote 1 to entry: It determines the heat flux.
3.51
metabolic rate
rate of transformation of chemical energy into heat and mechanical work by aerobic and anaerobic
metabolic activities within an organism, usually expressed in terms of unir area of the total body
surfacesNote 1 to entry: The metabolic rate varies with each activity. It is expressed in the met unit or in W/m ;
1 met = 58,2 W/m . 1 met is the energy produced per unit surface area of a sedentary person at rest. The surface
area of an average person can be determined by Dubois Equation, Body Surface Area (m ) = 0,20 247 × Height
0,725 0,425(m) × Weight (kg) .
3.52
minimum permissible surface temperature
S,min
minimum temperature permissible for physiological reasons or for the physical building, for calculation
of the limit curves, which may occur at a point on the surface (floor, wall, ceiling) in the occupied or
peripheral area depending on the particular usage at a temperature drop σ of the heating medium
equal to 03.53
nominal heat flux
limit heat flux achieved without surface covering
3.54
nominal heating/cooling medium differential temperature
absolute temperature difference at nominal heat flux q
3.55
non-active area
area of the surface not covered by a heating/cooling system
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3.56
number of active surfaces
number of surfaces in straight thermal connection with the pipe level, so that it distinguishes whether
the slab transfers heat both through the floor side and through the ceiling side or whether the ceiling
side is much more active than the floor sideNote 1 to entry: Two active surfaces when the conductive region extends from the floor to the ceiling, one active
surface otherwise.3.57
number of operation hours of the circuit
length of time during which the system runs in the day
3.58
occupied area
surface area which is heated or cooled, excluding peripheral area
3.59
occupied zone
part of the conditioned zone in which persons normally reside and where requirements as to the
internal environment are satisfiedNote 1 to entry: Normally, the zone between the floor and 1,8 m above the floor and 1,0 m from outside walls/
windows and heating/cooling appliances, 0,5 m from internal surfaces.3.60
open air gap
air gap in the floor, wall, or ceiling construction, where air exchange with space or the outside may occur
3.61operative temperature
uniform temperature of an imaginary black enclosure in which an occupant exchanges the same amount
of heat by radiation and convection as in the actual non-uniform environment3.62
orientation of the room
orientation of the main windowed external wall: East, South or West
Note 1 to entry: It is used to determine when the peak load from heat gains happens, since internal heat gains are
considered almost constant and the widest variation is expected to happen in solar heat gains.
3.63outward heat flux
heat flow which is exchanged through the construction with unconditioned spaces, another building
entity, the ground or outdoor air3.64
peak load
maximum cooling load to be extracted by the system used to keep comfort conditions in the room
3.65peripheral area
surface area which is heated or cooled to a higher or lower temperature
Note 1 to entry: It is generally an area of 1 m maximum in width along exterior walls. It is not an occupied area.
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3.66
pipe level
virtual plane where the pipe circuit lies
3.67
pipe level thermal resistance
thermal resistance associated to the 2-D conduction heat transfer taking place between the pipes and
the embedding layer, virtually referred to the pipe level, thus connecting the mean temperature of the
pipe outer side with the mean temperature at the pipe level3.68
pipe spacing
spacing or distance between pipes embedded in the surface
3.69
pipe thickness thermal resistance
thermal resistance associated to the conduction heat transfer taking place through the pipe wall, thus
connecting the mean temperature of the pipe inner side with the mean temperature of the pipe outer side
3.70predicted mean vote
PMVindex that predicts the mean value of the thermal sensation votes of a large group of persons on a
7-point thermal sensation scale3.71
predicted percentage of dissatisfied
PPDindex that establishes a quantitative prediction of the percentage of thermally dissatisfied people
who are either too warm of too cool3.72
primary air convective heat gains
heat gains acting in the room due to the infiltration or primary air inflow
3.73
radiant surface heating and cooling system
heating and cooling system that controls the temperature of indoor surfaces on the floor, walls, or ceiling
3.74radiant temperature asymmetry
difference between the plane radiant temperature of the two opposite sides of a small plane element
3.75relative air velocity
air velocity relative to the occupant, including body movements
3.76
regional dew point
Dp,R
dew point specified depending on the climatic conditions of the region
3.77
running mode
running mode of the circuit that defines whether the system is currently switched on or off
3.78slab
horizontal building structure separating two rooms placed one below the other, hence being the ceiling
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3.79
solar heat gains
sol
...
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