Building environment design - Design, dimensioning, installation and control of embedded radiant heating and cooling systems - Part 3: Design and dimensioning (ISO 111855-3:2012)

This European Standard shall stipulate the processes and conditions needed to design radiant heating and cooling systems embedded in the structures of the rooms. In addition, this standard includes the determination of heating and cooling capacity, dimensioning, dynamic analysis, installation, commissioning, operation, and control methods of radiant heating and cooling system. This international standard is applicable to embedded system that is integrated with the building structure. But this is not applicable to the panel system with open air gap, which is not integrated with the building structure. This standard applies also, as appropriate, to the use of other fluids or electricity instead of water as heating or cooling medium.
Part 3 of this standard deals with system design and dimensioning method to ensure the heating and cooling capacity of the radiant heating and cooling systems.

Umweltgerechte Gebäudeplanung - Planung, Auslegung, Installation und Steuerung flächenintegrierter Strahlheizungs- und -kühlsysteme - Teil 3: Planung und Auslegung (ISO 11855-3:2012)

Conception de l'environnement des bâtiments - Normes pour la conception, la construction et le fonctionnement des systèmes de chauffage et de refroidissement par rayonnement - Partie 3: Conception et dimensionnement (ISO 11855-3:2012)

ISO 11855-3:2012 définit une méthode de conception et de dimensionnement de systèmes permettant de garantir la puissance calorifique et frigorifique des systèmes de chauffage et de refroidissement par rayonnement.
La série ISO 11855 s'applique aux systèmes de chauffage et de refroidissement de surface intégrés à eau dans les bâtiments résidentiels, commerciaux et industriels. Ces méthodes s'appliquent aux systèmes intégrés dans les murs, sols ou plafonds, sans ouverture à l'air libre. Elles ne s'appliquent pas aux systèmes de panneaux avec ouvertures à l'air libre, qui ne sont pas intégrés dans une structure de bâtiment.
La série ISO 11855 s'applique également, le cas échéant, à l'utilisation d'autres fluides que l'eau en tant que medium de chauffage ou de refroidissement. La série ISO 11855 ne s'applique pas à l'essai des systèmes. Ces méthodes ne s'appliquent pas aux panneaux ou poutres de plafond chauffés ou refroidis.

Načrtovanje gradnje - Načrtovanje, dimenzioniranje, montaža in kontrola vgrajenih hladilnih in ogrevalnih sistemov - 3. del: Načrtovanje in dimenzioniranje (ISO 111855-3:2012)

Ta evropski standard določa procese in pogoje, potrebne za načrtovanje ogrevalnih in hladilnih sistemov, vgrajenih v strukture sobe. Poleg tega ta standard zajema določanje grelne in hladilne moči, dimenzioniranje, dinamično analizo, montažo, zagon, delovanje in kontrolne metode ogrevalnih in hladilnih sistemov. Ta mednarodni standard se uporablja za vgrajeni sistem, ki je vključen v strukturo stavbe. Vendar se ne uporablja za sistem plošč z odprtim vmesnim zračnim prostorom, ki ni vključen v strukturo stavbe. Ta standard, kadar je to ustrezno, velja tudi za uporabo drugih tekočin ali električne energije namesto vode za ogrevalni ali hladilni medij. 3. del tega standarda obravnava načrtovanje sistema in metodo za dimenzioniranje za zagotavljanje grelne in hladilne moči ogrevalnih in hladilnih sistemov.

General Information

Status
Withdrawn
Public Enquiry End Date
09-Jun-2015
Publication Date
09-Sep-2015
Withdrawal Date
07-Oct-2021
Technical Committee
Current Stage
9900 - Withdrawal (Adopted Project)
Start Date
29-Sep-2021
Due Date
22-Oct-2021
Completion Date
08-Oct-2021

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Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 11855-3:2015
01-oktober-2015
1DþUWRYDQMHJUDGQMH1DþUWRYDQMHGLPHQ]LRQLUDQMHPRQWDåDLQNRQWURODYJUDMHQLK
KODGLOQLKLQRJUHYDOQLKVLVWHPRYGHO1DþUWRYDQMHLQGLPHQ]LRQLUDQMH ,62

Building environment design - Design, dimensioning, installation and control of
embedded radiant heating and cooling systems - Part 3: Design and dimensioning (ISO
111855-3:2012)
Umweltgerechte Gebäudeplanung - Planung, Auslegung, Installation und Steuerung
flächenintegrierter Strahlheizungs- und -kühlsysteme - Teil 3: Planung und Auslegung
(ISO 11855-3:2012)
Conception de l'environnement des bâtiments - Normes pour la conception, la
construction et le fonctionnement des systèmes de chauffage et de refroidissement par
rayonnement - Partie 3: Conception et dimensionnement (ISO 11855-3:2012)
Ta slovenski standard je istoveten z: EN ISO 11855-3:2015
ICS:
91.140.10 Sistemi centralnega Central heating systems
ogrevanja
91.140.30 3UH]UDþHYDOQLLQNOLPDWVNL Ventilation and air-
VLVWHPL conditioning
SIST EN ISO 11855-3:2015 en,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------

SIST EN ISO 11855-3:2015

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SIST EN ISO 11855-3:2015

EUROPEAN STANDARD
EN ISO 11855-3

NORME EUROPÉENNE

EUROPÄISCHE NORM
August 2015
ICS 91.140.10; 91.140.30
English Version
Building environment design - Design, dimensioning, installation
and control of embedded radiant heating and cooling systems -
Part 3: Design and dimensioning (ISO 11855-3:2012)
Conception de l'environnement des bâtiments - Normes Umweltgerechte Gebäudeplanung - Planung, Auslegung,
pour la conception, la construction et le fonctionnement des Installation und Steuerung flächenintegrierter
systèmes de chauffage et de refroidissement par Strahlheizungs- und -kühlsysteme - Teil 3: Planung und
rayonnement - Partie 3: Conception et dimensionnement Auslegung (ISO 11855-3:2012)
(ISO 11855-3:2012)
This European Standard was approved by CEN on 30 July 2015.

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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, 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: Avenue Marnix 17, B-1000 Brussels
© 2015 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 11855-3:2015 E
worldwide for CEN national Members.

---------------------- Page: 3 ----------------------

SIST EN ISO 11855-3:2015
EN ISO 11855-3:2015 (E)
Contents Page
European foreword .3

2

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SIST EN ISO 11855-3:2015
EN ISO 11855-3:2015 (E)
European foreword
The text of ISO 11855-3:2012 has been prepared by Technical Committee ISO/TC 205 “Building environment
design” of the International Organization for Standardization (ISO) and has been taken over as EN ISO
11855-3:2015 by 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 2016, and conflicting national standards shall be withdrawn
at the latest by February 2016.
This standard is applicable for design, construction and operation of radiant heating and cooling systems. The
methods defined in part 2 are intended to determine the design heating or cooling capacity used for the design
and evaluation of the performance of the system.
For identifying product characteristics by testing and proving the thermal output of heating and cooling
surfaces embedded in floors, ceilings and walls the standard series EN 1264 can be used.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
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, Former Yugoslav Republic of Macedonia, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
Endorsement notice
The text of ISO 11855-3:2012 has been approved by CEN as EN ISO 11855-3:2015 without any modification.
3

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SIST EN ISO 11855-3:2015

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SIST EN ISO 11855-3:2015
INTERNATIONAL ISO
STANDARD 11855-3
First edition
2012-10-01
Building environment design —
Design, dimensioning, installation and
control of embedded radiant heating
and cooling systems —
Part 3:
Design and dimensioning
Conception de l’environnement des bâtiments — Normes pour la
conception, la construction et le fonctionnement des systèmes de
chauffage et de refroidissement par rayonnement —
Partie 3: Conception et dimensionnement
Reference number
ISO 11855-3:2012(E)
©
ISO 2012

---------------------- Page: 7 ----------------------

SIST EN ISO 11855-3:2015
ISO 11855-3:2012(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2012
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any
means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the
address below or ISO’s member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2012 – All rights reserved

---------------------- Page: 8 ----------------------

SIST EN ISO 11855-3:2015
ISO 11855-3:2012(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 1
5 Radiant panel . 3
5.1 Floor heating systems . 3
5.2 Ceiling heating systems .11
5.3 Wall heating systems .12
5.4 Floor cooling systems . .13
5.5 Ceiling cooling systems .14
5.6 Wall cooling systems .14
Bibliography .15
© ISO 2012 – All rights reserved iii

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SIST EN ISO 11855-3:2015
ISO 11855-3:2012(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 11855-3 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 and control of embedded radiant heating and cooling systems:
— Part 1: Definition, 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 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.
iv © ISO 2012 – All rights reserved

---------------------- Page: 10 ----------------------

SIST EN ISO 11855-3:2015
ISO 11855-3:2012(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 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, operation, and control method of embedded systems.
© ISO 2012 – All rights reserved v

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SIST EN ISO 11855-3:2015

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SIST EN ISO 11855-3:2015
INTERNATIONAL STANDARD ISO 11855-3:2012(E)
Building environment design — Design, dimensioning,
installation and control of embedded radiant heating and
cooling systems —
Part 3:
Design and dimensioning
1 Scope
This part of ISO 11855 establishes a system design and dimensioning method to ensure the heating and
cooling capacity of the 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 applies also, 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
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
EN 12831, Heating systems in buildings — Method for calculation of the design heat load
EN 15243, Ventilation for buildings — Calculation of room temperatures and of load and energy for buildings
with room conditioning systems
ISO 11855-1, Building environment design — Design, dimensioning, installation and control of embedded
radiant heating and cooling systems — Part 1: Definition, symbols, and comfort criteria
ISO 11855-2, Building environment design — Design, dimensioning, installation and control of embedded
radiant heating and cooling systems — Part 2: Determination of the design heating and cooling capacity
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 11855-1 apply.
4 Symbols and abbreviated terms
For the purposes of this document, the symbols and abbreviations in Table 1 apply.
Table 1 — Symbols and abbreviated terms
Symbol Unit Quantity
2
A m Area of the heating/cooling surface
F
© ISO 2012 – All rights reserved 1

---------------------- Page: 13 ----------------------

SIST EN ISO 11855-3:2015
ISO 11855-3:2012(E)
Table 1 (continued)
Symbol Unit Quantity
2
A m Area of the occupied heating/cooling surface
A
2
A m Area of the peripheral heating/cooling surface
R
C J/(kg⋅K) Specific heat of medium
W
2
K W/(m ⋅K) Equivalent heat transmission coefficient
H
l m Distance between the joists
p
l m Thickness of the joist
W
M kg/s Design heating/cooling medium flow rate
2
q W/m Design heat flux
des
2
q W/m Design heat flux in the occupied area
des,A
2
q W/m Design heat flux in the peripheral area
des,R
2
q W/m Limit heat flux
G
2
q W/m Maximum design heat flux
max
Q W Design heating/cooling capacity
des
Q W Design heating/cooling load
N
Q W Design sensible cooling load
N,s
Q W Design latent cooling load
N,l
Q W Heat output of supplementary heating equipment
out
2
R (m K)/W Partial inwards heat transmission resistance of the surface structure
o
2
R (m K)/W Partial outwards heat transmission resistance of the surface structure
u
2
Rλ (m ⋅K)/W Thermal resistance of surface covering
,B
2
Rλ (m ⋅K)/W Back side thermal resistance of insulating layer
,ins
s m Effective thickness of thermal insulating layer
ins
W m Pipe spacing
2
h W/(m K) Heat transfer coefficient
λ W/(m⋅K) Effective thermal conductivity of the thermal insulation layer
ins
λ W/(mK) Thermal conductivity of the thermal insulation layer between the joists
i
λ W/(mK) Thermal conductivity of the joist
w
θ °C Maximum surface temperature
F,max
θ °C Minimum surface temperature
F,min
θ °C Design indoor temperature
i
θ °C Return temperature of heating/cooling medium
R
θ °C Supply temperature of heating/cooling medium
V
θ °C Design supply temperature of heating/cooling medium
V,des
Δθ K Heating/cooling medium differential temperature
H
Δθ K Design heating/cooling medium differential temperature
H,des
Δθ K Limit of heating/cooling medium differential temperature
H,G
Δθ K Design heating/cooling medium differential supply temperature
V,des
σ K Temperature drop/rise between supply and return medium
2 © ISO 2012 – All rights reserved

---------------------- Page: 14 ----------------------

SIST EN ISO 11855-3:2015
ISO 11855-3:2012(E)
5 Radiant panel
5.1 Floor heating systems
5.1.1 Design procedure
Floor heating system design requires determining heating surface area, type, pipe size, pipe spacing, supply
temperature of the heating medium, and design heating medium flow rate. The design steps are as follows:
Step 1: Calculate the design heating load Q . The design heating load Q shall not include the adjacent
N N
heat losses. This step should be conducted in accordance with a standard for heating load
calculation, such as EN 12831, based on an index such as operative temperature (OT) (see
ISO 11855-1).
Step 2: Determine the area of the heating surface A , excluding any area covered by immovable
F
objects or objects fixed to the building structure.
Step 3: Establish a maximum permissible surface temperature in accordance with ISO 11855-1.
Step 4: Determine the design heat flux q according to Equation (1). For floor heating systems
des
including a peripheral area, the design heat flux of peripheral area q and the design heat
des,R
flux of occupied area q shall be calculated respectively on the area of the peripheral heat-
des,A
ing surface A and on the area of the occupied heating surface A complying with Equation
R A
(2).
Q
N
q =
des (1)
A
F

Qq=⋅Aq+⋅A
Ndes,R Rdes,A A (2)

Step 5: For the design of the floor heating systems, determine the room used for design with the
maximum design heat flux q = q .
max des
Step 6: Determine the floor heating system such as the pipe spacing and the covering type, and
design heating medium differential temperature Δθ based on the maximum design heat
H,des
flux q and the maximum surface temperature θ from the field of characteristic curves
max F,max
according to ISO 11855-2 and 5.1.7 in this part of ISO 11855.
Step 7: If the design heat flux q cannot be obtained by any pipe spacing for the room used for the
des
design, it is recommended to include a peripheral area and/or to provide supplementary heat-
ing equipment. In this case, the maximum design heat flux q for the embedded system may
max
now occur in another room. The amount of heat output of supplementary heating equipment
Q is determined by the following equation:
out
QQ=− Q
outN des (3)

where design heating capacity Q is calculated by:
des
Qq=×A
desdes F (4)

Step 8: Determine the backside thermal resistance of insulating layer R and the design heating
λ,ins
medium flow rate m (see 5.1.6 and 5.1.8).
Step 9: Estimate the total length of heating circuit.
© ISO 2012 – All rights reserved 3

---------------------- Page: 15 ----------------------

SIST EN ISO 11855-3:2015
ISO 11855-3:2012(E)
If intermittent operation is common, the characteristics of the increase of the heat flow and the surface
temperature and the time to reach the allowable conditions in rooms just after switching on the system
shall be considered.
5.1.2 Heating medium differential temperature
Heating medium differential temperature Δθ is calculated as follows (refer to ISO 11855-2):
H
θθ−
VR
Δθ = (5)
H
θθ−
Vi
ln
θθ−
Ri
In this equation, the effect
...

SLOVENSKI STANDARD
kSIST FprEN ISO 11855-3:2015
01-maj-2015
1DþUWRYDQMHJUDGQMH1DþUWRYDQMHGLPHQ]LRQLUDQMHPRQWDåDLQNRQWURODYJUDMHQLK
KODGLOQLKLQRJUHYDOQLKVLVWHPRYGHO1DþUWRYDQMHLQGLPHQ]LRQLUDQMH ,62

Building environment design - Design, dimensioning, installation and control of
embedded radiant heating and cooling systems - Part 3: Design and dimensioning (ISO
111855-3:2012)
Umweltgerechte Gebäudeplanung - Planung, Auslegung, Installation und Steuerung
flächenintegrierter Strahlheizungs- und -kühlsysteme - Teil 3: Planung und Auslegung
(ISO 11855-3:2012)
Conception de l'environnement des bâtiments - Normes pour la conception, la
construction et le fonctionnement des systèmes de chauffage et de refroidissement par
rayonnement - Partie 3: Conception et dimensionnement (ISO 11855-3:2012)
Ta slovenski standard je istoveten z: FprEN ISO 11855-3
ICS:
91.140.10 Sistemi centralnega Central heating systems
ogrevanja
91.140.30 3UH]UDþHYDOQLLQNOLPDWVNL Ventilation and air-
VLVWHPL conditioning
kSIST FprEN ISO 11855-3:2015 en,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------

kSIST FprEN ISO 11855-3:2015

---------------------- Page: 2 ----------------------

kSIST FprEN ISO 11855-3:2015

EUROPEAN STANDARD
FINAL DRAFT
FprEN ISO 11855-3
NORME EUROPÉENNE

EUROPÄISCHE NORM

January 2015
ICS 91.140.10; 91.140.30
English Version
Building environment design - Design, dimensioning, installation
and control of embedded radiant heating and cooling systems -
Part 3: Design and dimensioning (ISO 111855-3:2012)
Conception de l'environnement des bâtiments - Normes Umweltgerechte Gebäudeplanung - Planung, Auslegung,
pour la conception, la construction et le fonctionnement des Installation und Steuerung flächenintegrierter
systèmes de chauffage et de refroidissement par Strahlheizungs- und -kühlsysteme - Teil 3: Planung und
rayonnement - Partie 3: Conception et dimensionnement Auslegung (ISO 11855-3:2012)
(ISO 11855-3:2012)
This draft European Standard is submitted to CEN members for unique acceptance procedure. It has been drawn up by the Technical
Committee CEN/TC 228.

If this draft becomes a European Standard, 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.

This draft European Standard was established by CEN 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United
Kingdom.

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.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a European Standard.


EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2015 CEN All rights of exploitation in any form and by any means reserved Ref. No. FprEN ISO 11855-3:2015 E
worldwide for CEN national Members.

---------------------- Page: 3 ----------------------

kSIST FprEN ISO 11855-3:2015
FprEN ISO 11855-3:2015 (E)
Contents Page
Foreword .3
2

---------------------- Page: 4 ----------------------

kSIST FprEN ISO 11855-3:2015
FprEN ISO 11855-3:2015 (E)
Foreword
The text of ISO 11855-3:2012 has been prepared by Technical Committee ISO/TC 205 “Building environment
design” of the International Organization for Standardization (ISO) and has been taken over as FprEN ISO
11855-3:2015 by Technical Committee CEN/TC 228 “Heating systems and water based cooling systems in
buildings” the secretariat of which is held by DIN.
This document is currently submitted to the Unique Acceptance Procedure.
This standard is applicable for design, construction and operation of radiant heating and cooling systems. The
methods defined in part 2 are intended to determine the design heating or cooling capacity used for the design
and evaluation of the performance of the system.
For identifying product characteristics by testing and proving the thermal output of heating and cooling
surfaces embedded in floors, ceilings and walls the standard series EN 1264 can be used.
Endorsement notice
The text of ISO 11855-3:2012 has been approved by CEN as FprEN ISO 11855-3:2015 without any
modification.
3

---------------------- Page: 5 ----------------------

kSIST FprEN ISO 11855-3:2015

---------------------- Page: 6 ----------------------

kSIST FprEN ISO 11855-3:2015
INTERNATIONAL ISO
STANDARD 11855-3
First edition
2012-10-01
Building environment design —
Design, dimensioning, installation and
control of embedded radiant heating
and cooling systems —
Part 3:
Design and dimensioning
Conception de l’environnement des bâtiments — Normes pour la
conception, la construction et le fonctionnement des systèmes de
chauffage et de refroidissement par rayonnement —
Partie 3: Conception et dimensionnement
Reference number
ISO 11855-3:2012(E)
©
ISO 2012

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kSIST FprEN ISO 11855-3:2015
ISO 11855-3:2012(E)
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© ISO 2012
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Published in Switzerland
ii © ISO 2012 – All rights reserved

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kSIST FprEN ISO 11855-3:2015
ISO 11855-3:2012(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 1
5 Radiant panel . 3
5.1 Floor heating systems . 3
5.2 Ceiling heating systems .11
5.3 Wall heating systems .12
5.4 Floor cooling systems . .13
5.5 Ceiling cooling systems .14
5.6 Wall cooling systems .14
Bibliography .15
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kSIST FprEN ISO 11855-3:2015
ISO 11855-3:2012(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 11855-3 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 and control of embedded radiant heating and cooling systems:
— Part 1: Definition, 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 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.
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kSIST FprEN ISO 11855-3:2015
ISO 11855-3:2012(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 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, operation, and control method of embedded systems.
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kSIST FprEN ISO 11855-3:2015

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kSIST FprEN ISO 11855-3:2015
INTERNATIONAL STANDARD ISO 11855-3:2012(E)
Building environment design — Design, dimensioning,
installation and control of embedded radiant heating and
cooling systems —
Part 3:
Design and dimensioning
1 Scope
This part of ISO 11855 establishes a system design and dimensioning method to ensure the heating and
cooling capacity of the 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 applies also, 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
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
EN 12831, Heating systems in buildings — Method for calculation of the design heat load
EN 15243, Ventilation for buildings — Calculation of room temperatures and of load and energy for buildings
with room conditioning systems
ISO 11855-1, Building environment design — Design, dimensioning, installation and control of embedded
radiant heating and cooling systems — Part 1: Definition, symbols, and comfort criteria
ISO 11855-2, Building environment design — Design, dimensioning, installation and control of embedded
radiant heating and cooling systems — Part 2: Determination of the design heating and cooling capacity
3 Terms a nd definiti ons
For the purposes of this document, the terms and definitions given in ISO 11855-1 apply.
4 Symbols and abbreviated terms
For the purposes of this document, the symbols and abbreviations in Table 1 apply.
Table 1 — Symbols and abbreviated terms
Symbol Unit Quantity
2
A m Area of the heating/cooling surface
F
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kSIST FprEN ISO 11855-3:2015
ISO 11855-3:2012(E)
Table 1 (continued)
Symbol Unit Quantity
2
A m Area of the occupied heating/cooling surface
A
2
A m Area of the peripheral heating/cooling surface
R
C J/(kg⋅K) Specific heat of medium
W
2
K W/(m ⋅K) Equivalent heat transmission coefficient
H
l m Distance between the joists
p
l m Thickness of the joist
W
M kg/s Design heating/cooling medium flow rate
2
q W/m Design heat flux
des
2
q W/m Design heat flux in the occupied area
des,A
2
q W/m Design heat flux in the peripheral area
des,R
2
q W/m Limit heat flux
G
2
q W/m Maximum design heat flux
max
Q W Design heating/cooling capacity
des
Q W Design heating/cooling load
N
Q W Design sensible cooling load
N,s
Q W Design latent cooling load
N,l
Q W Heat output of supplementary heating equipment
out
2
R (m K)/W Partial inwards heat transmission resistance of the surface structure
o
2
R (m K)/W Partial outwards heat transmission resistance of the surface structure
u
2
Rλ (m ⋅K)/W Thermal resistance of surface covering
,B
2
Rλ (m ⋅K)/W Back side thermal resistance of insulating layer
,ins
s m Effective thickness of thermal insulating layer
ins
W m Pipe spacing
2
h W/(m K) Heat transfer coefficient
λ W/(m⋅K) Effective thermal conductivity of the thermal insulation layer
ins
λ W/(mK) Thermal conductivity of the thermal insulation layer between the joists
i
λ W/(mK) Thermal conductivity of the joist
w
θ °C Maximum surface temperature
F,max
θ °C Minimum surface temperature
F,min
θ °C Design indoor temperature
i
θ °C Return temperature of heating/cooling medium
R
θ °C Supply temperature of heating/cooling medium
V
θ °C Design supply temperature of heating/cooling medium
V,des
Δθ K Heating/cooling medium differential temperature
H
Δθ K Design heating/cooling medium differential temperature
H,des
Δθ K Limit of heating/cooling medium differential temperature
H,G
Δθ K Design heating/cooling medium differential supply temperature
V,des
σ K Temperature drop/rise between supply and return medium
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kSIST FprEN ISO 11855-3:2015
ISO 11855-3:2012(E)
5 Radiant panel
5.1 Floor heating systems
5.1.1 Design procedure
Floor heating system design requires determining heating surface area, type, pipe size, pipe spacing, supply
temperature of the heating medium, and design heating medium flow rate. The design steps are as follows:
Step 1: Calculate the design heating load Q . The design heating load Q shall not include the adjacent
N N
heat losses. This step should be conducted in accordance with a standard for heating load
calculation, such as EN 12831, based on an index such as operative temperature (OT) (see
ISO 11855-1).
Step 2: Determine the area of the heating surface A , excluding any area covered by immovable
F
objects or objects fixed to the building structure.
Step 3: Establish a maximum permissible surface temperature in accordance with ISO 11855-1.
Step 4: Determine the design heat flux q according to Equation (1). For floor heating systems
des
including a peripheral area, the design heat flux of peripheral area q and the design heat
des,R
flux of occupied area q shall be calculated respectively on the area of the peripheral heat-
des,A
ing surface A and on the area of the occupied heating surface A complying with Equation
R A
(2).
Q
N
q =
des (1)
A
F

Qq=⋅Aq+⋅A
Ndes,R Rdes,A A (2)

Step 5: For the design of the floor heating systems, determine the room used for design with the
maximum design heat flux q = q .
max des
Step 6: Determine the floor heating system such as the pipe spacing and the covering type, and
design heating medium differential temperature Δθ based on the maximum design heat
H,des
flux q and the maximum surface temperature θ from the field of characteristic curves
max F,max
according to ISO 11855-2 and 5.1.7 in this part of ISO 11855.
Step 7: If the design heat flux q cannot be obtained by any pipe spacing for the room used for the
des
design, it is recommended to include a peripheral area and/or to provide supplementary heat-
ing equipment. In this case, the maximum design heat flux q for the embedded system may
max
now occur in another room. The amount of heat output of supplementary heating equipment
Q is determined by the following equation:
out
QQ=− Q
outN des (3)

where design heating capacity Q is calculated by:
des
Qq=×A
desdes F (4)

Step 8: Determine the backside thermal resistance of insulating layer R and the design heating
λ,ins
medium flow rate m (see 5.1.6 and 5.1.8).
Step 9: Estimate the total length of heating circuit.
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kSIST FprEN ISO 11855-3:2015
ISO 11855-3:2012(E)
If intermittent operation is common, the characteristics of the increase of the heat flow and the surface
temperature and the time to reach the allowable conditions in rooms just after switching on the system
shall be considered.
5.1.2 Heating medium differential temperature
Heating medium differential temperature Δθ is calculated as follows (refer to ISO 11855-2):
H
θθ−
VR
Δθ = (5)
H
θθ−
Vi
ln
θθ−
Ri
In this equation, the effect of the temperature drop of the heating medium is taken into account.
5.1.3 Characteristic curve
The characteristic curve describes the relationship between the heat flux q and the heating medium
differential temperature Δθ . For simplicity, the heat flux q is taken to be proportional to the heating
H
medium differential temperature Δθ :
H
qK=⋅Δθ
...

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