Water based surface embedded heating and cooling systems - Part 3: Dimensioning

The EN 1264 series gives guidelines for surface embedded heating and cooling systems installed in buildings, residential and non-residential (e.g. office, public, commercial and industrial buildings) and focuses on systems installed for the purpose of thermal comfort.
The EN 1264 series gives guidelines for water based heating and cooling systems embedded into the enclosure surfaces of the room to be heated or to be cooled. It also specifies the use of other heating media instead of water, as appropriate.
The EN 1264 series specifies standardized product characteristics by calculation and testing the thermal output of heating for technical specifications and certification. For the design, construction and operation of these systems, see EN 1264-3 and EN 1264-4 for the types A, B, C, D, H, I and J. For the types E, F and G, see the EN ISO 11855 series.
The systems specified in the EN 1264 series are adjoined to the structural base of the enclosure surfaces of the building, mounted directly or with fixing supports. The EN 1264 series does not specify ceiling systems mounted in a suspended ceiling with a designed open air gap between the system and the building structure which allows the thermally induced circulation of the air. The thermal output of these systems can be determined according to EN 14037 series and EN 14240.
EN 1264-3 specifies the use in practical engineering of the results coming from EN 1264-2 and EN 1264-5.
For heating systems, physiological limitations are taken into account when specifying the surface temperatures. In the case of floor heating systems the limitations are realized by a design based on the characteristic curves and limit curves determined in accordance with EN 1264-2.
For cooling systems, only a limitation with respect to the dew point is taken into account. In predominating practice, this means that physiological limitations are included as well.

Raumflächenintegrierte Heiz- und Kühlsysteme mit Wasserdurchströmung - Teil 3: Auslegung

Die Normenreihe EN 1264 gibt Leitlinien für in Wohn- und anderen Gebäuden (z. B. Bürogebäuden, öffentlichen Gebäuden sowie Gewerbe- und Industriegebäuden) installierte raumflächenintegrierte Heiz- und Kühlsysteme und legt einen Schwerpunkt auf Systeme, die für den Zweck der thermischen Behaglichkeit installiert werden.
Die Normenreihe EN 1264 gibt Leitlinien für Heiz- und Kühlsysteme mit Wasserdurchströmung, die in die Raumum¬schließungsflächen des zu heizenden oder des zu kühlenden Raumes eingebettet sind. Sie legt ggf. auch die entsprechende Verwendung anderer Heizmittel als Wasser fest.
Die Normenreihe EN 1264 legt die Identifizierung standardisierter Produktmerkmale durch Berechnung und Prüfung der Wärmeleistung der Heizung für technische Spezifikationen und die Zertifizierung fest. Für das Design, den Bau und den Betrieb dieser Anlagen siehe EN 1264 3 und EN 1264 4 für die Typen A, B, C, D, H, I und J. Für die Typen E, F und G siehe Normenreihe EN ISO 11855.
Die in der Normenreihe EN 1264 festgelegten Systeme grenzen an den tragenden Untergrund der Umschließungsflächen des Gebäudes an und werden direkt oder mit Befestigungshalterungen angebracht. EN 1264 trifft keine Festlegungen für in abgehängten Decken montierte Deckensysteme mit einem auslegungsgemäßen offenen Luftspalt zwischen dem System und der Gebäudestruktur, der eine thermisch induzierte Umwälzung der Luft erlaubt. Die Wärmeleistung dieser Systeme kann nach der Normenreihe EN 14037 und EN 14240 bestimmt werden.
EN 1264 3 legt die Verwendung der Ergebnisse aus EN 1264 2 und EN 1264 5 im praktischen Ingenieur¬wesen fest.
Im Falle von Heizsystemen werden die physiologisch bedingten Grenzen bei der Festlegung der Oberflächentemperaturen berücksichtigt. Im Falle von Fußbodenheizsystemen wird den Grenzen durch eine Auslegung Rechnung getragen, die auf den nach EN 1264 2 ermittelten Kennlinien und Grenzkurven basiert.
Im Falle von Kühlsystemen wird eine Leistungsbegrenzung ausschließlich durch den Taupunkt berücksichtigt. In der Praxis bedeutet dies in der Regel, dass dadurch zugleich die physiologisch bedingten Grenzen einbezogen werden.

Systèmes de surfaces chauffantes et rafraîchissantes hydrauliques intégrées - Partie 3 : Dimensionnement

Ploskovni sistemi za ogrevanje in hlajenje z vodo - 3. del: Dimenzioniranje

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6060 - Definitive text made available (DAV) - Publishing
Due Date
19-May-2021
Completion Date
19-May-2021

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SLOVENSKI STANDARD
SIST EN 1264-3:2021
01-julij-2021
Nadomešča:
SIST EN 1264-3:2009
Ploskovni sistemi za ogrevanje in hlajenje z vodo - 3. del: Dimenzioniranje
Water based surface embedded heating and cooling systems - Part 3: Dimensioning
Raumflächenintegrierte Heiz- und Kühlsysteme mit Wasserdurchströmung - Teil 3:
Auslegung

Systèmes de surfaces chauffantes et rafraîchissantes hydrauliques intégrées - Partie 3 :

Dimensionnement
Ta slovenski standard je istoveten z: EN 1264-3:2021
ICS:
91.140.10 Sistemi centralnega Central heating systems
ogrevanja
SIST EN 1264-3:2021 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN 1264-3:2021
---------------------- Page: 2 ----------------------
SIST EN 1264-3:2021
EN 1264-3
EUROPEAN STANDARD
NORME EUROPÉENNE
May 2021
EUROPÄISCHE NORM
ICS 91.140.10 Supersedes EN 1264-3:2009
English Version
Water based surface embedded heating and cooling
systems - Part 3: Dimensioning

Systèmes de surfaces chauffantes et rafraîchissantes Raumflächenintegrierte Heiz- und Kühlsysteme mit

hydrauliques intégrées - Partie 3 : Dimensionnement Wasserdurchströmung - Teil 3: Auslegung

This European Standard was approved by CEN on 12 April 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 1264-3:2021 E

worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST EN 1264-3:2021
EN 1264-3:2021 (E)

Contents Page

European foreword ....................................................................................................................................................... 3

1 Scope .................................................................................................................................................................... 4

2 Normative references .................................................................................................................................... 4

3 Terms and definitions ................................................................................................................................... 5

4 Heating systems ............................................................................................................................................... 5

4.1 Floor heating systems .................................................................................................................................... 5

4.1.1 Basic principles ................................................................................................................................................ 5

4.1.2 Boundary conditions ...................................................................................................................................... 6

4.1.3 Design .................................................................................................................................................................. 9

4.1.4 Peripheral areas ........................................................................................................................................... 11

4.2 Ceiling heating systems .............................................................................................................................. 12

4.2.1 Basic principles ............................................................................................................................................. 12

4.2.2 Boundary conditions ................................................................................................................................... 12

4.2.3 Design ............................................................................................................................................................... 13

4.3 Wall heating systems .................................................................................................................................. 13

4.3.1 Basic principles ............................................................................................................................................. 13

4.3.2 Boundary conditions ................................................................................................................................... 13

4.3.3 Design ............................................................................................................................................................... 14

5 Cooling systems ............................................................................................................................................ 14

5.1 General ............................................................................................................................................................. 14

5.1.1 Basic principles ............................................................................................................................................. 14

5.1.2 Temperature differences .......................................................................................................................... 14

5.1.3 Regional dew point and standard indoor room temperature ..................................................... 14

5.1.4 Temperature difference between room and cooling water ......................................................... 15

5.1.5 Characteristic curves .................................................................................................................................. 15

5.1.6 Field of characteristic curves ................................................................................................................... 15

5.1.7 Limit curve ...................................................................................................................................................... 15

5.1.8 Thermal insulation ...................................................................................................................................... 16

5.2 Design ............................................................................................................................................................... 16

5.2.1 Pressure loss .................................................................................................................................................. 16

5.2.2 Design specific cooling load ..................................................................................................................... 16

5.2.3 Determination of the design flow (inlet) temperature and the design specific

thermal output .............................................................................................................................................. 16

5.2.4 Determination of the design cooling water flow rate ..................................................................... 18

Annex A (normative) Figures ................................................................................................................................ 19

Bibliography ................................................................................................................................................................. 21

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SIST EN 1264-3:2021
EN 1264-3:2021 (E)
European foreword

This document (EN 1264-3:2021) has been prepared by Technical Committee CEN/TC 130 “Space

heating appliances without integral heat sources”, the secretariat of which is held by UNI.

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 November 2021, and conflicting national standards

shall be withdrawn at the latest by November 2021.

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 1264-3:2009.
The main changes compared to the previous edition are listed below:
a) Clarification of the Scope;
b) Improved wording, especially the term “prove method”;
c) Deletion of the Note in 4.1.2.2;

d) Addition of new subclauses 4.1.3.1, 4.2.3.1, 4.3.3.1 and 5.2.1.1 Pressure loss;

e) Modification of the maximum average surface temperature for ceiling heating systems in 4.2.1.4;

f) Figures 1 and 3 replaced with Figures A.2 and A.3;
2 2

g) Correction of Formula (15) from 1/α = 0,009 3 (m ∙K)/W to 1/α = 0,092 6 (m ∙K)/W.

EN 1264, Water based surface embedded heating and cooling systems, consists of the following parts:

— Part 1: Definitions and symbols;

— Part 2: Floor heating: Methods for the determination of the thermal output using calculations and

experimental tests;
— Part 3: Dimensioning;
— Part 4: Installation;

— Part 5: Determination of the thermal output for wall and ceiling heating and for floor, wall and ceiling

cooling.

According to the CEN-CENELEC Internal Regulations, the national standards organisations 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.
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SIST EN 1264-3:2021
EN 1264-3:2021 (E)
1 Scope

The EN 1264 series gives guidelines for surface embedded heating and cooling systems installed in

buildings, residential and non-residential (e.g. office, public, commercial and industrial buildings) and

focuses on systems installed for the purpose of thermal comfort.

The EN 1264 series gives guidelines for water based heating and cooling systems embedded into the

enclosure surfaces of the room to be heated or to be cooled. It also specifies the use of other heating

media instead of water, as appropriate.

The EN 1264 series specifies standardized product characteristics by calculation and testing the

thermal output of heating for technical specifications and certification. For the design, construction and

operation of these systems, see EN 1264-3 and EN 1264-4 for the types A, B, C, D, H, I and J. For the

types E, F and G, see the EN ISO 11855 series.

The systems specified in the EN 1264 series are adjoined to the structural base of the enclosure

surfaces of the building, mounted directly or with fixing supports. The EN 1264 series does not specify

ceiling systems mounted in a suspended ceiling with a designed open air gap between the system and

the building structure which allows the thermally induced circulation of the air. The thermal output of

these systems can be determined according to EN 14037 series and EN 14240.

EN 1264-3 specifies the use in practical engineering of the results coming from EN 1264-2 and

EN 1264-5.

For heating systems, physiological limitations are taken into account when specifying the surface

temperatures. In the case of floor heating systems the limitations are realized by a design based on the

characteristic curves and limit curves determined in accordance with EN 1264-2.

For cooling systems, only a limitation with respect to the dew point is taken into account. In

predominating practice, this means that physiological limitations are included as well.

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.

EN 1264-1:2021, Water based surface embedded heating and cooling systems — Part 1: Definitions and

symbols

EN 1264-2:2021, Water based surface embedded heating and cooling systems — Part 2: Floor heating:

Methods for the determination of the thermal output using calculations and experimental tests

EN 1264-4:2021, Water based surface embedded heating and cooling systems — Part 4: Installation

EN 1264-5:2021, Water based surface embedded heating and cooling systems — Part 5: Heating and

cooling surfaces embedded in floors, ceilings and walls — Determination of the thermal output

EN 12831 (all parts), 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
---------------------- Page: 6 ----------------------
SIST EN 1264-3:2021
EN 1264-3:2021 (E)
3 Terms and definitions

For the purposes of this document, the terms and definitions given in EN 1264-1:2021 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/
4 Heating systems
4.1 Floor heating systems
4.1.1 Basic principles
4.1.1.1 Temperature difference between heating water and room

The temperature difference between the heating water and the room is calculated using Formula (1),

see also EN 1264-2. In this Formula, the effect of the temperature drop of the heating water is taken into

account.
ϑ −ϑ
V R
∆ϑ = (1)
ϑ −ϑ
V i
ϑϑ−
4.1.1.2 Characteristic curve

The characteristic curve describes the relationship between the specific thermal output q of a system

and the required temperature difference between heating water and room Δϑ . For a simplification, the

specific thermal output is taken directly proportional to the temperature difference, see Formula (2):

qK= ⋅∆ϑ
H H
(2)

where the gradient is the equivalent heat transmission coefficient determined according to EN 1264-2.

4.1.1.3 Field of characteristic curves

The field of characteristic curves of a floor heating system with a specific pipe spacing T shall at least

contain the characteristic curves for values of the thermal resistance R = 0 (m ∙K)/W,

λ,B
2 2 2

R = 0,05 (m ∙K)/W, R = 0,10 (m ∙K)/W and R = 0,15 (m ∙K)/W in accordance with EN 1264-2

λ,B λ,B λ,B

(see Figure A.1, in Annex A). Values of R > 0,15 (m ∙K)/W shall not be used if possible.

λ,B
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SIST EN 1264-3:2021
EN 1264-3:2021 (E)
4.1.1.4 Limit curves

The limit curves in the field of characteristic curves describe in accordance with EN 1264-2 the

relationship between the specific thermal output q and the temperature difference Δϑ between the

heating water and the room in the case where the physiologically agreed limit values of surface

temperatures ϑ = 29 °C (occupied area) or ϑ = 35 °C (peripheral area) are reached . For

F,max F,max

bathrooms (ϑ = 24 °C) the limit curve for (ϑ − ϑ ) = 9 K also applies. For design purposes, i.e. the

I F,max i

determination of design values of the specific thermal output and the associated temperature difference

between heating water and room, the limit curves are valid for the temperature drop σ of the heating

water in a range of:
0 K < σ ≤ 5 K

The limit curves are used to specify the maximum permissible flow temperature (see 4.1.3.2 and

Figure A.2).
4.1.1.5 Thermal inertia

The difference between the minimum and the maximum surface temperature of a floor heating system

is low. This means for design purposes that no consideration of thermal inertia is required.

4.1.2 Boundary conditions
4.1.2.1 Flow pipes to adjacent rooms

The heat output of service pipes, not serving rooms through which they pass, shall be limited by careful

design, or by use of thermal insulation coverings, so that any room temperature should not be increased

substantially. The heat output of service pipes passing through the room in question to adjacent rooms

is taken into account if the same type of room usage can be assumed.
4.1.2.2 Thermal insulation

To limit the heat flow through the floor to rooms below, the required thermal resistance of the

insulating layer R (see Figure A.3) shall be at minimum in accordance with of EN 1264-4 , Table 1. It

λ,ins
is calculated according to Formula (3).
ins
R = (3)
λ,ins
ins
where
s is the thickness of the insulating layer in m;
ins
λ is the thermal conductivity of the insulating layer in W/(m∙K).
ins

Depending on the construction of the floor heating system, the effective thickness of the insulating layer

s is determined differently.
ins

For floor heating systems with flat thermal insulating panels (see Figure 1), s is identical with the

ins
thickness of the thermal insulating panel.
National regulations may limit these temperatures to lower values.
National regulations may vary the requirements given in Table 1 of EN 1264-4.
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SIST EN 1264-3:2021
EN 1264-3:2021 (E)

For floor heating systems with profiled thermal insulating panels (see Figure 3), a surface-related

weighted calculation is made for the effective thickness of the insulating layer s :

ins
s ⋅ T− D + s ⋅ D
( )
s =
ins
(4)

For profiled thermal insulating panels shaped differently from that shown in Figure 3, the average

effective thickness of the insulating layer shall be calculated with an accordant application of

Formula (4).

The thermal resistance R of the insulating layers of the heating/cooling system shall be calculated as

λ,ins
reported in EN 1264-4:2021, Table 1.

This calculation can be done with the assumption that the thermal insulation is continuous parallel to

the pipes. For floor heating systems with thermal insulation panels with studs according to Figure 2

(Type A and Type C systems), only the flat part of the panel (without studs) shall be considered in

calculation of s .
ins
Figure 1 — Average thickness of insulating layer flat insulating panels
---------------------- Page: 9 ----------------------
SIST EN 1264-3:2021
EN 1264-3:2021 (E)
Key
1 floor covering
2 weight bearing and thermal diffusion layer
3 thermal insulation with studs
4 acoustic insulation (if present)
5 structural base
6 pipes
Figure 2 — Type A and Type C System with studs
Key
1 floor covering
2 weight bearing and thermal diffusion layer
3 thermal insulation
4 heat diffusion device
5 structural base

Figure 3 — Average thickness of insulating for layer for profiled insulating panels

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SIST EN 1264-3:2021
EN 1264-3:2021 (E)
4.1.3 Design
4.1.3.1 Pressure loss

The maximum pressure loss per heating circuit should be minimized in order to limit the electrical

power consumption of the pump, e.g. by hydronic balancing (see EN 1264-4:2021, 4.1). It should not

exceed 350 mbar.
4.1.3.2 Design specific thermal output

The design value q to design a floor heating system for a room is equal to the standard heat load Q

des N,f
(see EN 1264-1) divided by the heating surface A :
Nf,
q =
des
(5)

The standard heat load Q shall be calculated in accordance with EN 12831 (all parts). Normally, the

N,f

heat output Q of the floor heating system shall be equivalent to the standard heat load Q . If this is not

F N,f
possible, additional heating surfaces shall be used, see Formula (12).

The design thermal output Q of the entire heating surface A is calculated using Formula (6):

F F
Q q⋅ A
(6)

Where peripheral area is used, q shall be distributed between the peripheral area A and the occupied

area A according to a surface weighted calculation, see Formula (7) (see also 4.1.4):

qq= ⋅ + ⋅ q
(7)
where
q is the specific thermal output of the occupied area;
q is the specific thermal output of the peripheral area.
4.1.3.3 Determination of the design flow temperature

The design flow temperature is determined for the room (or the rooms respectively) with the maximum

specific thermal output q = q (excluding bathrooms). In the rooms being heated, it is assumed that

max des

floor coverings with a uniform thermal conduction resistance are used. Generally for the design of floor

heating systems in residential rooms, uniform floor coverings with R = 0,10 (m ⋅K)/W are assumed.

λ,B
In the case of using higher values R , these values shall be taken.
λ,B

For the room used for design, the temperature drop of the heating water is specified to σ ≤ 5 K. If

necessary, a subdivision of this room into heating circuits should be performed. Under these conditions,

the maximum value q may reach until the limit value q of the specific thermal output (see

max G
Figure A.2) .

This means that above the flow pipe the maximum floor temperature ϑ can be exceeded compared with

F,max

the centre of the room, corresponding to the higher heating water temperature by σ/2.

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SIST EN 1264-3:2021
EN 1264-3:2021 (E)

For the room with q , a pipe spacing is chosen with which q remains less or equal to the limit

max max

value q (q ≤ q , see Figure A.2). For this, small pipe spacing is recommended. In case of q ≤ q ,

G max G max G
design values of the temperature difference between flow heating water and room

Δϑ ≤ Δϑ + 2,5 K are permitted (see Figure A.2). The maximum permissible temperature

V,des H,G
difference between flow and room comes to:
∆ϑ =∆ϑ + where∆ϑϑ≤∆ (8)
V,des H,des H,,des H G
Formula (8) applies if σ/Δϑ ≤ 0,5. If σ/Δϑ > 0,5, Formula (9) applies:
H H
∆ϑϑ=∆ ++ (9)
V,,des H des
2 12⋅∆ϑ
H,des

The temperature drop σ in Formula (8) and in Formula (9), in Figure A.2 is designated σ .

des

The result of Formula (8) or Formula (9) provides the design flow temperature ϑ = Δϑ + ϑ .

V,des V,des i

For all other rooms operated at the same flow temperature ϑ , for σ/Δϑ ≤ 0,5 the associated the

V,des H,j

temperature drops σ of the heating water are taken from the field of characteristic curves (see

Figure A.2) or calculated according to Formula (10):
=∆ϑϑ−∆ (10)
V,,des H j

using the temperature differences Δϑ corresponding to the respective values of the specific thermal

H,j
output q (see Figure A.2).
For σ/ϑ > 0,5 the temperature drop σ has to be calculated using Formula (11):
H,j j
  2
4⋅ ∆ϑϑ−∆
( )
V,,des H j
 
(11)
σϑ3⋅∆ ⋅ 1+ − 1
j H,j 
 
3⋅∆ϑ
 
H,j
 

Formulae (8) and (10) are the result of simplifications and therefore valid only under the specified

condition σ/Δϑ ≤ 0,5. Compared to this, Formulae (9) and (11) generally are applicable, i.e. for any

relationship σ/Δϑ .

If the value q according to Formula (5) under the aforementioned conditions cannot be obtained by

des

any pipe spacing, it is recommended to include a peripheral area or to provide supplementary heating

surfaces. The supplementary heating surfaces shall be selected to suit the purpose and the location. The

additional required thermal output Q is determined with Formula (12):
out
Q QQ−
out N,f F
(12)

In this case, the maximum specific thermal output q now may occur in another room.

max
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SIST EN 1264-3:2021
EN 1264-3:2021 (E)
4.1.3.4 Heating Mode — Determination of the water flow rate

The total thermal output of a floor heating system is composed of the specific thermal output q and the

downward heat loss q , see EN 1264-2:2021, Clause 8. The design heating water flow rate m of a

U H
heating circuit is calculated using Formula (13):
 
A ⋅ q R ϑϑ−
F o iu
m ⋅+1 + 
 
σ⋅⋅c R qR
W  uu 
(13)
where (also see Figure A.3):
specific heat capacity of water; c = 4 190 J/(kg⋅K) ;

upwards partial heat transmission resistance of the floor structure (see Formula (14));

R downwards partial heat transmission resistance of the floor structure (see Formula (15));

standard indoor room temperature in accordance with EN 1264-2;
ϑ indoor temperature of a room under the floor heated room.

With respect to the thermal resistances indicated in Figure A.3, Formula (14) and (15) are valid:

(14)
RR=++
oBλ;
RR=++R R + R (15)
u λ,,ins λ ceiling λ,plaster α,ceiling
where
1/α

is the heat transfer resistance on the heating floor surface; 1/α = 0,092 6 (m ∙K)/W;

R is the heat transfer resistance on the ceiling under the floor heated room;
α;ceiling
R = 0,17 (m ⋅K)/W.
α;ceiling

NOTE The calculation procedure above described on the basis of Figure A.3 is to understand as a principle

one. For other structures, an appropriate modification can be necessary.
4.1.4 Peripheral areas

Peripheral areas A , with an increased surface temperature (up to a maximum of 35 °C) are generally

situated along the outer walls of a room with a maximum width of 1 m. As described in 4.1.3, design of

peripheral areas is based on the higher limit curve (ϑ − ϑ ) = 15 K (see Figure A.1). In case a series

F,max i

circuit is formed with a heating circuit in the occupied area, the temperature drop in the peripheral area

shall be selected, so that the flow temperature, calculated from the lower limit curve, is not exceeded by

entry of the heating water from the peripheral area into the occupied area.
4 2
Using this value together with q in W/m in Formula (13), m is provided in kg/s.
---------------------- Page: 13 ----------------------
SIST EN 1264-3:2021
EN 1264-3:2021 (E)
4.2 Ceiling heating systems
4.2.1 Basic principles
4.2.1.1 Temperature difference between heating water and room

For ceiling heating systems, the specifications and Formula (1) given in 4.1.1.1 apply.

4.2.1.2 Characteristic curve

For ceiling heating systems, Formula (2) and the respective specifications given in 4.1.1.2, apply. The

gradient K is determined according to EN 1264-2 and EN 1264-5. For detailed information about the

procedure, see EN 1264-5.
4.2.1.3 Field of characteristic curves

In principle, the specifications given in 4.1.1.3 also apply. With respect to the calculation method (see

EN 1264-5), the field of characteristic curves should contain the values of R specified in 4.1.1.3, even

λ,B
though not all together are needed for practical application.
4.2.1.4 Limit curve

Physiological limitations concerning the surface temperatures of ceiling heating systems depend on

geometrical conditions, i.e. in practice on the respective application. Therefore, in this document only

average conditions can be taken into consideration. Consequently, it is emphasized, in practical

engineering the real conditions shall be taken into account.

For rooms with a height ≤ 2,7 m, the average surface temperature (see EN 1264-1:2020, 3.4.2) should

not exceed ϑ = 33 °C. As a result, the limit curve within the field of characteristic curves is a

F,m
horizontal straight line in the distance q (see below).

Using the heat transfer coefficient α = 6,5 W/(m ∙K) coming from EN 1264-5, the limit of the specific

output at a room temperature of 20 °C results to:
q = 85 W/m (rounded)

At room heights > 2,7 m the average surface temperature of the heated ceiling can be increased. If

values ϑ > 33 °C are used, the compliance with physiological limitations should be proved. In general,

F,m
refer to EN ISO 7730.
4.2.2 Boundary conditions
4.2.2.1 Flow pipes to adjacent rooms
The same procedure described in 4.1.2.1 applies.
4.2.2.2 Thermal insulation

To limit the heat flow through the ceiling to rooms above, the required thermal resistance of the

insulating layer R (in principle see Figure A.3) shall be at minimum in accordance with

λ,ins
EN 1264-4:2021, Table 1.
As for the rest, the content of 4.1.2.2 applies accordingly.
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SIST EN 1264-3:2021
EN 1264-3:2021 (E)
4.2.3 Design
4.2.3.1 Pressure loss

The maximum pressure loss per heating circuit should not exceed 250 mbar in order to limit the

electrical power consumption of the pump, e.g. by hydronic balancing (see EN 1264-4:2021, 4.1).

4.2.3.2 Design specific thermal
...

SLOVENSKI STANDARD
oSIST prEN 1264-3:2020
01-januar-2020
Ploskovni sistemi za ogrevanje in hlajenje z vodo - 3. del: Dimenzioniranje
Water based surface embedded heating and cooling systems - Part 3: Dimensioning
Raumflächenintegrierte Heiz- und Kühlsysteme mit Wasserdurchströmung - Teil 3:
Auslegung

Systèmes de surfaces chauffantes et rafraîchissantes hydrauliques intégrées - Partie 3 :

Dimensionnement
Ta slovenski standard je istoveten z: prEN 1264-3
ICS:
91.140.10 Sistemi centralnega Central heating systems
ogrevanja
oSIST prEN 1264-3:2020 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN 1264-3:2020
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oSIST prEN 1264-3:2020
DRAFT
EUROPEAN STANDARD
prEN 1264-3
NORME EUROPÉENNE
EUROPÄISCHE NORM
January 2020
ICS 91.140.10 Will supersede EN 1264-3:2009
English Version
Water based surface embedded heating and cooling
systems - Part 3: Dimensioning

Systèmes de surfaces chauffantes et rafraîchissantes Raumflächenintegrierte Heiz- und Kühlsysteme mit

hydrauliques intégrées - Partie 3 : Dimensionnement Wasserdurchströmung - Teil 3: Auslegung

This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee

CEN/TC 130.

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, 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.

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: Rue de la Science 23, B-1040 Brussels

© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 1264-3:2020 E

worldwide for CEN national Members.
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oSIST prEN 1264-3:2020
prEN 1264-3:2020 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

1 Scope .................................................................................................................................................................... 4

2 Normative references .................................................................................................................................... 4

3 Terms and definitions ................................................................................................................................... 4

4 Heating systems ............................................................................................................................................... 5

4.1 Floor heating systems .................................................................................................................................... 5

4.1.1 Basic principles ................................................................................................................................................ 5

4.1.2 Boundary conditions ...................................................................................................................................... 6

4.1.3 Design .................................................................................................................................................................. 8

4.1.4 Peripheral areas ........................................................................................................................................... 11

4.2 Ceiling heating systems .............................................................................................................................. 11

4.2.1 Basic principles ............................................................................................................................................. 11

4.2.2 Boundary conditions ................................................................................................................................... 12

4.2.3 Design ............................................................................................................................................................... 12

4.3 Wall heating systems .................................................................................................................................. 12

4.3.1 Basic principles ............................................................................................................................................. 12

4.3.2 Boundary conditions ................................................................................................................................... 13

4.3.3 Design ............................................................................................................................................................... 13

5 Cooling systems ............................................................................................................................................ 14

5.1 General ............................................................................................................................................................. 14

5.1.1 Basic principles ............................................................................................................................................. 14

5.1.2 Temperature differences .......................................................................................................................... 14

5.1.3 Regional dew point and standard indoor room temperature ..................................................... 14

5.1.4 Temperature difference between room and cooling water ......................................................... 14

5.1.5 Characteristic curves .................................................................................................................................. 14

5.1.6 Field of characteristic curves ................................................................................................................... 15

5.1.7 Limit curve ...................................................................................................................................................... 15

5.1.8 Thermal insulation ...................................................................................................................................... 15

5.2 Design ............................................................................................................................................................... 15

5.2.2 Design value of specific cooling load ..................................................................................................... 15

5.2.3 Determination of the design flow (inlet) temperature and the design specific

thermal output .............................................................................................................................................. 15

5.2.4 Determination of design cooling water flow rate ............................................................................. 17

Annex A (normative) Figures ................................................................................................................................ 18

Bibliography ................................................................................................................................................................. 20

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oSIST prEN 1264-3:2020
prEN 1264-3:2020 (E)
European foreword

This document (prEN 1264-3:2020) has been prepared by Technical Committee CEN/TC 130 “Space

heating appliances without integral heat sources”, the secretariat of which is held by UNI.

This document is currently submitted to the CEN Enquiry.
This document will supersede EN 1264-3:2009.

This document, Water based surface embedded heating and cooling systems, consists of the following

parts:
— Part 1: Definitions and symbols;

— Part 2: Floor heating: Methods for the determination of the thermal output using calculations and

experimental tests;
— Part 3: Dimensioning;
— Part 4: Installation;

— Part 5: Determination of the thermal output for wall and ceiling heating and for floor, wall and ceiling

cooling.
The main changes with respect to the previous edition are listed below:
a) Clarification of the scope;
b) Improved wording, especially the term “prove method”;
c) Deleted the Note in 4.1.2.2;
d) Added new subclauses 4.1.3.1, 4.2.3.1, 4.3.3.1 and 5.2.1.1 Pressure loss;

e) Modified the maximum average surface temperature for ceiling heating systems in 4.2.1.4;

f) Replaced Figures 1 and 3 with Figures A.2 and A.3.
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oSIST prEN 1264-3:2020
prEN 1264-3:2020 (E)
1 Scope

EN 1264 covers surface embedded heating and cooling systems installed in buildings, residential and

non-residential (e.g. office, public, commercial and industrial buildings) and focuses on systems

installed for the purpose of thermal comfort.

EN 1264 applies to water based heating and cooling systems embedded into the enclosure surfaces of

the room to be heated or to be cooled. It also applies as appropriate to the use of other heating media

instead of water.

EN 1264 applies to identify standardized product characteristics by calculation and testing the thermal

output of heating for technical specifications and certification. For the design, construction and

operation of these systems, EN ISO 11855 applies.

The systems covered in EN 1264 are adjoined to the structural base of the enclosure surfaces of the

building, mounted directly or with fixing supports. It does not cover ceiling systems mounted in a

suspended ceiling with a designed open air gap between the system and the building structure which

allows the thermally induced circulation of the air. The thermal output of these systems can be

determined according to ISO 18566, EN 14037 and EN 14240.

EN 1264-3 deals with the use in practical engineering of the results coming from EN 1264-2 and

EN 1264-5.

For heating systems, physiological limitations are taken into account when specifying the surface

temperatures. In the case of floor heating systems the limitations are realized by a design based on the

characteristic curves and limit curves determined in accordance with EN 1264-2.

For cooling systems, only a limitation with respect to the dew point is taken into account. In

predominating practice, this means that physiological limitations are included as well.

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.

EN 1264-1:2019, Water based surface embedded heating and cooling systems - Part 1: Definitions and

symbols

prEN 1264-2:2019, Water based surface embedded heating and cooling systems — Part 2: Floor heating:

Methods for the determination of the thermal output using calculations and experimental tests

prEN 1264-4:2019, Water based surface embedded heating and cooling systems — Part 4: Installation

EN 1264-5, Water based surface embedded heating and cooling systems - Part 5: Heating and cooling

surfaces embedded in floors, ceilings and walls - Determination of the thermal output

EN 12831 (all parts), 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
3 Terms and definitions

For the purposes of this document, the terms and definitions given in EN 1264-1:2019 apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

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oSIST prEN 1264-3:2020
prEN 1264-3:2020 (E)
— ISO Online browsing platform: available at http://www.iso.org/obp
— IEC Electropedia: available at http://www.electropedia.org/
4 Heating systems
4.1 Floor heating systems
4.1.1 Basic principles
4.1.1.1 Temperature difference between heating water and room

The temperature difference between the heating water and the room is calculated using Formula (1),

see also EN 1264-2. In this equation, the effect of the temperature drop of the heating water is taken

into account.
ϑ −ϑ
V R
Δϑ = (1)
ϑ −ϑ
V i
ϑϑ−
4.1.1.2 Characteristic curve

The characteristic curve describes the relationship between the specific thermal output q of a system

and the required temperature difference between heating water and room Δϑ . For a simplification, the

specific thermal output is taken directly proportional to the temperature difference:

qK= ⋅∆ϑ (2)
H H

where the gradient is the equivalent heat transmission coefficient determined according to part 2 of this

European Standard.
4.1.1.3 Field of characteristic curves

The field of characteristic curves of a floor heating system with a specific pipe spacing T shall at least

contain the characteristic curves for values of the thermal resistance R = 0 (m ∙K)/W,

λ,B
2 2 2

R = 0,05 (m ∙K)/W, R = 0,10 (m ∙K)/W and R = 0,15 (m ∙K)/W in accordance with part 2 of

λ,B λ,B λ,B

this European Standard (see Figure A.1). Values of R > 0,15 (m ∙K)/W shall not be used if possible.

λ,B
4.1.1.4 Limit curves

The limit curves in the field of characteristic curves describe in accordance with part 2 of this European

Standard the relationship between the specific thermal output q and the temperature difference Δϑ

between the heating water and the room in the case where the physiologically agreed limit values of

surface temperatures ϑ = 29 °C (occupied area) or ϑ = 35 °C (peripheral area) are reached .

F,max F,max

For bathrooms (ϑ = 24 °C) the limit curve for (ϑ − ϑ ) = 9 K also applies. For design purposes, i.e.

I F,max i

the determination of design values of the specific thermal output and the associated temperature

difference between heating water and room, the limit curves are valid for the temperature drop σ of the

heating water in a range of
0 K < σ ≤ 5 K
) National regulations may limit these temperatures to lower values.
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oSIST prEN 1264-3:2020
prEN 1264-3:2020 (E)

The limit curves are used to specify the maximum permissible flow temperature (see Clause 4.1.3.2 and

Figure A.2).
4.1.1.5 Thermal inertia

The difference between the minimum and the maximum surface temperature of a floor heating system

is low. This means for design purposes that no consideration of thermal inertia is required.

4.1.2 Boundary conditions
4.1.2.1 Flow pipes to adjacent rooms

The heat output of service pipes, not serving rooms through which they pass, shall be limited by careful

design, or by use of thermal insulation coverings, so that any room temperature should not be increased

substantially. The heat output of service pipes passing through the room in question to adjacent rooms

is taken into account if the same type of room usage can be assumed.
4.1.2.2 Thermal insulation

To limit the heat flow through the floor to rooms below, the required thermal resistance of the

insulating layer R (see Figure A.3) shall be at minimum in accordance with of EN 1264-4 , Table 1.

λ,ins
It is calculated according to Formula (3).
ins
R = (3)
λ,ins
ins
where
s is the thickness of the insulating layer in m;
ins
λ is the thermal conductivity of the insulating layer in W/(m∙K).
ins

Depending on the construction of the floor heating system, the effective thickness of the insulating layer

s is determined differently:
ins

For floor heating systems with flat thermal insulating panels (see Figure 1), s is identical with the

ins
thickness of the thermal insulating panel.

For floor heating systems with profiled thermal insulating panels (see Figure 3), a surface-related

weighted calculation is made for the effective thickness of the insulating layer s :

ins
s ⋅ T− D + s ⋅ D
( )
s = (4)
ins

For profiled thermal insulating panels shaped differently from that shown in Figure 3, the average

effective thickness of the insulating layer shall be calculated with an accordant application of

Formula (4).

The thermal resistance R of the insulating layers of the heating/cooling system shall be calculated

λ,ins
as reported in EN 1264-4, Table 1.

This calculation can be done with the assumption that the thermal insulation is continuous parallel to

the pipes. If the thermal insulation is not continuous (see Figure 2), a measurement shall be done.

2) National regulations may vary the requirements given in Table 1 of EN 1264-4.
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oSIST prEN 1264-3:2020
prEN 1264-3:2020 (E)
Figure 1 — Average thickness of insulating layer flat insulating panels
Key
1 Floor covering
2 Weight bearing and thermal diffusion layer
3 Thermal insulation with studs
4 Acoustic insulation (if present)
5 Structural base
Figure 2 — Type A and Type C. System with studs
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oSIST prEN 1264-3:2020
prEN 1264-3:2020 (E)

Figure 3 — Average thickness of insulating for layer for profiled insulating panels

4.1.3 Design
4.1.3.1 Pressure loss

The maximum pressure loss per heating circuit should not exceed 250 mbar in order to limit the

electrical power consumption of the pump, e.g. by hydronic balancing (see prEN 1264-2:2019, 4.1).

4.1.3.2 Design value of specific thermal output

The design value q to design a floor heating system for a room is equal to the standard heat load Q

des N,f
(see part 1 of this Standard) divided by the heating surface A :
Nf,
q = (5)
des

The standard heat load Q shall be calculated in accordance with EN 12831 (all parts). Normally, the

N,f

heat output Q of the floor heating system shall be equivalent to the standard heat load Q . If this is

F N,f
not possible, additional heating surfaces shall be used, see Formula (12).

The design thermal output Q of the entire heating surface A is calculated using Formula (6):

F F
Q q⋅ A (6)

Where peripheral area is used, q shall be distributed between the peripheral area A and the occupied

area A according to a surface weighted calculation (see also Clause 4.1.4):
(7)
qq= ⋅ + ⋅ q
where:
q is the specific thermal output of the occupied area;
q is the specific thermal output of the peripheral area.
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oSIST prEN 1264-3:2020
prEN 1264-3:2020 (E)
4.1.3.3 Determination of the design flow temperature

The design flow temperature is determined for the room (or the rooms respectively) with the maximum

specific thermal output q = q (excluding bathrooms). In the rooms being heated, it is assumed

max des

that floor coverings with a uniform thermal conduction resistance are used. Generally for the design of

floor heating systems in residential rooms, uniform floor coverings with R = 0,10 (m ⋅K)/W are

λ,B
assumed. In the case of using higher values R , these values shall be taken.
λ,B

For the room used for design, the temperature drop of the heating water is specified to σ ≤ 5 K. If

necessary, a subdivision of this room into heating circuits should be performed. Under these conditions,

the maximum value q may reach until the limit value q of the specific thermal output (see

max G
Figure A.2) .

For the room with q , a pipe spacing is chosen with which q remains less or equal to the limit

max max

value q (q ≤ q , see Figure A.2). For this, small pipe spacing is recommended. In case of q ≤ q ,

G max G max G
design values of the temperature difference between flow heating water and room

Δϑ ≤ Δϑ + 2,5 K are permitted (see Figure A.2). The maximum permissible temperature

V,des H,G
difference between flow and room comes to:
Δϑ Δϑ+ where Δϑ≤∆ϑ (8)
V,,des H des H,des H,G
Formula (8) applies if σ/Δϑ ≤ 0,5. If σ/Δϑ > 0,5, Formula (9) applies:
H H
Δϑ Δϑ++ (9)
V,,des H des
2 12⋅ Δϑ
H,des

The temperature drop σ in Formula (8) and in Formula (9), in Figure A.2 is designated σ .

des

The result of Formula (8) or Formula (9) provides the design flow temperature ϑ = Δϑ + ϑ .

V,des
...

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