Bsi bs en 01264 2 2008 + a1 2012 (2013)

NORME EUROPÉENNE EUROPÄISCHE NORM November 2012 English Version Water based surface embedded heating and cooling systems - Part 2: Floor heating: Prove methods for the determination of

ICS 91.140.10

Water based surface

embedded heating and

cooling systems

Part 2: Floor heating: Prove methods

for the determination of the thermal

output using calculation and test

methods

This British Standard

was published under the

authority of the Standards

Policy and Strategy

This publication does not purport to include all the necessary provisions

of a contract Users are responsible for its correct application

Compliance with a British Standard cannot confer immunity from legal obligations.

Amendments/corrigenda issued since publication

28 February 2013 Implementation of CEN amendment A1:2012

This British Standard was

published under the authority

of the Standards Policy and

This British Standard is the UK implementation of EN 1264-2:2008+A1:2012

It supersedes BS EN 1264-2:2008, which is withdrawn

The start and finish of text introduced or altered by amendment is indicated

in the text by tags Tags indicating changes to CEN text carry the number ofthe CEN amendment For example, text altered by CEN amendment A1 isindicated by 

NORME EUROPÉENNE

EUROPÄISCHE NORM

November 2012

English Version

Water based surface embedded heating and cooling systems -

Part 2: Floor heating: Prove methods for the determination of the

thermal output using calculation and test methods

Systèmes de surfaces chauffantes et rafraîchissantes

hydrauliques intégrées - Partie 2 : Chauffage par le sol:

Méthodes de démonstration pour la détermination de

l'émission thermique utilisant des méthodes par le calcul et

à l'aide de méthodes d'essai

Raumflächenintegrierte Heiz- und Kühlsysteme mit Wasserdurchströmung - Teil 2: Fußbodenheizung: Prüfverfahren für die Bestimmung der Wärmeleistung unter Benutzung von Berechnungsmethoden und experimentellen Methoden

This European Standard was approved by CEN on 13 September 2008 and includes Amendment 1 approved by CEN on 1 October 2012 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

C O M IT É E U R O P É E N D E N O R M A LIS A T IO N EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels

© 2012 CEN All rights of exploitation in any form and by any means reserved Ref No EN 1264-2:2008+A1:2012: E

Contents

Foreword 3



Introduction 4



1





2





3





4





5





6





6.1





6.2





6.3





6.4





6.5





6.6





6.7





7





8





9





10





11





12





12.1





12.2





12.3





12.4





12.5





Annex A (normative) Figures and tables 23



Annex B (informative) Test procedure for the determination of parameters for application in EN 15377-1:2008 Annex C 40



Annex C (informative) !!Influence of the heat exchange coefficient inside the pipe on the specific thermal output"" 43



Bibliography 44



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 This document includes Amendment 1 approved by CEN on 1 October 2012

This document !supersedes EN 1264-2:2008"

The start and finish of text introduced or altered by amendment is indicated in the text by tags ! "

This European Standard, Water based surface embedded heating and cooling systems, consists of the

following parts:

 Part 1: Definitions and symbols;

 Part 2: Floor heating: Prove methods for the determination of the thermal output using calculation and

Introduction

This European Standard is based on the realisation that in the field of commercial trade, the thermal output

of heating and cooling systems represents the basis of rating In order to be able to evaluate and compare different heating and/or cooling systems, it is, therefore, necessary to refer to values determined using one single, unambiguously defined method The basis for doing so are the prove methods for the determination

of the thermal output of floor heating systems specified in Part 2 of this European Standard In analogy to the European Standard EN 442-2 (Radiators and convectors — Part 2: Test methods and rating), these prove methods provide characteristic partial load curves under defined boundary conditions as well as the characteristic output of the system represented by the standard thermal output together with the associated standard temperature difference between the heating medium and the room temperature

1 Scope

This European Standard specifies the boundary conditions and the prove methods for the determination of the thermal output of hot water floor heating systems as a function of the temperature difference between the heating medium and the room temperature

This standard shall be applied to commercial trade and practical engineering if proved and certifiable values

of the thermal output shall be used

This European Standard applies to heating and cooling systems embedded into the enclosure surfaces of the room to be heated or to be cooled This Part of this European Standard applies to hot water floor heating systems Applying of Part 5 of this European Standard requires the prior use of this Part of this European Standard Part 5 of this European Standard deals with the conversion of the thermal output of floor heating systems determined in Part 2 into the thermal output of heating surfaces embedded in walls and ceilings as well as into the thermal output of cooling surfaces embedded in floors, walls and ceilings

The thermal output is proved by a calculation method (Clause 6) and by a test method (Clause 9) The calculation method is applicable to systems corresponding to the definitions in EN 1264-1 (type A, type B, type C, type D) For systems not corresponding to these definitions, the test method shall be used The calculation method and the test method are consistent with each other and provide correlating and adequate prove results

The prove results, expressed depending on further parameters, are the standard specific thermal output and the associated standard temperature difference between the heating medium and the room temperature as well as fields of characteristic curves showing the relationship between the specific thermal output and the temperature difference between the heating medium and the room

2 Normative references

!The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application For dated references, only the edition cited applies For undated references, the latest edition of the referenced document (including any amendments) applies

EN 1264-1:2011, Water based surface embedded heating and cooling systems  Part 1: Definitions and symbols

EN 1264-3:2009, Water based surface embedded heating and cooling systems  Part 3: Dimensioning"

3 Definitions and symbols

For the purposes of this document, the terms and definitions given in !EN 1264-1:2011" apply

4 Thermal boundary conditions

A floor heating surface with a given average surface temperature exchanges the same thermal output in any room with the same indoor room temperature (standard indoor room temperature ϑi) It is, therefore, possible

to give a basic characteristic curve of the relationship between specific thermal output and average surface temperature that is independent of the heating system and applicable to all floor heating surfaces (including those having peripheral areas with greater heat emissions) (see Figure A.1)

In contrast, every floor heating system has its own maximum permissible specific thermal output, the limit

specific thermal output, qG This output is calculated for an ambient (standard) indoor room temperature

ϑi = 20 °C The other condition is the maximum surface temperature ϑF, max = 29 °C1) at temperature drop between supply and return of the heating medium σ = 0 K The maximum specific thermal output for the peripheral area will be achieved at a maximum surface temperature ϑF, max = 35 °C2) and σ = 0 K

For the calculation and for the test procedure, the centre of the heating surface is used as the reference point

for ϑF, max, regardless of system type

The average surface temperature ϑF, m, determining the specific thermal output (see basic characteristic curve) is linked with the maximum surface temperature In this context, ϑF, m < ϑF, max always applies

The achievable value ϑF, m depends on both the floor heating system and the operating conditions (temperature drop σ = ϑV – ϑR, downward thermal output qu and heat resistance of the floor covering Rλ, B) The calculation of the specific thermal output is based on the following conditions:

 The heat transfer at the floor surface occurs in accordance with the basic characteristic curve

 The temperature drop of the heating medium σ = 0; the extent to which the characteristic curve depends

on the temperature drop, is covered by using the logarithmically determined temperature difference between the heating medium and the room ∆ϑH [3] (see Equation (1))

 Turbulent pipe flow: mH/di > 4 000 kg/(h ⋅ m)

 There is no lateral heat flow

 The heat-conducting layer of the floor heating system is thermally decoupled by thermal insulation from the structural base of the building

NOTE The aforementioned last condition does not concern the test procedure of Clause 9

5 Documents for testing

The system supplier's documents are taken as the basis for the determination of the thermal output The following documents shall be provided:

 Installation drawing (section) of the floor heating system, covering two pipe spacing, including the peripheral area and giving information on the materials used (if necessary, the test results regarding the heat conductivity values of the materials shall be provided)

 Technical documentation of the system

This information shall contain any details necessary for the calculation of the construction customary on site

It shall be submitted to the installer in the same form

With a member of the testing body present, a demonstration surface of approximately 2 m × 2 m is constructed to represent the actual construction used on site

1) National regulations may limit this temperature to a lower value

6 Calculation of the specific thermal output (characteristic curves and limit

curves)

6.1 General approach (see [2], [4])

The specific thermal output q at the surface of a floor is determined by the following parameters:

 Pipe spacing T;

 Thickness su and heat conductivity λE of the layer above the pipe;

 Heat conduction resistance Rλ, B of the floor covering;

 Pipe external diameter D = da, including the sheathing (D = dM) if necessary and the heat conductivity of the pipe λR or the sheathing λM In case of pipes having non-circular cross sections, the equivalent diameter of a circular pipe having the same circumference shall be used in the calculation (the screed covering shall not be changed) Thickness and heat conductivity of permanently mounted diffusion barrier layers with a thickness up to 0,3 mm need not be considered in the calculation In this case,

D = da shall be used;

 Heat diffusion devices having the characteristic value KWL in accordance with 6.3;

 Contact between the pipes and the heat diffusion devices or the screed, characterised by the factor aK

The specific thermal output is proportional to (∆ϑH)n, where the temperature difference between the heating medium and the room temperature is:

∆ϑH =

i R

i V

R V

ϑϑ

ϑϑ

ϑϑ

−

−

−ln

A distinction shall be made between systems, where the pipes are installed inside or below the screed or

wood floors, and systems with surface elements (plane section systems) For usual constructions,

Equation (3) applies directly For systems with additional devices for heat distribution, for air filled hollow

sections or for other components influencing the heat distribution, the thermal output is determined

experimentally in accordance with Clause 9

6.2 Systems with pipes installed inside the screed (type A and type C)

For these systems (see Figure A.2), the characteristic curves are calculated in accordance with

The power product given before the temperature difference ∆ϑH is called the equivalent heat transmission

coefficient KH, which leads to the following abbreviated form of the expression:

where

B = B0 = 6,7 W/(m2 K) for a pipe heat conductivity λR = λR, 0 = 0,35 W/(m2 K) and a pipe wall

thickness sR = sR, 0 = (da – di)/2 = 0,002 m

For other materials with different heat conductivities or for different pipe wall thicknesses, or for sheathed

pipes, B shall be calculated in accordance with 6.6

For a heating screed with reduced moisture addition, λE = 1,2 W/(m2 K) shall be used This value is also

applicable to heating screeds If a different value is used, its validity shall be checked

aB is the floor covering factor in accordance with the following equation:

B λ, E u u u

B

R s

s a

++

+

=

λα

λα

0 ,

0 ,

0 ,

Rλ, B is the heat conduction resistance of the floor covering, in m2 ⋅ K/W;

λE is the heat conductivity of the screed, in W/(m ⋅ K);

aT is a spacing factor in accordance with Table A.1; aT = f (Rλ, B);

au is a covering factor in accordance with Table A.2; au = f (T, Rλ, B);

aD is the pipe external diameter factor in accordance with Table A.3; aD = f (T, Rλ, B)

075,0

T is the pipe spacing;

D is the external diameter of the pipe, including sheathing, where applicable;

su is the thickness of the screed covering above the pipe

For a pipe spacing T > 0,375 m, the specific thermal output is approximately calculated using

T q

where

q0,375 is the specific thermal output, calculated for a spacing T = 0,375 m

For coverings above the pipe su ≤ 0,065 m as well as for coverings above the pipe 0,065 m < su ≤ s (for u* s *u

see below), Equation (4a) applies directly The value of s depends on the pipe spacing as follows: u*

For a spacing T ≤ 0,200 m, s = 0,100 m applies *u

For a spacing T > 0,200, s = 0,5 T applies In this relation, always the actual spacing T shall be used, even u*

if the calculation is done in accordance with Equation (9)

For coverings above the pipe su > s , Equation (4b) shall be used In this case, the equivalent heat *u

transmission coefficient shall be determined in accordance with the following equation:

E

u u H

K

s s H,

−+

K = is the power product from Equation (4a), calculated for a covering s above the u*

pipe

The limit curves are calculated in accordance with 6.5

6.3 Systems with pipes installed below the screed or timber floor (type B)

For these systems (see Figure A.3), the variable thickness su of the weight bearing layer and its variable heat

conductivity λE are covered by the factor au The pipe diameter has no effect However, the contact between

the heating pipe and the heat diffusion device or any other heat distribution device is an important parameter

In this case, the characteristic curve is calculated as follows:

q = B ⋅ aB⋅ T

Tm

where

B = B0 = 6,5 W/(m2 ⋅ K) under the conditions given for Equations (4a) and (4b);

aT is the pipe spacing factor in accordance with Table A.6; aT = f (su/λE);

mT see Equation (6);

au is the covering factor, which is calculated in accordance with the following equation:

E u u u u

λα

λα

s

s a

0 ,

aWL is the heat conduction factor (see Tables A.8); aWL = f (KWL, T, D)

The following applies to the characteristic value KWL:

0,125u u EWL

bu = f (T) shall be taken from Table A.7;

sWL ⋅ λWL is the product of the thickness and the heat conductivity of the heat diffusion device;

su ⋅ λE is the product of the thickness and the heat conductivity of the screed or timber covering

If the width L of the heat diffusion device is smaller than the pipe spacing T, the value aWL, L = T determined in

accordance with Tables A.8, shall be corrected as follows:

aWL = aWL, L = T – (aWL, L = T – aWL, L = 0)[1 – 3,2(L/T) + 3,4 (L/T)2 – 1,2(L/T)3] (14)

The heat conduction factors aWL, L = T and aWL, L = 0 shall be taken from Tables A.8a to A.8f For L = T, the

tables with KWL in accordance with Equation (13) apply directly, for L = 0, the tables apply with KWL

determined in accordance with Equation (13) with sWL = 0

aK is the correction factor for the contact in accordance with Table A.9; aK = f (T)

The correction factor for the contact aK covers additional heat transmission resistances due to cases where

there is only spot or line contact between the heating pipe and the heat diffusion device These resistances

depend on the manufacturing tolerances of the pipes and heat conduction devices as well as on the care

taken in installing them, and are, therefore, subject to fluctuations in individual cases For this reason,

Table A.9 gives a calculated average value for aK

aB is the floor covering factor:

)T(fRaaaaB

with f (T) = 1 + 0,44 T

The limit curves are calculated in accordance with 6.5

6.4 Systems with surface elements (plane section systems, type D)

For floors covered with surface elements (see Figure A.4), the following equation applies:

au is the covering factor in accordance with Equation (12);

aB is the floor covering factor:

B λ, T u

R a a B

⋅

⋅

⋅+

=

1

6.5 Limits of the specific thermal output

The procedure for the determination of the limits of the specific thermal output is shown in principle within

Figure A.5

The limit curve (see Figure A.5) gives the relationship between the specific thermal output and the

temperature difference between the heating medium and the room for cases where the maximum

permissible difference between surface temperature and indoor room temperature (9 K or 15 K respectively)

is achieved

The limit curve is calculated using the following expression in form of a product:

G H G G

BG is a coefficient in accordance with Table A.4a (applicable to su/λE ≤ 0,079 2) and Table A.4b

(applicable to su/λE > 0,079 2) for type A and type C systems or in accordance with Table A.10 for

type B systems; or BG = 100 W/(m2 ⋅ K) for systems with surface elements;

nG is an exponent in accordance with Table A.5a (applicable to su/λE ≤ 0,079 2) and Table A.5b

(applicable to su/λE > 0,079 2) for type A and type C systems or in accordance with Table A.11 for

type B systems; or nG = 0 for systems with surface elements;

ϕ is a factor for the conversion to any values of the temperatures ϑF, max and ϑi

ϕ

1 , 1 o

=

The limit temperature difference between the heating medium and the room ∆ϑH, G is calculated as follows

from the intersection of the characteristic curve with the limit curve (see Figure A.5):

1

1

G i

i

G G

H,

Π

n m

i a B

For type A and type C systems, the above mentioned Equations (18) and (20) apply directly to pipe

spacing T ≤ 0,375 m In case of spacing T > 0,375 m, for these systems the following conversion shall be

made:

G G

T q

G G

H, G

H, =∆ ;0,375 ⋅ f

where

qG; 0,375 is the limit specific thermal output, calculated for a spacing T = 0,375 m;

ϑH, G; 0,375 is the limit temperature difference between the heating medium and the room,

calculated for a spacing T = 0,375 m

The factor fG shall be determined as follows, depending on the ratio su/T:

For su/T ≤ 0,173, fG = 1 applies

For su/T > 0,173, the following equation applies:

T q

e T q

q q

f

T s

375,0)375,0(

375 , 0

) 173 , 0 / ( 20 375

, 0

G

u

(23)

where

qG, max is the maximum permissible specific thermal output in accordance with Table A.12,

calculated for an isothermal surface temperature distribution using the basic characteristic curve (Figure A.1), with (ϑF, m – ϑi) = (ϑF, max – ϑi)

For type B systems, Equations (18) and (20) apply directly, when the pipe spacing T and the width of the heat diffusion device L are the same For L < T, the value of the specific thermal output qG, L = T, calculated in accordance with Equation (18), shall be corrected using the following equation:

T L G, T L WL,

aWL, L = T is the heat conduction factor in accordance with Table A.8;

aWL is the heat conduction factor, calculated in accordance with Equation (14)

The limit temperature difference between the heating medium and the room ∆ϑH, G remains unchanged as

with L = T

For ∆ϑF, max – ∆ϑi = 9 K, ϕ = 1 and Rλ, B = 0, the limit specific thermal output qG is designated as standard

specific thermal output qN, and the associated limit temperature difference between the heating medium and the room ∆ϑH, G is designated as standard temperature difference between the heating medium and the room ∆ϑN (see Figure A.5) These values serve as characteristic values in the system comparison

The maximum possible value of the specific thermal output qG, max for an isothermal surface temperature distribution is represented by the ordinate value for ϑF, m = ϑF, max on the basic characteristic curve (see Figure A.1)

Table A.12 gives values for qG, max, depending on the maximum floor surface temperature ϑF, max and the standard indoor room temperature ϑi

If (due to calculation and interpolation inaccuracies as well as linearization) higher values for qG than qG, maxare calculated using Equations (18), (21), (24), qG, max has to be used

6.6 Influence of pipe material, pipe wall thickness and pipe sheathing on the specific

thermal output

The factors B0 are specified in Equations (4a) and (11) for a pipe heat conductivity λR, 0 = 0,35 W/(m ⋅ K), a

wall thickness sR, 0 = 0,002 m For other materials (see Table A.13) with a heat conductivity of the pipe material λR or other wall thicknesses sR, the factor B shall be calculated using:

( )

−

−

dln2

1s

2d

dln

2

1

R, a

a R

R a

a R

If the pipe has an additional sheathing with an external diameter dM, an internal diameter da and a heat conductivity of the sheathing λM, the following equation applies:

( )

⋅ π

−

− λ

+

d ln 2

1 s

2 d

d ln 2

1 d

d ln

2

1

R, M

M R,

R a

a R

a

M M

Any oxygen diffusion barrier layers with thicknesses ≤ 0,3 mm need not be considered In this case, Equation (25) shall be used

In cases with air gaps within the sheathing, Equation (26) only applies if a valid average value λM including the air gaps is available

6.7 Heat conductivity of screed with inserts

Where system plates for type A systems are used, the heat conduction in the screed is changed by inserts (such as attachment studs or similar components) If their volume fraction in the screed amounts to

15 % ≥ ψ ≥ 5 %, an effective heat conductivity λE′ of the component is to be expected

E

where

λE is the heat conductivity of the screed;

λW is the heat conductivity of the attachment studs;

ψ is the volume fraction of the attachment studs in the screed

7 Heat conductivity of the materials

For carrying out the calculation, the heat conductivities specified in Table A.13 are used If the materials listed in Table A.13 are used, the values of this table shall be taken For other materials, the heat conductivities shall be taken from effectual European Standards if available or shall be verified by a certificate prepared by an approved testing body

8 Downward heat loss

The downward specific heat loss of floor heating systems towards rooms under the system is calculated in accordance with the following equation !(see Figure A.5 of EN 1264-3:2009)":

)q

R(R

qU downward specific heat loss

q specific thermal output of the floor heating system

RU downwards partial heat transmission resistance of the floor structure

RO upwards partial heat transmission resistance of the floor structure

ϑi standard indoor room temperature of the floor heated room

With respect to !Figure A.5 of EN 1264-3:2009" the following applies:

U

U B ,

R1

R

λ++

For a more detailed calculation of the downward heat loss, see Part 3 of this European Standard

9 Test procedure for the determination of the thermal output of systems that

cannot be calculated in accordance with Clause 6

For constructions which do not correspond to the basic construction of the types A, B, C or D, or in case of

dimensions or material data outside the scope of the calculation method, the specific thermal output shall be

determined by testing (experimentally) as follows

A test sample consisting of at least three heating pipes, with the pipe spacing to be tested, in accordance

with the system design of the floor heating to be investigated is positioned in the testing equipment according

to Figure A.6 [4] The size of the test sample shall be approximate 1 m × 1 m on appointment with the test

laboratory and shall cover preferably three-pipe spacing In Figure A.6 the cooling plates simulate the room

above the floor heating system (see key 1), i.e the temperature of the heated room ϑi, and the room below

(see key 4) For the cooling plates the construction according to Figure A.7 is recommended consisting of

panel radiators with flat tubes in which disconnecting points realize the appropriate cooling water flow The

heat transfer resistance 1/α at the floor surface is simulated by the heat transfer layer (see key 2).The two

lateral heating pipes serve as a protection field to enable the optimum undisturbed temperature field around

the central pipe The heat transfer resistance 1/α at the floor surface, given by the basic characteristic curve,

is replaced by the heat conduction resistance s/λ of the heat transfer layer (see key 2) of equal magnitude

(mean value):

The tolerance on the value s/λ is ± 0,01 m2⋅ K/W

The temperature drop of the sample ϑV –ϑR (see Figure A.8) shall not exceed 0,5 K The temperature rise of

the water flow in the cooling plates ϑC,out – ϑC,in (see Figure A.7) shall not exceed 0,3 K

ϑV is the heat water supply temperature of the sample

ϑR is the heat water return temperature of the sample

ϑC,out is the outlet cooling water temperature of the cooling plates

ϑC,in is the inlet cooling water temperature of the cooling plates

Temperatures shall be measured with a permissible uncertainty of ± 0,1 K

The temperature field of the floor surface is measured in order to determine the values ϑF, m andϑF, max The measurement shall be carried out in the undisturbed area around the central pipe or central pipes and, at least, over the width of one pipe spacing If possible, it is recommended using two pipe spacing The configuration of the measuring points using two pipe spacing should be done in principle as shown in Figure A.8 For an example, with the measuring values ϑF, i (see Figure A.8) the calculation procedure is as follows:

16/)2

11 Fi,

8

2 Fi,m

,

+ϑ+ϑ

=

2

14 , F 5 , F max

ϑ is the maximum floor surface temperature

In the case of not feasible values of the measured temperature field caused by inhomogeneity of the screed, another part of the surface shall be taken

NOTE 1 Because of the fact that the temperature drop of the sample ϑV –ϑR is very little and the fact that the

temperature measurements shall be carried out in the undisturbed area around the central pipe no variation is necessary depending on the laying system (spirally or meandering)

NOTE 2 The explanations above refer to the most usual case that the floor heating system is characterized by the repetition of the pipe spacing The test sample in Figure A.6 which is symmetrical with respect to the central pipe is based on this fact If another dimension characterizes the system the procedure has to be adjusted

In a first working step the test is realized for Rλ,B = 0

The average floor surface temperature ϑF, m is determining the specific thermal output, and the maximum floor surface temperature ϑF, max is limiting the thermal output The measurement is carried out when steady state conditions are reached and a temperature of both cooling plates of ϑi = 20 °C ± 0,5 K is maintained Under these conditions the average temperature of the heating medium ϑH is set to achieve a maximum floor surface temperature of ϑF, max = 29 °C (i.e ϑF, max – ϑi = 9 K), and in this case the difference between the average temperature of the heating medium and the temperature of the cooling plates ϑH - ϑi = ∆ϑH =

∆ϑN (standard value) applies

If it is not possible to set the value of the temperature difference (ϑF, max – ϑi) exactly to 9 K, a value slightly below and a value slightly above 9 K shall be set and the results used to formulate a mean value

Given that (ϑF, max – ϑi) = 9 K is maintained and the average temperature difference of the floor surface and the room (ϑF, m – ϑi) is determined, this temperature difference is used within the basic characteristic curve (Figure A.1) and gives the standard specific thermal output:

)1(

1

)(

−

′

′+

=

=

H

N H, B λ,

B λ,

N H, B

λ, H

H

K

K R R

K R

K

Using Equation (35), the gradients of the characteristic curves KH(Rλ, B) can be calculated for thermal

resistances Rλ, B = 0,05 m2 ⋅ K/W, 0,10 m2 ⋅ K/W and 0,15 m2 ⋅ K/W

In order to establish the gradient of the characteristic curve K′ to be used in Equation (35), another H

measurement like the one described above for Rλ, B = 0, has to be carried out, but with a resistance of the floor covering R′λ,B = 0,15 m2 ⋅ K/W ± 0,01 m2 ⋅ K/W By doing this measurement, the limit specific thermal output q′ and the limit temperature difference ∆ G ϑH,′ Gare determined, which give the needed value K′ : H

G H, B

λ, H

K

In accordance with the following Equation (37), the limit temperature differences ∆ϑH, G for the heat

conduction resistances Rλ, B > 0 are given by the interfaces of the characteristic curves and the limit curve

resulting from the measurement data and the gradient KH of the characteristic curve calculated from Equation (35):

∆ϑH, G = ϕ ⋅

G

G

q q

q q

′+

G H N N

ϑϑ

For systems having several spacing, the maximum and the minimum spacing as well as sufficient intermediate spacing to achieve a spacing ratio not exceeding 1:2, shall be tested in accordance with the method described Values for spacing not tested this way, shall be determined by interpolation using suitable polynomials The results shall be presented in a prove report as specified in Clause 11

10 Test procedure for the determination of the effective thermal resistance of

carpets

If carpets are used for floor covering a special problem occurs Because of the surface structure of carpets their thermal resistance Rλ,B cannot be determined by the two plate method as generally used for other materials This circumstance is primary due to the pressure which takes effect on a carpet sample if using this method Further a possible change of the heat exchange coefficient due to the surface structure has to

be considered For these reasons the effective (see below) thermal resistance Rλ,B of carpets shall be determined by a one plate method as described in this chapter

The equipment for testing is shown in Figures A.9, A.10 and A.11 The dimensions should be at least 1m x 1m The equipment is situated in the centre of the floor of a test booth in accordance with EN 14037-2 (Figure A.9), i.e in a room with constant controlled ambient room temperatures Between the test equipment and the floor of the booth insulation is recommended (key 3) The essential parts of the equipment are a heating plate (key 2) in accordance with the cooling plate in Figure A.7, a heat flow meter plate (key 1) with a well-known thermal conduction resistance RHFM, temperature measuring sensors on the surfaces and a globe thermometer Gl according to EN 14037-2

NOTE Between the heat flow meter plate (key 1) and the heating plate (key 2) an elastic layer shall be interposed, for instance consisting of PE lather of about 2 mm thickness

The meaning of the used symbols is as follows:

q specific thermal output

ϑGl ambient reference temperature measured with globe thermometer

ϑH average heating medium temperature

ϑHFM,a temperature of the surface on top of the heat flow meter plate

ϑHFM,b temperature of the surface at the bottom of the heat flow meter plate

Rα heat exchange resistance on the heating surface

RHFM thermal conduction resistance of the heat flow meter plate

Rλ,B effective thermal resistance of carpet covering

subscripts 1: means test 1 (example: ϑGl,1 is the valid value of ϑGl of test 1)

2: means test 2 (example: ϑGl,2 is the valid value of ϑGl of test 2)

For the thermal conduction resistance of the heat flow meter plate the following specification is valid:

The material of the plate is plexiglass with the thickness of 10 mm Its thermal conduction resistance depends on the temperature t as follows:

RHFM = - 0,000188 ⋅ t + 0,0578 m2·K/W with t = (ϑHFM,a + ϑHFM,b)/2

Temperatures shall be measured with a permissible uncertainty of ± 0,1 K Temperature differences shall be measured with a permissible uncertainty of ± 0,05 K

The temperature drop of the heating medium shall not exceed 0,5 K if possible

Two test procedures are necessary The globe thermometer in both cases is situated 0,75 m above the centre of the heating surface, i.e in test 2 higher above the floor of the test booth by the thickness of the carpet

Test 1

Test 1 aims to the determination of the heat exchange resistance Rα In this test the heating surface is the upper surface of the heat flow meter plate and no carpet exists, see Figure A.10

Remark: The value Rα coming from the basic characteristic curve (0,0926 (m2 K/W)) is not used because the

measured temperature ϑGl in this test doesn't exactly apply to the respective procedure used for the basic

characteristic curve [1]

With the measured temperatures ϑHFM,a,1, ϑHFM,b,1 the specific thermal output comes from the heat flow meter

plate using the following equation:

HFM

1 , a , HFM 1 , b

,

HFM

R

)(

During the test the ambient reference temperature is maintained on ϑGl,1 = 20 °C ± 0,5 K by appropriate

cooling of the test booth and the average heating medium temperature ϑH,1 is set to achieve with Equation

(38) a value q = 80 ± 2,0 W/m2

With this result and the measured corresponding temperatures ϑHFM,a,1, ϑGl,1 the heat exchange resistance Rα

can be calculated according to:

q

)(

Test 2

Test 2 aims to the determination of the effective thermal resistance of carpet covering Rλ,B using the result Rα

of test 1 In this test the respective carpet lies on the upper surface of the heat flow meter plate, see

Figure A 11

Corresponding to test 1 ϑGl,2 is maintained on 20 °C ± 0,5 K With the measured temperatures ϑHFM,a,2,

ϑHFM,b,2 the specific thermal output is given by the following equation:

HFM

2 , a , HFM 2 , b

,

HFM

R

)(

The average heating medium temperature ϑH,2 is set to achieve with Equation (40) again a value

q = 80 ± 2,0 W/m2 With this value, the measured temperatures ϑHFM,a,2, ϑGl,2 and the value Rα of test 1 the

effective thermal resistance of the carpet covering can be calculated as follows:

α

q

)(

Following from the described procedure, i.e the determination of Rα without carpet, the gained value Rλ,B of

Equation (41) includes not only the thermal conduction resistance but also (should the occasion arise) the

above mentioned effect of a changed heat exchange coefficient This attribute is necessary for using this

value for the determination of the thermal output according to the calculation method (Clause 6) and to the

test procedure (Clause 9) For that reason the supplement "effective" is used

For carpets used in practice as floor covering for floor heating systems only values Rλ,B determined by the

test method described above are valid to determinate the thermal output in accordance with this standard

This means that the effective thermal resistance Rλ,B of the respective carpet must be available

11 Prove report

For a given construction the results shall be documented for each scheduled pipe spacing T and each

scheduled thickness sU above the pipe The testing body presents this valid results in a prove report The

results are documented in a field of characteristic curves with linear coordinates, using the following equation:

Into this field of characteristic curves, also the limit curves in accordance with Equation (18) are entered

These characteristic curves give for Rλ, B = 0 the standard specific thermal output qN and the associated standard temperature difference ∆ϑN in accordance with 6.5 Further shall be documented the values of the limit specific output qG and the associated limit temperature difference ∆ϑH,G depending on the remaining

above mentioned values Rλ, B in accordance with 6.5

The proved system shall be identified by a technical description in accordance with Clause 5 These documents shall contain all dimensions and materials which influence the thermal properties The results are valid for that system defined in such a way If any change is made by the supplier of the system which affects the principles of the thermal proving, a new proving shall be carried out

12 Prove system

12.1 General

The prove system consists of the following components:

• Approved test laboratory which is accredited according to EN ISO/IEC 17025 The laboratory takes part

at all inter-comparison tests among the approved laboratories The laboratory shall fulfil the requirements

of this standard

• Computer system including the software to calculate the specific thermal output (field of characteristic curves and limit curves) according to Clause 6 of this standard

• Test equipment for the test procedure according to Clause 9 of this standard

• Test equipment for the test procedure according to Clause 10 of this standard

• Master sample, primary and secondary one

• Constructional conformity: The participating laboratory shall state the conformity of its test equipments to this European Standard

• Software conformity: The participating laboratory shall state the conformity of its software to this European Standard

12.2 Master samples

The construction and the materials of the master samples used for the test equipment of Clause 9 are shown

in Figure A.12 The primary and the secondary master sample are of the same construction and materials The laboratory shall equip itself with master sample 2 Master sample 1 will be circulated among the laboratories participating at the prove system The manufacturing process has to ensure that for all samples the materials are from the same charge and the dimensions correspond correctly About this a verification is requested in a complete report and kept available for any further check

For the purposes of the test equipment of Clause 10 a mat with smooth surfaces containing of foamed rubber ("Moosgummi") shall be chosen in coordination of the participating test laboratories and used as

master sample 1 as described above The thermal resistance shall be set in the range of Rλ, B = 0,1 to 0,15

m2·K/W About this a verification is requested in a complete report and kept available for any further check For the test equipment of Clause 10 a master sample 2 is not necessary, see below

The purpose of the master samples is as follows:

a) to verify if the reproducibility of test values among test laboratories is within the limits set by this European Standard,

b) to establish a common basis for all test equipments to verify that the repeatability of test values in each test equipment is within the limits set by this European Standard

12.3 Verification of test equipments

All test equipments shall be verified for:

Reproducibility precision of the test methods:

The reproducibility shall be proved by the prove laboratory using the primary master sample The results of the tests carried out with the test equipment in accordance with close 9 shall be within the tolerance

sm = ± a1 % (determination of a1 see 12.4) of the values qN,M,s and qG,M,s(Rλ;B=0,15) The results of the tests carried out with the test equipment in accordance with Clause 10 shall be within the tolerance sm = ± a2 % (determination of a2 see 12.4) of the value Rλ,B,M,s The prove laboratories have to prove the reproducibility in periodical tests

Repeatability precision of the test methods:

The repeatability shall be proved by the prove laboratory using its own secondary master sample The tests shall be carried out periodically in a distance of 12 months The results of the tests carried out with the test equipment in accordance with Clause 9 and with those in accordance with Clause 10 shall be within a tolerance range s0 = 2 % For the equipment of Clause 10 only Test 1 of Clause 10 is necessary (this means

a master sample 2 is not needed) At the starting of the test equipments three consecutive measurements shall be carried out to prove the fulfilment of the above requirements

12.4 Determination of the values s

and φφφφ

(q

, q

(Rλλλλ;B=0,15), Rλλλλ,B,M,s) of primary

no φO,s –values shall be used, which differ more than ± a1 % or a2 % respectively from the respective average value of all laboratories

12.5 Verification of software

For each calculation result shall be documented the valid boundary conditions

The software shall be verified for reproducibility and repeatability For this purpose the following systems shall be calculated and the results documented according to this European Standard:

1 Floor heating system with pipes inside the screed (type A), tacker system

Cement screed sU 50 mm

2 Floor heating system with pipes inside the screed (type A)

Pipe Cu 12 x 0,7 mm with PVC sheathing 2 mm with air included

The values qN,M,s and qG,M,s(Rλ;B=0,15) are determined in a procedure according to 12.4

The repeatability shall be proved periodically No deviations are allowed