SIST-TS CEN/TS 15548-1:2012

Thermal insulation products for building equipment and industrial installations - Determination of thermal resistance by means of the guarded hot plate method - Part 1: Measurements at elevated temperatures from 100 °C to 850 °C

New European standard for determination of the thermal resistance at high temperatures with a guarded hot plate apparatus. It is intended to add to and complement EN 12667:2001 and addresses insulation products of high and medium thermal resistance. It is intended that an internal suitable reference material will be rotated within the group.

Wärmedämmstoffe für betriebstechnische Anlagen in der Industrie und in der technischen Gebäudeausrüstung - Bestimmung des Wärmedurchlasswiderstandes nach dem Verfahren mit dem Plattengerät - Teil 1: Messungen bei erhöhten Temperaturen von 100 °C bis 850 °C

Dieses Dokument stellt zusätzliche Informationen zu den in EN 12667, EN 12664, EN 12939 und ISO 8302 enthal¬tenen Angaben zur Konstruktion des Prüfgeräts und zu den Arbeitsabläufen zur Verfügung, die für die Bestim¬mung des Wärmedurchlasswiderstandes von Wärmedämmstoffen im Temperaturbereich von 100 °C bis 850 °C bei Anwendung des Verfahrens mit dem Plattengerät erforderlich sind.

Produits isolants thermiques pour l’équipement du bâtiment et les installations industrielles - Détermination de la résistance thermique par la méthode de la plaque chaude gardée - Partie 1: Mesurages a températures élevées comprises entre 100 °C et 850 °C

Le présent document fournit des informations supplémentaires par rapport à celles données dans l’EN 12667, l’EN 12664, l’EN 12939 et l’ISO 8302 sur la conception de l’appareillage et les modes opératoires de fonctionnement nécessaires pour déterminer la résistance thermique des produits isolants thermiques dans la plage de températures allant de 100 °C à 850 °C par la méthode de la plaque chaude gardée.

Toplotnoizolacijski proizvodi za opremo stavb in industrijske inštalacije - Ugotavljanje toplotne upornosti z zaščiteno vročo ploščo - 1. del: Meritve pri povišani temperaturi od 100 °C do 850 °C

Ta dokument vsebuje dodatne informacije za standarde EN 12667, EN 12664, EN 12939 in ISO 8302 o načrtovanju naprav in delovnih postopkov za ugotavljanje toplotne upornosti toplotnoizolacijskih proizvodov v temperaturnem območju od 100 °C do 850 °C z zaščiteno vročo ploščo.

General Information

• Status: Withdrawn
• Public Enquiry End Date: 30-Oct-2006
• Publication Date: 02-Feb-2012
• Withdrawal Date: 13-Aug-2014
• ICS: 91.100.60 - Thermal and sound insulating materials
• Technical Committee: TOP - Thermal insulation
• Current Stage: 9900 - Withdrawal (Adopted Project)
• Start Date: 14-Aug-2014
• Due Date: 06-Sep-2014
• Completion Date: 14-Aug-2014
• Directive: 89/106/EEC - Construction products
• Ref Project: CEN/TS 15548-1:2011 - Thermal insulation products for building equipment and industrial installations - Determination of thermal resistance by means of the guarded hot plate method - Part 1: Measurements at elevated temperatures from 100 °C to 850 °C

Relations

• Replaced By: SIST-TS CEN/TS 15548-1:2014 - Thermal insulation products for building equipment and industrial installations - Determination of thermal resistance by means of the guarded hot plate method - Part 1: Measurements at elevated temperatures from 100 °C to 850 °C
• Effective Date: 01-Sep-2014

Standards Content (Sample)

SLOVENSKI STANDARD
SIST-TS CEN/TS 15548-1:2012
01-marec-2012
7RSORWQRL]RODFLMVNLSURL]YRGL]DRSUHPRVWDYELQLQGXVWULMVNHLQãWDODFLMH
8JRWDYOMDQMHWRSORWQHXSRUQRVWL]]DãþLWHQRYURþRSORãþRGHO0HULWYHSUL
SRYLãDQLWHPSHUDWXULRGƒ&GRƒ&
Thermal insulation products for building equipment and industrial installations -
Determination of thermal resistance by means of the guarded hot plate method - Part 1:
Measurements at elevated temperatures from 100 °C to 850 °C
Wärmedämmstoffe für betriebstechnische Anlagen in der Industrie und in der
technischen Gebäudeausrüstung - Bestimmung des Wärmedurchlasswiderstandes nach
dem Verfahren mit dem Plattengerät - Teil 1: Messungen bei erhöhten Temperaturen
von 100 °C bis 850 °C
Produits isolants thermiques pour l’équipement du bâtiment et les installations
industrielles - Détermination de la résistance thermique par la méthode de la plaque
chaude gardée - Partie 1: Mesurages a températures élevées comprises entre 100 °C et
850 °C
Ta slovenski standard je istoveten z: CEN/TS 15548-1:2011
ICS:
91.100.60 0DWHULDOL]DWRSORWQRLQ Thermal and sound insulating
]YRþQRL]RODFLMR materials
SIST-TS CEN/TS 15548-1:2012 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TS CEN/TS 15548-1:2012

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SIST-TS CEN/TS 15548-1:2012


TECHNICAL SPECIFICATION
CEN/TS 15548-1

SPÉCIFICATION TECHNIQUE

TECHNISCHE SPEZIFIKATION
November 2011
ICS 91.100.60
English Version
Thermal insulation products for building equipment and industrial
installations - Determination of thermal resistance by means of
the guarded hot plate method - Part 1: Measurements at
elevated temperatures from 100 °C to 850 °C
Produits isolants thermiques pour les équipements de
Wärmedämmstoffe für die Haustechnik und für
bâtiments et les installations industrielles - Détermination betriebstechnische Anlagen - Bestimmung des
de la résistance thermique par la méthode de la plaque Wärmedurchlasswiderstandes nach dem Verfahren mit
chaude gardée - Partie 1 : Mesurages à haute témperature dem Plattengerät - Teil 1: Messungen bei erhöhten
entre 100 °C et 850 °C Temperaturen von 100 °C bis 850 °C
This Technical Specification (CEN/TS) was approved by CEN on 14 May 2011 for provisional application.

The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit their
comments, particularly on the question whether the CEN/TS can be converted into a European Standard.

CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS available
promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the CEN/TS)
until the final decision about the possible conversion of the CEN/TS into an EN is reached.

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, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.





EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2011 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 15548-1:2011: E
worldwide for CEN national Members.

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Contents Page
Foreword .3
Introduction .3
1 Scope .4
2 Normative references .4
3 Definitions, symbols and units .4
3.1 Terms and definitions .4
3.2 Symbols and units .5
4 Principle .5
4.1 Apparatus .5
4.2 Measuring the density of heat flow rate .6
4.3 Measuring the temperature difference .6
4.4 Deriving the thermal resistance or transfer factor .6
4.5 Computing thermal conductivity or thermal transmissivity .6
4.6 Apparatus limits .6
4.7 Specimen limits.6
5 Apparatus description and design requirement .6
5.1 General .6
5.2 Two specimen apparatus .7
5.3 Single specimen apparatus .7
5.4 Plates .7
5.5 Main heating unit . 10
5.6 Edge insulation and auxiliary guards . 11
5.7 Cold plates . 11
5.8 Thickness measurement system . 11
5.9 Accuracy and repeatability . 11
5.10 Error analysis and equipment performance checks . 11
6 Test specimen . 11
6.1 General . 11
6.2 Selection and size . 12
6.3 Specimen preparation . 12
7 Testing procedure. 13
7.1 General . 13
7.2 Conditioning . 13
7.3 Measurements . 13
8 Calculations and test report . 15
8.1 Density and mass changes . 15
8.2 Heat transfer properties . 16
9 Test report . 17
Annex A (normative) Limits for equipment performance and test conditions . 19
A.1 General . 19
A.2 Accuracy and repeatability, stability, uniformity . 19
A.3 Suggested apparatus sizes . 20
A.4 Equipment design requirements . 20
A.5 Acceptable specimen characteristics . 21
A.6 Acceptable testing conditions . 23

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Foreword
This document (CEN/TS 15548-1:2011) has been prepared by Technical Committee CEN/TC 89 “Thermal
performance of buildings and building components”, the secretariat of which is held by SIS.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to announce this Technical Specification: 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, Romania, Slovakia, Slovenia,
Spain, Sweden, Switzerland and the United Kingdom.
Introduction
This technical specification is an interim solution to the need for a standard to complement EN 12667:2001 in
the approximate temperature range 100 °C to 850 °C.
The technical specification is chosen to publish the knowledge gained in the field of measuring thermal
conductivity at elevated temperature now, as the finalisation of a standard is a complex matter requiring
further investigations.
Among existing apparatus for steady state thermal testing, the guarded hot plate can be operated at selected
mean temperatures over the temperature range -100 °C to 850 °C. In general, these apparatus exist in three
forms covering roughly the following temperature ranges -100 °C to ambient, ambient to 100 °C and above
100 °C. However, it has been found that it is not possible to achieve the uncertainties of ± 2 % claimed as
achievable for the low and ambient temperature forms when using the high temperature version in accordance
with ISO 8302. More realistic figures adopting the method and procedures detailed in this document are ± 5 %
up to 450 °C and ± 7 % at temperatures above 450 °C.
Many issues are more difficult at high temperatures. There are design issues due to apparatus material
stability, the level of temperature measurement uncertainty is higher than at ambient temperatures and there
is also greater degradation in the performance of temperature sensors when operated at high temperatures,
requiring calibration checks to be more frequent. At high temperatures, it is more likely to get hot spots on a
plate due to non-uniformity of a heater; these could be near temperature sensors and give false readings. Any
air gaps will have greater heat flow across them due to radiation heat exchange and finally provisions for
specimen expansion or shrinkage are needed.
Due to the above considerations the following clauses of EN 12667:2001 have been expanded and detailed:
5 Apparatus
5.1 General
5.2.4 Heating Unit
5.2.5 Metering Area
5.2.6 Edge insulation and auxiliary guards
5.2.7 Cooling units
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5.3.5 Accuracy and repeatability
6 Test specimens
6.2 Selection and size
7 Testing procedure
7.3.8 Settling time and measurement interval
Annex A
Annex B.2
1 Scope
This document provides the additional information to that given in EN 12667, EN 12664, EN 12939 and
ISO 8302 on the design of apparatus and operational procedures required to determine the thermal resistance
of thermal insulation products in the temperature range 100 °C to 850 °C using the guarded hot plate method.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
EN 1946-2, Thermal performance of building products and components – Specific criteria for the assessment
of laboratories measuring heat transfer properties – Part 2: Measurements by guarded hot plate method
EN 12664, Thermal performance of building materials and products – Determination of thermal resistance by
means of guarded hot plate and heat flow meter methods – Dry and moist products of medium and low
thermal resistance
EN 12667:2001, Thermal performance of building materials and products – Determination of thermal
resistance by means of guarded hot plate and heat flow meter methods – Products of high and medium
thermal resistance
EN 12939, Thermal performance of building materials and products – Determination of thermal resistance by
means of guarded hot plate and heat flow meter methods – Thick products of high and medium resistance
EN ISO 7345, Thermal insulation – Physical quantities and definitions (ISO 7345:1997)
EN ISO 9288, Thermal insulation – Heat transfer by radiation – Physical quantities and definitions
(ISO 9288:1989)
ISO 8302:1991, Thermal insulation – Determination of steady state thermal resistance and related properties
– Guarded hot plate apparatus
3 Terms and definitions, symbols and units
3.1 Terms and definitions
For the purposes of this document the terms and definitions given in EN ISO 7345 and EN ISO 9288 apply.
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3.2
Symbols and units
Symbol Quantity Unit
2
A
metering area measured on a selected isothermal surface m
d thickness; average thickness of specimen m
e
edge number ratio -
m mass ( of the specimen ) kg
∆m mass change kg
2
q density of heat flow rate W/m
R thermal resistance m²·K/W
∆R increment of thermal resistance m²·K/W
r thermal resistivity m·K/W
T temperature of the warm surface of the specimen K

1
T temperature of the cold surface of the specimen K

2
T specimen edge temperature K
3
T mean test temperature (usually (T + T)/2) K

m 1 2
∆T temperature difference (usually T - T) K
1 2
∆t
time interval s
T transfer factor W/(m·K)
3
V volume m
Φ
heat flow rate W
λ thermal conductivity W/(m·K)
λ
thermal transmissivity W/(m·K)

t
3
ρ
density kg/m
4 Principle
4.1 Apparatus
The principle of the guarded hot plate method is as described in 1.6 of ISO 8302:1991.The guarded hot plate
apparatus is intended to establish a unidirectional constant and uniform density of heat flow rate within
homogeneous specimens, in the form of slabs with flat parallel faces. The part of the apparatus where this
takes place with acceptable accuracy is around its centre; the apparatus is therefore divided in a central
metering section in which measurements are taken, and a surrounding guard section.
NOTE Specimen homogeneity is discussed in A.3.2 of EN 12667:2001.
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4.2 Measuring the density of heat flow rate
Following the establishment of steady state in the metering section, the density of heat flow rate, q, is
determined from measurement of the heat flow rate, Φ, and the metering area, A, that the heat flow crosses.
4.3 Measuring the temperature difference
The temperature difference across the specimens, ∆T, is measured by temperature sensors fixed on or in the
surfaces of the plates in contact with the specimens and/or those fixed on/or in the surfaces of the specimens
themselves, where appropriate.
4.4 Deriving the thermal resistance or transfer factor
The thermal resistance, R, is calculated from q, A and ∆T. From the additional knowledge of the thickness, d,
of the specimen, the transfer factor, T, is computed; see A.2.8 of EN 12667:2001.
4.5 Computing thermal conductivity or thermal transmissivity
The mean thermal conductivity, λ or thermal transmissivity λ , of the specimen may also be computed if the
t
appropriate conditions to identify them and those given in A.4.3 of EN 12667:2001 are realised
4.6 Apparatus limits
The application of the method is limited by the capability of the apparatus to maintain an unidirectional,
constant and uniform density of heat flow rate in the specimen, coupled with the ability to measure power,
temperature and dimensions to the limit of accuracy required, see Annex A.
4.7 Specimen limits
The application of the method is also limited by the shape of the specimen(s) and the degree to which they
are identical in thickness and uniformity of structure (in the case of two specimen apparatus) and whether their
surfaces are flat or parallel, see Annex A.
5 Apparatus description and design requirement
5.1 General
A guarded hot plate apparatus used for measurements according to this document shall comply with the limits
on equipment performance and test conditions given in Annex A and shall conform with the requirements
concerning the assessment of equipment accuracy given in EN 1946-2; this requires that the equipment
design, error analysis and performance check be according to Section 2 of ISO 8302.
A guarded hot plate design for high temperature measurement needs detailed modelling of heater plates, gap,
imbalance sensors, guard plates, edge insulation and auxiliary guards and requires much more careful design
than its ambient temperature counterpart for the following reasons:
 The heater plate material needs to retain its mechanical properties to the higher operating temperatures.
Suitable materials with the higher strength requirements usually have a lower thermal conductivity than
pure copper and aluminium alloys that are normally used at ambient temperatures. This can mean that
the heater plates have to be thicker to ensure uniform temperature distribution across the plate, which in
turn can lead to higher heat losses or gains from the edges of the plate.
 Extra precautions have to be taken to electrically insulate heater wires and temperature sensors from the
metal heater plate. One solution is to use sheathed wires but this raises the problem of accurately
locating the voltage probes on the heater wire in the centre of the guard centre gap.
 The use of sheathed temperature sensors to limit the degradation of temperature sensors due to
oxidation can also create additional problems because of the increased area of metal that crosses the
guard centre gap compared to a 0,2 mm diameter thermocouple.
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 Despite the use of materials with high strength at high temperatures, there could still be problems with
plate distortion at higher temperatures due to residual stresses introduced by machining. This could result
in non-parallelism and unacceptable air gaps between the specimen and the heater plates.
In a guarded hot plate apparatus, the heat flow rate is obtained from the measurement of the electrical power
input to the heating unit in the metering section. The general features of the apparatus with specimens
installed are shown in Figure 1. The apparatus can have an enclosure to exclude air exchange from enclosure
to ambient and be provided with additional edge guard heaters or a temperature controlled environment
around the specimen assembly.
There exist two types of guarded hot plate apparatus, which conform to the basic principle outlined in
Clause 4:
a) with two specimens (and a central heating unit);
b) with a single specimen.
5.2 Two specimen apparatus
In the two specimen apparatus, (see Figure 1), a central round or square flat plate assembly, consisting of a
heater and metal surface plates, called the heating unit, is sandwiched between two nearly identical
specimens. The heat flow rate is transferred through the specimens to separate round or square isothermal
flat assemblies, which may consist of either a heated “cold plate” with additional cooling plates separated by
insulation slabs or separate cooling units.
5.3 Single specimen apparatus
In the single specimen apparatus (see Figure 2), one of the specimens and its cold plate is replaced by a
combination of a piece of insulation and a guard plate. Zero temperature difference is then established across
this combination. Providing all other applicable requirements of this document are fulfilled, accurate
measurements and reporting according to this method can be achieved with this type of apparatus, but the
test report shall state that a single specimen apparatus was used.
5.4 Plates
5.4.1 General
A guarded hot plate designed for high temperature measurements uses heated plates for both faces of the
specimen, the “cold” plates may also be equipped for cooling or the cooling can be established by other
means, e.g. separate cooling plates.
5.4.2 Plate material
The materials used in the construction of the heating unit must be chosen carefully to ensure adequate
performance at the temperatures at which the heating unit is to be operated. At high temperatures the chosen
material shall be
 resistant to further oxidation once an initial thin oxidation film has formed;
 able to withstand repeated cycling from room temperature to the highest design temperature without the
heating unit distorting beyond the flatness requirements;
 of sufficiently high thermal conductivity in relation to the plate thickness and the separation of the wires or
strips forming the heating element to ensure that uniform temperatures can be maintained across the
working surfaces.
Suitable materials might be pure nickel, Inconel alloys (low conductivity), silver or pure alumina (high
conductivity).
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5.4.3 Plate geometry
Plates are either square or circular.
Round plates are simpler to model and design although greater care is required both in the assembly and to
ensure uniform heating per area.
Square plates offer a simpler design but for high temperature operation additional heaters with control may be
required in the corners of the guard area in order to maintain a uniform temperature across the plates.
The surface departure from plane shall not exceed 0,025 % as specified in Annex A, A.4.

Key
A metering section heater J edge guard heater (optional)
B metering section surface plates L insulated enclosure (optional)
C guard section heater N differential temperature sensors
D guard section surface plates O metering section surface temperature sensors
E cooling unit (optional) P cold surface plate temperature sensors
F cold plate heater (optional) Q base plate
G cold surface plate R edge guard temperature sensors (optional)
H test specimen S specimen edge temperature sensors (optional)
I edge guard plate (optional)
Figure 1 —Schematic design of two specimen guarded hot plate apparatus
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Key
A metering section heater L insulated enclosure (optional)
B metering section surface plates N differential temperature sensors
C guard section heater O metering section surface temperature sensors
D guard section surface plates P cold surface plate temperature sensor
E cooling unit (optional) Q base plate
F cold plate heater (optional) R edge guard temperature sensors
G cold surface plate S specimen edge temperature sensors
H test specimen T guard insulation
I edge guard plate (optional) U guard insulation edge temperature sensor
J edge guard heater (optional)

Figure 2 —Schematic design of single specimen guarded hot plate apparatus
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5.4.4 Plate emissivity
The total hemispherical emissivity of the surfaces of the heater plates in contact with the specimen/s shall be
greater than 0,8. As radiative heat transfer through the specimen can be very significant at high temperatures
the actual total hemispherical emissivity shall be determined over the temperature range of the apparatus.
NOTE 1 Details of how to measure the plate emissivity is given in Annex A of EN 1946-2:1999.
5.4.5 Plate temperature uniformity
The heater and cold plates shall be designed carefully to ensure that the temperature uniformity across the
plates is better than 2 % of the temperature drop across the specimens from mean specimen temperatures
below and 450 °C and 3 % for temperatures above 450 °C.
5.4.6 Heating elements, principle and electrical insulation
The electrical insulation of the heater resistance wire shall provide an electrical resistance between the heater
windings and the metal heater plate greater than 100 MΩ over the whole temperature range of the apparatus.
Suitably insulated potential leads shall be attached to the heater wires at the mid point of the guard-centre gap
to determine the power delivered to the metering area, or a correction factor shall be determined by
measurement and/or calculation to account for the power lost in the guard area.
5.4.7 Plate temperature sensors
Great care shall be taken in choosing a temperature measurement system that does not deteriorate or
degrade with prolonged exposure to high temperatures. A solution to reduce degradation is to use sheathed
temperature sensors but this gives added heat exchange across the gap between the guard and metering
area. If sheathed temperature sensors are used then the outer diameter of the sheath material shall not
exceed 2 mm.
5.5 Main heating unit
5.5.1 General
The heating unit consists of a separate central metering section surrounded by a guard section with minimal
direct contact between the two and separated by a narrow gap. The heating units are applied to establish a
unidirectional, constant and uniform density of heat flow rate within the specimens to be measured.
5.5.2 Metering area and guard to metering area gap
The metering area is the central area of the specimen delimited by the centre line of the gap of the heating
unit. When relevant, this area shall be corrected for plate expansion.
This definition, which applies in principle to thick specimens only, has been retained for all the specimens to
be tested according to this document. Due to this approximation, the thickness of the specimen shall be at
least ten times the width of the gap.
5.5.3 Imbalance across gap and position of imbalance sensors
The imbalance sensors, e.g. thermocouples connected as a thermopile or resistance thermometers, shall be
of cross-section as small as possible in order to reduce heat transfer across the gap. Where possible the wire
shall be covered to avoid excessive exposure to air at high temperatures which causes oxidation and
degradation of performance and ultimate breakage of the wire. See ISO 8302:1991 for guidance on placement
and number of sensors.
If the apparatus is designed to operate at temperatures above 450 °C then in order to reduce radiation
exchange across the gap at high temperatures the guard-centre gap shall be filled with a material e.g. ceramic
that is opaque to thermal radiation and has a thermal conductivity less than 0,1 W/(m·K).
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