ISO 9869-1:2014
(Main)Thermal insulation — Building elements — In-situ measurement of thermal resistance and thermal transmittance — Part 1: Heat flow meter method
Thermal insulation — Building elements — In-situ measurement of thermal resistance and thermal transmittance — Part 1: Heat flow meter method
ISO 9869-1:2014 describes the heat flow meter method for the measurement of the thermal transmission properties of plane building components, primarily consisting of opaque layers perpendicular to the heat flow and having no significant lateral heat flow. The properties which can be measured are: a) the thermal resistance, R, and thermal conductance, Λ, from surface to surface; b) the total thermal resistance, RT, and transmittance from environment to environment, U, if the environmental temperatures of both environments are well defined. The heat flow meter measurement method is also suitable for components consisting of quasi homogeneous layers perpendicular to the heat flow, provided that the dimensions of any inhomogeneity in close proximity to the heat flow meter (HFM) is much smaller than its lateral dimensions and are not thermal bridges which can be detected by infrared thermography. ISO 9869-1:2014 describes the apparatus to be used, the calibration procedure for the apparatus, the installation and the measurement procedures, the analysis of the data, including the correction of systematic errors and the reporting format.
Isolation thermique — Éléments de construction — Mesurage in situ de la résistance thermique et du coefficient de transmission thermique — Partie 1: Méthode du fluxmètre
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 9869-1
First edition
2014-08-01
Thermal insulation — Building
elements — In-situ measurement
of thermal resistance and thermal
transmittance —
Part 1:
Heat flow meter method
Isolation thermique — Éléments de construction — Mesurage in
situ de la résistance thermique et du coefficient de transmission
thermique —
Partie 1: Méthode du fluxmètre
Reference number
©
ISO 2014
© ISO 2014
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ii © ISO 2014 – All rights reserved
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions, symbols and units . 2
3.1 Terms and definitions . 2
3.2 Symbols and units . 2
4 Apparatus . 4
4.1 Heat flow meter (HFM) . 4
4.2 Temperature sensors . 4
5 Calibration procedure . 5
5.1 Calibration of the HFM . 5
5.2 Temperature sensors . 6
5.3 Measuring equipment . 7
6 Measurements . 7
6.1 Installation of the apparatus . 7
6.2 Data acquisition . 8
7 Analysis of the data . 8
7.1 Average method . 8
7.2 Storage effects .10
7.3 Comparison of calculated and measured values .12
8 Corrections for the thermal resistance and the finite dimension of the HFM .12
9 Accuracy .12
10 Test report .13
Annex A (normative) Heat transfer at surfaces and U-value measurement .15
Annex B (normative) Dynamic analysis method .18
Annex C (normative) Examination of the structure of the element .23
Annex D (informative) Perturbations caused by the heat flow meter .25
Annex E (informative) Checking the accuracy of the measurement system of heat flow rate .31
Annex F (informative) Heat storage effects .34
Bibliography .36
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 163, Thermal performance and energy use in the
built environment, Subcommittee SC 1, Test and measurement methods.
This first edition cancels and replaces ISO 9869:1994, which has been technically revised.
Annexes A, B and C form an integral part of this part of ISO 9869. Annexes D, E and F are for information
only.
iv © ISO 2014 – All rights reserved
Introduction
The thermal transmittance of a building element (U-value) is defined in ISO 7345 as the “Heat flow rate
in the steady state divided by area and by the temperature difference between the surroundings on each
side of a system”.
In principle, the U-value can be obtained by measuring the heat flow rate through an element with a heat
flow meter or a calorimeter, together with the temperatures on both sides of the element under steady-
state conditions.
However, since steady-state conditions are never encountered on a site in practice, such a simple
measurement is not possible. But there are several ways of overcoming this difficulty:
a) Imposing steady-state conditions by the use of a hot and a cold box. This method is commonly used
in the laboratory (ISO 8990) but is cumbersome in the field;
b) Assuming that the mean values of the heat flow rate and temperatures over a sufficiently long period
of time give a good estimate of the steady-state. This method is valid if:
1) the thermal properties of the materials and the heat transfer coefficients are constant over the
range of temperature fluctuations occurring during the test;
2) the change of amount of heat stored in the element is negligible when compared to the amount
of heat going through the element. This method is widely used but may lead to long periods of
measurement and may give erroneous results in certain cases.
c) Using a dynamic theory to take into account the fluctuations of the heat flow rate and temperatures
in the analysis of the recorded data.
NOTE The temperatures of the surroundings, used in the definition of the U-value, are not precisely defined
in ISO 7345. Their exact definition depends on the subsequent use of the U-value and may be different in different
countries (see Annex A).
INTERNATIONAL STANDARD ISO 9869-1:2014(E)
Thermal insulation — Building elements — In-situ
measurement of thermal resistance and thermal
transmittance —
Part 1:
Heat flow meter method
1 Scope
This part of ISO 9869 describes the heat flow meter method for the measurement of the thermal
transmission properties of plane building components, primarily consisting of opaque layers
perpendicular to the heat flow and having no significant lateral heat flow.
The properties which can be measured are:
a) the thermal resistance, R, and thermal conductance, Λ, from surface to surface;
b) the total thermal resistance, R , and transmittance from environment to environment, U, if the
T
environmental temperatures of both environments are well defined.
The heat flow meter measurement method is also suitable for components consisting of quasi
homogeneous layers perpendicular to the heat flow, provided that the dimensions of any inhomogeneity
in close proximity to the heat flow meter (HFM) is much smaller than its lateral dimensions and are not
thermal bridges which can be detected by infrared thermography (see 6.1.1).
This part of ISO 9869 describes the apparatus to be used, the calibration procedure for the apparatus,
the installation and the measurement procedures, the analysis of the data, including the correction of
systematic errors and the reporting format.
NOTE 1 It is not intended as a high precision method replacing the laboratory instruments such as hot boxes
that are specified in ISO 8990:1994.
NOTE 2 For other components, an average thermal transmittance may be obtained using a calorimeter or by
averaging the results of several heat flow meter measurements.
NOTE 3 In building with large heat capacities, the average thermal transmittance of a component can be
obtained by measurement over an extended period, or the apparent transmittance of the part can be estimated
by a dynamic analysis of its thermal absorption response (see Annex B).
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.
ISO 6781:1983, Thermal insulation — Qualitative detection of thermal irregularities in building envelopes —
Infrared method
ISO 6946:2007, Building components and building elements — Thermal resistance and thermal
transmittance — Calculation method
ISO 7345:1987, Thermal insulation — Physical quantities and definitions
ISO 8301:1991, Thermal insulation — Determination of steady-state thermal resistance and related
properties — Heat flow meter apparatus
ISO 8302:1991, Thermal insulation — Determination of steady-state thermal resistance and related
properties — Guarded hot plate apparatus
ISO 8990:1994, Thermal insulation — Determination of steady-state thermal transmission properties —
Calibrated and guarded hot box
3 Terms, definitions, symbols and units
3.1 Terms and definitions
For the purpose of this document, the terms and definitions given in ISO 7345:1987 apply.
3.2 Symbols and units
Symbol Quantity Unit
thermal resistance m ·K/W
R
total thermal resistance m ·K/W
...
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