Isolering Standard ISO 9869 – 1-2014

ISO 9869 – 1: 2014

Uddrag af Standard

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.
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).
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, 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 (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
R
thermal resistance m2·K/W
RT
total thermal resistance m2·K/W
Rsi
internal surface thermal resistance m2·K/W
Rse
external surface thermal resistance m2·K/W
Λ
thermal conductance W/(m2·K)
U
thermal transmittance W/(m2·K)
Φ
heat flow rate W
A
area m2
q
density of heat flow rate =Φ/A W/m2
Ti
interior environmental (ambient) temperature °C or K
Te
exterior environmental (ambient) temperature °C or K
Tsi
interior surface temperature of the building element °C or K
Tse
exterior surface temperature °C or K
ρ
density of a material kg/m3
d
thickness of a layer m
c
specific heat capacity J/(kg·K)
C
thermal capacity of a layer: C=ρcd J/(m2·K))
Fi, Fe
correction factors calculated with Formula (8) to take into account the storage effects [J/(m2·K)]
E
operational error (of an installed HFM) which is the relative error between the measured and the actual heat flow –
NOTE The environmental (ambient) temperatures shall correspond with those used in the definition adopted for the U-value (see Annex A).
In the steady-state, the thermal properties of the elements have the following definitions:
R is the thermal resistance of an element, surface to surface and is given by
mml_m1
(1)
where Λ is the thermal conductance of the building element, surface to surface.
U is the thermal transmittance of the element, environment to environment and is given by
mml_m2
(2)
where RT is the total thermal resistance which is given by
mml_m3
(3)
where Rsi and Rse are the internal and external surface thermal resistances, respectively.
R and RT have units of square metres kelvin per watt (m2·K/W); U and Λ have units of watts per square metre kelvin [W/(m2·K)].
Only informative sections of standards are publicly available. To view the full content, you will need to purchase the standard by clicking on the “Buy” button.
Bibliography
[1] Ahvenainen S., Kokko E., Aittomäki A., Thermal conductances of wall structures, LVI-tekniikan laboratorio, report 54, Espoo (Finland) 1980
[2] KUPKE, Chr. Untersuchungen über ein Wärmedämm – Schnellmeßverfahren, lnstitut für Bauphysik, Stuttgart, BW 148/76, 1976
[3] Roulet C, Gass J, Marcus I, In situ U-value measurement: reliable results in shorter time by dynamic interpretation of the measured data. ASHRA E Transactions, 93, 1987, pp. 1371-1379
[4] ASTM C 1046 Standard Practice for In-Situ Measurement of Heat Flux and Temperature on Building Envelope Components
[5] Baba T., Ono A., Hat-Tori S., Analysis of operational errors of heat flux transducers placed on wall surfaces. Rev. Sci. Instrum. 1985, 56 pp. 1399–1401
[6] Bales E., Bomberg M., Courville G., Building Applications of Heat Flow Transducers, ASTM STP 885, Philadelphia, 1985
[7] Bomberg M., Solvason K.-R., Discussion of heat flow meter apparatus and transfer standards used for error analysis. Guarded hot plate and flow meter technology, ASTM STP 879, Philadelphia, 1985
[8] IMEKO workshop proceedings on Heat Flux Measurements, Budapest, April 23-25, 1986, OMIKK Technoinform, 1986. Available at the IMEKO Secretariat, POB 457, H-1371 Budapest
[9] Johanesson G., Vämeflödesmätningar. Termoelektriska mätare, funktionsprinciper och felkallor, (Heat flow measurements, thermo-electrical meters, function principles and sources of error), Report TVBH 3003, Division of building technology. Lund Institute of Technology, 1979
[10] Standaert P., Twee-en driedimensionale warmteoverdracht: numerieke methode, experimentele studie en bouwfysische toepassingen, (Two-and three-dimensional thermal bridges, experimental study and building physics applications), Thesis, Katolieke Universiteit Leuven, 1984
[11] Standaert P., Numerical Analysis Operating Errors with Surface Mounted Heat Flux Sensors, Report available at the Belgian Prime Minister Services, Policy of Science, Brussels, 1987
[12] Trethoven H., Measurement errors with surface mounted heat flux sensors. Build. Environ. 1986, 21 pp. 41–56
[13] Anderson B.R., The measurement of U-values on site, ASHRAE-DOE-BTECC Conference on Thermal Performance of the Exterior Envelopes of Buildings Ill, Clearwater Beach, Florida, December 2 to 5, 1985

 

 

 

 

 

.