ISO/DIS 23995

Thermal insulation for building equipment and industrial installations - Thermal transmittance - Determination of correction terms

Isolation thermique des équipements du bâtiment et des installations industrielles - Transmission thermique - Détermination des termes d'ajustement

Standards Content (sample)

DRAFT INTERNATIONAL STANDARD ISO/DIS 23995
ISO/TC 163/SC 2 Secretariat: NSF
Voting begins on: Voting terminates on:
2004-06-10 2004-11-10

INTERNATIONAL ORGANIZATION FOR STANDARDIZATION • МЕЖДУНАРОДНАЯ ОРГАНИЗАЦИЯ ПО СТАНДАРТИЗАЦИИ • ORGANISATION INTERNATIONALE DE NORMALISATION

Thermal insulation for building equipment and industrial
installations - Thermal transmittance - Determination of
correction terms

Isolation thermique des équipements du bâtiment et des installations industrielles - Transmission thermique -

Détermination des termes d'ajustement
ICS 27.220; 91.120.10
ISO/CEN PARALLEL ENQUIRY

This draft International Standard is a draft European Standard developed within the European Committee

for Standardization (CEN) and processed under the CEN-lead mode of collaboration as defined in the

Vienna Agreement. The document has been transmitted by CEN to ISO for circulation for ISO member

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this DIS directly to CEN/TC 89 (BST, 27, Möllerörsgatan, S - 216 11 Malmö) as well as returning their

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a final draft, established on the basis of comments received, will be submitted to a parallel two-month

FDIS vote in ISO and formal vote in CEN.

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Conformément aux dispositions de la Résolution du Conseil 15/1993, ce document est distribué

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© International Organization for Standardization, 2004
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ISO/DIS 23995
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ii ISO 2004 – All rights reserved
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prEN ISO 23995:2004 (E)
Contents Page

Foreword .............................................................................................................................................................3

Introduction.........................................................................................................................................................3

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

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

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

3.1 Symbols and units.................................................................................................................................5

4 Determination of total thermal transmittances...................................................................................5

5 Calculation rules for the additional terms...........................................................................................5

5.1 General....................................................................................................................................................5

5.2 Determination of the influence of thermal bridges ............................................................................6

Annex A (normative) Thermal bridges..............................................................................................................8

Bibliography......................................................................................................................................................11

Annex ZA (normative) Normative references to international publications with their relevant

European publications........................................................................................................................12

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prEN ISO 23995:2004 (E)
Foreword

This document (prEN ISO 23995:2004) has been prepared by Technical Committee CEN/TC 89

"Thermal performance of buildings and building components", the secretariat of which is held by SIS, in

collaboration with Technical Committee ISO/TC 163 "Thermal insulation".
This document is currently submitted to the parallel Enquiry.

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.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International

Standards adopted by the technical committees are circulated to the member bodies for voting.

Publication as an International Standard requires approval by at least 75 % of the member bodies

casting a vote.

ISO 23995 was prepared by Technical Committee CEN/TC 89, Thermal performance of buildings and

building components, in cooperation with Technical Committee ISO/TC 163, Thermal performance and

energy use in the built environment, Subcommittee SC 2, Calculation methods.

This standard is one of a series of standards on calculation methods for the design and evaluation of the

thermal performance of building equipment and industrial installations.
Introduction

Results of calculations of thermal transmittance made according to ISO 12241, Thermal insulation for

building equipment and industrial installations – Calculation rules, using design thermal conductivity,

may deviate from actual heat loss since the installations generally incorporate some singular points

which are not taken into account in the reference calculation methods.

To reduce this difference, the results of the calculations made according to ISO 12241, and based on

design thermal conductivity (ISO 23993 , Thermal insulation for building equipment and industrial

installations – Determination of design thermal conductivity), shall be corrected by additional thermal

transmittances (DU) for plane walls or by additional linear transmittance (DU ) for pipes. They correspond

to thermal bridges of irregular insulation related and of installation related components of the industrial

installation.
To be published
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prEN ISO 23995:2004 (E)
1 Scope

This standard gives methods to determine the correction terms for thermal transmittance and linear

transmittance for pipes which shall be added to the calculated thermal transmittance, U, or linear thermal

transmittance, U, according to ISO 12241 to obtain the total thermal transmittance U or U to calculate

l T T,l
the total heat losses for an industrial installation.

The values are valid for the temperature ranges indicated in the relevant annexes.

Excluded from the scope of the this document are wrong design of insulation system, unsuitable products

and improper workmanship.
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.
ISO 7345, Thermal insulation – Physical quantities and definitions

ISO 10211-1,Thermal bridges in building construction – Calculation of heat flow and surface temperatures –

Part 1: General calculation methods

ISO 10211-2,Thermal bridges in building construction – Calculation of heat flows and surface temperatures

– Part 2:Linear thermal bridges

ISO 12241, Thermal insulation for building equipment and industrial installations - Calculation rules

ISO 14683, Thermal bridges in building construction – Linear thermal transmittance – Simplified methods

and default values
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 7345 and the following apply.

3.1
calculated (linear) thermal transmittance
value of the thermal transmi
...