prEN ISO 23995

Thermal insulation for building equipment and industrial installations - Thermal transmittance - Determination of correction terms (ISO/DIS 23995:2004)

Migrated from Progress Sheet (TC Comment) (2000-07-10): WIs 089 & 090 = result of splitting of WI 087 (TC Res 274/1999) (CC/990702)++TC forecasts updated : This work item and GTR 00089090 are at the limit between present "state of art" and items for which pre-normative research is needed. Request for pre-normative research financing was considered but abandoned due to the heavy administrative work it requested and the low probability of getting financial support (TC forecasts updating exercise.sj 00-10-16)++

Wärmedämmung an haus- und betriebstechnischen Anlagen - Wärmedurchgangskoeffizient - Bestimmung von Korrekturtermen (ISO/DIS 23995:2004)

Diese Norm legt Verfahren zur Bestimmung der Korrekturterme für den Wärmedurchgangskoeffizienten und den längenbezogenen Wärmedurchgangskoeffizienten für Rohre fest, die zum berechneten Wärmedurchgangskoeffizienten U oder dem längenbezogenen Wärmedurchgangskoeffizienten Ul nach ISO 12241 zu addieren sind, um den Gesamt-Wärmedurchgangskoeffizienten UT oder UT,l für die Berechnung der Gesamtwärmeverluste für eine betriebstechnische Anlage zu ermitteln.
Die Werte gelten für die in den entsprechenden Anlagen angegebenen Temperaturbereiche.
Der Anwendungsbereich dieses Dokuments umfasst nicht die fehlerhafte Bemessung eines Dämmungssystems, ungeeigneter Produkte und einer ungeeigneten Ausführung.

Isolation thermique des équipements du bâtiment et des installations industrielles - Coefficent de transmission thermique - Détermination des corrections

Toplotnoizolacijski proizvodi za opremo stavb in industrijske inštalacije - (ISO/DIS 23995:2004)

General Information

• Status: Not Published
• Technical Committee: CEN/TC 89 - Thermal performance of buildings and building components
• Drafting Committee: CEN/TC 89/WG 3 - Calculation of thermal insulation of equipment in buildings
• Current Stage: 4598 - Decision to abandon - Finalization for Vote
• Start Date: 19-Oct-2006
• Completion Date: 19-Oct-2006
• Directive: 305/2011 - Regulation (eu) No 305/2011 of the European Parliament and of the Council of 9 march 2011 laying down harmonised conditions for the marketing of construction products and repealing council directive 89/106/eec
• Directive: 89/106/EEC - Construction products
• Ref Project: OSIST prEN ISO 23995:2004 - Thermal insulation for building equipment and industrial installations - Thermal transmittance - Determination of correction terms (ISO/DIS 23995:2004)

Overview

prEN ISO 23995 (ISO/DIS 23995:2004) specifies methods to determine correction terms for thermal transmittance in thermal insulation of building equipment and industrial installations. It defines how to add additional thermal transmittances (DU) or additional linear transmittances (DU_l) to the calculated values from ISO 12241 so that the total thermal transmittance (U_T or U_T,l) accounts for singularities not covered by the basic calculation rules - principally thermal bridges arising from installation details and irregular insulation.

This draft European standard was prepared by CEN/TC 89 in cooperation with ISO/TC 163 and is part of a series on calculation methods for thermal performance of plant and industrial piping.

Key Topics

• Purpose: Provide correction methods for plane walls and pipes to capture extra heat loss from thermal bridges and singular points.
• Scope & exclusions: Covers correction-term determination for the temperature ranges in the annexes; excludes incorrect insulation design, unsuitable products and poor workmanship.
• Calculation approach:
  • Base thermal transmittances (U or U_l) are calculated per ISO 12241.
  • Additional terms (DU_B for plane walls, DU_B,l for pipes) are added: U_T = U + DU_B; U_T,l = U_l + DU_B,l.
  • Correction factors (z, z*, y, y*) quantify irregular insulation–related and installation–related thermal bridges and depend on heat-flow magnitude and occurrence frequency.
• Determination methods:
  • Thermal-bridge transmittances are calculated according to ISO 10211 (Parts 1 & 2) or equivalent simplified methods (ISO 14683) where applicable.
  • For pipes, plant-related thermal bridges (flanges, fittings) may be represented as an equivalent length (Δl) that is added to the pipe length for linear transmittance calculations.
• Annex A: Normative guidance and tables with example equivalent lengths for common flanges, fittings and estimated z*-values for pipe suspensions; warns of significant losses if fittings are uninsulated.

Applications and Users

• Practical for mechanical and thermal engineers, insulation designers, energy assessors, HVAC and process-plant designers who need accurate heat-loss estimates for:
  • Industrial piping and plant installations
  • Building services and mechanical equipment insulation design
  • Energy-efficiency assessments and thermal performance modelling
• Useful in contractual specifications, energy audits and when comparing design calculations with measured heat loss.

Related Standards

• ISO 12241 - Calculation rules for thermal insulation of building equipment and industrial installations
• ISO 10211-1 / ISO 10211-2 - Thermal bridges: calculation of heat flow and surface temperatures
• ISO 14683 - Linear thermal transmittance simplified methods and default values
• ISO 7345 - Physical quantities and definitions for thermal insulation
• ISO 23993 - Determination of design thermal conductivity (referenced as a companion document)

Keywords: thermal insulation, thermal transmittance, correction terms, thermal bridges, linear thermal transmittance, ISO 23995, industrial installations, building equipment, equivalent length, DU, U_T.

Standards Content (Sample)

SLOVENSKI OSIST prEN ISO 23995:2004

PREDSTANDARD
september 2004
Thermal insulation for building equipment and industrial installations - Thermal
transmittance - Determination of correction terms (ISO/DIS 23995:2004)
ICS 91.120.10 Referenčna številka
©  Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno

EUROPEAN STANDARD
DRAFT
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2004
ICS
English version
Thermal insulation for building equipment and industrial
installations - Thermal transmittance - Determination of
correction terms (ISO/DIS 23995:2004)
Isolation thermique des équipements du bâtiment et des Wärmedämmung an haus- und betriebstechnischen
installations industrielles - Coefficent de transmission Anlagen - Wärmedurchgangskoeffizient - Bestimmung von
thermique - Détermination des corrections Korrekturtermen (ISO/DIS 23995:2004)
This draft European Standard is submitted to CEN members for parallel enquiry. It has been drawn up by the Technical Committee
CEN/TC 89.
If this draft becomes a European Standard, 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.
This draft European Standard was established by CEN 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 Management Centre has the same
status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2004 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN ISO 23995:2004: E
worldwide for CEN national Members.

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
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
l
to thermal bridges of irregular insulation related and of installation related components of the industrial
installation.
To be published
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 transmittance calculated according to ISO 12241
3.2
total (linear) thermal transmittance
calculated thermal transmittance calculated according to ISO 12241 increased with the correction terms
according to this standard
3.1 Symbols and units
Symbol Quantity Unit
U thermal transmittance of thermal bridge
W/(m²⋅K)
WB
additional term corresponding toDU W/(m²⋅K)
B
installation related and irregular insulation
related thermal bridges
Dadditional term for linear thermal W/(m⋅K)
B,l
transmittance
U total thermal transmittance incorporating
W/(m²⋅K)
T
the relevant corrections
U total linear thermal transmittance
T,l W/(m⋅K)
incorporating the relevant corrections
z or y correction term for irregular insulation– dimensionless
related ther
...