SVENSK STANDARD SS-EN ISO 12241

SVENSK STANDARD SS-EN ISO 12241 Handläggande organ Fastställd Utgåva Sida Byggstandardiseringen, BST 1998-09-25 1 1 (1+44) INNEHÅLLET I SVENSK STANDARD ÄR UPPHOVSRÄTTSLIGT SKYDDAT. SIS HAR COPYRIGHT PÅ SVENSK STANDARD. EFTERTRYCK UTAN TILLSTÅND ÄR FÖRBJUDET. Thermal insulation for building equipment and industrial installations Calculation rules (ISO 12241:1998) Värmeisolering av installationer Beräkningsregler (ISO 12241:1998) The European Standard has the status of a Swedish Standard. This document contains the official English version of EN ISO 12241: 1998. SS-EN ISO 12241 gives calculation methods for so called industrial insulation. The standard deals with the steady-state heat transfer through thermal insulation attached to pipes, ducts or other types of installations surrounded by air or located underground. The calculation rules can be used for installations in normal buildings as well as for equipment in industries. The equations are derived from basic physical formulas but often also include empirical elements being compromises between formulas used in different parts of the world. In some cases both the exact method and a simplified one is given. Swedish Standards corresponding to documents referred to in this Standard are listed in Catalogue of Swedish Standards, issued by SIS. The Catalogue lists, with reference number and year of Swedish approval, International and European Standards approved as Swedish Standards as well as other Swedish Standards. Europastandarden EN 12241:1998 gäller som svensk standard. Detta dokument innehåller den officiella engelska versionen av EN 12241:1998. SS-EN ISO 12241 ger beräkningsmetoder för s k teknisk isolering. Standarden behandlar stationär värmeöverföring genom värmeisolering som monterats runt rör, kanaler eller andra typer av installationer omgivna av luft eller förlagda i mark. Beräkningsmetoderna kan tillämpas både för teknisk isolering i byggnader och för installationer inom industrin. De angivna beräkningssambanden bygger på grundläggande teorier men innehåller också empiriska förenklingar, grundade på kompromisser mellan samband som använts i skilda delar av världen. Ibland ges både en exakt metod och en förenklad version. Motsvarigheten och aktualiteten i svensk standard till de publikationer som omnämns i denna standard framgår av Katalog över svensk standard, som ges ut av SIS. I katalogen redovisas internationella och europeiska standarder som fastställts som svenska standarder och övriga gällande svenska standarder. ICS 27.220.00; 91.120.10; 91.140.01 Standarder kan beställas hos SIS som även lämnar allmänna upplysningar om svensk och utländsk standard. Postadress: SIS, Box 6455, 113 82 STOCKHOLM Telefon: 08-610 30 00. Telefax: 08-30 77 57 Upplysningar om sakinnehållet i standarden lämnas av BST. Telefon: 08-617 74 00. Telefax: 08-617 74 30 Prisgrupp S Tryckt i november 1998

EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM EN ISO 12241 March 1998 ICS 91.120.00; 91.140.10 Descriptors: thermal insulation, buildings, pipelines, fluid pipelines, pipes (tubes), equipment, heat transfer, heat losses, rules of calculation English version Thermal insulation for building equipment and industrial installations Calculation rules (ISO 12241:1998) Isolation thermique des équipements du bâtiment et des installations industrielles Méthodes de calcul (ISO 12241:1998) Isolation thermique des équipements du bâtiment et des installations industrielles Méthodes de calcul (ISO 12241:1998) This European Standard was approved by CEN on 1 January 1998. 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. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists 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 Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comité Européen de Normalisation Europäisches Komitee für Normung Central Secretariat: rue de Stassart 36, B-1050 BRUSSELS 1998 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members Ref. No. E

Provläsningsexemplar / Preview Contents Forword... 3 Introduction... 4 1 Scope... 5 2 Normative references... 5 3 Definitions, symbols and abbreviations... 5 3.1 Physical quantities, symbols and units... 6 3.2 Subscripts... 7 4 Calculation methods for heat transfer... 7 4.1 Fundamental equations for heat transfer... 7 4.2 Surface temperature... 20 4.3 Prevention of surface condensation... 23 5 Calculation of the temperature change in pipes, vessels and containers... 23 5.1 Longitudinal temperature change in a pipe... 23 5.2 Temperature change and cooling times in pipes, vessels and containers... 24 6 Calculation of cooling and freezing times of stationary liquids... 25 6.1 Calculation of the cooling time for a given thickness of insulation to prevent the freezing of water in a pipe... 25 6.2 Calculation of the freezing time of water in a pipe... 26 7 Thermal bridges... 26 8 Underground pipelines... 27 8.1 Calculation of heat loss (single line)... 27 9 Tables and diagrams... 30 Annex A: (informative) Comments on thermal conductivity... 34 Annex B: (informative) Examples... 36 B.1 Calculation of the necessary insulation thicknesses for a double layered wall of a firebox... 36 B.2 Heat flow rate and surface temperature of an insulated pipe... 37 B.3 Temperature drop in a pipe... 38 B.4 Temperature drop in a container... 39 B.5 Cooling and freezing times in a pipe... 40 B.6 Underground pipeline... 41 B.7 Required insulation thickness to prevent surface condensation... 42 Annex C: (informative) Bibliography... 43 Annex ZA (normative) Normative references to international publications with their relevant European publications... 44

Foreword The text of the International Standard ISO 12241:1998 has been prepared by Technical Committee ISO/TC 163 Thermal insulation in collaboration with Technical Committee CEN/TC 89 Sanitary appliances, the secretariat of which is held by SIS. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by September 1998, and conflicting national standards shall be withdrawn at the latest by September 1998. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of the International Standard ISO 12241:1998 was approved by CEN as a European Standard without any modification. NOTE: Normative references to International Standards are listed in annex ZA (normative).

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