Foreword

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This document was prepared by Technical Committee ISO/TC 163, Thermal performance and energy use in the built environment.

This third edition of ISO 7345 cancels and replaces the second edition (ISO 7345:1987), which has been technically revised.

This edition includes the following significant changes with respect to the previous edition:

— title of the standard updated from ‘Thermal insulation — Physical quantities and definitions’ to ‘Thermal performance of buildings and building elements — Physical quantities and definitions’;
— title of ISO/TC 163 corrected (Foreword);
— ISO 31‑4 replaced by ISO 80000‑5 in the note in the Scope and added to the Bibliography;
— symbols, names and definitions (in 3.3 and 3.4) adapted to current state (Λ → L, Λ_l → L_2D, U_l → Ψ, coefficient of heat loss → heat transfer coefficient);
— “areal” used instead of “surface” in quantity names (Clause 3) where “surface” was meant to distinguish between a length-related quantity (“linear”) and an area-related quantity (now “areal”) with similar name;
— Formula in 3.1.4 corrected;
— subscript l added in 3.4;
— added a Note 1 to entry in 3.1.11 and a Note 3 to entry in 3.1.13;
— H’ added in 3.2.2 as an alternative name for F_s;
— added “for homogeneous solids” to A.1 in Annex A.

BS EN ISO 7345:2018

Thermal performance of buildings and building components. Physical quantities and definitions

Current

Published:

30 Apr 2018