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Conventions for U-value calculations (BR443 2019)  <B>Download</B>

Conventions for U-value calculations (BR443 2019) Download

by [Brian Anderson], Ludmilla Kosmina (18-Nov-2020)

Book Description

Since publication in 2019, section 11.1 has been updated. The update has been added at the end of this document.


The guidance in this document is concerned with the calculated U-values of new building elements, including walls, roofs, floors, windows and doors. Guidance is given on: thermal conductivity of materials (section 3); various issues that commonly arise when undertaking U-value calculations (section 4); various types of construction element, identifying which of the issues mentioned in section 4 apply to which construction type (sections 7 to 14). The document does not reproduce the details of the calculation methods, for which the reader is referred to the relevant British Standards and other sources (see References and further reading).

The 2002 edition of BR443 can be obtained here.

The 2006 edition of BR443 can be obtained here.



1 Introduction
2 U-value calculation: Simplified methods and numerical methods
4 Details of U-value calculations
5 Elements adjacent to an unheated space
6 Expression of results and areas to which U-values apply
7 U-values for walls
8 U-values for roofs
9 U-values for floors
10 U-values for basements and swimming pools
11 U-values for windows, roof windows and rooflights
12 Curtain walls
13 Dynamic transparent building elements
14 U-values for doors
15 U-values of existing (old) walls, roofs, and floors in dwellings
16 Appendix A: Glossary/definitions
17 Appendix B: U-values of uninsulated floors
18 Appendix C: Example of calculating U-value for elements
19 References and further reading 

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