Conventions for U-value calculations

Report BR 443

BRE, 2019
Conventions for U-value calculations Download document

Document Status

Current

Supplement

Core Supplement

Series

Report

Abstract

Appropriate British, European and international standards used to establish the measured values of thermal transmittance (U-value) and thermal resistance (R-value) of a construction layer by numerical calculation, focussing on new building elements such as walls, roofs, floors, windows and doors.

Author

Anderspn, B. and Kosmina, L.

History

Third edition published November 2019; incorporating the April 2021 update to Section 11.1. Supersedes the 2006 second edition. First published in 2002.

Subjects

  • Coverings and surface finishes
  • Waterproofing/damp proofing
  • Felt/flexible sheets
  • Internal environment
  • Windows
  • Flexible sheet tanking/damp proofing
  • Special subject areas
  • Environmental issues/energy
  • Windows and doors

Publisher History

BRE is a building science centre that generates new knowledge through research. This is used to create products, tools and standards that drive positive change across the built environment. BRE helps its government and private sector clients meet the significant environmental, social and economic challenges they face in delivering homes, buildings and communities. BRE is owned by the BRE Trust, a registered charity. The Trust uses the profits made by the BRE companies to fund research and education that advances knowledge of the built environment.

Information

NBS

NBS has produced specification systems and information products for construction industry professionals for more than 40 years. The National Building Specification is the recognised UK national standard and is used by over 5,000 organisations. NBS is part of RIBA Enterprises Ltd.

Accuris

We connect trusted knowledge to customers' workflows – mitigating risk, increasing efficiency and accelerating innovation For more than 60 years, leading R&D and engineering-intensive organizations have relied on us to achieve on-time, on-budget delivery of complex projects and new products. We deliver an unparalleled combination of technical content and Artificial Intelligence (AI) technologies to surface answers from the vast universe of technical knowledge, both inside and outside the organization. In a single interface, we connect the dots between information scattered across many different sources, allowing technical professionals to make better, more informed decisions faster.