U-value conventions in practice: Worked examples using BR 443
BRE (Building Research Establishment) is an independent, research-based consultancy, testing and training organisation, operating in the built environment and associated industries.
U-value conventions in practice: Worked examples using BR 443 was written by Sean Doran and published by BRE on 13 Jan 2012. The 36 page publication helps designers develop a better understanding of how to calculate U-values and kappa-values for use in calculation tools. See also Conventions for U-value calculations (2006 edition) BR 443.
U-values, (sometimes referred to as thermal transmittances) measured in W/m²K represent how effective elements of a buildings fabric are as insulators. That is, how effective they are at preventing heat from transmitting between the inside and outside of a building. The lower the U-value of an element of a building's fabric, the more slowly heat is able to transmit through it, and so the better it performs as an insulator.
Kappa values (sometimes referred to as thermal mass values) measured in kJ/m2K represent the heat capacity per square metre of a material. This is used to quantify the thermal mass of building elements such as walls and floors. The higher the kappa-value, the greater the thermal mass, that is the more heat the element is able to store.
These values are integral to the use of energy calculation tools such as the Standard Assessment Procedure (SAP) and the Simplified Building Energy Model (SBEM), which support Part L of the Building Regulations, Conservation of Fuel and Power. As a result, it is important that they are calculated reliably.
U-value conventions in practice:
- Supports the Building Regulations Part L and other legislation on the energy performance of buildings.
- Helps raise an awareness of and understanding of U-values and kappa-values.
- Encourages a unified, consistent approach to calculating U-values and kappa-values.
- Explains calculation methods using worked examples for wall, roof and floor designs.
- Supports training programmes for practitioners carrying out energy assessments and using U-value calculation software.
- Provides guidance about calculating U-values using standard simplified methods.
Its contents include:
- Introduction.
- Summary outline of the U-value calculation method.
- The worked examples.
- References and further reading.
[edit] Find out more
[edit] Related articles on Designing Buildings Wiki
- Approved document L.
- BRE articles on Designing Buildings Wiki.
- Building regulations.
- Building Research Establishment.
- Conventions for calculating linear thermal transmittance and temperature factors.
- Conventions for U-value calculations (2006 edition) BR 443.
- Energy performance certificate.
- Insulation.
- Kappa value.
- PA ratio.
- Simplified Building Energy Model.
- Standard Assessment Procedure.
- Thermal bridge.
- Thermal mass.
- U value.
Featured articles and news
The impact of COVID-19 on global HVAC&R markets
Reviewing trends and projections.
Legislation will establish initiatives to move towards net zero.
Status determination statement
How to document contractor employment status.
Social distancing goes high tech
Tech tools to help manage people and space post-pandemic.
Eclectic Edwardian architecture
A style that ranges from mock Tudor to arts and crafts to the 'Wrenaissance'.
Free guide from Secured by Design.
Building Back Better: Circularity
BREEAM strategy for sustainability and the circular economy.
Free tool to improve the construction programming process.
Building services verification
Are buildings doing what they're supposed to be doing?
Cities with quick access to everything by foot or bike.
The pressures and pinch points of global destinations.
The green economic recovery beyond COVID-19
Making the case for a sustainable future.
Building Conservation Certification Scheme expands eligibility
Retrofit professionals now entitled to enter CIOB programme.
Unlimited Potential report looks at gender and racial bias
How, where, when and why stereotypes happen.
Comments