Building Envelope Calculator

CA Building Envelope Calculator

The CA Building Envelope Calculator allows you to see at a glance what impact your building envelope design decisions will have in passing Part L2A 2010 requirements.

The calculator is simple to use and only requires some basic details on the parameters of the building. From there information such as U-values and air permeability can be altered to see what the effect is on the overall percentage improvement of the building envelope in accordance with Part L.

The CA Building Envelope Calculator produces results for:

  • Warehouses
  • Supermarkets
  • Schools
  • Retail
  • Hotels
  • Office: Shallow Pan – Heated
  • Office: Shallow Pan – Air Con
  • Office: Deep Pan – Air Con

The amendments that can be made are indicative only for the external envelope. The enhancements for the Actual building over the 2010 Notional building with the same envelope areas including the same areas of rooflights. The calculator does not take account of solar gains, heating, cooling, lighting, etc.

In accordance with Approved Document L2A 2010, the whole building must be calculated for compliance using Simplified Building Energy Model (iSBEM) tool or similar, which takes in to consideration; solar gains, heating, cooling, lighting, etc. This CA Building Envelope Calculator should only be used to establish the principles of enhancing the thermal elements of the building i.e. the overall performance of the external building envelope (including floor). The CA Building Envelope Calculator is not a replacement for iSBEM.

Air leakage has been widely identified as the primary source of heat loss from a building’s interior.

Reducing air permeability is a major factor in demonstrating compliance with Building Regulations, and where heating is required can make the difference between a pass and fail. A good air permeability result will aid in delivering Energy Performance Certificate (EPC) ratings in Band A. With return on investment (ROI) and yields likely to be affected by the overall thermal performance of the envelope, the designer needs to select the most flexible roof and wall system available.

Heat loss not only contributes to higher building running costs but also increases unnecessary CO2 emissions, due to the additional heating load required to replace it.

Lower air permeability rates are harder to achieve as the building decreases in size. This is because the smaller the building, the larger the ratio of building air space to areas where air leakage can occur ie. perimeter details and doors.

To receive a copy of the CA Building Envelope Calculator, complete the following form and a training session can be arranged.

Friday, July 27th, 2012