Uncontrolled air infiltration in buildings is compromising energy efficiency and wrecking attempts to reduce CO2 emissions. The time is right to act. This month, Building Services Journal announces a joint initiative involving the CIBSE, BRE and the BSRIA, aimed at improving building airtightness. In an exclusive report, ClBSE president Geoffrey Brundrett launches the airtightness campaign. 

The authors' previous analysis of dynamic insulation is extended to include the inner and outer air film resistances with the objective of modelling the variation in surface temperature with air flow. The boundary condition that comes closest to predicting the variation of the surface temperature with air flow is one which assumes that the conduction heat flux at the wall surface, rather than the net heat flux, is equal to the flux incident on the wall from global environmental temperature, T.;.

Draughtproofing the doors, windows and other sources of excessive air leakage of a dwelling can be an effective and relatively inexpensive means of improving comfort and reducing heat loss by natural ventilation. The doors and windows considered in this digest are existing components not originally designed for draughtproofing. Products for general use on these components have to fill a wide range of gap sizes, be durable and retain the ease of opening and closing.

The need to conserve energy in buildings of all types has led to improved standards of insulation, including those of flat roofs in domestic, public and industrial buildings. This Digest discusses the properties required of thermal insulation in flat and low-pitched roofs with continuous waterproof coverings. It reviews the wide range of products available and suggests criteria for selection.

This paper presents an investigation into natural ventilation in the field of computational fluid dynamics using in particular rather rough mesh cells. The CFD results were then  compared to the wind tunnel results obtained by Gouin at the Centre Scientifique et Technique du Batiment ( CSI'B) in Nantes. The role of eaves, and that of window configuration on windward and leeward sides of buildings was also investigated to search for a better interior airflow.