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.;.