ACH – air changes per hour
Air barrier - a line through the envelope of the dwelling where the barrier to air leakage will be.
Air leakage - the uncontrolled flow of air through gaps and cracks in the fabric of dwellings (sometimes referred to as infiltration, exfiltration or draughts).
Air Permeability - is the physical property used to measure Air Tightness of the building fabric. It is defined as air leakage rate per envelope area at the test reference pressure differential across the building envelope of 50 Pascal (50N/m2 )
Cavity barrier - a construction provided to close a concealed space against penetration of smoke or flame, or provided to restrict the movement of smoke or flame within such a space.
Cavity closer - masonry unit or plastics component that closes a cavity at the vertical sides of an opening
CPC - Carbon Performance Coefficient - the calculated carbon dioxide emission rate of the building divided by that of the reference dwelling in Building Regulations 2011 TGD-L (Dwellings) Appendix C.
Dewpoint is the temperature at which air becomes saturated with vapour.
EPC - Energy Performance Coefficient -the calculated primary energy consumption of the proposed dwelling divided by that of the reference dwelling, Appendix C, Building Regulations 2011 TGD-L (Dwellings).
Appropriate air tightness sealant - sealant should be fit for purpose and meet guidance in Technical Guidance D-Materials and Workmanship.
Appropriate air tightness tape - tape fit for purpose and meet guidance in Technical Guidance D-Materials and Workmanship.
Interstitial condensation - condensation within building elements.
MPCPC - Maximum Permitted Carbon Performance Coefficient
MPEPC - Maximum Permitted Energy Performance Coefficient
Documents Referred To*
Building Regulations Part L 2011 Technical Guidance Document L Conservation of Fuel and Energy – Dwellings
BRE Report BR 497, Conventions for calculating linear thermal transmittance and temperature factors, BRE, 2007
HomeBond House Building Manual 6th Edition
EST Guide GPG224 – Improving airtightness in dwellings, 2005 Edition. Further information on airtightness principles and practice is contained within this document
BRE Information Paper IP 1/06 – Assessing the effects of thermal bridging at junctions and around openings, 2006
ATTMA TS1 – Measuring air permeability of building envelopes, 2006 Edition.