Air Tightness |
A calibrated fan is positioned wihtin a doorway of the dwelling to be tested. The remainder of the building is closed up and where appropriate temporary seals placed on extract fans etc.
The internal building envelope is measured which includes the area of the building fabric including the floors, ceilings and external walls.
The fan is run up to depressurise the building and the airflow noted from 25 - 75 Nm-2. Calculations are then undertaken to establish the airflow at a standard pressure of 50 Nm-2.
Air Tightness Testing
Air Tightness / Permeability Testing
Approved Document L1A: 2013
ATTMA Technical Standard L1: 2010
BS 13489: 2001