- Project plans
- Project activities
- Legislation and standards
- Industry context
Last edited 06 Nov 2020
‘…the physical property used to measure airtightness of the building fabric. It is defined as air leakage rate per hour per square metre of envelope area at the test reference pressure differential of 50 pascals (50 N/m2). The envelope area, or measured part of the building, is the total area of all floors, walls and ceilings bordering the internal volume that is the subject of the pressure test. This includes walls and floors below external ground level. Overall internal dimensions are used to calculate this envelope area and no subtractions are made for the area of the junctions of internal walls, floors and ceilings with exterior walls, floors and ceilings.’
The limiting air permeability is the worst allowable air permeability.
The assessed air permeability is the value used in establishing the Dwelling Emission Rate (DER) and Dwelling Fabric Energy Efficiency (DFEE) rate and is based on specific measurement of the dwelling concerned or on measurements of other dwellings of the same dwelling type.
 Related articles on Designing Buildings Wiki
- Air permeability in isolation rooms.
- Air permeability testing.
- Air tightness in buildings.
- Approved documents.
- Building emission rate.
- Dwelling emission rate.
- Dwelling type.
- Energy performance certificates.
- Standard assessment procedure.
- Target emission rate.
- The history of non-domestic air tightness testing.
Featured articles and news
TASC/CIOB study looks at post-pandemic struggles and trends.
The Government announces recalibrated goals.
ECA proposes strategies for the present and the future.
Paul Morrell to lead independent review of the construction products testing regime.
Standard will help employers foster wellbeing and manage psychosocial risks.
Global fire standards for safety of people and property.
An introduction to the 5 core principles of lean.
Can the profession use its skills to save the world from climate change?
How faulty science resulted in sanitation reform.
Improving facilities, accessibility and overall appearance.
Free download of TG 12/2021 available.
TESP works with The Youth Group to form skill sharing network.
Big tech collaborates on platform for the built environment.
Letter signed by 21 organisations sent to MHCLG.
Click the button to subscribe.