Equivalent area
Domestic Ventilation Compliance Guide, 2010 Edition (with 2011 amendments), published by the Department for Communities and Local Government in July 2011, suggests that equivalent area is: ‘…a measure of the aerodynamic performance of a ventilator. It is the area of a sharp-edged circular orifice which air would pass through at the same volume flow rate, under an identical applied pressure difference, as the opening under consideration.’
Approved Document O: Overheating, published by HM Government in 2021, defines equivalent area as: ‘A measure of the aerodynamic performance of an opening. It is the area of a sharp-edged circular orifice through which air would pass at the same volume flow rate, under an identical applied pressure difference, as through the opening under consideration.’
The equivalent area of a background ventilator is determined at 1Pa pressure difference in accordance with Table 1.7 of Approved document F: Volume 1: Dwellings, 2021 edition.
See also: Effective area and Discharge coefficients, free, effective and equivalent areas
[edit] Related articles on Designing Buildings
- Air change rates.
- Approved Document F.
- Background ventilator.
- Cross ventilation.
- Discharge coefficients, free, effective and equivalent areas
- Displacement ventilation.
- Effective area.
- Free area.
- Heat recovery ventilation.
- Mechanical ventilation.
- Natural ventilation.
- Stack effect.
- Thermal comfort.
- Underfloor air distribution.
- Ventilation.
- Whole building ventilation.
Discharge coefficients, free, effective and equivalent areas
Featured articles
Check out some of the best features and news from Designing Buildings as well as key stories from around the web.
Construction Management, 24 June
FMB pilot aims to build pipeline of site-ready tradespeople.
A quick introduction.
CLC publishes Mental Health Joint Code of Practice.
A quick introduction to its uses and risks.
Construction Management, 17 June
Government rolls out digital planning tool to all local authorities.
Your views needed - a strategy for the professions, trades and occupations.
Confronting competency, codes, capacity and costs.
The hidden risk in modern construction supply chains.
Construction Management, 10 June
24 months to 14: CITB launches accelerated apprenticeships.
Bridging the gap between clients and contractors
Concerns remain around contractor quality, capability, and delivery.
Construction Management, 10 June.
Heat pumps beat boilers in new home tests.
















