Airtightness Testing in the Republic of Ireland



Part L – Domestic Dwellings

Part L applies to works to new dwellings, where the work commences or takes place on or after 1 July 2008.

A proportion of dwellings on all development sites should be tested - see below.

Number of Pressure Tests per Dwelling Type
No. of Units Number of tests
4 or less One test
Greater than 4, but equal to or less than 40 Two tests
Greater than 40, but equal or less than 100 At least 5% of the dwelling type
More than 100
a) where the first five tests achieve the design air permeability
b) Where one or more of first five tests do not achieve the design air permeability

a) At least 2% (for dwellings in excess of 100 units)

b) At least 5% of units, until 5 successful consecutive tests are achieved, 2% thereafter

This guide explains what the requirements mean to all parties in the construction process, and provides ready-made checklists and specification clauses to use when procuring an airtightness test.  BSRIA are in a unique position to  explain the requirements of Part L as they are referred to in the Technical Guidance Document L.

Non – Domestic Dwellings

Airtightness testing is not currently mandatory for commercial buildings, however, many clients are specifying air permeability targets to improve energy efficiency and occupancy comfort.  Rising energy costs and environmentally driven regulatory changes are forcing rapid and demanding changes in the way buildings are constructed. 

Airtightness is a vital component of sustainable design.  Buildings that are not airtight will cause their mechanical ventilation and air conditioning systems to struggle to maintain comfort conditions.  A leaky naturally-ventilated  building will suffer poor control, draughty conditions, and, in all likelihood, excessive energy consumption for heating.

In order to control this energy loss, the Building Regulations will regulate the overall leakage of the building structure by testing, using a pressurising/depressurising fan method.

We have recently completed a number of high-profile Airtightness tests (including consultancy) for commerical buildings. See our sample Airtightness project list.


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Tel: + 44 (0) 28 38 891 320


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