Air testing, air leakage testing, air permeability testing, part L1a L2a L2b

The 2010 revisions for Building Regulations are now L1A, L2A and L2B concluded.

A summary of the key factors affecting Air Testing are detailed below.

Perhaps one of the most significant factors is the tightening of the definition of a dwelling type

From:

A dwelling type is defined as a group of dwellings on a site having the same generic form (detached, semi-detached including end terrace, mid terrace mid-floor flat, ground-floor flat, top-floor flat) and where the same construction methods are used for each of the main elements (walls, floors, roofs etc). Small variations in the floor area do not constitute a different dwelling type.

To:

Dwelling type is a means of allocating each dwelling on a development to a particular group to provide the basis for assessing the pressure testing regime. To be classed as of the same type dwellings have to:
i)be of the same generic form (i.e. detached, semi-detached, end terrace, mid terrace, ground floor flat (inc. ground floor maisonette), mid floor flat, top floor flat (inc. top floor maisonette);
ii)be of the same number of storeys;
iii)be of the same design air permeability;
iv)have similar adjacency to unheated spaces such as stairwells, integral
garages etc;
iii)have the same principal construction details (as identified by the ACD or bespoke detail reference codes);
iv)have a similar (i.e. ±1) number of significant penetrations, i.e. for windows, doors, flues/chimneys, supply/exhaust terminals, waste water pipes);
vii)have envelope areas that do not differ by more than 10% (see air permeability for a definition of envelope area).

The relevant documents can be viewed at:

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