1st June 2017

Scotland

Building Regulations for Scotland, through Section 6.2 of the technical handbook (‘Energy – Building Insulation Envelope”), stipulate the requirement for air tightness testing of buildings. Currently, this requirement exists in both the domestic and non-domestic technical handbooks and applies to new dwellings and non-dwellings respectively.

Testing Requirements – Dwellings

Section 6.2.5 of The Scottish Technical Handbook 6 for Dwellings reads:

“Testing of completed dwellings should be carried out on at least 1 in 20 dwellings or part thereof. The verifier may request that the frequency of testing be varied as considered appropriate to ‘reasonable inquiry’ and in response to previous test results within a development.
In larger developments, it is advisable to test more than one example of the same dwelling type and form, completed at different stages in the overall development, to help establish consistency in quality of construction. In smaller developments, the proportion of dwellings tested may also need to increase, dependent on the range of type and form of dwellings present, to ensure a representative sample is taken.
Normally, for a development of one dwelling, an air-tightness test should be carried out as it will not be possible to obtain comparative data on the quality of construction from similar dwellings.”

Test Standard

Section 6.2.5 references different standards from the rest of the UK:

Testing should be in accordance with BS EN 13829: 2001 – ‘Thermal performance of buildings – determination of air permeability of buildings – fan pressurization method’.
Practical advice on procedure for pressure testing is given in the ATTMA publication ‘Measuring Air Permeability of Building Envelopes’.

Dwelling Types

A BSD document Sound and Air-Tightness Testing 2015 Edition which is referenced in Section 6 – Energy (Dwellings) makes reference to dwelling types in Scotland:

  • “Flat” means a dwelling on one storey, forming part of a building from some other part of which it is divided horizontally, and includes a dwelling of which the main entrance door and associated hall are on a different storey from the remainder of the dwelling.
  • “High rise domestic buildings” means a domestic building with any storey at a height of more than 18 metres above the ground.
  • “House” means a dwelling on one or more storeys, either detached or forming part of a building from all other parts of which it is divided only vertically.
  • “Maisonette” means a dwelling on more than one storey, forming part of a building from some other part of which it is divided horizontally.

Non-Dwellings

Section 6.2.7 of The Technical Handbook 2016 – Energy (Non-Dwellings) states:

All new non-domestic buildings and large extensions which are subject to Standard 6.1 (carbon dioxide emissions) should be tested on completion, with the following exceptions:

  • a. multiple units, under the same building warrant, of not more than 150m² in floor area and of the same form and construction. A sample of 1 in 20 units or part thereof may be tested as it can be considered that all units will have a similar build standard. The verifier should select the units to be tested by the applicant
  • b. modular building of less than 500m² where no site work is needed other than connection of modules, provided test results for similar configuration of modules with the same connection details is available
  • c. large extensions subject to Standard 6.1, where a default infiltration rate of 10m³/h.m² @ 50 Pa is declared for the actual building, and
  • d. new buildings where due to size or complexity, it is impractical to carry out testing of the building, provided this has been demonstrated as part of the building warrant submission and evidence to support the declared infiltration rate is provided.

Shell and Fit-out Buildings

Section 6.2.7 of The Technical Handbook 2016 – Energy (Non-Dwellings) states:

Shell and fit-out buildings – where a shell building is subject to a continuing requirement under Standard 6.1, testing should be carried out both at completion of the shell and, again when the fit-out is completed