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Reina Compliance – New Build Air Tightness Testing

Reina Compliance provides air testing for all types of domestic dwellings including new build houses and flats, in the South East.  Our service is quick and seamless with all testing complying to up-to-date Building Regulations.

An air tightness test measures the uncontrolled flow of air through a building envelope.  Air leakage or air infiltration can lead to energy wastage, resulting from the increased loads placed on the space heating and/or air conditioning systems by the constant uncontrolled flow of air through the fabric of the building.

The test involves connecting a fan to a suitable aperture in the building envelope and creating a pressure differential between the internal and external atmosphere.  The fan speed is increased in steps to a maximum and then decreased in steps.  The air volume flow rate through the fan (equal to the air leaking through the building envelope) is measured at each fan speed to calculate the overall air permeability.

Technical Competence

Our testers are fully accredited with the Independent Airtightness Testing Scheme conducting tests to Air Tightness Testing and Measurement Association Technical Standard 1, using equipment calibrated annually at a certified UKAS laboratory.

Building Regulations

The latest version of Building Regulations Approved Document Part L1A (2013) incorporating 2016 amendments (for England) took effect on 6th April 2014 and applies to all new dwellings registered with a Building Control Body on or after this date. The previous version L1A (2010)
will apply to any developments registered before this date that have made a meaningful start.

Test Requirement

On each new development under Part L1A (2013) an air tightness test should be carried out on three units of each dwelling type or 50% of all instances of that type, whichever is the less.

Each unit tested must achieve a standard of air leakage no greater than the (q50) “Design Air Permeability” shown in the SAP calculation with a maximum allowed of 10 m3/(m2.h) nb. Other units of the same dwelling type that are not tested will use the value equal to the average result of the units of the same type tested with the addition of 2 m3/(m2.h) when completing the “As-Built” SAP calculations and On Construction EPC

Alternative Approach

Sites of no more than two dwellings can avoid the need for an air tightness test:-

  • By using a value of 15 m3/(m2.h) when calculating the Dwelling CO2 Emission Rate (DER) OR
  • By demonstrating that during the preceding 12-month period a dwelling of the same dwelling type constructed by the same builder had been air tightness tested and had achieved the design air permeability required by the newly constructed dwelling.

Dwelling Type

For dwellings to be classed as of the same type they have to fit with the following criteria:

  1. Be of the same generic form (i.e. Detached, Semi Detached, Mid Terrace, End Terrace, Ground Floor Flat inc. Maisonette, Mid Floor Flat and Top Floor Flat inc. Maisonette).
  2. Be of the same number of storeys.
  3. Be of the same “Design Air Permeability.”
  4. Have similar adjacency to unheated spaces such as corridors, stairwells and integral garages etc.
  5. Have the same principal construction details.
  6. Have a similar number of significant penetrations (i.e. doors, windows, chimneys, flues, supply/exhaust terminals and waste water pipes)
  7. Have envelope areas that do not differ by more than 10%

Test Preparation

The air tightness test is best carried out after second fixing (i.e. When all plumbing work has been completed and heating/ventilation systems installed) ideally just prior to carpet and/or other flooring being laid. External doors and windows must be fitted.

All designed ventilation such as trickle vents, extractor fans, air supply grilles and open flues will be temporarily sealed by the air tightness testing technician.

The test is designed to measure the air leakage of the building in its finished state and as such, areas that are unfinished are not permitted to be “taped up” in order to pass the test.

For more information regarding all our Reina Compliance services and our Air Testing please contact us on 01303 268468 or email



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