Airtightness testing is a method that measures the extent of air leakage in a building. When a building is airtight, it not only increases the comfort of the people living in it, but it also enhances its energy efficiency.

It is usually difficult to detect any cracks or gaps in the building that are causing air leakage. These gaps and cracks can be obscured by the finishing of the internal building or the external cladding. Therefore, the only way for airtightness testing is to find out and measure the leakage paths in the building fabric.

According to the new regulations, all developers should test a minimum of 20% of the dwellings on a building site. However, it also depends on the different types of houses to make sure that a consistent sample is taken from the construction site.

Things to Consider for Airtightness Testing:

Before testing a building or a construction site for airtightness, you should consider:

  • You send the drawing of the development and the design of air permeability requirements to the engineers you need to hire for airtightness testing.

  • This testing is usually undertaken in 30 to 60 minutes.

  • The weather condition of the site can affect the testing. Wind should not be more than 6m s-1.

  • Provide all the required information such as the size of the building envelope to the engineer before he comes to your site.

Prepare the Site:

  • Open all internal doors and secure them

  • Close all windows

  • All mechanical ventilation systems should be switched off

  • All ventilation grids should be sealed

  • Smoke vents should be closed

  • Fill all the drainage traps

On-Site Testing Procedures:

  • Check all the weather conditions including temperature, wind speed, and barometric pressure.

  • Connect a fan to an aperture of the building envelope e.g. a door.

  • Set up all the testing equipment

  • Gradually increase the speed of the fan and bring it to 50 Pa.

  • Gradually decrease the speed of the fan to 20 Pa.

  • Record the air volume that flows through the fan. It will be equal to the air leakage through the building envelope.

  • Record pressure difference across the building at each fan speed (if using more than 1 fan).

This whole procedure helps in determining the airtightness of the building.