Air tightness measurements with blower door measurement method

In well-insulated buildings, up to 60 % of heating energy can be lost through gaps and cracks in the building envelope. Energy-efficient construction can therefore only be achieved with a highly airtight building envelope. This also prevents structural damage caused by condensation and the penetration of draughts, noise or odors. The blower door measurement method can be used to check the tightness of the building envelope.

Buildings should be free of damage, durable and fit for purpose. The SIA Standard 180 therefore formulates requirements for the building envelope as well as limit and target values for airtightness. For buildings constructed in accordance with the Minergie standard, airtightness measurements for quality assurance are recommended (Minergie®) or mandatory (Minergie-P® & Minergie-A®).

Even with a positive measurement result (= limit value fulfilled) with regard to the general tightness of the building envelope, a careful check for individual leaks must be carried out in order to prevent any damage (e.g. due to condensation) to critical components.

In addition to airtightness, the quality of the indoor air in Minergie-ECO® buildings must also be checked after the end of construction (acceptance measurements). As a certified sampling point for indoor air measurements, we can offer you these two services from a single source.

How does the blower door measurement method work?

The blower door measurement method determines how often the air volume of a building is exchanged per hour at a certain pressure difference to the outside air. In order to build up the differential pressure (negative or positive pressure), a fan is installed in an opening in the building. The power of the fan is regulated in such a way that a defined pressure difference is created between the outside and inside air. The air volume flow that the fan must deliver to maintain the pressure corresponds to the volume flows through leaks in the building envelope. The so-called air volume flow characteristic curve is calculated from this.

In negative pressure mode, leaks in the building envelope can be easily identified by hand, smoke tubes or thermography. In positive pressure mode, air leaks can also be visualized using a fog generator.

Ecosens AG is now offering airtightness testing of building envelopes using the blower door measurement method.

Raphael Rapold
Project manager indoor air quality
MSc Business Chemistry

Pascal Diefenbacher
Head of Indoor Air Quality
Dr. sc.ETH, Environmental Nat.