Lufttæthedsprøvninger

Lufttæthedsprøvninger, also known as airtightness testing or blower door testing, are crucial procedures used to measure the air leakage rate in buildings. This process quantifies how much uncontrolled air enters or leaves a building through cracks, gaps, and openings in the building envelope. The primary tool used is a blower door, which consists of a powerful fan mounted in an exterior doorway. This fan is used to either pressurize or depressurize the building, creating a controlled airflow.

During a lufttæthedsprøvning, the fan speed is adjusted to achieve a specific pressure difference between the inside and outside of the building, typically 50 Pascals. By measuring the volume of air the fan needs to move to maintain this pressure, the air leakage rate can be calculated. This rate is often expressed in terms of air changes per hour (ACH) or as a leakage coefficient. The testing is performed with all natural ventilation openings like windows and doors closed, and mechanical ventilation systems either switched off or sealed.

The results of a lufttæthedsprøvning are vital for several reasons. They help identify areas where heat loss is occurring due to air infiltration, leading to increased energy consumption for heating and cooling. Furthermore, excessive air leakage can compromise indoor air quality by allowing pollutants, dust, and moisture to enter the building, potentially leading to mold growth and other health issues. Building regulations in many countries mandate specific airtightness levels for new constructions, and these tests are used to verify compliance. Understanding a building's airtightness also aids in the proper design and commissioning of mechanical ventilation systems.