Ilmanpitävyystesti

An ilmanpitävyystesti, or airtightness test, is a procedure used to measure how airtight a building envelope is. This is crucial for evaluating a building's energy efficiency and ensuring occupant comfort. The test typically involves depressurizing or pressurizing the building using a large fan and then measuring the rate at which air leaks into or out of the structure. This leakage rate is then normalized to the building's size, often expressed in terms of air changes per hour at a specific pressure difference (e.g., ACH50).

The primary goal of an ilmanpitävyystesti is to identify and quantify air leakage pathways. These leaks can occur through cracks, joints, and penetrations in the building's exterior walls, roof, and foundation. Excessive air leakage can lead to significant heat loss in winter and heat gain in summer, increasing energy consumption for heating and cooling. Furthermore, uncontrolled air movement can contribute to moisture problems, such as condensation within building materials, leading to mold growth and potential structural damage. It can also affect indoor air quality by allowing pollutants to enter the building or conditioned air to escape.

The results of an ilmanpitävyystesti are valuable for builders, architects, and homeowners. They help in assessing the quality of construction, identifying areas that require improvement, and verifying compliance with building codes and energy efficiency standards. For new constructions, a low air leakage rate is often a target for achieving high performance. For existing buildings, the test can diagnose issues contributing to high energy bills or discomfort, guiding renovation efforts. Specialized equipment, including a blower door system and a pressure gauge, is used to conduct the test accurately.