From time to time, Mason is contracted to supply duct silencers which are required to withstand very high air pressures. In order to ensure that the silencers meet the pressure performance requirements, each unit is subjected to air pressure testing.

During the test, air pressure within the unit is raised to the specified level and must not drop below that level for a minimum of 15 minutes.

Air leakage at seams and welds is checked using water and detergent to check for air bubbles.