How are ATCOs pressure ratings determined?
Atco’s UL Listed pressure ratings are determined by testing duct in straight lengths, at ambient temperatures. Testing is done in a static condition (no airflow). The test sample is sealed airtight on both ends and pressurized to 2 ½ times the manufacturers desired rated pressure for a test period of one hour. A minimum of 1 1/4″ of positive pressure must be achieved in order to pass the test.
