Leakage factor – Retrotec Commercial 441 and 451 DucTester User Manual
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©Retrotec Inc. 2015
Leakage Factor
Leakage Factor, F, is the maximum allowable leakage in CFM per 100 square feet of ductwork
(not counting blanking plates used to seal the ducts). This can be obtained from the graph, the table
or the formula.
Leakage Factor from the table. For example, if the Test Pressure was 2 in WC and the
Leakage Class was 12 then the Leakage Factor, F would be 18.8 CFM per 100 square feet.