A flow rate test, sometimes called an airflow test, extractor fan test or Part F test, is a test which directly measures the airflow of an extractor fan for Part F compliance.

Part F of the Building Regulations requires that air flow rates for all mechanical ventilation systems (i.e. extractor fans) installed in new dwellings must be tested on site using an Approved Method. A Commissioning Notice including the results of these tests must be given to Building Control. These Commissioning Notices are also known as PEATA Certificates.

A flow rate test measures the amount of air passing through the extractor fan in a period of time. It is measured in litres per second (l/s), cubic metres per second (m3/s), or cubic feet per minute (CFM). The test results on a Commissioning Notices / PEATA Certificate must be specified in l/s

Flow rate test equipment must be calibrated annually.Flow rate tests are performed using specialist equipment which must be calibrated annually at a UKAS-approved laboratory. PEATA members can get a free loan of this equipment for their first test, and advice on hiring or purchasing their own equipment. Various calculations must be performed to ensure measured flow rates are compliant, but these are done automatically via the PEATA web app, which also creates the PEATA Certificate.