When installed or modified and at least annually thereafter, fume hoods, fume hood exhaust systems, and laboratory special exhaust systems should be inspected and tested as follows:
- Visual inspection of the physical condition of the hood interior, sash, and ductwork
- Measuring device for hood airflow
- Low-airflow and loss-of-airflow alarms at each hood
- Face velocity
- Verification of inward airflow over the entire hood face
Changes in laboratory conditions that might affect hood performance such as system rebalancing and a change in the source of make-up air should trigger an inspection and test.
Deficiencies in hood performance should be corrected or one of the following should apply:
- The activity within the hood should be restricted to the capability of the hood.
- The hood should not be used.