The experiments were conducted in a pattern where the tests start with lowest flow rate and then the
face velocity is increased until the test under highest
face velocity was completed.
Hood monitors are required by code to monitor hood
face velocity and provide alarms if velocity is below a minimum setpoint.
In 1979, an article published in ASHRAE Journal recommended that a
face velocity of 0.3 m/s (60 fpm), with the sash fully open, was sufficient to protect the user (Fuller and Etchells 1979).
The CE's low flow constant volume by-pass design maintains consistent
face velocity. CE fume hoods are offered in 30" 36" 48" and 72" widths and can be equipped with a wide selection of accessories to meet specific process needs.
In this setup, the exposed effective filtration area of the medium was [10.sup.4] [mm.sup.2] (15.5 [in.sup.2]), and the filter medium
face velocity was 0.053 m/s (0.17 ft/s) at the system airflow rate of 32 L/min (1.13 cfm).