face velocity

face velocity

The velocity of air at the face of an air diffuser or air terminal unit.
References in periodicals archive ?
In the 1990s, this was further studied, and a correlation of face velocity was developed for the hole-to-hole timing of a blast and confirmed that when the hole-to-hole timing is reduced, the throw is improved.
100 fpm face velocity creates highly turbulent air that can allow the nanoparticles to escape, causing a number of health risks.
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).
Small-scale version showed average collection efficiency of 80% over a wide range of diesel exhaust mass concentrations (5 to 400 mg/[m.sup.3]) and 1.5 m/s diesel exhaust face velocity. When ESBEC was tested continuously for 6 hours with diesel exhaust concentration of 300-400 mg/[m.sup.3], it maintained collection efficiency of >95%.
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.
Also, various technologies for managing airflow through fume hoods have become more widely accepted, including such measures as zone presence sensors to reduce face velocity when an operator isn't present, automatic sash closers and constant face velocity flow control, according to Yacknowitz.
They feature the easy-to-use AirSafe[TM] TOUCH automatic safety controller, which automatically increases or decreases blower speed to maintain the users' pre-set face velocity, ensuring airflow is within standard operating parameters.
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).
A face velocity at 100 fpm ensures containment of fumes and an alarm will alert the operator when the airflow falls to an unacceptable level.