To collect xylene vapors from the source of production,
one canopy hood for the filling unit and two
canopy hoods for the capping units, similar to VS-
903 hood type recommended by the ACGIH’s, were
designed and installed on top of a conveyor belt.
These hoods with exhaust flow capture polluted air
without interfering with processing machinery or
occupational tasks (Fig. 1). Capture velocity of
0.508 m second21 (100 fpm) was chosen for filling
and capping units’ hoods.25