Primary Procedure:
The primary procedure to determine inflow velocity uses a Direct Inflow Measurement (DIM) Instrument
(i.e. shortridge flowhood). The DIM Instrument can be used directly on the cabinet with NO
CORRECTION FACTORS REQUIRED if operated in the local density default mode. NSF has tested
the cabinet and established listed air velocities expressed in local density. The DIM Instrument should be
equipped with a flowhood that is as close as possible to the width of the cabinet (i.e. NU-425-400 should
use 1 x 4 foot flowhood). The DIM Instrument should also be duct taped to the cabinet to prevent any
sneak air paths from occurring.
The DIM Instrument will read inflow volume (i.e. CFM). Use the window access opening area to
calculate inflow velocity.