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High Velocity Cartridge Filters
A. Exhaust
With all the filters in place, determine the total hood exhaust
volume with a shortridge meter as follows:
1. All cooking equipment should be on. If the hood has
internal short circuit make-up air, it should be turned off.
. Measuring Velocities
• Set up the shortridge meter. Leave all holes of
Velgrid open. Do NOT tape over holes that are not
over openings. The conversion factor takes this into
account.
• Position the grid over each filter as shown.
• Take velocity readings for each filter.
3. *Calculate each filter's volumetric flow rate by summing
the flow rate of each individual filter in the hood.
4. *Calculate the total hood's volumetric flow rate by
summing the flow rate of each individual filter in the hood.
*Note: For best accuracy multiply the velocity of each filter by
its conversion factor and sum the flow rates. Averaging the velocity
measured for all filters may cause error.
Nominal Filter Size (H x L)
Inches
Millimeters
16 x 16
16 x 0
0 x 16
0 x 0
Example: Measured velocities for 0 x 0 filter = 8 fpm (5157 m/hr)
Flow rate for one filter
(Imperial)
(Metric)
Total hood flow rate
Imperial
Conversion Factor
400 x 400
400 x 500
500 x 400
500 x 500
Conversion
=
x
Factor
=
1.50
x
=
.139
x 5157 m/hr =
= (Filter 1 Flow Rate) + ... + (Filter X Flow Rate)
= 43.0 + 41.8 + 40.7 + 418. = 1683.7 cfm
= 717 + 717 + 715 + 711
Metric
Conversion Factor
ft
1.
.113
ft
1.67
.155
ft
1.1
.11
ft
1.50
.139
Average
Velocity
8 fpm
=
43.0 cfm
717 m
= 860 m
m
m
m
m
1/ width
3
/hr
3
/hr
Fig. 9
1/ height
Fig. 30
1
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