Greenheck 452413 Installation, Operation And Maintenance Manual page 23

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.
2. 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
16 x 16
16 x 20
20 x 16
20 x 20
Example: Measured velocities for 20 x 20 filter = 282 fpm (5157 m/hr)
Flow rate for one filter
(Imperial)
(Metric)
Total hood flow rate
23
Canopy Hood
Conversion Factor
Millimeters
400 x 400
400 x 500
500 x 400
500 x 500
Conversion Average
= x
Factor Velocity
= 1.50 x 282 fpm
= .139 x 5157 m/hr =
= (Filter 1 Flow Rate) + ... + (Filter X Flow Rate)
= 423.0 + 421.8 + 420.7 + 418.2 = 1683.7 cfm
= 717 + 717 + 715 + 711
Imperial Metric
Conversion Factor
ft 2
1.22 .113
ft 2
1.67 .155
ft 2
1.21 .112
ft 2
1.50 .139
= 423.0 cfm
3
717 m /hr
= 2860 m 3 /hr
m 2
m 2
m 2
m 2
1/2 width
Fig. 37
1/2 height
Fig. 38
®