Testing Hood Air Volume - Procedures; With Baffle Filters (Xb Series) - Accurex XBEW Installation, Operation And Maintenance Manual

Testing Hood Air Volume
Baffle Filter - Rotating Vane Method
With all the filters in place, determine the total hood
exhaust volume with a rotating vane anemometer as
follows:
Airflow
1. All cooking equipment should be on.
2 in.
(50.8 mm)
2. Measure the velocities. Velocity measurements
should be taken at five locations per filter. These
must be over a filter slot as in Fig. 7.
Fig. 7
X
X
X
L
Nominal Filter Size
Measure and record the velocity of each location.
A digital 2.75 in. (69.85 mm) rotating vane anemometer
or equivalent is suggested. The center of the
anemometer should be held 2 in. (50.8 mm) from the
face of the filters. It is helpful to make a bracket to keep
Example: Exhaust only hood with three 20 x 16 filters
Measured velocities in ft/min. for one 20 x 16 filter
Average Velocity =
=
(Imperial)
=
(Metric)
For a nominal filter size of 20 x 16, the conversion factor is 1.90 Imperial (.177 Metric)
Volume for one filter = Conversion Factor x
=
(Imperial)
=
(Metric)
Total hood volume =
=
(Imperial)
=
(Metric)
16 Kitchen Hoods • Type I and Type II
Rotating Vane
Anemometer
H/4
X
H
X
H/2
H/4
Sum of Velocity Readings
Number of Readings
255 + 250 + 256 + 248 + 240
5
4663 + 4572 + 4681 + 4535 + 4389
5
Average Velocity
1.90 x
.177 x
(Filter 1 Volume) + (Filter 2 Volume)
474.6 +
809 +
the anemometer at the 2 in. (50.8 mm) distance and
parallel to the filter. Both squareness and distance are
very important for accuracy.
Airflow
Calculate the average velocity for the filter.
3. Determine the filter's conversion factor from the
table.
4. Calculate the filter's volume in CFM (m
multiplying the average velocity by the conversion
X
factor.
5. Calculate the hood's volume by repeating the
process for the remaining filters and summing the
individual filter volumes.
Nominal Filter Size (H x L)
X
Inches Millimeters
16 x 16
16 x 20
20 x 16
20 x 20
= 249.8 ft/min.
= 4568 m/hr
249.8 ft/min. = 474.6 cfm
4568 m/hr = 809 m
+ (Filter 3 Volume)
455.4 +
880 +
Rotating Vane
Anemometer
2 in.
(50.8 mm)
3 /hr) by
X
X
Imperial
X
Conversion
Factor
400 x 400 1.63
500 x 400 2.13
L
400 x 500 1.90
500 x 500 2.48
255
(4572 m/h)
(4663.44 m/h)
256
(4681.73 m/h)
248
(4535.42 m/h) (4389.12 m/h)
3
/hr
470.1 = 1400.1 cfm
799 = 2488 m
H/4
H
Metric
H/2
Conversion
H/4
Factor
.157
.198
.177
.230
250
240
3
/hr