MEASURING AIRFLOW
Measuring Airflow
The XG hood has been designed to give you
an approximate airflow per linear foot of hood
based on the static pressure measured at a
particular location on you XG hood section.
The method will require the balancer to have a
manometer, (Dwyer 475-00 FM
recommended), which he/she will use to get a
static pressure measurement for every hood
section. The static tap, as seen in fig. 8, will be
located behind a small 4 to 6 screw access
cover, located directly above your filters.
Instructions:
1. Turn on the exhaust fan to the hood
section you intend to measure the
exhaust airflow.
2. Remove access cover as seen in fig. 8.
3. Locate the static tap, and remove the
sealing boot.
4. Zero you Dwyer 475-00 Digital
Manometer.
5. Take the 1/8
”
vinyl tube attached to your
Dwyer 475-00 Digital Manometer and
attach it to the static tap.
6. Record the value indicated on your
meter.
7. Compare your recorded values to Fig. 9,
Airflow vs. Static Tap Chart to determine
your rate of flow for the hood per unit length
of the hood. Total flow will be the CFM/LF
obtained from Fig. 9 multiplied by the
length of the ventilator section.
8. Design values will be noted on the
listing label attached to the inside of the
ventilator, or sticker attached to the
inside of the access cover.
Fig. 9, Airflow vs. Static Tap Chart
Balancing
Hood system flow rates are to be adjusted to
obtain the correct pressures noted above. Flow
adjustment for the XG ventilator is to be done by
either manipulation of the Gaylord Industries
GBD, or GFBD balancing dampers, or by fan
pulley adjustment. Reference your GBD/GFBD
technical manual for more details
Consult the Gaylord Industries factory for Listed,
and recommended airflow rates over particular
equipment line up, as well as best practice
system balancing, and equipment place.
BDL Hood
DS-CL Hood
SP Tap
CFM/LF
SP Tap
CFM/LF
0.07
100
0.10
200
0.10
120
0.12
240
0.15
150
0.15
280
0.19
170
0.17
300
0.23
190
0.21
340
0.28
210
0.25
380
0.30
220
0.34
440
0.36
240
0.37
460
0.43
265
* Values need to be
multiplied by the
hood sections overall
length to get the total
CFM.
0.55
300
0.63
320
0.75
350
Figure 8
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