Measuring Airflow - GAYLORD XG SERIES Operation & Maintenance Manual

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.
Figure 8
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.
MEASURING AIRFLOW
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.
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.
6
BDL Hood
SP Tap CFM/LF SP Tap
0.07 100 0.10
0.10 120 0.12
0.15 150 0.15
0.19 170 0.17
0.23 190 0.21
0.28 210 0.25
0.30 220 0.34
0.36 240 0.37
* Values need to be
0.43 265
multiplied by the
0.55 300
hood sections overall
0.63 320
length to get the total
0.75 350 CFM.
Fig. 9, Airflow vs. Static Tap Chart
DS-CL Hood
CFM/LF
200
240
280
300
340
380
440
460