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Roof Downblast - Belt Drive
Size- : GB • H-GB
Performance certified is for installation type A: Free inlet, Free outlet. Power rating (BHP) does not include transmission losses. Performance ratings include the effects
of a birdscreen. The sound ratings shown are loudness values in hemispherical sones at 5 ft. (1.5 m) in a hemispherical free field calculated per AMCA Standard 301.
Values shown are for installation type A: free inlet hemispherical sone levels.
Damper Size = 16 x 16 (406 x 406)
Roof Opening = 18 x 18 (470 x 470)
Shroud Thickness = 0.051 (1.3)
Motor Cover Thickness = 0.040 (1.0)
Curb Cap Thickness = 0.064 (1.6)
^Approximate Unit Weight = 88 lbs. (40 kg)
All dimensions in inches (millimeters). *May be greater depending on motor.
^Weight shown is largest cataloged Open Drip-Proof motor.
Roof Downblast - Exhaust
Belt Drive
GB-161HP
Motor
HP
Fan
RPM
Static Pressure in Inches wg
0.5 0.625 0.75 1 1.25 1.5 1.75 2 2.25 2.5
161HP
1/4
825
CFM
702
BHP
0.11
Sones
6.5
960
CFM
1093 919 585
BHP
0.18 0.17 0.15
Sones
7.7 7.6 8.0
1095
CFM
1380 1271 1139 589
BHP
0.26 0.26 0.26 0.21
Sones
9.0 9.0 8.9 9.5
1/3 1210
CFM
1606 1514 1416 1149
BHP
0.34 0.35 0.35 0.34
Sones
10.6 10.3 10.4 10.3
1/2
1270
CFM
1718 1636 1545 1333 949
BHP
0.39 0.40 0.40 0.41 0.37
Sones
11.4 11.2 11.1 11.1 11.4
1330
CFM
1829 1753 1668 1483 1204
BHP
0.44 0.45 0.46 0.47 0.45
Sones
12.3 12.1 11.9 12.1 12.0
1390
CFM
1938 1865 1789 1619 1399 1032
BHP
0.50 0.51 0.52 0.53 0.53 0.48
Sones
13.3 13.0 12.8 12.7 12.7 13.1
3/4
1485
CFM
2109 2041 1973 1822 1654 1416 1012
BHP
0.60 0.61 0.63 0.64 0.65 0.63 0.57
Sones
14.9 14.7 14.4 13.8 13.7 14.0 14.7
1580
CFM
2275 2214 2150 2016 1868 1704 1447 1034
BHP
0.72 0.73 0.75 0.77 0.77 0.791 0.75 0.67
Sones
16.7 16.7 16.4 15.5 14.7 14.8 15.4 16.6
1
1660
CFM
2414 2357 2297 2175 2037 1887 1702 1441 996
BHP
0.82 0.84 0.85 0.89 0.89 0.91 0.90 0.86 0.75
Sones
18.3 18.8 18.3 16.7 16.2 15.8 15.8 17.1 20
1740
CFM
2551 2497 2442 2325 2200 2066 1917 1714 1452 987
BHP
0.94 0.96 0.97 1.01 1.03 1.03 1.05 1.03 0.98 0.85
Sones
20 21 21 18.4 17.5 17.2 16.8 17.2 19.2 28
D
O
N
O
T
S
E
L
E
C
T
T
O
T
H
E
L
E
F
T
O
F
T
H
I
S
S
Y
S
T
E
M
C
U
R
V
E
Static Pressure (in. wg)
Static Pressure (Pa)
Volume (cfm)
3
Volume (m
/hr)
RPM (Belt)
HP
Density 0.075 lb/ft
3
Density 1.2 kg/m
3
MAXIMUM BHP AT A GIVEN RPM = (RPM/1708)
3
MAXIMUM RPM = 1740
TIP SPEED (ft/min) = RPM x 4.352
MAXIMUM MOTOR FRAME SIZE = 145T
1
3
⁄4 (44)
4 (102)
*23
3
⁄4
(603)
22
(559)
28
3
⁄8
(721)