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LB Dimensions
LBP Dimensions
1
3
⁄4
(44)
1
3
⁄4
(44)
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 in the airstream. The sound ratings shown are loudness values in fan sones at 5 feet (1.5 m) in a hemispherical free field calculated per AMCA Standard 301. Values
shown are for installation type A: Free inlet hemispherical sones.
LB/LBP 21
Belt Drive
0 2 4 6 8 10 12
0
100
200
300
400
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
0 1000 2000 3000 4000 5000 6000 7000 8000
0.0
0.5
1.0
1.5
2.0
Static Pressure in. wg
cfm
m
3
/hr X 1000
Static Pressure Pa
1200
1053
906
612
465
1 1/2 hp
1/4 hp
1/3 hp
1/2 hp
3/4 hp
1 hp
2 hp
RPM
HP
Density 0.075 lb/ft
3
759
Model
Number
Motor
HP
Fan
RPM
CFM / Static Pressure in Inches wg
0 0.25 0.375 0.5 0.625 0.75 1 1.25 1.5 1.75
LB/LBP-21-4 1/4
465
CFM 2820 1732
BHP 0.12 0.13
Sones 6.6 5.2
595
CFM 3609 2938 2457
BHP 0.24 0.28 0.28
Sones 8.8 7.8 6.9
LB/LBP-21-3 1/3 651
CFM 3948 3371 2970 2354
BHP 0.32 0.36 0.36 0.34
Sones 10.1 8.8 8.2 6.9
LB/LBP-21-5 1/2
699
CFM 4239 3724 3362 2954 1964
BHP 0.39 0.44 0.45 0.45 0.38
Sones 11.6 9.9 9.3 8.6 7.1
747
CFM 4531 4056 3741 3390 2909
BHP 0.48 0.53 0.54 0.55 0.53
Sones 13.4 11.2 10.4 9.8 9.1
LB/LBP-21-7 3/4
801
CFM 4858 4424 4157 3833 3491 2937
BHP 0.59 0.65 0.66 0.67 0.68 0.64
Sones 15.5 12.9 11.8 11.3 10.8 10.1
855
CFM 5186 4790 4553 4261 3954 3608
BHP 0.72
0.79 0.8 0.81 0.82 0.82
Sones 16.7 14.4 13.3 12.8 12.1 11.5
LB/LBP-21-10 1 899
CFM 5452 5087 4858 4602 4313 4019 2894
BHP 0.83 0.91 0.93 0.94 0.95 0.96 0.86
Sones 17.1 15.4 14.5 13.9 13.4 12.7 11.7
LB/LBP-21-15 1
1
⁄2
1010
CFM 6126 5826 5614 5415 5183 4926 4386 3369
BHP 1.18 1.26 1.3 1.32 1.34 1.35 1.36 1.24
Sones 20 18.9 18.1 17.3 16.6 16.2 15.0 14.0
1077
CFM 6532 6260 6068 5877 5691 5451 4965 4395
BHP 1.43 1.52 1.56 1.59 1.61 1.62 1.65 1.63
Sones 22 21 20 19.4 18.8 18.2 17.3 16.4
LB/LBP-21-20 2 1200
CFM 7278 7034 6890 6712 6542 6375 5954 5517 5013 4122
BHP 1.98 2.07 2.12 2.18 2.2 2.22 2.25 2.28 2.26 2.11
Sones 26 25 25 24 23 23 22 21 20 18.5
MAX. BHP AT A GIVEN RPM - (rpm/910)
3
MAXIMUM FRPM = 1200
TIP SPEED = rpm x 5.596
MAX. MOTOR FRAME SIZE = 145T
30
(762)
51
(1295)
23
(584)
23
(584)
6
(152)
36
(914)
46
(1168)
24
1
⁄2
(622)
19
(483)
43
(1092)
30
(762)
30
(762)
30
(762)
LB-21 LBP-21
Hood Thickness 22 ga -
Cover Thickness - 0.064 (0.029)
Louver Thickness - 0.081 (0.036)
Curb Cap Thickness 0.064 (0.029) 0.064 (0.029)
Damper Size Square 18 (457) 18 (457)
Roof Opening Square 20
1
⁄2 (521) 20
1
⁄2 (521)
Weight*
Galvanized,
145
(66)
Aluminum,
191 (86)
All dimensions are in inches (millimeters). Weight in pounds
(kilograms). *Weight shown is the largest cataloged
Open Drip Proof motor. See page 8 for severe duty LBP
dimensions.