Airflow Data; Fan Ratings - Honeywell AUTOMATIC CONTROL Engineering Manual

AIRFLOW DATA

FAN RATINGS

Fans are rated at standard conditions of air: 0.075 lb/ft 3 and 70F at sea level. Therefore, pressures corrected to standard conditions
must be used when selecting fans from fan rating tables or curves. Table 29 gives correction factors.
Pressure at operating conditions x factor = pressure at standard conditions.
Horsepower at standard conditions ÷ factor = horsepower required at operating conditions
CAUTION: Size motor for highest density (lowest factor) condition at which it is expected to operate.
Temp Ft 0
F in. Hg 29.92
–40 0.79
0 0.87
40 0.94
70 1.00
80 1.02
100 1.06
120 1.09
140 1.13
160 1.17
180 1.21
200 1.25
250 1.36
300 1.43
350 1.53
400 1.62
450 1.72
500 1.81
550 1.91
600 2.00
650 2.09
700 2.19
750 2.28
800 2.38
EXAMPLE:
Air at 1000 ft and 140F: 28.86 in. Hg x 1.17 = 33.77 in. Hg
Table 29. Altitude and Temperature Correction Factors.
Altitude with Barometric Pressure
500 1000 1500 2000
29.38 28.86 28.33 27.82
0.81 0.82 0.84
0.88 0.90 0.92
0.96 0.98 1.00
1.02 1.04 1.06
1.04 1.06 1.08
1.08 1.10 1.12
1.11 1.13 1.16
1.15 1.17 1.20
1.19 1.21 1.24
1.23 1.25 1.28
1.27 1.29 1.32
1.36 1.39 1.41
1.46 1.49 1.51
1.56 1.58 1.61
1.65 1.68 1.71
1.75 1.78 1.81
1.84 1.88 1.91
1.94 1.98 2.01
2.04 2.07 2.11
2.13 2.17 2.21
2.23 2.27 2.31
2.32 2.37 2.41
2.42 2.46 2.51
2500 3000
27.31 26.82
0.85 0.87 0.88
0.93 0.95 0.97
1.01 1.03 1.05
1.08 1.10 1.12
1.10 1.12 1.14
1.14 1.16 1.18
1.18 1.20 1.22
1.22 1.24 1.26
1.26 1.28 1.31
1.30 1.32 1.35
1.34 1.36 1.39
1.44 1.47 1.49
1.54 1.57 1.60
1.64 1.67 1.70
1.75 1.78 1.81
1.85 1.88 1.92
1.95 1.98 2.02
2.05 2.09 2.13
2.15 2.19 2.23
2.25 2.29 2.34
2.35 2.40 2.44
2.46 2.50 2.55
2.56 2.60 2.65
489 ENGINEERING MANUAL OF AUTOMATIC CONTROL
GENERAL ENGINEERING DATA
3500 4000 4500
26.32 25.84 25.36
0.90 0.92 0.93
0.99 1.00 1.02
1.07 1.09 1.11
1.14 1.16 1.18
1.16 1.18 1.20
1.20 1.22 1.25
1.24 1.27 1.29
1.29 1.31 1.34
1.33 1.35 1.38
1.37 1.40 1.42
1.42 1.44 1.47
1.52 1.55 1.58
1.63 1.66 1.69
1.74 1.77 1.80
1.84 1.88 1.91
1.95 1.99 2.03
2.06 2.10 2.14
2.17` 2.21 2.25
2.27` 2.32 2.36
2.38 2.43 2.47
2.49 2.53 2.58
2.60 2.64 2.69
2.70 2.75 2.80
5000
24.90
0.95
1.04
1.13
1.20
1.22
1.27
1.31
1.36
1.41
1.45
1.50
1.61
1.72
1.84
1.95
2.06
2.18
2.29
2.40
2.52
2.63
2.74
2.86