MFC Series Boiler Vent and Combustion Air Guide
TAG-0080_OG
•
GF-148-V
•
3/29/2023
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TABLE 5: Ducted Combustion Air Duct Pressure Drop (Eq. Ft.)
for
MFC 8000
MMBTU Boiler
Inlet Duct
& No.
Boilers
Duct Section
Type
OUTSIDE AIR TEMPERATURE (°F)
-30 °F
-15 °F
0 °F
20 °F
40 °F
60 °F
80 °F
100 °F
120 °F
16" Duct
Single
Boiler
Straight Run
0.19
0.20
0.21
0.22
0.24
0.25
0.27
0.29
0.31
90° Elbow
2.00
2.10
2.20
2.35
2.51
2.68
2.86
3.05
3.25
45° Elbow
1.56
1.64
1.72
1.83
1.96
2.09
2.23
2.38
2.54
Ent. Loss
5.63
5.91
6.20
6.61
7.05
7.52
8.03
8.57
9.14
18" Duct
Single
Boiler
Straight Run
0.11
0.11
0.12
0.12
0.13
0.14
0.15
0.16
0.17
90° Elbow
1.19
1.25
1.31
1.40
1.49
1.59
1.69
1.81
1.93
45° Elbow
0.93
0.97
1.02
1.09
1.16
1.24
1.32
1.41
1.51
Ent. Loss
3.51
3.69
3.87
4.13
4.40
4.70
5.01
5.35
5.70
20" Duct
Two
Boilers
Straight Run
0.23
0.25
0.26
0.27
0.29
0.31
0.33
0.36
0.38
90° Elbow
2.98
3.13
3.28
3.50
3.73
3.98
4.25
4.53
4.84
45° Elbow
2.32
2.44
2.56
2.73
2.91
3.11
3.31
3.54
3.77
Ent. Loss
9.22
9.68
10.15
10.83
11.55
12.33
13.15
14.03
14.97
22" Duct
Two
Boilers
Straight Run
0.15
0.15
0.16
0.17
0.18
0.19
0.21
0.22
0.23
90° Elbow
1.95
2.04
2.14
2.29
2.44
2.60
2.78
2.96
3.16
45° Elbow
1.52
1.59
1.67
1.78
1.90
2.03
2.16
2.31
2.46
Ent. Loss
6.30
6.61
6.94
7.40
7.89
8.42
8.98
9.58
10.23
22" Duct
Three
Boilers
Straight Run
0.31
0.33
0.35
0.37
0.39
0.42
0.45
0.48
0.51
90° Elbow
4.38
4.60
4.82
5.15
5.49
5.86
6.25
6.67
7.11
45° Elbow
3.41
3.58
3.76
4.01
4.28
4.56
4.87
5.19
5.54
Ent. Loss
14.17
14.87
15.60
16.64
17.76
18.94
20.21
21.57
23.01
24" Duct
Three
Boilers
Straight Run
0.20
0.21
0.22
0.24
0.25
0.27
0.29
0.31
0.33
90° Elbow
2.96
3.11
3.26
3.48
3.71
3.96
4.22
4.50
4.80
45° Elbow
2.30
2.42
2.54
2.71
2.89
3.08
3.29
3.51
3.74
Ent. Loss
10.01
10.50
11.02
11.75
12.54
13.38
14.27
15.23
16.24
24" Duct
Four
Boilers
Straight Run
0.35
0.37
0.39
0.41
0.44
0.47
0.50
0.53
0.57
90° Elbow
5.26
5.52
5.79
6.18
6.59
7.03
7.50
8.01
8.54
45° Elbow
4.10
4.30
4.51
4.81
5.13
5.47
5.84
6.23
6.65
Ent. Loss
17.79
18.67
19.59
20.89
22.29
23.78
25.37
27.07
28.88
26" Duct
Four
Boilers
Straight Run
0.24
0.25
0.26
0.28
0.29
0.31
0.33
0.36
0.38
90° Elbow
3.65
3.83
4.01
4.28
4.57
4.87
5.20
5.55
5.92
45° Elbow
2.84
2.98
3.13
3.33
3.56
3.80
4.05
4.32
4.61
Ent. Loss
12.92
13.55
14.22
15.17
16.18
17.26
18.42
19.65
20.97
NOTES:
1) Calculation assumes
1870 scfm
per boiler at full fire rate
2) Units for "Straight Run" pressure drop values are (eq. ft. / foot)
3) Units for "Elbows" and "Ent. Loss" are (equivalent feet / item)
