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MFC Series Boiler Vent and Combustion Air Guide
TAG-0080_OG
•
GF-148-V
•
3/29/2023
Technical Support
•
(800) 526-0288
•
Mon-Fri, 8 am - 5 pm EST Page 24 of
33
TABLE 5: Ducted Combustion Air Duct Pressure Drop (Eq. Ft.)
for
MFC 4000
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
12" Duct
Single
Boiler
Straight Run
0.22
0.23
0.24
0.26
0.27
0.29
0.31
0.33
0.35
90° Elbow
1.81
1.90
1.99
2.13
2.27
2.42
2.58
2.75
2.94
45° Elbow
1.40
1.47
1.54
1.64
1.75
1.87
2.00
2.13
2.27
Ent. Loss
4.45
4.67
4.90
5.22
5.57
5.95
6.34
6.77
7.22
14"
Duct
Single
Boiler
Straight Run
0.10
0.11
0.11
0.12
0.13
0.14
0.15
0.15
0.17
90° Elbow
0.91
0.95
1.00
1.06
1.14
1.21
1.29
1.38
1.47
45° Elbow
0.71
0.74
0.78
0.83
0.88
0.94
1.01
1.07
1.15
Ent. Loss
2.40
2.52
2.64
2.82
3.01
3.21
3.42
3.65
3.90
16"
Duct
Two
Boilers
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
Two
Boilers
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
18"
Duct
Three
Boilers
Straight Run
0.23
0.24
0.25
0.27
0.29
0.31
0.33
0.35
0.37
90° Elbow
2.67
2.81
2.94
3.14
3.35
3.57
3.81
4.07
4.34
45° Elbow
2.09
2.19
2.30
2.45
2.61
2.79
2.98
3.18
3.39
Ent. Loss
7.91
8.30
8.71
9.29
9.91
10.57
11.28
12.03
12.84
20"
Duct
Three
Boilers
Straight Run
0.14
0.14
0.15
0.16
0.17
0.18
0.19
0.21
0.22
90° Elbow
1.68
1.76
1.85
1.97
2.10
2.24
2.39
2.55
2.72
45° Elbow
1.31
1.37
1.44
1.54
1.64
1.75
1.86
1.99
2.12
Ent. Loss
5.19
5.44
5.71
6.09
6.50
6.93
7.40
7.89
8.42
20"
Duct
Four
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
10.1
5
10.83
11.55
12.33
13.15
14.03
14.97
22"
Duct
Four
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
NOTES:
1) Calculation assumes
935 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)