Bryan Boilers Forced Draft Steam Boilers User Manual
Page 8
FIG. 1.8.1: VENT DESIGN INSTRUCTION -
REFERENCES
TABLE 1.8.1A: ESTIMATING FLUE GAS VOLUMETRIC FLOW RATE
Approximate Flue Gas VOLUMETRIC FLOW RATE
(Per 1000 Btu/hr Input)
(Multiply factor listed times boiler input in MBH)
BOILER TYPE
SCFM Per
1000 Btu/hr
INPUT
ACFM Per
1000 Btu/hr
INPUT
APPROXIMATE
FLUE GAS
TEMPERATURE
Water & 15# Steam
Gas Fired
Oil Fired
0.230
0.230
0.402
0.402
450 F
450 F
150# Steam
Gas Fired
Oil Fired
0.230
0.230
0.425
0.425
500 F
500 F
TABLE 1.8.1B: STACK EXIT VELOCITY
Estimated STACK EXIT VELOCITY Calculation
(Multiply total ACFM times the velocity factor below velocity in feet per second)
STACK INSIDE
DIAMETER (Inches)
VELOCITY
FACTOR
STACK INSIDE
DIAMETER (Inches)
VELOCITY
FACTOR
STACK INSIDE
DIAMETER (Inches)
VELOCITY
FACTOR
6
7
8
10
12
14
16
0.0849
0.0624
0.0477
0.0306
0.0212
0.0156
0.0119
18
20
22
24
26
28
32
0.00943
0.00764
0.00631
0.00531
0.00390
0.00340
0.00298
34
36
38
40
48
60
0.00264
0.00236
0.00212
0.00191
0.00133
0.00085