Specifications

42
Equivalent Diameter
(ID) (inch)
A B 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
4 4 4 5 5 5 6 6 6 6 6 6 6 6 6 7 7 7
5 4 5 5 6 6 6 7 7 7 7 7 8 8 8 8 8 8
6 5 5 6 6 7 7 8 8 8 8 8 9 9 9 9 9 9
7 5 6 6 7 7 8 8 9 9 9 9 10 10 10 10 10 10
8 5 6 7 7 8 8 9 9 10 10 10 10 11 11 11 11 11
9 6 6 7 8 8 9 9 10 10 11 11 11 12 12 12 12 12
10 6 7 8 8 9 9 10 10 11 11 12 12 12 13 13 13 13
11 6 7 8 9 9 10 10 11 11 12 12 13 13 13 14 14 14
12 6 7 8 9 10 10 11 11 12 12 13 13 14 14 14 15 15
13 6 7 8 9 10 11 11 12 12 13 13 14 14 15 15 15 16
14 6 7 8 9 10 11 12 12 13 13 14 14 15 15 16 16 16
15 6 8 9 10 10 11 12 13 13 14 14 15 15 16 16 17 17
16 6 8 9 10 11 12 12 13 14 14 15 15 16 16 17 17 18
17 6 8 9 10 11 12 13 13 14 15 15 16 16 17 17 18 18
18 7 8 9 10 11 12 13 14 14 15 16 16 17 17 18 18 19
19 7 8 9 10 11 12 13 14 15 15 16 17 17 18 18 19 19
20 7 8 9 10 11 12 13 14 15 16 16 14 18 18 19 19 20
B
A
Appendix B: Conversion table from rectangular to round ues
Gas Vent Pressure
Stack
Clay Tile
Liner
Poured/Cast
Liner
Single Wall
Steel
Corrugated
Steel/Alum.
Pipe Coefcient 0.25 0.22 0.38 0.34 0.32 0.50
30° Elbow 0.15 0.12 0.18 0.18 0.15 0.30
45° Elbow 0.25 0.15 0.28 0.28 0.25 0.50
90° Elbow 0.75 0.30 0.90 0.90 0.75 1.5
Tee or 90° Connector 1.25 1.25 1.25 1.25 1.25 1.75
90° WYE 0.60 0.60 0.60 0.60 1.60 0.60
Barometric Damper 0.50 0.50 0.50 0.50 0.50 0.50
Round to Square Transition 0.50 0.50 0.50 0.50 0.50 0.50
Low Resistance Cap (listed) 0.50 0.50 0.50 0.50 0.50 0.50
Standard Cap (not listed) 1.00 1.00 1.00 1.00 1.00 1.00
Bird Screen 0.50 0.50 0.50 0.50 0.50 0.50
Tapered Reducer From d
1
to d
2
: 1 - (d
2
/ d
1
)
4
Appendix C: Resistance Factors