DETERMINING EQUIVALENT PIPE LENGTH
Installation Guidelines (cont.)
To determine whether a 3” or 4” exhaust system is required for your installation, review the
sample installation below. Fill out the top chart, and calculate your total equivalent pipe length.
After you have the total equivalent pipe length, use the chart at the bottom of the page to deter-
mine if your installation requires 3” or 4” exhaust pipe.
Type of Pipe
# of Elbows or
Equivalent Feet Total Equivalent Feet
Feet of pipe
90
o
Elbows/Tee(A &F)
2
x
5 ft. (1.5m)
10 (3m)
45
o
Elbows(C)
1
x
3 ft. (1m)
3 (1m)
Horizontal Pipe(B&E)
3
x
1 ft. (.3m)
3 (1m)
Vertical Pipe(D)
8
x
.5 ft. (.15m)
4 (1.2m)
Sample Installation Chart
TOTAL: 20
A
-
90 Deg. Elbow
B
-
1’ Horizontal Pipe
C
-
45 Degree Elbow
D
-
Standoff Braces
30
20
10
0
1
2
3
4
5
6
7
8
9
1 0
4 INCH DIAMETER ONLY
3 OR 4 INCH DIAMETER
Pipe Selection Chart
Type of Pipe # of Elbows or Feet of pipe
Equivalent Feet Total Equivalent Feet
90
o
Elbows
x
5(1.5m)
45
o
Elbows
x
3(1m)
Horizontal
Pipe
x
1(.3m)
Vertical
Pipe
x
5(.15m)
Altitude in Thousands of Feet
20
A
E
F
H
G
B
C
D
(Figure 22)-Equivalent Length versus Altitude Chart
(Figure 21)-Sample Pipe Configuration
NOTE: For the example installations
above, 4 inch diameter pipe would be used
for installations at altitudes above 3,000
feet; 3 or 4 inch pipe would be suitable
below 3,000 feet.
E
-
8’ Vertical Pipe
F
-
2’ Horizontal Pipe
G
-
90 Degree Tee
H
-
Wall Thimble
