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GUIDELINES FOR EXHAUST VENTING SYSTEMS DESIGN, CONT……
To determine whether a 3” or 4” exhaust system should be used, follow the guidelines below:
1)
Determine the “equivalent pipe length” for each component used according to the comparison chart
below. Add the “equivalent pipe length” of all components to get the “total equivalent pipe length”.
2)
Determine the altitude at which you are installing the stove.
3)
Cross-reference the “total equivalent pipe length” and the altitude using the graph below.
NOTE:
The “total equivalent pipe length” should not exceed 30 feet. The installer is responsible for
Determining proper total equivalent pipe length depending on installation conditions.
Component
Equivalent Length
Equivalent Pipe Length
Horizontal Straight Pipe
Actual Length in ft. x 1.0
Horizontal Pipe
=
1 x (2+1) =
3 ft.
Vertical Straight Pipe
Actual Length in ft. x 0.5
Vertical Pipe
=
0.5 x 8 =
4 ft.
90
0
Elbow or Tee
5.0 feet
90 Degree Tee
=
2 x 5 =
10 ft.
45
0
Elbow
3.0 feet
45 Degree Tee
=
1 x 3 =
3 ft.
TOTAL
=
20
ft.
NOTE: These are guidelines only. Proper venting is accomplished by design and common sense. In most
installations 3 inch diameter venting is adequate. If it does not vent properly you will have to change it to 4”.
0 2 4 6 8 10 12
ALTITUDE X 1,000 FEET
25
20
15
10
5
0
4” DIAMETER ONLY
3” OR 4” DIAMETER
CRITERIA FOR SELECTING PIPE DIAMETER
MAXIMUM
0 2 4 6 8 10 12
