507769-05G / 31-5000656
Page 23 of 55
Issue 2223
Maximum Allowable Exhaust Vent Pipe Length
3
(in ft.) without Insulation in Unconditioned Space for Winter Design
Temperatures Single - Stage High Efficiency Furnace
Winter Design Temperatures
1
ºF (ºC)
Vent Pipe
Diameter
Unit Input Size
045
070
090
32 to 21
(0 to -6)
PVC
2
PP
PVC
2
PP
PVC
2
PP
1-1/2 in.
20
N/A
20
N/A
N/A
N/A
2 in.
18
16
31
28
50
48
2-1/2 in.
13
N/A
24
N/A
42
N/A
3 in.
9
9
18
18
35
35
20 to 1
(-7 to -17)
1-1/2 in.
15
N/A
20
N/A
N/A
N/A
2 in.
9
8
18
16
32
29
2-1/2 in.
5
N/A
13
N/A
24
N/A
3 in.
1
1
8
8
19
19
0 to -20
(-18 to -29)
1-1/2 in.
10
N/A
15
N/A
N/A
N/A
2 in.
5
3
12
10
22
19
2-1/2 in.
1
N/A
7
N/A
15
N/A
3 in.
N/A
N/A
2
2
10
10
1
Refer to 99% Minimum Design Temperature table provided in the current edition of the ASHRAE Fundamentals Handbook.
2
Poly-Propylene vent pipe (PP) by Duravent and Centrotherm
3
Vent length in table is equivalent length. Each elbow is equivalent to 5ft of straight pipe and should be included when measuring
total length.
NOTE
- Concentric terminations are the equivalent of 5’ and should be considered when measuring pipe length.
NOTE
- Maximum uninsulated vent lengths listed may include the termination (vent pipe exterior to the structure ) and cannot exceed
5 linear feet or the maximum allowable intake or exhaust vent length listed in Table 7A through Table 7D or Table 8A through Table
NOTE
- If insulation is required an unconditioned space, it must be located on the pipe closed to the furnace.
Table 9.
