Maximum length of exhaust duct
Number of 90˚
elbows/bends
0
1
2
3
4
Number of 90˚
elbows/bends
0
1
2
3
4
For exhaust systems not covered by the exhaust duct length charts (such as multiple unit
hook-ups, plenums, and power-assist fans), call our Customer Care Center:
TOLL FREE 1 888 9 FNP USA (1 888 9 367 872).
Preferred 4" Hoods
When you have a 4" (100 mm) Hood
Maximum length of 4" diameter metal duct.
Rigid
64 ft
19.5 m
54 ft
16.5 m
44 ft
13.4 m
35 ft
10.6 m
27 ft
8.2 m
Acceptable 2 ½" Hood
When you have a 2 ½" (60 mm) Hood
Maximum length of 4" diameter metal duct.
Rigid
58 ft
17.6 m
48 ft
14.6 m
38 ft
11.5 m
29 ft
8.8 m
21 ft
6.4 m
Installation instructions
Thick Wall Flexible Metal
(fully extended)
36 ft
31 ft
27 ft
25 ft
23 ft
Thick Wall Flexible Metal
(fully extended)
28 ft
23 ft
19 ft
17 ft
15 ft
15
EN
10.9 m
9.4 m
8.2 m
7.6 m
7.0 m
8.5 m
7.0 m
5.7 m
5.1 m
4.5 m