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" (10cm) Hood
Maximum length of 4" diameter metal duct.
Rigid
64ft
19.5m
54ft
16.5m
44ft
13.4m
35ft
10.6m
27ft
8.2m
Acceptable 2 ½"Hood
When you have a 2 ½" (6cm) Hood
Maximum length of 4" diameter metal duct.
Rigid
58ft
17.6m
48ft
14.6m
38ft
11.5m
29ft
8.8m
21ft
6.4m
Thick Wall Flexible Metal
(fully extended)
36ft
31ft
27ft
25ft
23ft
Thick Wall Flexible Metal
(fully extended)
28ft
8.5m
23ft
7.0m
19ft
5.7m
17ft
5.1m
15ft
4.5m
US
CA
10.9m
9.4m
8.2m
7.6m
7.0m
17