English 10
DUCT EQUIVALENT CHART
Size
(in./mm)
Equivalent
Length
(ft/m)
Size
(in./mm)
Equivalent
Length
(ft/m)
6 (152)
1.2 (0.37)
6 (152)
10 (3)
8 (203)
0.7 (0.21)
10 (254)
0.6 (0.18)
3¼" x 10"
(83mm x 254mm)
straight
N/A
1 (0.3)
3¼" x 10" (83mm x 254mm),
Center reverse elbow , right
N/A
25 (7.6)
3¼" x 14"
(83mm x 356mm)
straight
N/A
0.7 (0.21)
3¼" x 10" (83mm x 254mm),
Left reverse elbow
N/A
15 (4.6)
3¼" x 10" (83mm x 254mm),
Right reverse elbow
N/A
25 (7.6)
6 (152)
12 (3.7)
6 (152)
2 (0.6)
2 (0.6)
2 (0.6)
8 (203)
6 (1.8)
10 (254)
5 (1.5)
8 (203)
10 (254)
6 (152)
5 (1.5)
8 (203)
3 (0.9)
10 (254)
2 (0.6)
3¼" x 10"
(83mm x 254mm),
90° Elbow , round
N/A
5 (1.5)
2" (51mm) long, 3¼" x 10"
(83mm x 254mm) flex
N/A
20 (6.1)
3¼" x 10"
(83mm x 254mm),
45° Elbow , round
N/A
15 (4.6)
3¼" x 10" (83mm x 254mm),
Roof jack and shutter
N/A
2 (0.6)
3¼" x 10"
(83mm x 254mm),
Flat elbow
N/A
20 (6.1)
6 (152)
5 (1.5)
8 (203)
2 (0.6)
6 (152)
10 (3)
NOTE: These commonly used installation parts can be purchased at
a local hardware store.
Measurements in inches (mm).
Round wall cap
Round roof cap
3¼" x 10" (83mm x 254mm)
to round 90° Elbow ,
Duct Piece
3¼" x 10" (83mm x 254mm)
Center reverse elbow , left
15 (4.6)
N/A
3¼" x 10" (83mm x
254mm) to round
Round to 3¼" x 10"
(83mm x 254mm)
90° Elbow ,
Duct Piece
Smooth, straight
90° Elbow , round
45° Elbow , round
6 (152)
2 (0.6)
2 (0.6)
2 (0.6)
8 (203)
10 (254)
