WORKSHEET—CALCULATE TOTAL EQUIVALENT DUCTWORK LENGTH
DUCT
EQUIVALENT NUMBER
PIECES
LENGTH
" x 10"
3
⁄
1 Ft.
1
4
Rect.,
straight
7" Round,
1 Ft.
straight
6" Round,
1 Ft.
straight
" x 10"
3
1
⁄
14 Ft.
4
Rect. 90°
elbow
" x 10"
3
⁄
8 Ft.
1
4
Rect. 45°
elbow
" x 10"
3
1
⁄
33 Ft.
4
Rect. 90°
flat elbow
" x 10"
3
1
⁄
24 Ft.
4
Rect.
(18 ft. w/o
wall cap
damper)
with
damper
" x 10"
3
1
⁄
2 Ft.
4
Rect. to
6" round
transition
" x 10"
3
1
⁄
4 Ft.
4
Rect. to
6" round
transition
90° elbow
6" Round,
12 Ft.
90° elbow
6" Round,
7 Ft.
45° elbow
Subtotal column 1
MAXIMUM DUCT LENGTH: For satisfactory air
movement, the total duct length of a 3
rectangular, 6" or 7" diameter round duct should
not exceed 65 equivalent feet.
Installation Instructions
x USED
= TOTAL
x (
)
=
Ft.
x (
)
=
Ft.
x (
)
=
Ft.
x (
)
=
Ft.
x (
)
=
Ft.
x (
)
=
Ft.
x (
)
=
Ft.
x (
)
=
Ft.
x (
)
=
Ft.
x (
)
=
Ft.
x (
)
=
Ft.
x (
)
=
Ft.
=
Ft.
" x 10"
1
⁄
4
DUCT
EQUIVALENT
PIECES
LENGTH
6" Round
24 Ft.
wall cap
(18 ft. w/o
with
damper)
damper
6" Round
33 Ft.
roof cap
6" Round
2 Ft.
to
" x 10"
3
⁄
1
4
rect.
transition
6" Round
4 Ft.
to
" x 10"
3
1
⁄
4
rect.
transition
90° elbow
7" Round,
14 Ft.
90° elbow
7" Round,
9 Ft.
45° elbow
7" Round
28 Ft.
wall cap
(21 ft. w/o
with
damper)
damper
7" Round
39 Ft.
roof cap
7" Round
1 Ft.
to
" x 10"
3
1
⁄
4
rect.
transition
7" Round
5 Ft.
to
" x 10"
3
1
⁄
4
rect.
transition,
90° elbow
8
NUMBER
x USED
= TOTAL
x (
)
=
x (
)
=
x (
)
=
x (
)
=
x (
)
=
x (
)
=
x (
)
=
x (
)
=
x (
)
=
x (
)
=
x (
)
=
x (
)
=
Subtotal column 2
=
Subtotal column 1
=
Total ductwork
=
Ft.
Ft.
Ft.
Ft.
Ft.
Ft.
Ft.
Ft.
Ft.
Ft.
Ft.
Ft.
Ft.
Ft.
Ft.