Advance Planning
DUCT FITTINGS
Use this chart to compute maximum permissible lengths for duct runs to outdoors.
For best results, use 10" diameter duct.
Note: Do not exceed maximum permissible equivalent lengths!
Maximum recommended duct length for these hoods: 150 feet
Flexible ducting:
If flexible metal ducting is used, all the equivalent feet values in the table should be doubled. The flexible metal duct should be straight and smooth and extended as much as possible.
Do NOT use flexible plastic ducting.
| Equivalent | Quantity | Total |
Duct Piece | Length* | Used | Length |
10" round |
|
|
|
to 8" round | 5 ft. |
|
|
Round, | 1 ft. |
|
|
straight | (per foot |
|
|
| length) |
|
|
90° elbow | 8" Dia. 52 ft. |
|
|
| 10" Dia. 24 ft. |
| |
45° elbow | 8" Dia. 31 ft. |
|
|
| 10" Dia. 14 ft. |
| |
Round | 8" Dia. 99 ft. |
|
|
wall cap | 10" Dia. 41 ft. |
| |
with damper |
|
|
|
Round | 8" Dia. 136 ft. |
| |
roof cap | 10" Dia. 56 ft. |
| |
Note: Any home ventilation system, such as a ventilation hood, may interrupt the proper flow of combustion air and exhaust required by fireplaces, gas furnaces, gas water heaters and other naturally vented systems. To minimize the chance of interruption of such naturally vented systems, follow the heating equipment manufacturer’s guidelines and safety standards such as those published by NFPA and
ASHRAE.
Total Duct Run
Hoods Are Equipped
For 10" Round Duct
*Hoods are supplied with a 10" round transition. A locally supplied transition is required for other sizes.
Note: Outlet on top of hood is
*Actual length of straight duct plus duct fitting equivalent. Equivalent length of duct pieces are based on actual tests conducted by GE Evaluation Engineering and reflect requirements for good venting performance with any ventilation hood.
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