Advance Planning

DUCT FITTINGS

This Hood Must Use an

8Round Duct. It Can

Transition to a

3-1/4x 12Duct.

Use this chart to compute maximum permissible lengths for duct runs to outdoors.

NOTE: Do not exceed maximum permissible equivalent lengths!

Maximum duct length: 100 foot for range hoods.

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.

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

 

 

Equivalent

Quantity

Equivalent

Duct Piece

Dimensions

Length*

Used

Length

 

Round,

1 ft .

 

 

 

straight

(per foot

 

 

 

 

length)

 

 

 

3-1/4x 12

1 ft .

 

 

 

straight

(per foot

 

 

 

 

length)

 

 

 

90° elbow

17 ft .

 

 

 

 

 

 

 

45° elbow

10 ft .

 

 

 

 

 

 

 

3-1⁄4x 12

 

 

 

 

90° elbow

43 ft .

 

 

 

3-1/4x 12

 

 

 

 

45° elbow

26 ft .

 

 

 

3-1/4x 12

 

 

 

 

90° flat elbow

102 ft .

 

 

 

8round to

 

 

 

 

3-1/4x 12transition

2 ft .

 

 

 

3-1/4x 12to 8

 

 

 

 

round transition

5 ft .

 

 

 

8round

 

 

 

 

to 3-1/4x 12

 

 

 

 

transition 90° elbow

6 ft .

 

 

 

3-1/4x 12to 8

 

 

 

 

round transition 90° elbow

13 ft .

 

 

 

Round

 

 

 

 

wall cap

 

 

 

 

with damper

32 ft .

 

 

 

3-1/4x 12wall cap

 

 

 

 

with damper

75 ft .

 

 

 

Round

 

 

 

 

roof cap

44 ft .

 

 

*Actual length of straight duct plus duct fitting

equivalent . Equivalent length of duct pieces are

based on actual tests conducted by GE Evaluation Total Duct Run Engineering and reflect requirements for good

venting performance with any ventilation hood.

10

Page 10
Image 10
GE ZVC36, ZVC42, ZVC48, ZVC30 installation instructions Duct Fittings, Flexible ducting, Do not use flexible plastic ducting