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Ventin, Venting – Raypak MVB 5042004 User Manual

Page 25

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Table L: Category I Vertical Venting

1

Vent lengths are based on a lateral length of 2 ft. Refer to the latest edition of the NFGC for further

details. When vertical height exceeds 25 ft, consult factory prior to installation.

* Subtract 10 ft per elbow. Max. 4 elbows.

** Adapters supplied by others.

Fig. 23: Vertical Venting

Model

No.

Certified

Vent

Material

Vent Size

(in.)

Vertical Vent

Height

1

(ft)

Combustion Air

Intake Pipe

Material

Air Inlet

Max. Length* (ft)

Min.

Max.

6” Ш

8” Ш 10” Ш

504

Category I

(Type B

Equivalent)

8

5

25

Galvanized

Steel,

PVC,

ABS,

CPVC

45

100**

754

10

1104

10

1504

12

45

85**

2004

14

The diameter of vent flue pipe should be sized accord-

ing to the NFGC (U.S.) and B149 (Canada).

The connection from the appliance vent to the stack

must be as direct as possible. The horizontal breach-

ing of a vent must have an upward slope of not less

than 1/4 inch per linear foot from the heater to the vent

terminal. The horizontal portions of the vent shall also

be supported for the design and weight of the material

employed to maintain clearances and to prevent phys-

ical damage or separation of joints.

Termination

The vent terminal should be vertical and should termi-

nate outside the building at least 2 ft above the highest

point of the roof that is within 10 ft. The vent cap

should have a minimum clearance of 4 ft horizontally

from and in no case above or below (unless a 4 ft hori-

zontal distance is maintained) electric meters, gas

meters, regulators and relief equipment. The distance

of the vent terminal from adjacent public walkways,

adjacent buildings, open windows and building open-

ings must be consistent with the NFGC (U.S.) or B149

(Canada). Gas vents supported only by flashing and

extended above the roof more than 5 ft should be se-

curely guyed or braced to withstand snow and wind

loads.

CAUTION: A listed vent cap terminal adequately

sized, must be used to evacuate the flue products

from the building.