Vertical direct venting, Prepare roof penetrations

4 Vertical direct venting

Vent/air termination – vertical

WARNING Follow instructions below when determining vent location to avoid

possibility of severe personal injury, death or substantial property damage.

Determine location

Locate the vent/air terminations using the following guidelines:

1.The total length of piping for vent or air must not exceed the limits given in the General Venting Section on page 16 of this manual.

2.Prepare the vent termination and the air termination elbow (FIG. 4-1) by inserting bird screens. Bird screens should be obtained locally.

3.The vent must terminate at least 3 feet above the highest place in which the vent penetrates the roof and at least 2 feet above any part of a building within 10 horizontal feet.

4.The air piping must terminate in a down-turned 180° return pipe no further than 2 feet from the center of the vent pipe. This placement avoids recirculation of flue products into the combustion air stream.

5.The vent piping must terminate in an up-turned coupling as shown in FIG. 4-1. The top of the coupling must be at least 1 foot above the air intake. When the vent termination uses a rain cap as illustrated in FIG. 4-1 maintain at least 36" (914 mm) above the air inlet. The air inlet pipe and vent pipe can be located in any desired position on the roof, but must always be no further than 2 feet (.6 m) apart and with the vent termination at least 1 foot for PVC and 3 feet for stainless steel, above the air intake.

6.Maintain the required dimensions of the finished termination piping as shown in FIG. 4-1.

7.Do not extend exposed vent pipe outside of building more than shown in this document. Condensate could freeze and block vent pipe.

WARNING Rooftop vent and air inlet terminations must terminate in the same pressure

zone, unless vertical vent sidewall air is set up as shown in the General Venting - Vertical Vent, Sidewall Air Section.

Installation & Operation Manual

Figure 4-1PVC/CPVC/Polypropylene Vertical Termination

of Air and Vent

ALTERNATE INTAKE LOCATIONS:

INTAKE PIPES MAY BE LOCATED

ANYWHERE WITHIN 24" (610 MM)

OF VENT PIPE

BIRD SCREEN

(TYPICAL)VENT

COUPLING

(FIELD SUPPLIED) 6" (152 MM) MINIMUM

ABOVE ROOF / SNOW LINE

	VENT OUTLET	COMBUSTION
	12" MINIMUM
		AIR
	ABOVE AIR INLET

Figure 4-2Stainless Steel Vertical Termination of Air

and Vent

ALTERNATE INTAKE LOCATIONS:

INTAKE PIPES MAY BE LOCATED

ANYWHERE WITHIN 24” (610 MM)

OF VENT PIPE

VENT	BIRD SCREEN
	(TYPICAL)

6" (152 MM) MINIMUM

ABOVE ROOF /

SNOW LINE

COM,BUSTION

AIR

VENT OUTLET

36” (914 MM) MINIMUM

ABOVE AIR INLET

5.Locate terminations so they are not likely to be damaged by foreign objects, such as stones or balls, or subject to buildup of leaves or sediment.

Prepare roof penetrations

1.Air pipe penetration:

a.Cut a hole for the air pipe. Size the air pipe hole as close as desired to the air pipe outside diameter.

2.Vent pipe penetration:

a.Cut a hole for the vent pipe. For either combustible or noncombustible construction, size the vent pipe hole with at least a 1/2 inch clearance around the vent pipe outer diameter:

•7½ inch (178 mm) hole for 6 inch (152 mm) vent pipe

•8½ inch (203 mm) hole for 7 inch (178 mm) vent pipe

b.Insert a galvanized metal thimble in the vent pipe hole (when required by local codes).

3.Space the air and vent holes to provide the minimum spacing shown in FIG.’s 4-1 and 4-2.

4.Follow all local codes for isolation of vent pipe when passing through floors, ceilings, and roofs.

5.Provide flashing and sealing boots sized for the vent pipe and air pipe.