Heatiator NNXT4236I, NNXT3933IL Vent Clearances and Framing, Pipe Clearances to Combustibles

8 Vent Clearances and Framing

A. Pipe Clearances to Combustibles

WARNING! Risk of Fire! Maintain air space clearance to vent. DO NOT pack insulation or other combustibles:

•Between ceiling firestops

•Between wall shield firestops

•Around vent system

Failure to keep insulation or other material away from vent pipe may cause over heating and fire.

Note: Heat shields MUST overlap by a minimum of 1-1/2 in. (38 mm).

•DVP heat shield - designed to be used on a wall 4 in. to 7-1/4 in. (102 mm to 184

mm)thick.

•If wall thickness is less than 4 in. the existing heat shields must be field trimmed. If wall thickness is greater than 7-1/4 in. an extended heat shield will be required.

•SLP heat shield - designed to be used on a wall 4-3/8 in. to 7-5/8 in. (111 mm to 194 mm thick).

•If wall thickness is less than 4-3/8 the existing heat shields must be field trimmed. If wall thickness is greater than 7-5/8 in. an extended heat shield will be required.

(DVP Pipe Shown)

B. Wall Penetration Framing

Combustible Wall Penetration

Whenever a combustible wall is penetrated, you must frame a hole for the wall shield firestop(s). The wall shield firestop maintains minimum clearances and prevents cold air infiltration.

•The opening must be framed on all four sides using the same size framing materials as those used in the wall construction.

•SLP pipe - A wall shield firestop must be placed on each side of an interior wall. A minimum 1 1/2 in. (38 mm) overlap of attached heat shields must be maintained.

•DVP pipe - A wall shield firestop is required on one side only on interior walls. If your local inspector requires a wall shield firestop on both sides, then both wall shield firestops must have a heat shield attached to them.

•See Section 10.L. for information for regarding the installation of a horizontal termination cap.

3 in. (76 mm) top clearance

1 in. (25 mm) clearance around vertical sections

Heat	3 in. (76 mm)
Shield	top clearance *
	Heat
	Shield
	1 in. (25 mm)
Wall	clearance
Shield	bottom & sides
Firestop
	WALL

Non-Combustible Wall Penetration

If the hole being penetrated is surrounded by non-combus- tible materials such as concrete, a hole with diameter one inch greater than the pipe is acceptable.

Whenever a non-combustible wall is penetrated, the wall shield firestop is only required on one side and no heat shield is necessary.

10 in.

Vent framing hole.

Heat

Shield

Wall

Shield

Firestop

WALL

3 in. (76 mm) top clearance *

Heat

Shield

1 in. (25 mm) clearance bottom & sides

12 in.

The center of the framing hole is

1 in. (25mm) above the center of the horizontal vent pipe.

DO NOT PACK WITH

INSULATION OR

OTHER MATERIAL.

* When using SLP pipe, minimum clearances from the vent pipe to combustible materi-

als at inside wall firestops are:Top: 2-1/2 in. (64 mm) Bottom: 1/2 in. (13 mm) Sides: 1 in. (25 mm)

Framing should be constructed of 2 X 4 lumber or heavier.

A*

B*

Figure 8.1 Horizontal Venting Clearances To Combustible Materials

* To center of pipe.

		A	B
Model		Top Vent	Rear Vent
NNXT4236	in.	39-1/2	23-1/2
NNXT3933	mm	1003	597

Figure 8.2 Wall Penetration

Heatilator • Novus NNXT • 4055-879 • Rev. o • 2/12 35