Constructing the Fireplace Chase

Installing the Fireplace

A chase is a vertical box-like structure built to enclose the gas fireplace and/or its vent system. Vertical vents that run on the outside of a building may be, but are not required to be, installed inside a chase.

CAUTION: TREATMENT OF FIRESTOP SPACERS AND CONSTRUCTION OF THE CHASE MAY VARY WITH THE TYPE OF BUILDING. THESE INSTRUCTIONS ARE NOT SUBSTITUTES FOR THE REQUIREMENTS OF LOCAL BUILDING CODES. THEREFORE, YOUR LOCAL BUILD- ING CODES MUST BE CHECKED TO DETERMINE THE REQUIREMENTS FOR THESE STEPS.

Factory-built fireplace chases should be constructed in the manner of all outside walls of the home to prevent cold air drafting problems. The chase should not break the outside building envelope in any manner.

This means that the walls, ceiling, base plate and cantilever floor of the chase should be insulated. Vapor and air infiltra- tion barriers should be installed in the chase as per regional codes for the rest of the home. Additionally, Heat-N-Glo rec- ommends that the inside surfaces be sheetrocked and taped for maximum air tightness.

To further prevent drafts, the firestops should be caulked to seal gaps. Gas line holes and other openings should be caulked or stuffed with insulation. If the unit is being in- stalled on a cement slab, we recommend that a layer of plywood be placed underneath to prevent conducting cold up into the room. Be sure to include spark arrestors for woodburning units if they are required.

THE CHASE SHOULD BE CONSTRUCTED SO THAT ALL CLEARANCES TO THE FIREPLACE ARE MAINTAINED AS SPECIFIED WITHIN THIS INSTALLERS GUIDE.

Step 1. Locating the Fireplace

The following diagram shows space and clearance require- ments for locating a fireplace within a room.

Clearance Requirements

The top, back, and sides of the fireplace are defined by stand-offs. The minimum clearance to a perpendicular wall extending past the face of the fireplace is one inch (25 mm). The back of the fireplace may be recessed 21 1/2 inches (546 mm) into combustible construction.

1” MIN. (25mm)
B
A
E	D
E
C
1/2” MIN. (13mm)

A	B	C	D	E
49”	22”	39 1/2”	56”	79”
Figure 2. Fireplace Dimensions, Locations,
	and Space Requirements
	Minimum Clearances
from the Fireplace to Combustible Materials
		Inches		mm
Glass Front	........................	36		914
Floor		0		0
Rear		1/2		13
Sides		1/2		13
Top		3 1/2		89
Ceiling**		31		787

*See Figure 3.

**The clearance to the ceiling is measured from the top of the unit, excluding the standoffs (see Figure 40).

The distance from the unit to combustible construction is to be measured from the unit outer wrap surface to the combustible construction, NOT from the screw heads that secure the unit together.

Minimum Clearances

from the Vent Pipe to Combustible Materials

	Inches	mm
Vertical Sections	1	25
Horizontal Sections
Top	3	75
Bottom	1	25
Sides	1	25
At Wall Firestops
Top	2 1/2	63.7
Bottom	1/2	13
Sides	1	25

For minimum clearances, see the direct vent termination clearance diagrams on pages 23 and 24 in this manual.

Installing the Fireplace