9 Chase Installations
A. Construct the Chase
A chase is a vertical boxlike structure built to enclose the fireplace and/or its vent system. Vertical chimneys that run on the outside of a building must be installed inside a chase.
Construction of the chase may vary with the type of build- ing. These instructions are not substitutes for the require- ments of local building codes. Local building codes MUST be checked.
A chase 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 build- ing envelope in any manner. All outer walls need to be insulated.
Building codes require false ceiling and ceiling firestops at each floor of the chase or every 10 ft (3.05 m) of clear space to control spread of fire.
Walls, ceiling, base plate and cantilever floor at the first level of the chase should be insulated. See Figure 9.1. Vapor and air infiltration barriers should be installed in the chase as per regional codes for the rest of the home. Ad- ditionally, Hearth & Home Technologies recommends that the inside surfaces be sheet rocked and taped (or the use of an equivalent method) for maximum air tightness.
Round Termination Cap |
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Metal Chase Top |
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| Firestop |
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| Spacer |
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| False Ceiling |
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| Attic |
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Tabs | Insulation |
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Shield |
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| Firestop | Insulation in the |
| outside walls | |
| Spacer | |
| of the chase | |
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Insulation | Insulation |
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False Ceiling | False Ceiling |
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| Chimney |
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Figure 9.1 | Chase Assembly |
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Gas line holes and other openings should be caulked with high temperature caulk or stuffed with unfaced fiberglass insulation. If the fireplace is being installed on a cement slab, we recommend that in cold climates, a sheet of plywood or other raised platform be placed underneath to prevent conducting cold up into the room.
Three examples of chase applications are shown in Fig- ure 9.2.
1.Fireplace and chimney enclosed in an exterior chase.
2.Chimney offset through exterior wall and enclosed in chase.
3.Chase constructed on roof.
Note: In cooler climates, all chase walls should be insulated.
1 | 2 | 3 |
Figure 9.2 Chase Constructions
WARNING! You must install false ceilings and ceiling
firestops at each floor of the chase or every 10 ft (3.05 m) to control spread of fire.
WARNING! Risk of Fire! DO NOT seal area between fire stop opening and chimney pipe. Restricting air flow around chimney may cause fire.
WARNING! Risk of Fire! You must maintain a minimum 2 in. (51 mm) air space clearance to insulation and other materials surrounding the chimney system.
•Insulation and other materials must be firmly secured to prevent accidental contact with chimney system.
•The chase must be properly blocked to prevent blown insulation or other combustibles from entering and making contact with fireplace or chimney.
•Failure to prevent contact between insulation or other materials and chimney system may cause overheating and fire.
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