How To Reduce Clearance to Combustible Requirements Using Heat Shields
Heat shields are a great way to reduce required clearances to combustibles. The information in this article is intended as a guide. For specific details to your heat reduction requirements, you should contact your local Certified Chimney Professional
Clearance Requirements for Non Certified Stoves
A wood stove without a CSA \ ULC listing tag is classified as a non certified or uncertified appliance. As such, the following clearance to combustibles are required in Canada. Please check your Provincial building code requirements, and local authority having jurisdiction for the requirements specific to your area.
Clearance to combustible requirements for non certified radiant wood stove is 1200 mm (48"). A stove with a metal jacket casing requires 900 mm (36"). Wood stoves certified for installation in an alcove may not be reduced, unless otherwise stated by the appliance manufacturer or AHJ.
The shielding on a non certified stove can come in many forms and has to be spaced out from the appliance at least 50 mm (2") using non combustible spacers. Installing a jacket onto a non certified stove reduces the clearance requirements from 1200 mm (48") to 900 mm (36").
Heat Shield Clearance Reduction By Material
Heat shields may be constructed using sheet metal, ceramic tiles, bricks, or a combination of sheet metal with brick or tile.
Reducing Required Clearance to Combustibles Using a Heat Shield
The table above illustrates that a maximum of 67% of clearance reduction can be achieved by using a compliant heat shield. These clearance reductions do not apply to floor protection. Floor protection requirements for non certified stoves can be complicated, so it's best to contact your local certified chimney sweep for details.
Heat Shield Construction Rules
- Minimum space between shield and combustibles: 21 mm (7/8 in.).
- Minimum clearance along the bottom of shield: 25 mm (1 in.).
- Maximum clearance along the bottom of shield: 75 mm (3 in.).
- Minimum clearance along the top of shield at ceiling: 75 mm (3 in.).
- Shield extension beyond each side of appliance: 450 mm (18 in.).
- Shield extension above appliance: 500 mm (20 in.).
- Edge clearance for ceiling shields: 75 mm (3 in.).
- Adhesives used in shield construction must not ignite or lose adhesive qualities at temperatures likely to be encountered.
- Mounting hardware must allow full vertical ventilation.
- Mounting hardware must not be located closer than 200 mm (8 in.) from the vertical centre line of the appliance.
- Mounting hardware which extends from the shield surface into combustibles may be used only at the lateral extremities of the shield
- Shields must be permanently mounted to walls and not temporary or a folding type shield.