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CSA B365-17: Installation Code for Solid-Fuel-Burning Appliances and Equipment – Technical Overview
Ensuring Safety and Performance in Solid-Fuel Appliance Installations
CSA B365-17 provides the minimum requirements for the installation of solid-fuel-burning appliances and equipment in Canada. This standard is crucial for ensuring safe operation, preventing fires, and maintaining indoor air quality. It covers everything from wood stoves and pellet appliances to masonry heaters and fireplace inserts. This article unpacks the key provisions of the 2017 edition, including scope, technical specifications, and compliance strategies.
Scope and Application
CSA B365-17 applies to the installation of solid-fuel-burning appliances, including but not limited to: wood-burning stoves, pellet stoves, fireplace inserts, masonry heaters, and central heating furnaces. It also covers the installation of chimney connectors, factory-built chimneys, and relining of existing masonry chimneys used for solid-fuel appliances. The standard does not apply to manufactured homes (mobile homes) unless specifically referenced, nor does it cover outdoor burning appliances or barbecues.
This standard is referenced in the National Building Code of Canada and is adopted by most provincial authorities. Compliance is mandatory for all new installations and retrofits where local regulations apply.
Tip: Always verify which edition of CSA B365 is adopted in your jurisdiction. Some provinces may reference older editions or include amendments.
Technical Requirements
Appliance Clearance to Combustibles
One of the most critical aspects of CSA B365-17 is the specification of minimum clearance distances between a solid-fuel appliance and nearby combustible materials. These clearances depend on whether the appliance is tested and listed to a safety standard (e.g., ULC S627, UL 1482, or UL 127) and on the type of shielding used.
| Condition | Minimum Clearance to Combustibles (mm) | Notes |
|---|---|---|
| Unlisted single-wall wood stove | 900 (36 in.) from sides and rear 1200 (48 in.) from front (connector) | Requires non-combustible floor protection |
| Listed wood stove (e.g., ULC S627) | As per manufacturer’s label (typically 450–600 mm) | May be reduced with approved shielding |
| Chimney connector – single-wall | 450 (18 in.) to combustibles | Reduce to 225 mm (9 in.) if guarded or shielded |
| Chimney connector – double-wall (listed) | As per listing (typically 150–200 mm) | Must be listed for use with solid fuel |
| Factory-built chimney | 50 mm (2 in.) minimum to combustibles (as per listing) | Must maintain specified air space; do not fill with insulation |
Common Error: Installing a non-listed single-wall connector too close to walls, ceilings, or wooden joists without proper shielding. Always measure from the nearest combustible surface, including framing.
Chimney and Venting Systems
CSA B365-17 provides comprehensive rules for chimney connectors, masonry chimneys, and factory-built chimneys.
- Chimney Connectors: Must be made of steel with a minimum thickness of 0.5 mm for single-wall and 0.4 mm for double-wall. Connectors must be supported at intervals not exceeding 1.8 m (6 ft). They must not pass through combustible walls or ceilings unless listed for that purpose (e.g., a thimble or wall pass-through system).
- Factory-Built Chimneys: Must be listed to ULC S604 (for solid fuel) and installed per the manufacturer’s instructions. The chimney must extend at least 0.6 m (2 ft) above any roof or structure within 3 m (10 ft) horizontally. Vertical rise must be maintained; offsets must not exceed 45° from vertical unless otherwise specified.
- Masonry Chimneys: When relining an existing masonry chimney for solid fuel, a stainless steel liner listed to ULC S635 or ULC S640 must be used. The liner must be continuous and insulated if required.
Combustion Air Supply
Modern airtight homes can starve a solid-fuel appliance of combustion air, leading to backdrafting and carbon monoxide hazards. CSA B365-17 requires that a combustion air supply be provided for appliances installed in homes built after 1990 or with tight construction. The standard specifies:
- A permanent outside air duct with a minimum cross-sectional area of 200 cm² (31 in²) for appliances rated up to 1.2 kW/L (50,000 Btu/hr).
- Ducts must be screened with rust-resistant mesh, have a manual damper, and be positioned to avoid blockage.
- Existing appliances may require an air supply if negative pressure is detected.
Compliance Tip: Many manufacturers now include a dedicated outside air kit. Using this kit ensures compliant combustion air supply and reduces the risk of indoor air quality issues.
Hearth and Floor Protection
Floor protection must be non-combustible and extend a specified distance in front and to the sides of the appliance. For listed stoves, the required dimensions are on the label. For unlisted stoves, the protection must extend at least:
- 400 mm (16 in.) in front of the loading door
- 200 mm (8 in.) beyond each side of the unit
- Full coverage under the appliance and up to the wall if clearance is less than 150 mm
Materials must have a thermal conductance (k-value) of no more than 0.84 W/m·K or an R-value of at least 1.19 m²·K/W. A material like 8 mm (5/16 in.) cement board or two layers of 0.5 mm (20 ga.) sheet metal with a ventilated air space is common.
Safety Alert: Never install a wood stove on a combustible floor without proper non-combustible protection. Many house fires originate from heat transfer through unprotected floors.
Implementation Highlights
1. Always Use Listed Appliances When Possible. Listed appliances have been tested for safety and performance. Using them simplifies clearance and installation requirements.
2. Proper Chimney Height and Termination. The chimney must extend at least 0.6 m (2 ft) above the highest point of the roof within 3 m (10 ft). This reduces downdrafts and improves draft.
3. Follow Manufacturer Instructions. Where more restrictive than the standard, the manufacturer’s instructions take precedence (as noted in the standard). Always keep a copy at the installation site.
4. Interconnection with Carbon Monoxide Alarms. While not directly covered by CSA B365, many provinces require a CO alarm in rooms with solid-fuel appliances. A CO alarm is a critical backup.
Caution: Don’t assume older installations meet the latest code requirements. Retrofits and chimney liners should be upgraded to CSA B365-17 standards when possible.
Compliance Notes
- Authority Having Jurisdiction (AHJ): The AHJ (e.g., municipal building department, fire marshal) may require plan review or inspection. Always know who has jurisdiction.
- Inspections: Many installations require a final inspection. Use a certified chimney sweep or WETT-certified technician (Wood Energy Technology Transfer) in regions where WETT is recognized.
- Documentation: Keep records of appliance listing labels, chimney listing, and any variances granted by the AHJ.
- Changes from Previous Editions: CSA B365-17 introduced enhanced requirements for clearance reduction methods, stricter rules for used chimneys, and updated references to other standards.
Frequently Asked Questions
Q: Is CSA B365-17 a mandatory standard across Canada?
A: Yes, it is referenced in the National Building Code of Canada and adopted by provinces and territories. However, local amendments may apply, so always check with your local building authority.
A: Yes, it is referenced in the National Building Code of Canada and adopted by provinces and territories. However, local amendments may apply, so always check with your local building authority.
Q: Can I use a galvanized steel pipe for chimney connectors?
A: No. CSA B365-17 prohibits the use of galvanized pipe because the zinc coating can release toxic fumes when heated. Only black steel or stainless steel connectors are allowed.
A: No. CSA B365-17 prohibits the use of galvanized pipe because the zinc coating can release toxic fumes when heated. Only black steel or stainless steel connectors are allowed.
Q: What is the difference between a “listed” and a “certified” appliance?
A: Listing means the appliance has been tested by an accredited third-party laboratory (e.g., ULC, CSA, UL) to a specific safety standard. Certification may refer to both safety and emissions performance (e.g., EPA in the US). For CSA B365 purposes, only safety listing is required.
A: Listing means the appliance has been tested by an accredited third-party laboratory (e.g., ULC, CSA, UL) to a specific safety standard. Certification may refer to both safety and emissions performance (e.g., EPA in the US). For CSA B365 purposes, only safety listing is required.
Q: Does the standard apply to fireplaces with gas logs?
A: No. CSA B365-17 covers only solid-fuel-burning appliances. Gas-fired appliances are subject to CSA B149.1 (Natural Gas and Propane Installation Code).
A: No. CSA B365-17 covers only solid-fuel-burning appliances. Gas-fired appliances are subject to CSA B149.1 (Natural Gas and Propane Installation Code).
Last updated: January 15, 2026. This article is for informational purposes. Always refer to the official CSA B365-17 standard and local codes for complete requirements.