Restaurant ventilation installation

Type I vs Type II hoods: choosing by cooking appliance

The hood type follows the appliances underneath it, not the size of the room. A Type I hood handles grease and smoke: fryers, griddles, ranges, woks, rotisseries, conveyor pizza ovens. It uses baffle filters, welded grease duct and an automatic fire-extinguishing system. A Type II hood handles steam, heat and odour without grease: dishwashers, steam kettles and steamers, pasta cookers. When it is close, the fire inspector decides, and we document the choice. See commercial kitchen hood installation.

Quebec regulations for commercial kitchens

Kitchen exhaust design in Quebec rests on NFPA 96 (Ventilation Control and Fire Protection of Commercial Cooking Operations), adopted through the Quebec Construction Code (National Building Code). It governs the hood, filters, duct, clearances, fan, suppression and cleaning.

MAPAQ does not certify hoods. MAPAQ issues the food permit and regulates food safety; exhaust compliance is a fire-code matter. In Quebec the local fire prevention officer is the authority having jurisdiction (AHJ) — they interpret the standard and inspect. The RBQ licenses contractors and publishes an inspection log. We build the system to pass the inspection. See NFPA 96 kitchen hood compliance.

Grease duct: materials, clearances and access doors

Grease duct is not ordinary sheet metal: it must be continuously welded, liquid-tight steel. Galvanized and aluminium are not permitted. Clearances are at least 18 in. to combustible material and 3 in. to limited-combustible material, reducible only with a listed protection system installed to its listing. The duct is sloped to a drain point, and access doors are required at every change of direction, at the base of vertical risers and at intervals on horizontal runs — grease-tight and genuinely reachable. On the roof, the fan must discharge away from air intakes, windows and combustibles. See kitchen hood inspection.

Sizing the hood to the cooking line

Airflow is set by the appliances. As a rule of thumb, a wall-mounted Type I hood needs roughly 200 CFM per linear foot for light-duty, 300 medium-duty and 400 heavy-duty cooking (charbroilers, woks); island hoods typically need more. These are planning figures — final airflow comes from the hood listing and the engineer’s calculation. An undersized or too-high hood spills heat and grease into the kitchen. See hood sizing.

Make-up air: balancing the kitchen

All the air you exhaust has to be replaced. Without a make-up air unit the kitchen goes into negative pressure: doors that fight you, back-drafting flues, cooking odours pulled into the dining room and collapsing hood capture. In practice, supply about 80–90% of the exhaust volume as conditioned outside air, with the balance from building transfer air. The make-up unit must start and stop with the hood. In Quebec the outside air is heated in winter; introducing it through the hood (a compensating hood) is often the most comfortable option.

Demand-controlled ventilation and heat recovery

The energy-efficiency chapter of the Quebec Construction Code requires airflow reduction for kitchens whose combined exhaust exceeds roughly 2,360 L/s (~5,000 CFM). A variable-flow (smart) hood with cooking-effluent sensing cuts exhaust and make-up by at least half when cooking stops. The gains are real — energy, noise, comfort — and utility programs (Énergir, Hydro-Québec) may offer rebates. For heat, the most robust kitchen solution is a run-around water/glycol loop: it moves heat from exhaust to make-up air without ever mixing the two streams.

Permits and inspections in Montreal and Laval

A kitchen touches several permits: municipal construction/renovation (borough in Montreal, city in Laval), roof penetrations and rooftop equipment, gas and electrical connections, and sometimes a fire-prevention review. Nadair prepares and files applications, schedules inspections and hands over system documentation (equipment, compliance, commissioning). The earlier we join a fit-out, the more easily duct clearances and rooftop equipment locations are settled. Note: MAPAQ handles the food permit; the hood is the fire inspector’s file. See NFPA 96 compliance.

What drives the cost

Cost depends on the cooking line and required airflow, duct length and number of elbows, roof access, whether a make-up air unit is needed, whether you add variable-flow control or a fire-rated enclosure, and the schedule (work outside service hours). We price after a site visit, with a quote that separates scope, equipment and timeline. Request a quote.

The projects we deliver

Restaurants and chains (wall or island hood, grease duct, make-up air), rotisseries and production kitchens, caterers and central kitchens, cafés and bakeries: each project starts from the real cooking line, then the duct route the building allows. See our projects.