Commercial kitchen hood requirements (US)

Type I or Type II?

Under the International Mechanical Code (2024 edition; as adopted by your state or city, and California uses its own Mechanical Code), Type I hoods are required where cooking appliances produce grease or smoke, and over medium-, heavy- and extra-heavy-duty cooking appliances (IMC §507.2). Type II hoods cover heat and moisture, such as dishwashers and appliances that don't produce grease or smoke.

What NFPA 96 (2027 edition) adds

Your state or local authority enforces the edition it has adopted, which may be earlier.

• Where enclosures aren't required, hoods, grease removal devices, exhaust fans and ducts need clearance of at least 18 in (457 mm) to combustible material, 3 in (76 mm) to limited-combustible material and 0 in to noncombustible material (NFPA 96 §4.2.1 as extracted by NFPA; your fire code may enforce an earlier edition).
• When the cooking fire-extinguishing system goes off, all fuel and electric power that produces heat to the protected equipment must shut off automatically (§10.4.1). Gas appliances under the same hood that don't need protection shut off too (§10.4.3).

What the health department checks

The FDA Food Code (2026 model) asks for hood systems sufficient to stop grease or condensation collecting on walls and ceilings (§4-301.14), designed so grease and condensation don't drip onto food or equipment (§4-204.11), and mechanical ventilation where needed to remove heat, steam, smoke and fumes (§6-304.11). States enforce the edition they've adopted.

State example

In California, mechanical exhaust is required over all cooking equipment as needed, installed to the California Mechanical Code (2025 edition from 1 Jan 2026), with makeup air at the rate exhausted (H&S Code §114149.1). In Florida, where a suppression system is required, DBPR says a Class K extinguisher must be within 30 ft of the cooking equipment.

Who signs it off

Your building or mechanical department and fire marshal. Hood design, airflow and makeup air are calculated by a mechanical engineer or hood manufacturer. KitchenSpace Pro flags cooking equipment without a hood; it doesn't size the system.