A commercial kitchen needs an exhaust hood over most cooking equipment, and the International Mechanical Code, which many states and cities adopt, sorts hoods into two kinds. A Type I hood goes over anything that makes grease or smoke: ranges, fryers, griddles and charbroilers, and in general any medium-, heavy- or extra-heavy-duty appliance. Those appliances also need an automatic fire suppression system under the hood. A Type II hood goes over dishwashers and appliances that make heat, steam or combustion fumes without grease, like a steamer or a pasta cooker, unless the building's air handling is designed to carry that load. If any appliance under one hood needs a Type I, the whole hood is Type I. Canopy hoods overhang the equipment by at least 6 inches on each open side, with the lower lip no more than 4 feet above the cooking surface, and a Type I hood carries a label with its minimum exhaust rate. The Food Code's part is simpler: hoods that keep grease and condensation off food and walls. In the example below, a tamale maker lays out the hood line for its own kitchen.
The short version
- Type I hood: over appliances that make grease or smoke, and medium-, heavy- and extra-heavy-duty appliances.
- Type I hoods need an automatic fire suppression system.
- Type II hood: over dishwashers and steam or heat appliances that make no grease.
- One appliance needing a Type I makes the whole hood Type I.
- Overhang of at least 6 inches on open sides; lower lip no more than 4 feet above the cooking surface.
- The Food Code: no grease or condensation dripping on food, and enough hoods to keep it off walls and ceilings.
- TaroStack plans production against the hours your kitchen has. More below.
Type I or Type II
| Type I | Type II | |
|---|---|---|
| Over | Grease or smoke: ranges, fryers, griddles, charbroilers | Heat, steam or combustion fumes without grease: dishwashers, steamers |
| Fire suppression | Required, automatic | Not required by the hood rule |
| Ducts | Grease ducts of heavy steel, separate from other exhaust | Rigid metal ducts |
| Label | Minimum exhaust rate per foot of hood |
What else a kitchen needs is in commercial kitchen requirements, and the layout in commercial kitchen floor plan.
The rules
| Rule | Where |
|---|---|
| Type I | Over appliances that produce grease or smoke, and medium-, heavy- and extra-heavy-duty appliances (IMC 2021, 507.2) |
| One hood, one type | Where any appliance under a single hood needs a Type I hood, a Type I hood is installed (507.1) |
| Type II | Over dishwashers and appliances that make heat, moisture or combustion products without grease or smoke (507.3) |
| Size | At least 6 inches of overhang on open sides; no more than 4 feet from the cooking surface to the lower lip (507.4.1) |
| Label | A Type I hood shows its minimum exhaust rate per linear foot (507.2.1) |
| Fire suppression | Appliances that need a Type I hood get an automatic fire suppression system (509.1) |
| Food Code | No dripping grease or condensation; enough hoods to keep it off walls and ceilings; ventilation where needed (Food Code 2022, 4-204.11, 4-301.14, 6-304.11) |
Your city adopts its own edition and may amend it, and the fire marshal and building department sign off on the hood. This is general information, not legal advice.
An example: a tamale kitchen's hood line
Rocktown Tamales, a made-up tamale maker in Harrisonburg, Virginia, is moving from a shared kitchen into its own 600 sq ft kitchen. Its cooking line and what each piece needs:
| Equipment | Makes | Hood |
|---|---|---|
| Six-burner range, braising pork and chile | Grease and smoke | Type I |
| 40-gallon tilting kettle, masa and fillings | Grease from the pork | Treated as Type I |
| Two gas tamale steamers | Steam and combustion fumes, no grease | Type II on its own, but under the Type I line |
| Dish machine | Heat and steam | Type II, separate |
Range, kettle and steamers, 124 inches of equipment, sit in one line under a Type I hood: 11.3 feet with the overhang, built as 12 feet, with an automatic fire suppression system, 6 inches of overhang past the ends and front, and its exhaust rate on the label. The dish machine gets a small Type II hood on the other wall. The quote came to $18,000 for the Type I hood and suppression and $6,000 for the make-up air that replaces what the hood pulls out. Putting the steamers under the Type I line, instead of a second hood, kept the duct work to one run through the roof. The drains on the same line are in grease trap requirements.
Get the planner
Download the hood planner. One sheet: list each appliance, whether it makes grease or smoke, heat or steam only, or neither, its width and which hood it sits under; the hood type each needs, each hood's type, its length with 6 inches of overhang at each open end, and whether it needs fire suppression fill in. It's an ordinary Excel file with no macros, and it works in Google Sheets, LibreOffice and Numbers.
Where this stops working
The hood decides which appliances can run where. It doesn't decide how many hours of range time the week needs, and a second shift of tamales is a question of hours, not hoods.
How TaroStack does it
TaroStack doesn't design hoods. It plans what the kitchen makes against the hours it has.
Capacity against hours. Work centers, like the range line and the steamers, have hours, so a week's production plan doesn't promise more steamer time than there is.
Batches with labor. Each batch records what it made and the labor minutes it took, so the real hours behind a dozen tamales are on record.
What could I make right now. From your recipes and what's on hand, TaroStack shows what can be made today.
| The job | Whiteboard | In TaroStack |
|---|---|---|
| Whether the week fits the steamers | Guessed | Plan against work center hours |
| Hours behind a batch | Remembered | Labor minutes on the batch |
| What can be made today | A walk to the walk-in | What could I make right now |
Recipes and batches are on every plan, from $49 a month; planning against work center hours is on Standard, at $99 a month. The first 30 days are free, with no credit card. If you'd like a hand setting up, ask, and we'll do it with you.