Commercial Kitchen Hood Design and Exhaust Engineering
Type I and Type II hoods, grease ducts, exhaust fans, makeup air and suppression systems engineered to NFPA 96 for restaurant permits.
- Stamped by a PE licensed in your state
- Built to IBC, IRC and local amendments
- Plan-check comments answered
Restaurant hood systems that pass mechanical and fire review
Commercial kitchen hood design is where restaurant permits most often stall. The hood has to capture smoke and grease from every appliance on the line, the grease duct has to be built and enclosed to fire code, the exhaust fan has to discharge where it will not foul the roof or a neighbor’s air intake, and makeup air has to replace everything the hood removes.
PE Engineer prepares hood and exhaust drawings for new restaurants, food halls, cafes, bakeries, ghost kitchens, schools, churches and any commercial space adding cooking equipment. Designs follow NFPA 96 and the commercial kitchen hood provisions of the International Mechanical Code or Uniform Mechanical Code, and every set is sealed by a Professional Engineer licensed in the state where the project is located.
A hood touches every trade. We coordinate the fire suppression system with the fire alarm plans, the exhaust fan and makeup air unit with the electrical design, grease waste with the plumbing, and the roof curb and duct penetrations with the structure, so the kitchen is buildable exactly as drawn.
What you receive
- Hood plan and appliance line-up
- Exhaust and makeup air calculations
- Grease duct routing and section details
- Exhaust fan and makeup air unit schedules
- Suppression and shutdown interlocks
- PE stamped PDF set ready to submit
Kitchen ventilation systems we design
We size each component from the actual cooking line, so the hood works at the first inspection and the dining room is not starved for air.
Type I grease hoods
Hoods over fryers, griddles, charbroilers, ranges and woks that produce grease or smoke, sized from appliance duty and hood style using listed hood data or the mechanical code exhaust rates.
Type II hoods
Heat and moisture hoods over dishwashers, steamers and ovens that do not produce grease-laden vapors, where the mechanical code or the local authority requires one.
Grease duct and enclosure
Liquid-tight welded grease duct routing with slope, cleanouts, clearance to combustibles, and rated shaft enclosures or listed duct wrap where the duct passes through the building.
Exhaust fans and termination
Upblast or utility set exhaust fans with hinged access and grease containment, located with the clearances from roof surfaces, property lines and air intakes that NFPA 96 requires.
Makeup air
Dedicated or tempered makeup air units and transfer air, balanced against the exhaust so doors open normally, the hood captures properly and gas appliances vent the way they were designed.
Fire suppression coordination
Coordination of UL 300 wet chemical systems, such as Ansul, with automatic fuel and electrical shutoff, manual pull station location and connection to the building fire alarm.
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Send your drawings or describe the project. A licensed engineer reviews it and sends a clear, fixed-fee proposal, often within hours.
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Type I and Type II hoods in commercial kitchen hood design
The mechanical code divides commercial kitchen hoods into two types, and choosing the right one for each appliance is the first step in any design.
Type I hoods are required over commercial cooking appliances that produce grease-laden vapors or smoke, such as fryers, griddles, charbroilers, ranges, woks and tilting skillets. A Type I hood includes listed grease filters or baffles, connects to a welded grease duct, and is protected by a fire suppression system. It is the most heavily regulated part of a restaurant permit.
Type II hoods capture heat, steam and odors from appliances that do not produce grease, such as dishwashers, steamers, pasta cookers and some ovens. They connect to ordinary exhaust ductwork and do not require suppression, but they still need exhaust and makeup air sized to the load.
Some light-duty electric appliances, such as countertop ovens or soup wells, may be exempt from hood requirements depending on their listing and how the local authority interprets the code. Those decisions can save a tenant the cost of a hood entirely, so we review every appliance on the equipment list with you before we draw. We also note which appliances belong under which hood, so a future menu change that adds a fryer is easy to evaluate against the existing system.
Exhaust airflow and makeup air calculations
Hood exhaust rates depend on the hood style and the appliance duty. The mechanical code assigns appliances to light, medium, heavy and extra-heavy duty categories and sets minimum exhaust rates per linear foot of hood for each combination of hood style and duty. Listed hoods tested to UL 710 can often operate at lower airflows than the code tables, which saves fan energy and makeup air cost, so we use the listed rates when a listed hood is specified.
Every cubic foot of air the hood removes must be replaced. Makeup air can come from a dedicated makeup air unit, from the building’s rooftop units, or partly from transfer air out of the dining room. Too little makeup air leaves the kitchen under strong negative pressure, which makes doors hard to open, pulls in unfiltered air and can cause gas appliances to backdraft. We size and temper the makeup air, interlock it with the exhaust fan, and check that the space stays close to neutral pressure.
Larger kitchen exhaust systems may also be subject to energy code requirements such as demand-controlled kitchen ventilation or energy recovery. We flag those early, because they affect the hood and fan selection and are coordinated with the mechanical HVAC design for the rest of the building.
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Grease duct, clearances and roof penetrations
A Type I hood connects to a grease duct that must contain a grease fire for its entire length. NFPA 96 and the mechanical code require the duct to be built of steel with continuous liquid-tight welds, sloped back toward the hood so grease drains, and fitted with cleanouts where the duct changes direction and at regular intervals so it can be cleaned.
Where the duct runs through a building, it must keep the required clearance to combustible construction and, in most cases, be enclosed in a fire-resistance-rated shaft from the ceiling of the kitchen to the roof. A listed field-applied or factory-built grease duct system can reduce clearances and sometimes replace the shaft, which is often the only practical option in an existing building. We evaluate both approaches and show the one that fits your space.
At the roof, the exhaust fan must discharge with the required clearances from the roof surface, from walls and parapets, from property lines and from outdoor air intakes. Upblast fans need a hinge kit for cleaning access and a grease containment system. The fan, curb and makeup air unit add weight to the roof, so we check that the framing can carry them. Where the roof needs reinforcement, we provide the structural detail in the same set.
Fire suppression and the restaurant permit package
Every Type I hood protecting grease-producing appliances needs an automatic fire extinguishing system, and current codes require systems listed to UL 300. Wet chemical systems such as Ansul are the most common choice. The suppression system is usually designed by the distributor or installer to the manufacturer’s listing, while our drawings show the coordination: automatic shutoff of gas and electric power to the cooking appliances, the manual pull station location along the means of egress, and the connection to the building fire alarm system where one exists.
A restaurant permit typically passes through several reviewers. The building department reviews mechanical, structural and accessibility items, the fire department reviews the hood suppression and fire alarm, and the health department reviews the kitchen layout, finishes and plumbing fixtures. We prepare the hood drawings so each reviewer finds what they need, and we coordinate floor sinks, hand sinks and grease interceptor sizing with our plumbing design.
To start, send the floor plan, the kitchen equipment list with cut sheets, the hood manufacturer’s drawings if a hood has already been selected, the number of floors above the kitchen, and photos of the roof. If the building department has already commented, include those comments and we will respond to each one.
You likely need this if
- You are opening a new restaurant or cafe
- You are adding a fryer, griddle or charbroiler
- Retail space is being converted to food service
- An existing hood system is being replaced
- The city flagged makeup air or the grease duct
- Your landlord requires engineered hood plans
How it works, start to finish
From your first message to stamped drawings, you work directly with the engineering team.
- 1Share your projectSend the address, scope and any drawings, photos or plan-check comments. Two minutes is enough.
- 2Receive a fixed-fee proposalAn engineer reviews the scope and replies with a firm price and delivery date for your kitchen hood & exhaust drawings.
- 3Engineering and draftingWe run the calculations and prepare drawings to the codes your jurisdiction enforces, checked before sealing.
- 4Stamped set deliveredYou receive a sealed PDF set ready to submit, and we answer any plan-check comments within scope.
Codes and standards we design to
Kitchen ventilation designs follow the editions adopted by your jurisdiction, along with local fire and health department requirements:
- NFPA 96, Ventilation Control and Fire Protection of Commercial Cooking Operations
- International Mechanical Code (IMC) Chapter 5, or the Uniform Mechanical Code (UMC)
- International Fire Code (IFC) commercial cooking provisions
- UL 710 for listed exhaust hoods
- UL 300 for fire extinguishing systems protecting commercial cooking equipment
- NFPA 17A for wet chemical extinguishing systems
How licensing works. Engineering drawings must be sealed by a Professional Engineer licensed in the state where your project is located. PE Engineer works with a network of state-licensed PEs, so every set is reviewed and stamped by an engineer with an active license in the state where your project is located. Their name and license number appear on the seal, exactly as your building department requires.
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Do I need a Type I hood for my kitchen?
If you cook with commercial appliances that produce grease-laden vapors or smoke, such as fryers, griddles or charbroilers, you almost certainly need a Type I hood. Some light-duty electric equipment may be exempt depending on its listing and the local interpretation. We review your equipment list and confirm.
How much makeup air does my kitchen need?
Approximately as much as the hoods exhaust, less any air transferred from other spaces. We calculate the exhaust from the hood type and appliance duty or the hood listing, then size and temper the makeup air so the kitchen stays close to neutral pressure.
Can you design a hood for a space that was not built as a restaurant?
Yes. The main challenges are routing the grease duct to the roof, providing a rated shaft or listed duct wrap, and confirming the roof can carry the fan and makeup air unit. We evaluate those early so you know what the conversion involves before signing a lease.
Who designs the Ansul or other fire suppression system?
The suppression system is normally designed and installed by a certified distributor following the manufacturer’s UL 300 listing. Our drawings show the hood, the protected appliances, the fuel and power shutoffs, the pull station and the fire alarm connection, so the suppression submittal fits the overall design.
Will both the building and health departments review my hood plans?
Usually, yes. The building and fire departments review the hood, duct, fan and suppression system, while the health department reviews the kitchen layout and sanitation items. We prepare the drawings so each reviewer finds the information they need in one coordinated set.
Can you stamp drawings from the hood manufacturer?
Many jurisdictions want a sealed mechanical plan that shows the entire system, not only the hood. We incorporate the manufacturer’s hood and fan data into a complete set with exhaust and makeup air calculations, grease duct routing and roof details, sealed by a PE licensed in your state.
Get your free kitchen hood & exhaust proposal
Tell us where the project is and what you need. Attach any drawings, photos or plan-check comments. A licensed engineer reviews every request.
- Upload your filesPlans, sketches, photos or comments
- Get a fixed-fee proposalUsually the same day
- Receive stamped drawingsSealed by a PE licensed in your state