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Commercial kitchen ventilation works when the hood matches the cooking process, exhaust airflow meets the applicable code and listed-equipment requirements, and replacement air is supplied without disrupting capture. Type I hoods collect grease vapors and smoke; Type II hoods address heat, steam, odors and products of combustion where grease or smoke is not produced. The exact requirements depend on the locally adopted codes, amendments, appliance classification and hood listing.
What is the difference between a Type I and Type II hood?
Type I: grease and smoke
A Type I hood collects and removes grease vapors and smoke. The cited 2021 International Mechanical Code (IMC) adoption requires Type I hoods over medium-, heavy- and extra-heavy-duty appliances and where cooking produces grease or smoke, subject to the code’s exceptions. The cooking process and appliance classification—not simply the appliance’s fuel—are central to determining which provisions apply.
Type II: heat, steam and combustion products
A Type II hood addresses heat, steam, odors and products of combustion when the appliance does not produce grease or smoke. Do not infer that a particular appliance can operate without a hood, or that it qualifies for a ventless exception, from the hood type alone. Check the appliance and hood listings, manufacturer installation requirements and adopted local code.
One narrow example illustrates why the jurisdiction matters: the 2021 IMC adoption with Rhode Island amendments allows an exception for an electric cooking appliance when an approved testing agency documents grease effluent of no more than 5 mg/m³ at 500 cfm under UL 710B testing. That is a condition in that specific adoption, not a general exemption for electric appliances.
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- No More Cloudy Smoke: Quality stainless steel commercial exhaust hood boasts 2 more smoke-locking tripods than the ordinary exhaust hood. With 94.48-inch large space for smoke capture, our exhaust hood can be used with more than 2 cooktops at the same time, while making sure the oil smoke will not spread around. Wide smoke capture area effectively removes a large amount of smoke and cooking smell in the air.
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- Easy Installation: No complicated assembly required! Our rust-resistant vent hood is pre-assembled as one unit and comes with hanging loops for convenient installation. Easily install the restaurant hood vent and upgrade your kitchen with ease.
- Widely Applicable: Tired of cloudy smoke taking over your kitchen? VEVOR under cabinet vent hood is essential equipment for large commercial kitchens, as well as RVs and outdoor food trucks, capable of effectively removing large amounts of smoke and cooking odors. Whether you're cooking in a professional kitchen or preparing food on-the-go, it is the perfect solution to create a more comfortable and hygienic cooking environment.
How many CFM does a commercial kitchen hood need?
There is no single CFM figure that applies to every commercial hood. In the cited 2021 IMC adoption with Rhode Island amendments, minimum net exhaust is expressed in cubic feet per minute (cfm) per linear foot of hood, and varies with hood configuration and appliance duty. The table gives selected minimums from that specific adoption; it is not a universal design table.
| Appliance duty | Wall-mounted canopy | Single-island canopy | Backshelf/pass-over |
|---|---|---|---|
| Light duty | 200 cfm/linear ft | 400 cfm/linear ft | 250 cfm/linear ft |
| Medium duty | 300 cfm/linear ft | 500 cfm/linear ft | 300 cfm/linear ft |
| Heavy duty | 400 cfm/linear ft | 600 cfm/linear ft | 400 cfm/linear ft |
| Extra-heavy duty | 550 cfm/linear ft | 700 cfm/linear ft | Not allowed in the cited table |
How to interpret the rate
- Use the configuration that matches the hood. Wall-mounted canopy, single-island canopy and backshelf/pass-over hoods have different rates in the cited table.
- For a shared hood, use the heaviest appliance duty. Under the cited rule, when appliances of different duty share a hood, the rate for the heaviest-duty appliance applies across that hood.
- Distinguish total from net exhaust. The cited rule calculates net exhaust by subtracting airflow supplied directly to the hood cavity from the hood’s total exhaust flow.
- Check the listed hood and actual design. A table minimum alone does not establish the right airflow for a particular installation. Hood geometry, listed performance, appliance duty, local amendments and demonstrated capture all matter.
UL 710 evaluates Type I hoods under laboratory capture-and-containment conditions for minimum exhaust airflow and maximum supply airflow. Its results and a prescriptive code rate are related design considerations, but neither should be treated as a substitute for checking the applicable listing and local requirements.
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- Built to Last: Revamp your kitchen with VEVOR 4FT concession trailer hood ! The food truck exhaust hood is crafted from high-quality 201 stainless steel, with exceptional heat resistance and sturdiness. Its superior anti-corrosion properties and stable structure can prevent any deformation over time.
- No More Cloudy Smoke: Quality stainless steel commercial exhaust hood boasts 2 more smoke-locking tripods than the ordinary exhaust hood. With 47.24-inch large space for smoke capture, our exhaust hood can be used with more than 2 cook tops at the same time, while making sure the oil smoke will not spread around. Wide smoke capture area effectively removes a large amount of smoke and cooking smell in the air.
- Easy to Clean: 2 Removable U-shaped grid oil filter meshes allow for thorough cleaning both inside and out, while the stainless steel material ensures that grease adheres to the surface, making cleaning a breeze without leaving any odors behind. Keep your kitchen spotless and hygienic with ease.
- Easy Installation: No complicated assembly required! Our rust-resistant vent hood is pre-assembled as one unit and comes with hanging loops for convenient installation. Easily install the restaurant hood vent and upgrade your kitchen with ease.
- Widely Applicable: Tired of cloudy smoke taking over your kitchen? VEVOR under cabinet vent hood is essential equipment for large commercial kitchens, as well as RVs and outdoor food trucks, capable of effectively removing large amounts of smoke and cooking odors. Whether you're cooking in a professional kitchen or preparing food on-the-go, it is the perfect solution to create a more comfortable and hygienic cooking environment.
Does a commercial kitchen hood need make-up air?
Yes. When commercial kitchen exhaust operates, replacement air must be supplied so the building can meet the exhaust demand. Under the cited 2021 IMC adoption with Rhode Island amendments, makeup air supplied to the building from all sources should be approximately equal to the total exhaust from all systems, and must not reduce the hood’s effectiveness. Mechanical makeup-air systems are required by that adoption to start and operate automatically with the exhaust.
This is a building-level balance, not a rule that a fixed percentage of replacement air must always be delivered directly at the hood. The design should identify exhaust, replacement-air sources and any net exfiltration, while ensuring that the air entering the kitchen does not interfere with capture and containment. A supply arrangement that satisfies an airflow total but disrupts the hood is not a successful balance.
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- Built to Last: Revamp your kitchen with VEVOR 7FT concession trailer hood ! The food truck exhaust hood is crafted from high-quality 201 stainless steel, with exceptional heat resistance and sturdiness. Its superior anti-corrosion properties and stable structure can prevent any deformation over time.
- No More Cloudy Smoke: Quality stainless steel commercial exhaust hood boasts 2 more smoke-locking tripods than the ordinary exhaust hood. With 82.67-inch large space for smoke capture, our exhaust hood can be used with more than 2 cooktops at the same time, while making sure the oil smoke will not spread around. Wide smoke capture area effectively removes a large amount of smoke and cooking smell in the air.
- Easy to Clean: 3 Removable U-shaped grid oil filter meshes allow for thorough cleaning both inside and out, while the stainless steel material ensures that grease adheres to the surface, making cleaning a breeze without leaving any odors behind. Keep your kitchen spotless and hygienic with ease.
- Easy Installation: No complicated assembly required! Our rust-resistant vent hood is pre-assembled as one unit and comes with hanging loops for convenient installation. Easily install the restaurant hood vent and upgrade your kitchen with ease.
- Widely Applicable: Tired of cloudy smoke taking over your kitchen? VEVOR under cabinet vent hood is essential equipment for large commercial kitchens, as well as RVs and outdoor food trucks, capable of effectively removing large amounts of smoke and cooking odors. Whether you're cooking in a professional kitchen or preparing food on-the-go, it is the perfect solution to create a more comfortable and hygienic cooking environment.
The same Rhode Island adoption limits the temperature difference between makeup air and conditioned space to 10°F (6°C), except where the added heating and cooling loads do not exceed HVAC capacity. Confirm whether this provision, including its exception, applies under the project’s adopted code.
How do you test whether a kitchen hood captures smoke?
The cited code calls for a performance test after installation and before final approval. It checks exhaust airflow, makeup airflow and proper operation; a visual capture-and-containment observation is only one part of that test.
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- Weatherproof Design: Designed with outdoor environments in mind, this food truck exhaust fan features a weatherproof construction (IP54) that stands up to rain, wind, and extreme temperatures
- Durable Construction: This commercial kitchen exhaust fan is made from high-quality, corrosion-resistant aluminum alloy for long-lasting performance, whether it's exposed to harsh outdoor elements or used intensively in a commercial kitchen
- Strong Suction: Powered by a 375W pure copper motor, this direct drive fan delivers 1616 CFM airflow for effective smoke and heat removal. With a low noise level of ≦75db, it ensures powerful yet quiet operation
- Quick & Easy Installation: This roof exhaust fan can be set up in minutes with a simple, user-friendly installation process that requires no specialized tools
- Wide Application: Ideal for a variety of settings, including kitchens, food trucks, warehouses, agricultural environments, hotel, and restaurant. This food truck exhaust fan provides reliable ventilation in any space that needs powerful air circulation and smoke removal
- Set up operating conditions. Bring all appliances under the hood to operating temperature. Run outdoor makeup-air sources and recirculated conditioning air that will be operating during the test.
- Verify airflow. Measure and check the required exhaust and makeup airflow, and confirm that the systems operate correctly. A smoke pencil or smoke generator can help visualize movement, but cannot measure required airflow or certify the installation on its own.
- Observe capture and containment. Use smoke or steam from actual or simulated cooking and visually check whether the hood captures and contains it under the operating conditions.
- Document and resolve problems. Record the test conditions and measured airflow, correct deficiencies, and follow the approval process required by the authority having jurisdiction.
Testing with appliances cold or with makeup-air and conditioning systems off does not reproduce the operating conditions specified for the cited capture-and-containment test.
Which codes, standards and listings apply?
Code adoption is local, so first identify the mechanical and fire codes and amendments adopted for the project, then confirm the applicable equipment listing and manufacturer instructions with the design professional and authority having jurisdiction. A standard or product listing does not displace local code requirements.
Quick Recap
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- Weatherproof Design: Designed with outdoor environments in mind, this food truck exhaust fan features a weatherproof construction (IP54) that stands up to rain, wind, and extreme temperatures
- Durable Construction: This commercial kitchen exhaust fan is made from high-quality, corrosion-resistant aluminum alloy for long-lasting performance, whether it's exposed to harsh outdoor elements or used intensively in a commercial kitchen
- Strong Suction: Powered by a 180W pure copper motor, this direct drive fan delivers 612 CFM airflow for effective smoke and heat removal. With a low noise level of ≦75db, it ensures powerful yet quiet operation
- Quick & Easy Installation: This roof exhaust fan can be set up in minutes with a simple, user-friendly installation process that requires no specialized tools
- Wide Application: Ideal for a variety of settings, including kitchens, food trucks, warehouses, agricultural environments, hotel, and restaurant. This food truck exhaust fan provides reliable ventilation in any space that needs powerful air circulation and smoke removal
- Mechanical code: The cited airflow, makeup-air and performance-test examples come from the 2021 IMC with Rhode Island amendments. They should not be applied as universal requirements or assumed to be the rules in another jurisdiction.
- UL 710: Titled Exhaust Hoods for Commercial Cooking Equipment, its seventh edition was published April 29, 2024. UL describes laboratory evaluation of minimum exhaust and maximum supply airflow for capture and containment.
- NFPA 96: The Standard for Ventilation Control and Fire Protection of Commercial Cooking Operations addresses subjects including hoods, grease removal devices, exhaust duct systems and air movement. NFPA’s 2024 edition page identifies these topics.
- Equipment documentation: Check the hood and appliance listings and the manufacturer’s installation requirements alongside the adopted code. UL Solutions notes that mechanical codes and NFPA 96 contain installation requirements and that listed hood capacities are evaluated through UL 710 certification.
What to confirm before designing or approving a system
- The cooking processes and appliance duty classifications, including whether cooking produces grease or smoke.
- The required hood type and configuration, and whether the hood and appliances are listed for the intended installation.
- The adopted mechanical and fire code editions, local amendments and applicable standards editions.
- The exhaust-rate basis for each hood, including the heaviest-duty appliance under a shared hood and any direct supply to the hood cavity.
- The building-wide exhaust and replacement-air balance, makeup-air operation and temperature conditions.
- The manufacturer’s installation requirements and the authority having jurisdiction’s approval and test expectations.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
