/ Field knowledge · IMC 507.1 exceptions
A hood exception starts with the exact appliance and its evidence.
The 2024 model IMC 507.1 provides narrow paths for certain commercial kitchen equipment. A generic “listed” label does not waive a hood. First identify every appliance and its cooking process; then match each proposed path to the model-specific listing, installation instructions and required room ventilation or exhaust.
Educational reference to the 2024 model IMC. For permit work, confirm the locally adopted edition, amendments, appliance use and authority having jurisdiction (AHJ). This page does not determine whether a proposed lineup qualifies.
Potential paths to check, one appliance at a time
- UL 710B recirculating system: verify the complete listed factory-built assembly—not just a loose hood or filter—and install it as evaluated. The space remains a kitchen requiring ventilation under Table 403.3.1.1; count at least 100 square feet per appliance for that floor-area calculation.
- Integral downdraft: the appliance and its integrated exhaust must be listed and labeled for the application in accordance with NFPA 96. Document the exhaust route to the outdoors.
- Smoker oven with integral exhaust: obtain evidence that the oven and integral exhaust were listed and tested for the proposed application; show the exhaust connection and discharge route.
- Wood-fuel oven: verify the UL 2162 listing for wood-fuel use and vent it in accordance with the manufacturer's instructions.
- Reduced-grease electric cooking: confirm the exact appliance's UL 197 listing specifically identifies reduced grease emissions. A general UL 197 mark alone does not establish this path.
- Self-condensing dishwasher: confirm the commercial electric dishwasher has a self-contained condensing system listed and labeled to UL 921.
- Heat or moisture without grease or smoke: document that the HVAC design or a separate system removes those loads. Where this path applies, provide space exhaust at 0.70 cfm per square foot and count at least 100 square feet for each qualifying appliance that does not require a Type II hood.
What the field answer should say
If the equipment schedule lacks the model, the qualifying listing or the ventilation calculation, the exception remains unverified. If an appliance under one hood requires Type I, the hood serving that lineup follows the Type I path under the applicable code. Calling a different hood “Type I” does not by itself resolve capture, grease duct, suppression, makeup air or installation requirements.
Common failure: a category in place of proof
“Recirculating,” “downdraft” or “electric” describes equipment; it does not prove that the exact tested configuration meets the proposed path. The UL 710B example is a complete system, while UL 197 requires the reduced-grease designation for the specific appliance.
Evidence to put on the drawings
- Appliance-by-appliance schedule with manufacturer, model, process, fuel, output and the proposed hood or exception path.
- Listing or certification record and manufacturer instructions identifying the exact model, configuration and applicable performance claim.
- Plan and section showing equipment layout, any listed integral exhaust, duct or vent route, termination and required installation details.
- Kitchen ventilation and exhaust calculations for the selected path, including Table 403.3.1.1 or the heat/moisture-only floor area and 0.70 cfm per square foot where applicable.
- Adopted-code citation and any AHJ response for a disputed or locally amended path; avoid relying on an exception number copied from a different edition.
References: ICC 2024 IMC Chapter 5 (model code) and UL's explanation of complete recirculating systems and reduced-grease listings. See the split field-tool screen, Daily Code Talk on 507.1, Type I hood requirements and domestic versus commercial cooking. Educational packet (PDF).
What to send
Send the menu and appliance lineup, model-specific listings and manuals, the proposed hood or integral system, the kitchen plan, and ventilation or exhaust calculation. Flag the exact path you want reviewed.
When the drawings claim “no hood required”
Run the exception screen and identify any missing evidence. MasterBuild can review the proposed path under a written scope; the AHJ decides permit acceptance.
Send Project Background+1 (786) 398-6940 · osmany.portal@masterbuildconsulting.com
Educational model-code guide only. Verify the adopted edition, local amendments, complete listing and AHJ path before using an exception on a project.