A "kitchen hood" is not one line on M-101. IMC 507 is where you prove the hood matches the appliances, captures the effluent, and ties correctly to ducts, makeup air, and fire protection.
We'll cover IMC 507 in 6 parts:
Part 1 (507.1): The rules that drive everything
Type I vs Type II, "one Type I appliance makes the whole hood Type I," operation and interlocks, hood geometry basics, and the required performance test.
Part 2 (507.1.6): Hood size and placement
Canopy overhang and max height, noncanopy setback and max height, and the layout mistakes that cause capture failures.
Part 3 (507.2-507.2.7): Type I construction and installation
Labeling, materials and liquid-tight construction, supports, clearances, penetrations of ceilings and why this ties back to IMC 506 enclosures.
Part 4 (507.2.8-507.2.11): Type I filters, gutters, exhaust rates, suppression
UL 1046 filters, filter height and angle rules, grease gutters, exhaust flow basis by duty class and hood type, and fire suppression.
Part 5 (507.3): Type II hoods
What qualifies as Type II, materials and sealing, and exhaust rates for light-duty vs dishwashers.
Part 6 (507.1 exceptions + "odd cases"): When a hood may not be required
UL 710B recirculating systems, listed downdraft appliances, certain ovens and low-grease electric appliances, and when "no Type II hood" still triggers space exhaust.
On Plans: Why it matters
Most redlines are predictable: wrong hood type, no interlock language, geometry not shown, missing net exhaust basis, no performance test note, and "Type II" drawn like a generic exhaust hood with no capacity callout.
Code Path: Where to show it
M-001: Hood compliance note (Type I/II basis, interlocks, test requirement, net exhaust basis, and "one Type I makes all Type I").
M-101 + roof plan: duct routing and termination coordination (ties to IMC 506 and 508 as applicable).
M-601: Hood schedule with hood type, duty class, net cfm per LF, listing references, filters or none, suppression (Y/N), and interlock (Y/N).
Check: Hood Summary on M-001
M-001 must list each commercial kitchen hood: Type (I or II), listed manufacturer and model (or site-built specifications), appliances beneath it, required capture velocity, and design exhaust rate.
Confirm hood overhang dimensions are shown on the hood elevation or detail - overhang must extend beyond the appliance per IMC 507.1.6 for the hood type and duty class.
Cross-reference the fire suppression shop drawing for each Type I hood - the suppression listing determines maximum overhang and nozzle placement.
Review Risk:
Hood-to-appliance coordination failure - the hood does not overhang the appliances per IMC 507.1.6 - is the most common kitchen hood review stall.
Type I hood specified without fire suppression coordination means the suppression shop drawing may not cover the final appliance layout.
Mixed-duty appliance lineup not accounted for in the hood type selection (entire hood must be Type I if any appliance requires it) is a fast redline.
Field Tip:
Before you submit, do a "HOOD MATCH" sweep: APPLIANCE DUTY -> HOOD TYPE -> NET CFM/LF -> INTERLOCK -> MUA/SUPPRESSION -> TEST NOTE. If any link is missing, the plan review comments write themselves.
Masterbuild QA Lens
Hood selection is the decision that drives every other commercial kitchen exhaust parameter. Confirm the hood type (Type I or Type II) is matched to each cooking appliance before the exhaust cfm, duct sizing, or suppression system is designed. A hood type change after the permit set is submitted requires a full mechanical re-review. Get the cooking equipment list from the kitchen designer in writing before issuing for permit.
Drawing / Submittal Check
M-001 must list each commercial kitchen hood, its Type (I or II), its listed manufacturer and model or its site-built specifications, the appliances beneath it, the appliance BTU/hr rating, the required capture velocity, and the exhaust rate. This master list is the starting point for the reviewer - missing it means each hood will be questioned individually.
Common Review Risk
Commercial kitchen hood review most commonly stalls at hood-to-appliance coordination. The reviewer checks the hood size against the appliance footprint - if the hood does not overhang the appliances per IMC 507.1.6, it gets flagged as a coordination failure, the most common kitchen hood review stall.
When To Escalate
Escalate when the kitchen equipment layout is not confirmed before the mechanical permit is filed, and for any hood system that requires a site-built custom hood instead of a listed manufactured hood. Site-built hoods require AHJ approval of the construction as an alternative to a listed product - this approval must be obtained before the permit is filed, not during plan review.
Kitchen Exhaust Coordination
For kitchen exhaust, tie the hood schedule, appliance lineup, grease duct route, cleanouts, fan discharge, fire suppression interface, and make-up air strategy into one reviewable story.
Duct System Coordination
The 507 series sets hood type, capture velocity, and exhaust CFM before the duct schedule can be built. Establish hood classification and design airflow first - duct sizing follows from those numbers.