Most "hood failures" are geometry failures. If the hood is too short, too high, or too far back, it will never capture consistently, no matter how much CFM you throw at it.
Plain English:
507.1.6 applies to BOTH Type I and Type II: Hood overhang, setback, and mounting height must match the hood type.
507.1.6.1 canopy hoods (Type I and II)
Overhang: inside lower edge must extend at least 6 in beyond the edge of the appliance cooking surface on all open sides.
Height: front lower lip of hood must be no more than 4 ft above the cooking surface.
Exception: Hood can be flush at the appliance edge where the appliance side is closed off by a noncombustible wall or panel.
507.1.6.2 noncanopy hoods
Height: locate hood no more than 3 ft above the cooking surface.
Setback: hood edge set back no more than 1 ft from the edge of the cooking surface.
On Plans: Why it matters
Common redlines: canopy hood drawn tight to the appliance with no 6 in overhang, noncanopy hood located too high, or "setback" not coordinated with equipment lineups. Result: smoke rollout, odor complaints, and failed capture tests.
Code Path: Where to show it
Kitchen plan/elevations: dimension hood overhang and lip height above cooking surface.
Hood schedule: list hood type (canopy vs noncanopy) and required geometry.
Coordination details: show wall/panel closures where using the flush exception.
Check: Do
Dimension the 6 in overhang on all open sides for canopy hoods.
Call out mounting height from cooking surface (4 ft max canopy lip, 3 ft max non-canopy).
Review Risk: Don't
Don't rely on "CFM fixes" when the hood geometry is wrong.
Don't leave hood location undimensioned and expect field install to match intent.
Field Tip:
On the hood tag, add a quick "CAPTURE GEOMETRY" line: CANOPY 6" MIN OVERHANG + 4'-0" MAX LIP HEIGHT OR NONCANOPY 3'-0" MAX HEIGHT + 1'-0" MAX SETBACK (IMC 507.1.6).
Masterbuild QA Lens
Hood sizing per 507.2 must be shown on the plan and schedule - not just in the equipment spec. Confirm the plan shows the hood footprint relative to the cooking equipment, the overhang dimension, and the capture velocity calculation result. Hoods that are correctly sized but not dimensioned on the drawings will generate a plan check comment.
Drawing / Submittal Check
For hood size and location (507.1.6): the drawings must show the hood overhang dimensions relative to the cooking surface below - plan and section views. Show the hanging height, the cooking appliance footprint, and the required overhang on all four sides (or all applicable sides for wall-mounted hoods). Missing section views are the leading cause of hood-overhang comments - the overhang and hanging height can only be verified in section.
Common Review Risk
Hood overhang errors discovered during inspection require moving the hood - a significant structural, exhaust, and makeup air rework. The most common: a hood sized to the exhaust rate instead of the appliance footprint. Exhaust rate and overhang are related but separate requirements. Size the hood to the appliance first, then calculate the exhaust rate from the sized hood.
When To Escalate
Escalate when the kitchen equipment layout cannot accommodate the required hood overhang without a hood that is larger than the exhaust fan capacity can economically support, and for any hood installation where the hanging height is variable (adjustable-height hoods, cooking equipment on movable platforms). Variable-height hood systems require the overhang compliance to be confirmed at the minimum hanging height.
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.