Part 4 is where Type I hoods go from "shown on plans" to "works in the field": filters, drainage, capture airflow, and suppression.
Plain English: Plain-English Highlights
507.2.8 grease filters (UL 1046): Type I hoods must have grease filters listed/labeled to UL 1046 with access for cleaning/replacement.
Minimum height from cooking surface to lowest filter edge (Table 507.2.8):
No exposed flame: 0.5 ft (6 in)
Exposed flame/burners: 2 ft
Exposed charcoal/charbroil: 3.5 ft
507.2.8.1 filter criteria
Size/arrange filters so airflow does not exceed approved ratings.
Removable without tools (unless clean-in-place and system supports it).
If removable, make them a size that fits a dishwasher/pot sink.
Prevent grease/condensate drip onto food or prep surfaces.
507.2.8.2 mounting: Filters minimum 45 degrees from horizontal plus drip tray under the lower edge.
507.2.9 grease gutters: Gutters must drain to an approved collection receptacle with access for cleaning.
507.2.10 Type I hood capacity (NET exhaust)
NET = total exhaust minus any air supplied directly to the hood cavity.
If mixed duty appliances are under one hood, size the whole hood to the highest duty appliance.
Minimum NET airflow (cfm per linear ft):
Extra-heavy: wall 550 | single island 700 | double island 550 per side (no backshelf, no eyebrow)
Heavy: wall 400 | single island 600 | double island 400 per side | backshelf 400 (no eyebrow)
Medium: wall 300 | single island 500 | double island 300 per side | backshelf 300 | eyebrow 250
507.2.11 fire suppression: Type I hoods require an approved automatic fire suppression system per IBC 904.13 and IFC.
On Plans: Why it matters
Common stops: filters not UL 1046, wrong filter height for charbroilers, missing drip tray, NET cfm not shown, mixed duty sized too low, suppression not coordinated.
Code Path: Where to show it
Hood schedule: duty class, total cfm, NET cfm, UL 1046 filters.
Elevation/detail: filter height and 45 degree mounting with drip tray.
Notes: grease gutter to receptacle and Type I suppression coordination.
Field Tip: Field tip
Put this on the hood schedule: UL 1046 (Y/N) | FILTER HT (6 IN, 2 FT, 3.5 FT) | 45 DEG + DRIP TRAY | NET CFM | HIGHEST DUTY UNDER HOOD | SUPPRESSION (Y/N).
Comment "IMC507-P4" if you want a paste-ready hood schedule template with NET CFM and filter height notes.
Masterbuild QA Lens
Exhaust systems need a source-to-discharge story. Identify what is being captured, how it is captured, how it is routed, where it terminates, and what interlocks or separations protect the building.
Drawing / Submittal Check
Verify source classification, hood or pickup point, duct material, route, cleanouts or access, fan selection, discharge location, make-up air, controls, and required coordination with fire protection or alarms.
Common Review Risk
The expensive miss is treating all exhaust the same. Grease, dryer, dust, hazardous, smoke control, battery, and specialty exhaust systems carry different proof requirements.
When To Escalate
Escalate when exhaust involves grease, hazardous materials, combustible dust, battery charging, smoke control, rated shafts, energy recovery, or any discharge that can re-enter the building.
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.