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:
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.
Check: Hood Detail and Schedule
Hood schedule must show: UL 1046 grease filter listing (Y/N), filter height above cooking surface (6 in / 2 ft / 3.5 ft per appliance duty class), and 45 degrees mounting with drip tray.
Drawings must show grease gutter draining to an approved collection receptacle with cleaning access.
Fire suppression nozzle layout must be shown as a separate sheet or coordinated overlay - confirm coverage matches the final appliance layout and duct collar per the suppression listing.
Review Risk:
Fire suppression nozzle coverage gaps after appliances shift during construction are the most common Type I commissioning correction - verify final appliance layout against the fire suppression shop drawing before commissioning.
NET cfm not shown on the hood schedule (total exhaust minus supply directly into the hood cavity) is a consistent plan review flag for Type I hoods.
Mixed-duty appliances under one hood sized to a lower duty class than the highest-duty appliance will trigger immediate re-review.
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).
Masterbuild QA Lens
Exhaust outlets within Type I hoods (507.2.5) must be sized to maintain capture velocity at the hood face. Confirm the number, size, and location of exhaust outlets are shown on the hood detail and that the cfm per outlet is traceable from the equipment schedule. An outlet count that does not match the required cfm distribution will generate an AHJ question.
Drawing / Submittal Check
For Type I hood filters, gutters, airflow, and fire suppression: the drawings must show the grease filter type and listing, the filter bank slope, the grease gutter and collection cup location, the exhaust plenum depth, and the fire suppression nozzle locations. The fire suppression drawing must be a separate sheet or a coordinated overlay - confirm the nozzle pattern covers all cooking surfaces and the duct collar per the suppression system listing.
Common Review Risk
Fire suppression nozzle coverage is the most common Type I hood correction during commissioning. The fire suppression contractor may position nozzles based on the original appliance layout - if the appliances shift during construction, the nozzle coverage may no longer cover the cooking surfaces. Confirm the final appliance layout matches the fire suppression shop drawing before the system is commissioned.
When To Escalate
Escalate when the fire suppression system design is not available at the time of the mechanical permit submittal. Many jurisdictions require the fire suppression drawings to be submitted with the mechanical permit - or at minimum, a letter from the fire suppression contractor confirming the system will cover the hood per the listing. Missing fire suppression coordination is the leading cause of kitchen mechanical permit delays.
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.