Plain English:
506.3.13 exhaust outlets: Grease duct exhaust outlets must meet the termination rules in 506.3.13.1 through 506.3.13.3.
506.3.13.1 above-roof terminations: If you terminate above the roof, the discharge opening must be at least 40 in above the roof surface.
506.3.13.2 through-wall terminations: Wall terminations are allowed only when the discharge will not create a public nuisance or fire hazard.
Also:
You cannot terminate where the IBC requires protected openings.
Keep it at least 3 ft from any opening in the exterior wall.
Still must meet the separation rules in 506.3.13.3.
506.3.13.3 separation distances: Unless you qualify for the exception, locate the exhaust outlet:
At least 10 ft horizontally from parts of the same/contiguous building, adjacent buildings, and adjacent property lines.
And at least 10 ft above adjoining grade.
Also: at least 10 ft horizontally from, OR at least 3 ft above, outside air intakes into any building.
Exception: You can reduce the 10 ft horizontal separation to 5 ft (from buildings, property lines, and air intakes) when the exhaust discharges away from those locations.
On Plans: Why it matters
Common redlines: "mystery" wall terminations near windows, terminations too close to OA intakes, and roof fans too low above roofline. These become real issues fast: grease staining, and odor complaints.
Code Path: Where to show it
Roof plan: dimension from exhaust outlet to OA intakes, roof edges/property lines (as applicable), and note "40 IN MIN ABOVE ROOF."
Exterior elevations: call out wall termination distances to nearby openings and the discharge direction (especially if using the 5 ft exception).
Mechanical schedules/notes: identify "ABOVE ROOF" vs "THRU WALL" and reference IMC 506.3.13.
Check: Do
Dimension the termination clearances on the drawings (don't make the AHJ guess).
Call out discharge direction when you're relying on the 5 ft exception.
Review Risk: Don't
Don't place a grease duct outlet near OA intakes, operable windows, or property lines without checking the separation rules.
Don't assume a wall termination is acceptable on tight sites unless nuisance/fire risk and IBC opening protection are addressed.
Field Tip:
On your roof plan template, add a "GREASE EXHAUST TERMINATION CHECK" note next to each outlet:
40 IN ABOVE ROOF (Y/N) + DIST TO OA INTAKE + DIST TO PROPERTY LINE/ADJ BUILDING + DISCHARGE DIRECTION (IF USING 5 FT EXCEPTION).
It turns terminations into a quick, defensible plan-review item.
Masterbuild QA Lens
Grease duct access panels must be shown on the permit set - location, spacing, and minimum size. Confirm access panels are at every change in direction, at the inlet, and at intervals not exceeding 20 ft per Section 506.3.8. Put access panel tags on the isometric drawing. Missing access documentation is a common first-cycle comment.
Drawing / Submittal Check
For exhaust outlet terminations (506.3.13): the drawings must show the termination location on the roof plan, the clearances from rooftop air intakes, property lines, and combustible construction. The termination detail must show the spark arrestor (where required), the termination guard, and the required clearances. Rooftop plans that show only the fan curb without the termination clearances are common - add a note or detail showing the required separation.
Common Review Risk
Termination location on the roof is commonly the last thing coordinated on a commercial kitchen project. By the time the exhaust fan location is confirmed, the roof curb is already framed, and the separation from the HVAC air intake may be too short. Check the separation between the grease exhaust termination and every air intake on the roof before the roof curb location is set.
When To Escalate
Escalate when the grease exhaust termination location on the roof conflicts with occupied outdoor areas (rooftop dining, terraces, or amenity spaces) or when the termination clearance from a neighboring building's air intake cannot be achieved without a significant duct extension. Termination location conflicts in urban settings often require AHJ approval of an alternative location.
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
Grease duct exhaust outlet location (506.3.13) sets minimum clearances from windows, doors, and adjacent structures. Show the outlet elevation, clearances, and discharge direction on the roof or exterior elevation drawing.