Guide
Rooftop grease containment systems overview
Grease that gets past filters still leaves the building at the fan. Operators and landlords often collapse two different layers into one word — “containment” — then argue past each other on the roof. One layer is the small grease receptacle under the upblast drain. The other is a larger rooftop collection pad, tray, or listed system under/around the curb. This page is the systems overview: when you need which layer, what it protects, and what it never replaces. For the walk-the-roof inspection points on the cup itself, use the grease-cup guide.
Short answer
Secondary NFPA 96 (2024) excerpts require upblast fans to drain to a readily accessible, visible grease receptacle not over 1 gal (3.8 L), and rooftop terminations to drain traps/low points into a noncombustible, closed, rainproof, structurally sound collection container that does not hurt fan performance — with listed collection systems commonly cited under UL 710A. A larger listed pad does not excuse a missing or overflowing cup. A cup does not mean the roof is protected if grease still stains the membrane. Containment protects the roof and walking surfaces; it does not replace a duct/fan clean to bare metal, and it does not authorize washing grease or chemicals into roof drains. Your AHJ’s adopted edition wins.
Two layers operators confuse
| Layer | What it is | Typical secondary cite | Does not replace |
|---|---|---|---|
| Fan grease receptacle (“cup”) | Small drain cup under the upblast fan drain tube — emptyable, visible, ≤1 gal | NFPA 96 §8.1.2.3 (secondary); IMC 511.1.1 mirror ≈1 gal / 4 L | Duct/fan interior clean; roof membrane protection when overflow or curb weep continues |
| Rooftop collection / containment system | Larger pad, tray, absorbent media, or enclosure under/around the fan curb that catches what the cup misses | NFPA 96 §7.8.2.1(4)–(6) (secondary); UL 710A listing commonly referenced | The ≤1 gal cup; stormwater rules for wash water; full-system cleaning |
Facility write-ups commonly group approaches as absorbent media around the curb, drip-cup / collection-tray combinations, and listed UL 710A systems — versus field-fab pans and tarps that lack listing and airflow engineering. Prefer listed gear when the AHJ or insurer asks for it; do not invent product rankings here.
What containment does / does not do
What it is for
- Catch grease leaving the fan drain and curb so it does not soak the roof membrane
- Reduce slip risk for HVAC, cleaners, and inspectors on grease-wet walking surfaces
- Give landlords a documented barrier against “grease on roof” CAM / damage disputes
- Support fire / FOG conversations when grease would otherwise track to roof drains and storm
What it is not
- Not a substitute for cleaning plenum, duct, and fan to bare metal
- Not permission to hose wash water or degreaser into roof drains / scuppers
- Not a free pass for a missing, overflowing, or open rain-catch “cup”
- Not a fire-suppression system or a filter upgrade
When to add or upgrade containment
| Signal on the roof | Operator / landlord move |
|---|---|
| Black grease halo around the curb despite a cup | Cup overflow, clogged drain, or curb weep — fix drain path and empty cadence; evaluate larger listed pad if staining continues |
| High grease load (char, wok, 24-hour, solid fuel) | Expect faster cup fill; schedule empty/check with each clean; ask whether listed containment is warranted for the roof asset |
| Landlord / insurer roof-warranty pressure | Ask for UL 710A–listed collection where secondary code language and the AHJ expect listed systems; keep photos + service notes |
| Open bucket sold as “containment” | Reject — rain fills it, diluted grease overflows; secondary language wants closed, rainproof, noncombustible containers |
| Makeshift pan jammed in the airstream | Reject — secondary §7.8.2.1(5) frames collection devices that must not inhibit fan performance |
| Cup OK, no pad, no staining, low volume | May be enough for now — still empty the cup and photo it; reassess after volume or menu changes |
Selection & inspection checklist
- ≤1 gal cup present — under the drain, visible, emptyable without removing the fan.
- Drain path clear — tube points into the cup; not pinched, iced, or painted shut.
- Larger system (if used) — listed to UL 710A when the site claims a listed collection system; not a tarp or plywood box.
- Closed / rainproof — containers that fill with rain and overflow fail the secondary closed/rainproof framing.
- Does not choke the fan — clear of blade path and discharge; no vibration-rub damage to media or trays.
- Service access — hinge/hold-open so the cleaner can open the fan and service the drain/cup (see hinge checklist guide).
- Empty / media cadence — named in the work order; saturated media and full cups photographed.
- Wash-water plan — containment emptied to agreed disposal; no push to roof drains (see chemical-runoff guide).
- Report language — “rooftop fan + grease receptacle / containment” named; inaccessible or missing gear written, not silently skipped.
Field note — UL 710A in plain terms
- UL 710A covers outdoor rooftop grease and oil collection / containment systems used with commercial cooking exhaust on Class A/B/C roof assemblies (UL 790 fire tests of roof coverings). Secondary scope language: outdoor use only; not for permanent attachment to the roof membrane; install per NFPA 96 and IMC/UMC as adopted.
- Secondary NFPA 96 §7.8.2.1(6) text points to grease collection systems listed in accordance with UL 710A that also meet the closed/rainproof container and non-inhibiting-fan rules in (4) and (5).
- We do not rank brands or claim affiliate partnerships here. Ask the installer for the listing mark and the AHJ for what they accept at your address.
- Confirm section numbers against the NFPA 96 / IMC edition your jurisdiction adopts — secondary republishers can lag or renumber.
Who it’s for / not for
- For: GMs and facilities leads deciding whether a pad is needed beyond the cup; landlords writing roof-protection language into tenant scopes; operators after a “grease on roof” note
- Not for: designing a UL 710A system yourself; inventing product rankings or prices; treating containment as the whole NFPA 96 clean; legal or environmental counsel
Sources
- HoodFilters — NFPA 96 excerpts (2024) (secondary; §7.8.2.1(4)–(6) collection container + UL 710A; §8.1.2.3 ≤1 gal receptacle)
- HoodFilters — grease containment requirements FAQ (secondary; same rooftop termination + receptacle language)
- UpCodes — Exhaust fans for commercial cooking (IMC 511.1) (code text mirror; hinged upblast + drain to ≤1 gal / 4 L; cites NFPA 96:8.1.2)
- UL 710A — Rooftop Grease and Oil Collection and Containment Systems (standard scope summary; outdoor collection; not permanent roof attachment; install per NFPA 96 / IMC / UMC)
- Retail & Restaurant Facility Business — Reducing Rooftop Risk (secondary facility overview; absorbent media vs drip cups vs listed UL 710A vs field-fab; roof/warranty framing)
- US Made Supply — NFPA 96 kitchen exhaust overview (secondary; fan inspection row: grease drain/receptacle + rooftop containment)
Next step
Walk the roof (or demand photos): cup present and not overflowing, any larger pad listed and clear of the airstream, no grease halo. Put “empty grease receptacle / service containment” and “no discharge to roof drains” in the next work order. If staining continues with a working cup, price a listed collection system separately from the clean — don’t call the canopy wipe “done.”