Guide
Vertical duct sections that get skipped
The riser is where grease stacks when crews only wash the canopy. Multi-story shafts with no floor-by-floor doors look “done” from the hood and the rooftop fan — and stay dirty for years. This page is about vertical sections that get skipped, not the broader missing-panels bid checklist. For panel inventory questions and report language when doors are missing, use the duct access panels guide. For long horizontal runs and spacing, use that companion page.
Short answer
Secondary sources republishing NFPA 96 (2024 ed.) require all interior exhaust surfaces to be accessible for cleaning and inspection. On vertical ductwork, where personnel entry is possible, access at the top of the riser must allow descent; where entry is not possible, adequate cleaning access on each floor. High openings that cannot be reached from a ~10 ft stepladder need safe access / a work platform. A “hood-only” or “everything accessible” clean that never opens floor doors leaves the shaft as a fire path. Put floor-by-floor riser access, photo proof, and inaccessible riser sections in writing. Your AHJ’s adopted edition wins — confirm section numbers locally.
Secondary NFPA language for vertical risers (verify edition)
| Requirement (secondary excerpt) | What to check in the building |
|---|---|
| §4.1.8 — all interior surfaces of the exhaust system accessible for cleaning and inspection (HoodFilters 2024 republish) | Can every story of the shaft be opened somehow — not just the hood plenum and the fan? |
| §7.4.2.1 — where personnel entry is possible, access at the top of the vertical riser to accommodate descent (UpCodes IMC mirror / NFPA 96 cite) | Top-of-riser door usable for entry when the duct is large enough; not sealed shut or blocked by other trades |
| §7.4.2.2 — where personnel entry is not possible, adequate access for cleaning on each floor | Multi-story kitchens: one door at the hood does not clean intermediate floors or the chase |
| §7.4.2.3 — if not easily accessible from a 10 ft (3 m) stepladder, openings need safe access and a work platform | Ceiling / chase panels you cannot stand at do not count as usable access |
| §12.6.4 / §12.6.10 (Facilitec secondary) — entire system accessible; opened panels get a service tag (company + date; areas cleaned through that panel) | Riser doors opened this visit should show tags; untagged floors usually mean unopened floors |
IMC mirrors (UpCodes §510.3.4) restate the same vertical-access split. Section numbering shifts by edition and code path — treat secondary cites as pointers, then verify with the AHJ.
How vertical sections get skipped in the field
| Pattern | What the crew did | Operator risk |
|---|---|---|
| Hood-only / canopy wipe | Filters and canopy polished; riser never opened | Looks clean under the hood; shaft still loaded — not a full-system clean |
| “Everything accessible” | Cleaned reachable doors only; no floor doors exist so the riser is silently out of scope | Vendor scope sounds complete; operator still owns the inaccessible shaft (Facilitec secondary framing) |
| Top and bottom only | Opened roof / fan and kitchen base; skipped intermediate floors | Middle stories never inspected or brought to bare metal |
| Blocked chase doors | Doors exist but pipes, cable trays, or storage block removal | Access on paper, not in practice — clear before the clean night |
| Fire-rated enclosure ignored | Crew refuses to cut into a rated chase without a listed panel / enclosure opening | Correct refusal — schedule listed/fire-rated panel work as a separate line, not a surprise add-on |
Work-order / quote language that helps
- “Vertical riser included — access on each floor where personnel entry is not possible”
- “List every floor door opened; photo through each; tag affixed near opened panels”
- “Inaccessible riser sections named on the written report — not silently skipped”
- “If floor doors missing: separate written retrofit price vs recurring clean”
- “Horizontal-to-vertical transition and fan takeoff included (see horizontal / hinge guides)”
Patterns that leave the riser dirty
- Low canopy price with no mention of stories or shaft length
- “We’ll clean what’s accessible” with no floor list
- Photos only of the hood — nothing at intermediate floors or the top of the riser
- Assuming a hinged rooftop fan means the vertical duct was cleaned
- Sealed construction openings left closed after a remodel
Operator checklist before you book the multi-story clean
- Story count — How many floors does the grease duct rise through? Sketch it.
- Door inventory — Which floors have grease-duct access doors today? Which have none?
- Top of riser — Is there a usable opening for descent when the duct is large enough?
- Blocked doors — Who clears other trades before the clean night?
- Enclosure rating — Fire-rated chase openings need listed / rated panels — price separately.
- Report lines — Require inaccessible riser sections and panel locations on the cleaning report (see missing panels and the two-week report window).
- Rooftop interface — Fan hinge / hold-open and grease cup are separate from the shaft — see hinge checklist and containment overview.
Field note — grease loads at the base of the rise
- Trade write-ups commonly note that vapor cools as it climbs, so heavy deposits often sit at the base of the riser and at the horizontal-to-vertical transition — not only at the fan.
- Secondary sources (Facilitec access-panel rule explainers) call out panels at the base of vertical risers and at every level of a multi-story rise as practical locations that make §12.6.4 accessibility real.
- We do not invent measurements beyond the secondary 10 ft stepladder / floor-access language above. If your AHJ or adopted edition uses different wording, follow that.
- A hinged fan that opens cleanly still does not prove intermediate floors were entered.
Who it’s for / not for
- For: facilities leads in multi-story hotels, hospitals, and mixed-use kitchens; landlords reviewing tenant clean reports; operators whose last report never named floor doors
- Not for: DIY cutting into fire-rated greaseshafts; treating canopy photos as proof the riser is bare metal; inventing dollar figures without a site walk
Sources
- HoodFilters — NFPA 96 excerpts (2024) (secondary; §4.1.8 accessibility; §7.4.2.2 vertical floor access; §7.4.1.x horizontal companion rules)
- UpCodes — Exhaust duct systems (IMC 510) (code text mirror; §510.3.4 vertical ducts: top-of-riser descent / each-floor access / 10 ft stepladder + work platform)
- Facilitec Southwest — access panel rule explained (secondary; “everything accessible” loophole; multi-story vertical rise; panel tags §12.6.10)
- Facilitec Southwest — NFPA 96 codes notes (secondary; restore panels §12.6.9; inaccessible lists on reports)
- Phil Ackland — need for proper access (PDF) (secondary / older edition citations; vertical openings each floor or top of riser)
- US Made Supply — NFPA 96 access summary (secondary; accessibility + blocked cleanouts after other trades)
Next step
Walk (or photo) every floor the grease duct passes. Mark doors present vs missing. Put that floor list in every bid package and require inaccessible riser sections named on the report. Price missing floor doors separately from the next clean — do not accept a canopy-only night as proof the shaft is done.