Hood and grease management

The problem

Grease-laden vapor does not stop at the hood. It condenses along the whole exhaust path — filters, plenum, the duct run, the fan, the roof — and every surface it settles on becomes fuel arranged in a line that leads out of the kitchen. That is the reason this is governed at all: NFPA 96 is the standard covering commercial cooking ventilation and grease removal, and it exists because a flare-up on a cooking surface has somewhere to travel.

Who is qualified to do the work is decided locally, and the marketing does not say so. NFPA writes the standard; it does not certify, license, or accredit contractors, so a company advertising itself as "NFPA 96 certified" is naming a credential that does not exist. What the standard calls for is work by people who are properly trained, qualified, and certified, and who are acceptable to the authority having jurisdiction. The word certified is in there — the standard asks for it and does not supply it, which is the whole distinction. Credentials are how a contractor evidences the first three: IKECA credentials technicians, other training programs are recognized, and some states register technicians directly. None of them settles the fourth. The local fire marshal decides what they accept, and that is the question to put to a vendor rather than a claim to take at face value.

The part that gets cleaned is the part that can be seen. A hood cleaning that returns the visible stainless to a shine can leave the horizontal duct runs and the fan housing largely as they were, and the customer has no way to tell the difference from the floor. Two invoices carrying the same line item may not describe the same work.

Capture is the other half, and it is quietly structural. A hood only removes what it can pull in, which depends on filters being present and correctly seated, on the hood being sized and positioned for the equipment actually beneath it, and on enough makeup air entering the room to replace what is being exhausted. A kitchen starved of makeup air pulls it through doorways instead, and the vapor that escapes the hood settles on the ceiling, the walls, and everything else in the room.

Then the line changes. Equipment gets moved, replaced, or added, and the ventilation and suppression that were designed around the old arrangement stay where they were. The system slowly stops matching the kitchen it is protecting, and nothing announces it.

Why it costs

Most of the costs in this category are ordinary, and one of them is not.

The ordinary ones accumulate. Grease that escapes capture lands on surfaces that then need cleaning, which is labor. Grease at the fan and on the roof degrades the membrane and can become an environmental item at the drain. A system that cannot pull properly makes the cook line hot, smoky, and unpleasant, which is a staffing problem in a department that already has one. None of these get charged to ventilation.

The one that is not ordinary is fire. This is a rare category where the failure mode is not incremental — it is a single event that can close an operation permanently, and the exhaust system is the path by which a manageable flare-up becomes a structural one. That asymmetry is the whole argument: the routine spend is small and predictable, and the tail is not.

Enforcement and insurance look at the same system at different moments, and that is what makes the paperwork matter. An inspector assesses condition directly and can act on what they find — heavy buildup is enough to stop an operation on the spot. A carrier reviewing a loss is looking at a system that no longer exists. After a fire the condition is gone, and cleaning logs, service records and photo documentation are what remain to describe it; those are the materials examined in post-incident review.

The asymmetry is temporal, not a matter of one caring about paperwork and the other about grease. Condition is checkable right up until the moment it becomes the thing in question, and then only the record is. An operation with a genuinely clean system and no evidence of it is in a materially worse position than its kitchen suggests — and the evidence has to be created before it is needed, which means it is a purchasing and scheduling decision rather than a filing one.

None of this is a cleaning line item. It is a system: what is cooked and how much grease it actually produces, whether the hood captures it, whether the full duct run is being reached, whether the makeup air balances the exhaust, whether the suppression still matches the equipment layout, and whether any of it can be evidenced. The cleaning frequency and the specification follow from that assessment and from what the authority having jurisdiction requires — not from the invoice cycle.

What a rep can see on a walkthrough, without asking a question

• Grease beading, running, or pooling on the inside surfaces of the hood
• Grease weeping from hood seams or from the joint where the hood meets the ceiling
• Filters missing, installed backwards, or leaving open gaps between them
• Drip cups or troughs overflowing, dry-caked, or absent altogether
• Staining or discoloration on the ceiling around the hood perimeter
• A cleaning certificate or service sticker that is absent, illegible, or long out of date
• A posted sticker or certificate, and what it claims about who did the work
• Grease on the roof around the exhaust fan, or a containment box that is saturated or overflowing
• Suppression nozzles that do not line up with the appliances currently underneath them
• Appliances visibly moved — old scorch marks, floor scuffs, or utility stubs that no longer match the line
• The suppression pull station blocked, stacked in front of, or obscured
• Doors propped open at the cook line, or paper visibly pulled at a doorway
• Haze or smoke lingering over the line during service rather than being captured

How to use these: These are observations, not findings. Whether a system is compliant is determined against NFPA 96 and the authority having jurisdiction, by someone qualified to inspect it, with access to the duct run and the service records — none of which a walkthrough provides. Note also that NFPA does not certify, license, or accredit hood-cleaning contractors, so there is no such thing as an "NFPA 96 certified" company. What NFPA 96 calls for is work by people who are properly trained, qualified, and certified, and who are acceptable to the authority having jurisdiction — four requirements, and the last one decides the other three. So the standard does use the word certified; it simply does not issue the certificate, and it leaves which credential counts to the local fire marshal. IKECA credentials technicians, other training programs are recognized, and some states register technicians directly, but which of them satisfies a given jurisdiction is that jurisdiction's decision. A missing sticker might mean the paperwork lives in the office, and a filter out of place might have been pulled ten minutes ago. What these cues do establish is whether grease is being managed as a system or as a visible surface, and that is a question worth putting to whoever signs the cleaning invoice.

Where the fix usually lives

• Grease filters and baffles
• Rooftop grease containment
• Hood and duct cleaning chemicals
• Heavy-duty degreasers
• Ventilation system assessment support

Categories, not part numbers. The specific spec depends on your load, your line speed, and your freight profile.

Take this further

Lines that address it

Available from your Legends rep for your territory.

Competitor cross-reference

Your rep can cross a competitor part number to an equivalent Legends line item.

Spec sheets and pricing

Held in the manufacturer collateral library and shared by your rep.

Who to ask

The Foodservice division team, via contact.