Hoods and Fire Suppression

The exhaust hood and its fire suppression system are where maintenance, fire code and insurance meet. This is the one area where the schedule is not a management choice.

The system

The hood and its filters, capturing grease-laden vapour.

Ductwork, carrying it to the exterior.

The exhaust fan, usually on the roof.

Make-up air, replacing what is extracted.

The fire suppression system — nozzles positioned over each appliance, a wet chemical agent, detection links, a manual pull station, and automatic gas and electrical shut-off.

Each part has its own requirement and they are inspected together.

Cleaning requirements

Hood cleaning frequency is set by code and depends on cooking volume and type. High-volume solid-fuel operations require the most frequent attention; low-volume light cooking the least. Typical intervals for a standard restaurant run quarterly to semi-annual, with heavier operations monthly.

Cleaning must cover the whole system — hood, filters, ductwork, and fan. Cleaning only the visible hood interior is a widespread shortcut and it leaves the actual fire risk in the duct.

Certification. Cleaning is performed by a certified contractor who issues a certificate and typically places a sticker with the date. Inspectors look for this and insurers ask for it.

Records are the compliance evidence, and they must be retained.

Filters are cleaned far more often than the system — commonly daily or weekly by kitchen staff, in the dishwasher or by soaking.

Fire suppression requirements

Inspection at code-specified intervals, commonly semi-annual, by a licensed contractor.

What the inspection covers: agent level and pressure, nozzle position and condition, detection links, manual pull station, gas and electrical shut-off operation, and the piping.

Fusible links are replaced on a defined schedule, typically annually, because they degrade with grease and heat.

Nozzle position must match the appliance layout. This is the requirement most often broken by operators without realising it.

The appliance change problem

Worth stating separately because it is the most common serious compliance failure in this area.

Moving, replacing or adding a cooking appliance can put it outside suppression coverage. Nozzles are positioned for specific appliances at specific locations. A fryer moved two feet, or replaced with a wider model, may no longer be protected.

This is not obvious visually and the system will still appear to be present and inspected.

Any change to the cooking line requires the suppression system to be reviewed by the servicing contractor, and adjusted if necessary.

Insurers and inspectors treat this seriously. A fire in an unprotected appliance where the layout had been changed is a claim problem as well as a safety failure.

Build it into the process: no cooking equipment is installed, moved or replaced without a suppression review scheduled.

What happens after a discharge

The system must be recharged and recertified before cooking resumes. This is not optional and it is not quick.

The kitchen is closed until it is done.

Everything is contaminated with wet chemical agent and requires thorough cleaning before food production.

The cause is investigated. A discharge without a fire indicates a detection or system fault.

Preventive tasks

Daily, by staff: filter cleaning, wiping accessible hood surfaces, checking nothing obstructs the nozzles or the pull station.

Weekly: thorough filter cleaning, grease cup emptying where fitted.

At code interval, by certified contractor: full system cleaning including ductwork and fan, with certificate.

At code interval, by licensed contractor: suppression system inspection, with certificate.

Annually: fusible link replacement, fan belt and bearing service, make-up air check.

On any equipment change: suppression coverage review.

The compliance file

For each site, retained and current:

Hood cleaning certificates for the required retention period. Suppression inspection reports. Fusible link replacement records. Any deficiency notices and evidence of correction. The appliance layout drawing showing nozzle coverage.

An inspector asking for these expects them immediately. Producing them from a shared folder in thirty seconds is a materially different inspection from a search through email.

Insurers ask for the same documents after a claim, and the absence of a current cleaning certificate is a problem at exactly the wrong moment.

Reading the contractor's report

Suppression and hood cleaning reports are frequently filed without being read, and they routinely contain deficiencies requiring action.

Look for the deficiency section. Nozzle caps missing, links overdue, agent pressure low, ductwork inaccessible, appliance not covered.

Ductwork inaccessible is the common one. Where access panels are missing or blocked, the cleaner cannot reach the duct and it is noted rather than cleaned. The certificate still issues. The grease remains.

Appliance not covered is the serious one, and it means what it says.

Each deficiency becomes a work order with a date, tracked to closure, with evidence retained alongside the original report.

A report filed unread with an uncorrected deficiency is worse than no report at the point of a fire investigation, because it establishes that the operator was told.