How Often Does a Restaurant Hood Need Cleaning in Denver? The NFPA 96 Schedule

Under NFPA 96, restaurant exhaust hoods and ducts must be cleaned monthly for high-volume cooking, quarterly for moderate-volume cooking, and semiannually for low-volume cooking. Solid-fuel cooking requires monthly cleaning. Denver restaurants should match their cleaning schedule to their actual cooking volume, because inspectors and insurers judge grease buildup, not the calendar.

The NFPA 96 Cleaning Schedule

NFPA 96 is the national standard for ventilation control and fire protection of commercial cooking operations. Fire marshals and insurance carriers rely on it. The standard sets minimum inspection and cleaning frequencies based on how much grease your kitchen produces.

• Monthly: systems serving solid-fuel cooking, and high-volume operations such as 24-hour restaurants, charbroiling, and wok cooking.
• Quarterly: systems serving moderate-volume cooking.
• Semiannually: systems serving low-volume cooking, such as churches, day camps, seasonal businesses, and senior centers.
• Annually: some seasonal or very low-use operations, where the authority having jurisdiction allows it.

These are minimums. If inspection shows grease accumulation above the allowed threshold, the system must be cleaned regardless of the schedule.

How to Classify Your Kitchen

High-Volume Operations

If you run fryers, griddles, or charbroilers for long hours every day, you are high volume. Fast-food outlets, burger and wing restaurants, barbecue operations, and any location open late or around the clock fit here.

Moderate-Volume Operations

Most full-service restaurants fall into this group. They cook throughout service but do not run heavy grease-producing equipment all day.

Low-Volume Operations

Kitchens that cook lightly or occasionally, such as a small cafe serving mostly cold items, may qualify. Be honest about this classification. Underestimating your volume is the most common reason a kitchen fails inspection.

What Gets Cleaned

A complete cleaning covers the whole exhaust path, not only the visible hood. A thorough service includes:

• Hood interior and exterior surfaces
• Grease filters or baffles
• Plenum above the filters
• Entire duct run from hood to rooftop
• Exhaust fan, fan blades, and housing
• Rooftop grease containment

Hidden grease in the duct is what feeds serious fires. A hood that looks clean from below can still have heavy buildup in the vertical riser or at the fan.

Why Compliance Matters Beyond the Fine

• Fire risk: accumulated grease is fuel. A fire that starts at the cooking surface can travel into the duct and spread through the building.
• Insurance: carriers may deny or reduce a claim if records show you skipped required cleaning. Keep your service reports.
• Inspections: a fire inspection can result in correction orders or, in serious cases, an order to stop cooking until the system is cleaned.
• Performance: clean systems pull air better, which keeps the kitchen cooler and reduces odor.

Signs Your Hood Needs Cleaning Sooner

• Grease dripping from the filters or hood edges
• Visible residue on the hood interior or ceiling
• Smoke or odor lingering in the kitchen or dining room
• A fan that sounds strained or vibrates
• Grease pooling on the roof near the exhaust fan
• A change in menu or hours that increases cooking time

Cleaning Is One Part of Kitchen Fire Safety

Hood cleaning works alongside two other requirements:

Fire Suppression Inspection

Wet-chemical suppression systems over your cooking line need professional inspection, typically every six months. A tagged, current system is part of what an inspector will check.

Portable Fire Extinguishers

Kitchens need appropriate extinguishers, inspected on schedule and recharged after use. Staff should know where they are and how to use them.

Records to Keep on Site

• Dated cleaning reports and the service company's certificate
• Photos of hood and duct condition, if provided
• Suppression system inspection tags and reports
• Extinguisher inspection tags
• A posted label showing the date of last cleaning

How to Choose a Hood Cleaning Provider

1. Ask whether they clean the entire system, including the duct and fan, not just the visible hood.
2. Ask for a written report with before-and-after documentation.
3. Confirm they carry insurance and follow NFPA 96.
4. Ask whether they can also handle suppression and extinguisher service, so you have one provider and one schedule.
5. Schedule service outside peak hours to avoid disrupting your kitchen.

Key Takeaways

• Cleaning frequency depends on cooking volume: monthly, quarterly, or semiannually.
• Clean the entire exhaust path, not only the hood.
• Keep dated service records for inspectors and insurers.
• Pair cleaning with six-month suppression inspections.

Frequently Asked Questions

Who decides whether my kitchen is high, moderate, or low volume?

You classify it based on actual cooking activity, and the fire inspector can disagree. If an inspector finds grease buildup between cleanings, expect to move to a more frequent schedule. Keeping cleaning records helps you show a consistent practice.

Can my staff clean the hood themselves?

Staff can and should clean accessible surfaces and filters regularly, such as wiping the exterior and washing baffle filters. The duct, plenum, and fan require trained professionals with the right equipment and access, and the work must reach the full exhaust path.

How long does a professional cleaning take?

It depends on system size, duct length, and grease load. Most restaurants schedule cleaning after closing so service is not interrupted. Ask the provider for an estimated window and whether they protect equipment and floors during the work.

What is the sticker on my hood for?

A service label records the date of the last cleaning and the company that did it. Inspectors use it for a quick check, and it also supports your insurance records. It should be updated after every cleaning.

Does cleaning affect my fire suppression system?

Cleaning is separate from suppression inspection, but the two should be coordinated. Technicians must avoid disturbing nozzles and detection devices, and the suppression system should be checked on its own six-month schedule.

What if my hood has no access panels?

Grease ducts need access openings so the full run can be cleaned. If panels are missing or blocked, the duct cannot be cleaned properly, which is a code problem and a fire risk. Adding compliant access panels is a standard repair that a qualified contractor can do.

Is cleaning a one-time fix for odors and smoke?

Often it improves them, but persistent smoke can also come from an undersized fan, missing make-up air, or damaged filters. If problems continue after cleaning, have the whole system evaluated.

Next Step

APS-Hoods provides hood cleaning, fire protection, and kitchen safety services for Denver restaurants. Review our restaurant fire code compliance service, our fire suppression inspections, and our grease management services.

To schedule a cleaning or get a free estimate, call (800) 750-7313.