Grease Fire Prevention in Commercial Kitchens: A Complete Guide

Grease fires are the most serious fire risk in commercial kitchens. They start fast, burn hot, and spread quickly through exhaust systems that have not been properly maintained. In a city as densely built as New York, a single kitchen fire can threaten an entire building.

This guide covers the real statistics, the primary causes, and the specific steps you can take to prevent a grease fire in your commercial kitchen.

The Numbers

The National Fire Protection Association reports that eating and drinking establishments experience an average of 7,500 structure fires per year in the United States. Here is what the data shows:

• Cooking equipment is involved in 61% of restaurant fires
• Failure to clean is the leading factor in fires involving commercial cooking equipment
• Grease fires spread faster than most other fire types because they involve both the cooking surface and the exhaust system
• The average commercial kitchen fire causes over $23,000 in direct property damage — not counting lost revenue, temporary closure costs, liability claims, and increased insurance premiums
• Kitchen fires peak between 10 AM and midnight, coinciding with active cooking hours

In NYC, where restaurants operate in multi-story buildings with shared walls and ductwork chases, the risk of fire spreading beyond the kitchen is higher than in standalone buildings.

How Grease Fires Start

Understanding the chain of events that leads to a grease fire helps you prevent one:

1. Grease Accumulates in the Exhaust System

Every time you cook with oil, fat, or grease, vapors rise from the cooking surface. The hood captures these vapors and draws them through filters, into the ductwork, and out through the rooftop fan. At each point in this path, grease condenses on surfaces. Over weeks and months, these deposits thicken.

2. The Deposits Become Fuel

Accumulated grease is a fuel source. It is hydrocarbon-based and highly flammable. The thicker the deposit, the more fuel is available. In sections of ductwork that are difficult to reach — horizontal runs, elbows, areas without access panels — grease can accumulate to dangerous levels.

3. An Ignition Source Reaches the Fuel

The ignition source can be:

• A flame flare-up on a grill or range that enters the hood
• Superheated oil splashing onto the hood interior
• A spark from cooking equipment
• A grease fire on the cooking surface that spreads upward
• In rare cases, self-ignition of grease deposits that have reached their flash point (approximately 600 degrees Fahrenheit for most cooking oils)

4. The Fire Spreads Through the System

Once grease in the ductwork ignites, the fire follows the fuel. It travels through the ducts to the rooftop fan, into wall cavities and ceiling spaces where ductwork runs, and potentially into other parts of the building. Duct fires are particularly dangerous because they burn inside concealed spaces where they are difficult to detect and fight.

Prevention: The Role of Hood Cleaning

Professional hood cleaning is the primary defense against exhaust system grease fires. It removes the fuel that makes these fires possible.

What Professional Cleaning Does

A thorough cleaning — performed in accordance with NFPA 96 requirements — includes:

• Scraping and degreasing the hood interior (plenum area)
• Removing and cleaning all grease filters
• Cleaning the entire ductwork from the hood to the fan, including all horizontal and vertical runs
• Cleaning the rooftop fan — housing, blades, and grease containment
• Inspecting the system for damage, wear, or conditions that increase fire risk
• Documenting the cleaning with photos and a compliance certificate

Cleaning Frequency Matters

NFPA 96 specifies cleaning intervals based on cooking type because different operations produce grease at different rates. A high-volume charbroiling operation produces far more grease than a bakery. Cleaning at the wrong frequency — too infrequently for your operation — leaves dangerous accumulation in the system between cleanings.

Refer to our hood cleaning frequency guide to determine the right schedule for your kitchen.

Beyond Hood Cleaning: Additional Prevention Measures

Fire Suppression Systems

Every commercial kitchen with grease-producing cooking equipment must have an automatic fire suppression system. These wet chemical systems are designed specifically for commercial kitchen fires:

• Automatic activation: Heat sensors above the cooking line detect a fire and trigger the system
• Wet chemical agent: The agent is designed for grease fires — it cools the fire and creates a foam blanket that prevents re-ignition
• Automatic shutoffs: The system shuts off gas and electrical supply to cooking equipment when it activates
• Manual pull station: Allows anyone to activate the system by pulling a clearly marked handle

Fire suppression systems must be inspected every six months by a qualified technician. This is not optional — it is a code requirement enforced by the FDNY.

Staff Training

Your kitchen staff is your first line of defense. Every employee should know:

• How to activate the fire suppression system — where the pull station is and how it works
• How to use a Class K fire extinguisher — Class K is specifically rated for commercial cooking fires involving grease and oil
• Never to use water on a grease fire — this is critical. Water on burning grease causes an explosive steam reaction that spreads the fire instantly
• Evacuation procedures — how to get everyone out of the kitchen and the building quickly
• When to call 911 — immediately, before attempting to fight the fire yourself

Conduct fire safety training at least annually, and whenever you hire new kitchen staff. A five-minute demonstration of the pull station location and fire extinguisher use can save lives.

Daily Kitchen Practices

Prevention starts with everyday habits:

• Clean filters regularly: Your kitchen staff should remove and clean hood filters at least weekly. Grease-saturated filters reduce airflow and increase the risk of grease reaching the ductwork
• Monitor cooking temperatures: Overheated oil is a primary ignition source. Use thermometers and train staff to recognize when oil is approaching its smoke point
• Keep the cooking line clean: Grease splatter on walls, equipment surfaces, and the floor near cooking equipment is fuel for a fire
• Maintain cooking equipment: Faulty burners, damaged gas connections, and worn electrical components are ignition sources
• Never leave cooking unattended: This is the most basic fire prevention practice and the one most frequently ignored during busy service

Equipment and Infrastructure

• Grease traps and interceptors: These capture grease before it enters the sewer system and reduce the overall grease load in your kitchen. Learn about NYC grease trap requirements
• Non-combustible surfaces: Walls and surfaces near cooking equipment should be stainless steel, tile, or other non-combustible materials
• Proper ventilation: Ensure your exhaust system is providing adequate airflow. Poor ventilation causes grease to accumulate faster. See our commercial kitchen ventilation guide
• Electrical safety: All kitchen electrical systems should be up to code, with GFCI protection where required and no overloaded circuits

What to Do If a Grease Fire Occurs

Despite prevention measures, fires can still happen. Here is the correct response:

Immediate Actions

1. Activate the fire suppression system — pull the manual station
2. Evacuate — get everyone out of the kitchen immediately
3. Call 911 — do this immediately, not after trying to fight the fire
4. Close doors — if you can safely do so, close the kitchen door to contain the fire
5. Meet at the assembly point — account for all staff and customers

What NOT to Do

• Never use water on a grease fire
• Do not try to carry a burning pot or fryer outside
• Do not re-enter the kitchen once you have evacuated
• Do not attempt to fight a fire that has entered the ductwork — that is beyond what a fire extinguisher can handle

After the Fire

• Do not re-enter the kitchen until the fire department clears the building
• The fire suppression system must be recharged and inspected before cooking operations resume
• The entire exhaust system must be cleaned and inspected
• Document everything for your insurance claim
• The FDNY will investigate and review your compliance records

The Insurance Connection

Grease fire prevention is directly tied to your insurance coverage:

• Your commercial property policy likely conditions fire coverage on NFPA 96 compliance
• After a fire, the insurer will request your hood cleaning records, fire suppression inspection reports, and any FDNY violation history
• If your maintenance was not current, the insurer can deny or reduce your claim
• Conversely, a documented history of consistent maintenance strengthens your claim and demonstrates due diligence

For more on how much hood cleaning costs and why it is a worthwhile investment, see our pricing guide.

NYC-Specific Considerations

Operating in New York City adds specific fire prevention considerations:

• Dense building construction: Fires in one kitchen can spread through shared walls, ductwork chases, and building infrastructure
• FDNY response time: While FDNY response times are generally fast, prevention is always better than relying on suppression
• Building code requirements: NYC Building Code has specific requirements for fire-rated construction around kitchen exhaust systems
• Neighbor liability: If a fire in your kitchen damages other tenants, you face significant liability — and their insurers will investigate your compliance record
• FDNY enforcement: NYC has among the most active commercial kitchen fire safety enforcement in the country

Bottom Line

Grease fire prevention in a commercial kitchen comes down to three fundamentals: keep the exhaust system clean, maintain the fire suppression system, and train your staff. Of these, regular professional hood cleaning is the most impactful because it removes the fuel source that enables the most destructive type of kitchen fire.

Do not wait for a close call to take fire prevention seriously. Schedule a hood cleaning with Empire Hoods and keep your kitchen safe.