Last week a food truck in Venice, CA had a fire which engulfed the truck in flames. The fire originated in in the deep fryer. Luckily nobody was hurt, but the damage to a truck may require an entire kitchen remodel and weeks of rebuilding while the truck is off the street.
Today we’ll look at the causes of these fires and how food truck operators can keep their employees and mobile kitchen safe from disasters like this.
A deep fat fryer is a vat, or multiple vats, filled with cooking oil that is heated by burners running through tubes underneath. The tubes may serve as a heat exchanger for a gas burner, or electric coils. Baskets of food are submerged in cooking oil heated from 325ºF to 375ºF.
A grease fire typically occurs when cooking oil becomes too hot. When heating, oils first start to boil, then they’ll start smoking, and then they’ll catch on fire. Most vegetable oils have a smoking point around 450°F, while animal fats like lard or goose fat will start smoking around 375°F.
What Causes Deep Fat Fryer Fires?
Poor Mechanical Maintenance
Open fryers are particularly susceptible to poor mechanical maintenance. Normal cooking temperature for deep fryer vegetable oil is about 375ºF. Thermostat malfunction is a primary cause for deep fryer fires in commercial kitchens. If a thermostat malfunctions, cooking temperatures can rise. At 424ºF oil starts to smoke. Smoke production will increase as the temperature rises.
Auto ignition takes place at approximately 523º to 788ºF, depending on the type of oil, the amount of impurities in it and usage. New “high-temperature” fryers are designed to maintain the heat of the oil longer and cook at higher temperatures, making these units a more significant fire risk. Appliance manufacturers should be involved in notifying end-users that new “high-temp” fryers require upgraded fire-extinguishing systems.
Fryer Grease Buildup
In nearly all fryer designs, the gas exhaust vent for the heat from the burner elements goes up the back of the unit behind the vat. With repeated splashing a substantial coating of grease can build up and harden on top of and around this exhaust stack.
This residue provides an excellent fuel source especially if some of the buildup falls close to the burner elements below. Most new fryers are constructed with the chimney open at the bottom, so any debris that falls down the gas flue should fall straight to the floor.
NFPA 96 requires a clearance of at least 16 inches between fryers and any open flame burners. An 8 inch metal or tempered glass panel can be used to achieve this clearance. If this clearance is not met, open flames can ignite the cooking oil.
What to do if a fire does break out?
- Turn the Heat Off. Don’t try to move the fryer. You might accidentally splash the burning oil.
- Cover the Fryer with a Metal Lid. Fire cannot exist in the absence of oxygen. With the lid on (and the heat off), the fire should quickly consume all the oxygen and put itself out.
- Pour on Baking Soda. Baking soda will extinguish grease fires, but only if they’re small. It takes a lot of baking soda to do the job.
- Spray the Fryer with a Class K Dry Chemical Fire Extinguisher. This is your last resort, as fire extinguishers will contaminate your kitchen.
- Get Out and Call 911. If the fire does break out of control don’t try to be a hero. Get yourself and your entire staff out of the truck and call 911.
What not to do:
- Do Not Use Water. Pouring water can cause the oil to splash and spread the fire. The vaporizing water can also carry grease particles in it, also spreading the fire.
- Do Not Throw Any Other Baking Product On the Fire. Flour might look like baking soda, but it won’t react the same. Only baking soda can help put out a grease fire.
Deep Fryer Maintenance and Service
Every two weeks:
- Take down, clean, and degrease the baffle filters in the hood to reduce buildup and the risk of fire.
Every six months:
- Hire a professional cleaning contractor to clean the exhaust duct and flue above the fryer.
- Have a fire service professional inspect and service the food truck fire suppression system.
- Filter and change the oil consistently, per the manufacturer’s specifications, to help prevent a fire.
- Confirm that fire suppression nozzles line up directly over each deep fryer and cooking appliance in your food truck kitchen.
- Confirm that a Class K fire extinguisher is located inside the truck near of the hood system for additional fire suppression capability.
- Prior to operating, review the operations manual provided by the manufacturer. Follow all recommendations on proper installation and maintenance of deep frying equipment.
- Provide employee safety. Provide proper training before employees are allowed to operate a deep fryer and adequate supervision while it is being operated.
We hope this article shed some light on keeping your staff members and food truck safe from deep fryer fires. If you have any additional tips, please share them in the comment section below.