Fire Safety For Commercial Kitchens: 8 Recommendations

2020 Fire Prevention Week from NFPA includes serving up guidance to restaurant facility professionals.

By Jacqueline Wilmot

Restaurant facility professionals are charged with protecting their spaces from a potential fire by complying with the minimum fire safety requirements adopted by the local jurisdiction. A 2017 NFPA Research reported titled “Structure Fires in Eating and Drinking Establishments” shows that U.S. fire departments responded to an average of 7, 410 structure fires per year in restaurants and bars over a four year period. These incidents caused an average annual loss of three civilian deaths, 110 civilian injuries, and $165 million in direct property damage at commercial cooking facilities. Given this, is it any wonder why fire protection is at the top of the menu for many restaurant facility professionals?

commercial cooking
Photo: Getty Images

NFPA 96, Standard for Ventilation Control and Fire Protection of Commercial Cooking Operations provides preventative and operative minimum fire safety requirements for the design, installation, operation, inspection, and maintenance of all public and private cooking operations. Guidelines for exhaust systems, clearance requirements, construction materials for hoods, types of fire extinguishing equipment, routine cleaning, employee training, solid fuel cooking, and inspection, testing, and maintenance of equipment can all be found in the current 2021 edition of the standard. Understanding and following the provisions in NFPA 96 can help facility managers reduce fire hazards and the probability of their restaurant turning into another statistic.

NFPA has been the official sponsor of Fire Prevention Week™ since 1922. Fire Prevention Week, the longest running public health and safety observance on record, takes place October 4-10, 2020.

So, let’s use this week’s Fire Prevention theme, Serve Up Fire Safety in the Kitchen!™ as the springboard for ensuring that commercial cooking facilities are optimizing safety.

1.When does cooking equipment require an exhaust system?
Although many would think this is a straightforward requirement, the number of questions the NFPA Advisory Service Program receives on this section is surprising. The answer depends on the type of food being cooked, how that food is being cooked, the cooking medium, cooking appliance, and how often this is taking place. For example, grilling burgers and cooking French fries will produce grease-laden vapors and require a Type I exhaust hood to capture the vapors and remove them from the kitchen. If muffins are being baked in an oven, a Type II hood, which is designed for heat and steam removal and other non-grease applications, would be required (however Type II hoods are not applicable to NPFA 96).

The only exception to this rule is if the cooking equipment has been listed in accordance with ANSI/UL 197, Standard for Commercial Electric Cooking Appliances, or an equivalent standard for reduced emissions. This requirement specifically applies to equipment served by recirculation systems, also known as ventless type cooking equipment which is addressed in Chapter 13 of NFPA 96.

2. Recognizing the significance of clearance requirements
Clearance between cooking equipment and combustible materials is particularly important to prevent fires from spreading in commercial cooking environments. Fires that burn in ducts can reach very high temperatures that can create a large amount of radiant heat on the outside, even where the duct is not compromised. The radiant heat has the potential to ignite combustible materials and start fires in the combustible concealed spaces of a building, thus the reason for clearance.

Section 4.2 of NFPA 96 recommends a minimum clearance of 18 inches. The definitions for combustible material, limited-combustible material, and non-combustible material are provided in Chapter 3, along with examples of each material in the annex. Although these are considered construction requirements, clearances should be observed during operation. For example, placing combustible boxes on top of a hood or directly against the side of it can present the same hazards noted above.

In many existing commercial cooking facilities, combustible materials might already be present making clearance requirements difficult, if not impossible to achieve. Section 4.2.3 of NFPA 96 provides requirements for clearance reduction systems.

3.Understanding the ins and outs of hoods
Chapter 5 of NFPA 96 touches on all hood requirements, specifically hood construction materials, how to construct the hood, and hood size.

Hoods are required to be construed of and be supported by steel not less than No. 18 MSG in thickness, stainless steel not less than No. 20 MSG in thickness, or other approved material of equivalent strength and fire and corrosion resistance. In addition, all seams, joins, and penetration of the non-listed hood enclosure that direct and capture grease-laden vapor and exhaust gases are required to have liquid tight continuous external weld to the hood’s lower outmost perimeter. This is to prevent grease and, in the event of a fire, flame from extending into the overhead of the building.

A common misconception is that NFPA 96 requires a specific value for the size of a hood. Section 5.2 requires hoods to be sized and configured to provide for the capture and removal of grease-laden vapors. While overhang dimensions are typically provided for listed hoods, based on the requirement in Section 5.2, no overhang is actually specified or even necessarily required.

To determine the size of a hood, measure the front and side overhang requirements from the hood to the cooking appliance, dimensions “F” and “S”, respectively. For example, the hood listing could call for 12 inches for dimension “F” when the hood is over a char broiler, 9 inches when over a griddle, and only 6 inches when over a convection oven. One important difference between the non-listed and the listed hood is that the listed hood “F” dimension is measured from the front of the cooking surface, not the front of the cooking appliance.

While the hood can be sized perfectly at the initial installation, installing new cooking equipment underneath the hood, or moving the equipment for cleaning and not returning it to the properly location defeats the proper hood sizing.

4. Know your exhaust duct systems.
The requirements for exhaust duct systems, provided in Chapter 7, make up the largest focus of NFPA 96. This chapter provides requirements for clearance, openings, other grease ducts, exterior installation, interior installations, and termination of exhaust ducts which includes both rooftop terminations and wall terminations.

To understand the purpose of all these provisions, think about the air flow through the system. Once the smoke and grease-laden vapors have been captured by the hood and most of the grease removed from the air by the grease removals devices, the air is carried through the exhaust duct to be expelled at the system termination. The main principals of the duct system design are to provide enough access so that it can be cleaned and inspected; ensure that it is constructed with materials and connections that will not compromise its integrity should a fire occur in the duct; and make sure that the termination is at a location that will not exhaust any contaminated air in a location where that air could be recirculated back into the building or any adjacent building.

5. Identify your fire extinguishing systems — and know how to use them.
Cooking equipment that produces grease laden vapors that could be a source of ignition of grease in the hood, grease removal device, or duct are required to be protected by fire-extinguishing equipment that include automatic primary protection and portable fire extinguishers for backup.

Automatic extinguishing systems are required to comply with the ANSI/UL 300, Standard for Fire Testing of Fire Extinguishing Systems for Protection of Commercial Cooking Equipment, or other equivalent standards and need to be installed with the requirements of the listing. What is important to note: is that in the early 1990s, the ANSI/UL 300 test standard was modified to reflect modern cooking conditions with better energy efficient appliances and an updated cooking medium in the test by replacing animal lard with vegetable oil, which burns hotter. With the “new” test standard, dry chemical systems are no longer capable of passing the ANSI/UL 300 test standard. Check the fire extinguishing systems installed in your facility and make sure the system complies with the ANSI/UL 300 test standard, or an equivalent test standard.

It is also important to note that all sources of fuel and electrical power that produce heat to equipment requiring protection by a fire extinguishing system need to be automatically shut off to prevent re-ignition.

Manual pull stations associated with automatic fire extinguishing systems are required to be accessible and located a minimum of 3 feet and maximum of 6 feet from the protected hood and the path of egress. Remember, systems are required to be accessible (i.e. do not have materials blocking these manual pull stations or any means of egress), and all employees should know the location of these manual pull stations, as well as how and when to operate them.

commercial kitchen
Figures 1 (left) shows a blocked manual pull station. Figure 2 (right) shows an accessible manual pull station.

Portable fire extinguishers are required to be selected and installed in accordance with NFPA 10, Standard on Portable Fire Extinguishers and be listed for their use. Class K fire extinguishers should be used if vegetable oils and animal oils/fats are present in the kitchen. However, all buildings have Class A fire hazards and where ordinary combustibles are present (i.e. in dining areas of restaurants), employees should be trained on the various types of portable extinguishers and how to use them in the event of a fire.

Most fire extinguishers use the P.A.S.S. technique:
Pull the pin
Aim low, pointing the extinguisher nozzle at the base of the fire
Squeeze the handle to release the extinguishing agent
Sweep from side to side at the base of the fire until it appears to be out

6. Inspect, test, and maintain your commercial cooking operation.
Although inspections for grease buildup and fire extinguishing systems at specified intervals tend to be contracted out, restaurant employees can be trained to inspect this equipment each day and management can be responsible for enforcing this expectation. Encourage employees to routinely look out for normal wear and tear of equipment (i.e. broken seals, missing screws, exposed wires). All employees should start their routine with inspecting the equipment to ensure it was properly cleaned from the previous night (or shift), confirm that if the equipment requires a fire extinguishing system, the nozzles are clear and not clogged with grease. Many restaurants utilize heaters to keep the food hot after it’s been cooked; make sure employees know to check that there are no flammable materials on top of or near the heaters. Before starting the fryer, employees should check to make sure the oil level isn’t too low because if the heating coil is exposed above or close to the oil surface, residue and oil can catch fire. These are all very simple, yet effective steps in the fire protection program of your facility that do not require hiring an outside contractor to perform the work.

There are items that need to be inspected that only trained, qualified, and certified people can conduct. For example, the inspection and service of the cooking equipment must be completed annually; the fire extinguishing system needs to be inspected at least every 6 months; and the entire exhaust system is required to be inspected for grease buildup in accordance with Table 11.4 of NFPA 96, which bases the quantity of inspections on the amount of cooking and type of cooking taking place at a facility.

commercial cooking
Figure 3: Schedule of Inspection for Grease Buildup (NFPA 96, 2021 edition)

7. Importance of Cleaning
Since 1 in every 5 of the fires cited in the NFPA Research report mentioned above had a failure to clean as a factor contributing to its ignition, cleaning seems like an easy and obvious solution to mitigate fire risks. However, when many hear (or in this case read) the word “cleaning” they assume hiring a company to clean the grease within the ductwork, and although this is a critical process that cannot be missed, there are many ways restaurant facility professionals can ensure that staff know how to reduce the risk of fire within their facility. Developing and/or enforcing a training program for all employees is a great way to achieve this goal. New employees should be trained, and current employees should be recertified on specific facility procedures every 6 to 12 months.

If during the scheduled inspection, the exhaust system is found to be contaminated with deposits from grease-laden vapors, the contaminated portions of the system are required to be cleaned by properly trained, qualified, and certified people. Once the cleaning is complete, a written report detailing the amount of grease buildup, as well as any maintenance or repairs needed, and any areas that were inaccessible or not cleaned have been marked, the report must be provided to the owner of the system.

commercial kitchen
Figure 4 (left) shows unacceptable amount of grease. Figure 5 (right) shows acceptable baffle plate accumulation on baffle plate.

8. Owners take responsibility
NFPA 96 requires that the standard be applied as a united whole. It is important to recognize that all the chapters in NFPA 96 may be working on individual components of ventilation control and fire protection, but each of them is needed for the overall goal of reducing the potential fire hazard of cooking operations.

Ultimately, it is the owner’s responsibility that cooking equipment, hoods, ducts, fans, fire-extinguishing equipment, and special effluent or energy control equipment installed in their facility is maintained to ensure the entire system works properly and provides the appropriate level of protection. In addition, the owner is responsible for the inspection, testing, maintenance, and cleanliness of the ventilation control and fire protection of the commercial cooking operation, provided that this responsibility has not been transferred in written form to a management company, tenant, or other party.

NFPA research shows that cooking fires are the greatest cause of fires in eating and drinking establishments, with three out of five fires (61%) originating in equipment and causing 38% of direct property damage. Given these statistics and this year’s Fire Prevention Week theme of Serve Up Fire Safety in the Kitchen!™, it is a great time for facility managers to see what’s cooking on their premises.

Wilmot is a research project manager at the Fire Protection Research Foundation, an affiliate of the National Fire Protection Association (NFPA). She graduated from Worcester Polytechnic Institute with a Master’s degree in Fire Protection Engineering.


Click here to read more stories related to the NFPA and fire safety.