Restaurant Fire Suppression System Operation & Maintenance

Fire Suppression Systems

As a restaurant owner, you understand the importance of practicing fire safety routines in your kitchen. You've trained employees to use equipment safely, keep it clean and maintained, and follow the proper shut down and startup procedures. In spite of all that planning, fires can still happen. That's why understanding your kitchen's fire suppression system is so important.

Fire Suppression History

The basic fire suppression system we know today was developed in the 1960s as a way to automatically extinguish fires that broke out in commercial kitchens. Originally, this equipment took advantage of the same dry chemicals as general-purpose fire extinguishers. Those chemicals are good at smothering fires fueled by wood, paper, and textiles. Because the majority of commercial kitchen fires involve cooking oils, engineers developed special chemicals to use in fire suppression systems for those facilities.

Modern fire suppression equipment dispenses wet chemical extinguishing agents. When these substances come in contact with blazing cooking oil, they react to create a soapy layer on the oil's surface, extinguishing the fire while cooling the oil and cutting it off the from the oxygen that is essential to keep a fire going. These chemicals sometimes come premixed and are other times made from a solution of water and chemical concentrate that's created as the two are dispensed. A major advantage that wet chemicals have over dry is that they're good at keeping oil from reigniting after it has been extinguished.

Fire suppression equipment has evolved over the years to meet a number of challenges presented by modern kitchens. Today's powerful, efficient cooking equipment creates more intense, concentrated heat than its predecessors. Modern kitchens also primarily use vegetable-based cooking oils that burn hotter than traditional animal fats, so the fires they create tend to be harder to put out and keep out.

How Fire Suppression Systems Work

The majority of restaurant hood fire suppression systems depend on a mechanical device called a fusible link. This device contains two pieces of metal connected with a special alloy engineered to melt at a specific temperature. When heat from a fire causes that to happen, the link separates and triggers the release of the fire-extinguishing chemical.

The most effective suppression systems will also shut off the flow of fuel to all gas-fired cooking equipment in the area that it covers, stopping the flow of heat into the source of the fire. Generally, a fire suppression system can extinguish flames within a few seconds, so a well-designed system can prevent a fire from causing extensive damage to the surrounding equipment and building, though a good deal of cleanup will be in order after the equipment has been discharged.

Fire suppression systems are typically integrated within a restaurant exhaust hood and must be configured to suit the equipment they're designed to protect. Each piece of equipment underneath the hood must be covered by the system. Equipment with large, flat cooking surfaces, including ranges, charbroilers, and griddles, must be protected with overhead nozzles aimed straight down or at an angle. Enclosed or partially-enclosed equipment like salamanders and broilers must be protected with nozzles aimed inside the equipment. Other nozzle designs protect all the equipment in a given area and don't need to be trained at a specific piece.

Fire suppression systems aren't just designed to protect cooking equipment. They're also equipped to protect hood plenums and ducts, components that tend to collect grease that rises from equipment, which can create a hazard in the event of a fire.

Installing & Maintaining a Restaurant Fire Suppression System

Because fire suppression systems almost always come integrated with restaurant hood systems, you'll need to collaborate with your hood vendor to make sure your fire suppression system is optimized to protect your equipment. Wisconsin-based Ansul provides fire suppression systems to many of the most popular hood manufacturers. Their R-102 fire suppression system has become the industry standard for basic fire suppression systems, and you'll likely receive a visit from an Ansul technician to provide your system's initial suppression chemical charge in the days following your hood's installation.

There are a few critical steps you should take to make sure your fire suppression equipment will do its job if there's ever a fire in your kitchen:

  • Schedule regular maintenance and service check-ins with certified technicians. Fire suppression systems are complex assemblies that must be checked regularly. Follow the manufacturer's recommended maintenance schedule and contract with a factory-certified technician who can keep your equipment in top shape.
  • Train your employees. Employees should understand how the fire suppression system works and which equipment it is intended to protect. Every restaurant hood fire suppression system includes a manual activation switch located conspicuously in the kitchen. Every member of the staff should understand how and when to activate that switch.
  • Have a backup suppression method. It's good practice to keep a supplementary fire extinguisher near your cooking equipment for suppressing fires in the event that your suppression system fails or is unable to completely put out a fire. An extinguisher intended to put out a cooking fire must be rated as "Class K," meaning it is suitable for suppressing kitchen fires.
  • Keep all cooking equipment clean and maintained. Clean, well-maintained equipment carries a lower risk of causing a fire to begin with, but if a fire should break out, a fire system will be better able to extinguish a fire that isn't intensified by a buildup of grease.
  • Consult a technician before making any changes to your lineup. Most fire suppression systems are configured specifically to protect your cook-line equipment. If you ever need to change your lineup by installing new equipment or rearranging your existing equipment, you'll need to consult a technician to see if your suppression system needs to be reconfigured.

Standards & Agencies

A number of agencies are involved in setting standards and requirements for the features and capabilities of fire suppression systems for restaurants. The National Fire Protection Agency (NFPA) is the organization responsible for compiling and maintaining the most widely-recognized standards that fire suppression equipment must follow. A number of local agencies have adopted these standards as their own, so there's a good chance your local building and health codes will be based in whole or in part on NFPA requirements.

NFPA standards 17A and 96 are the two most important ones regulating kitchen fire suppression systems. NFPA 17A sets the standards for wet chemical extinguishing systems. NFPA 96, titled "Standard for Ventilation Control and Fire Protection of Commercial Cooking Operations," according to the agency's website, "provides preventive and operative fire safety requirements intended to reduce the potential fire hazard of both public and private commercial cooking operations."

Underwriters Laboratory is the agency involved in regulating the more technical features of fire suppression systems. They also design and perform the tests that verify that equipment can do what its manufacturers claim. The UL 300 Standard for Fire Testing of Fire Extinguishing Systems for Protection of Commercial Cooking Equipment is the main standard that defines what a fire suppression system should be able to do. UL 710 Standard for Exhaust Hoods for Commercial Cooking Equipment sets required capabilities for the exhaust hood systems that fire suppression systems are typically part of.

Before any fire suppression system can be taken to market, it must pass the test defined in UL Standard 300. This test involves bringing a commercial fryer to a temperature high enough to ignite the cooking oil contained within. Technicians performing the test allow the fire to burn for 2 minutes before engaging the suppression system. The system must suppress the fire without splashing grease outside of the equipment area, and the dispensed agent must also prevent the oil from reigniting for 20 minutes. The equipment's fuel source is left on for the duration of the test to simulate a worst-case scenario.

Advanced Fire Suppression System Features

As with most types of restaurant equipment, fire suppression systems are available with a number of advanced systems that can make them more reliable and easier to maintain.

  • Electronic controls rely on electronic sensors, instead of the classic mechanical fusible link technology, to trigger the system. These may detect fires more quickly than mechanical components.
  • Many electronically controlled systems can send diagnostic information to a web interface or a smartphone app that lets operators keep an eye on the status of the system from any location with an internet connection.
  • Advanced fire suppression systems include self-cleaning systems that periodically wash down hoods, baffles, and plenums to help keep them clear of excess grease that could create a fire hazard.