by | Property, Safety |

UL 300, Standard for Safety for Fire Testing of Fire Extinguishing Systems for Protection of Restaurant Cooking Areas, became effective in 1994.  In the years just before then, changes in cooking methods to vegetable based cooking oils, and use of high energy efficiency appliances significantly increased the fire hazard in cooking operations. Commercial kitchen fires became hotter, more difficult to extinguish and the chances of re-ignition substantially increased. Underwriters Laboratories (UL) recognized these changes, and that previous simulation testing, utilizing pans of oil, did not represent actual conditions in place in real kitchens.

Extinguishing systems needed to become safer, more effective and more reliable. Therefore, UL updated their test criteria, to use actual appliances, oils with auto-ignition temperatures resembling vegetable oils, increased pre-burn times and kept appliance fuel on.

Splash tests were also added to ensure system activation did not splash burning grease from certain appliances and to reduce the chances of spreading fire beyond the appliance(s) involved. Limiting splash also increased safety for cooks or other nearby personnel, reducing the chance of burns from splashing grease.

The combination of all these required changes in fire extinguishing systems in order to pass a new UL 300 test standard. Changes included extinguishing agents, nozzle placement, limiting obstructions, more nozzles and more extinguishing agent quantity. By 1994, all newly manufactured systems had to be tested in compliance with UL 300, before they can receive a UL Listing.

There were some changes and revisions to UL 300 through the 1990s, and in 1998, National Fire Protection Standards, including NFPA 96 – Standard for Ventilation Control and Fire Protection of Commercial Cooking Operations, adopted requirements that all new installations be UL 300 Listed.

That adoption created some confusion and different interpretations about what to do with existing installations that do not meet the new listing. Those systems continued to carry their old UL Listing, unless physical changes occurred. There were three choices:

  1. Replace existing systems;
  2. Upgrade existing to meet UL 300;
  3. Continue to operate as long as the system is in compliance with its original listing and there are no changes in the installation or process.

Around 2003, we recognized that option #3 no longer seemed viable because movement or changes in appliances, oils or installations were inevitable or had already occurred. Secondly, proper replacement parts for older systems were becoming unavailable. Accidental discharge of an older system could change a simple recharge into the need to replace entire system(s).

What if that happened during a facility’s busy weekend, busy season or during holiday periods? That could close an entire restaurant for days, instead of a well-planned replacement during a normally slow or closed period. Therefore, we began recommending replacement or upgrade of older, non-compliant systems with UL 300 listed protection in cooking operations. In the meantime, many various governmental entities or other Authorities Having Jurisdiction, have since adopted requirements that all cooking fire extinguishing systems must be UL 300 Listed.

Current Acadia Guidance on UL 300

We currently recommend that all grease producing commercial cooking operations be protected by UL 300 Listed systems. The enhanced protection provided by UL 300 Listed Equipment helps ensure that cooking facilities are safer and the protection is more reliable..

A few important additional considerations pertaining to installation, changes and operation of fixed cooking protection systems and portable fire extinguishers in recent years:

  • Fire suppression systems should be the primary line of defense against commercial kitchen fires.
  • For a cooking equipment fire beyond its incipient stage, the usual recommended actions are ICE-IT:
  1. Immediately activate the manual release, instead of waiting for automatic discharge.
  2. Call the fire department.
  3. Evacuate the building (activate building fire alarm, where applicable, if not already sounding).
  • ITrained in use and limitations of portable extinguishers, a trained person may stand by with the proper extinguisher in the event of a possible reflash.
  • Manual activation is typically best in the earliest stages of a fire. The manual release actuator should be:
    • In a path of exit or egress, away from the hazard.
    • At a height easily reached and operated.
    • Visible and accessible at all times.
    • Clearly identify the hazard protected.
  • With the advent of new wet chemical extinguishing systems meeting UL 300, came the introduction of Class K Portable Fire Extinguishers. These are considered more compatible, with UL 300 Listed systems.
    • Generally, Class K extinguisher(s) should be installed within 30 feet of appliances using combustible cooking oils.
    • A sign should be placed near each extinguisher that states the fire protection system should be activated prior to using the fire extinguisher.
    • Cooking oil fires require an extinguishing agent that reacts with the oil and forms a soapy foam layer (saponification). Most ordinary fire extinguishers do not support saponification, and for this reason, Class K extinguishers should be considered for appliances using cooking oils.
    • Portable fire extinguishers for other hazards in kitchen areas should be in accordance with NFPA 10.
    • Portable fire extinguishers are for back-up purposes, and are usually not the preferred method of extinguishment.
    • Kitchens with solid fuel appliances should have an appropriate Class K Extinguisher, (e.g. minimum 2-A rating), within 20 ft. of the appliance, plus a water pipe system with a hose which can reach the firebox. Fixed pipe and hose are required where fireboxes are larger than 5 ft3.
    • When a fire alarm system is in the same facility, activation of the fire extinguishing system should activate the fire alarm system.

This blog is limited to Acadia’s guidance for UL 300 fire extinguishment in commercial cooking operations which produce grease laden vapors. It is not a comprehensive guide to all fire hazards or fire protection for commercial cooking. For further or additional information, refer to your local Authorities and:

NFPA 96 – Standard for Ventilation Control and Fire Protection of Commercial Cooking Operations

NFPA 1 – Fire Code, CHAPTER 50: Commercial Cooking Equipment

Video: UL 300 – Protecting Commercial Restaurant Kitchens, Fire Equipment Manufacturers Association

Video: How to Use a Portable Fire Extinguisher Training Video, Fire Equipment Manufacturers Association


Acadia is pleased to share this material with its customers.  Please note, however, that nothing in this document should be construed as legal advice or the provision of professional consulting services.  This material is for general informational purposes only, and while reasonable care has been utilized in compiling this information, no warranty or representation is made as to accuracy or completeness.  Distribution of this information does not constitute an assumption by us of your obligations to provide a safe workplace. Maintaining a safe workplace in accordance with all laws is your responsibility. We make no representation or warranty that our activities or recommendations will place you in compliance with law, relieve you of potential liability or ensure your premises or operations are safe. We exercise no control over your premises or operations and have no responsibility or authority to implement loss prevention practices or procedures.

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