Kitchen Fire Suppression/Ventilation

What is UL 300?

In November 1994, Underwriters Laboratories, a safety consulting and certification company, introduced the UL 300 Standard for Testing of Fire Extinguishing Systems for the Protection of Restaurant Cooking Surfaces. UL 300 was established in response to changes in cooking styles, processes, and equipment present in modern commercial kitchens. Restaurant fires were becoming increasingly difficult to suppress and contain due to these changes, and the creation of UL 300 addressed these issues.

For example, before 1994, commercial cooking involved primarily animal fat. In an effort to lower the fat and cholesterol content of food, restaurants began switching to vegetable oils. Vegetable oils burn at higher temperatures, however, making fires more difficult to suppress.

Additionally, modern and high-efficiency cooking appliances also add to the challenge of total fire protection because they are well-insulated and slow to cool. Dry chemical systems that worked well on these appliances in the past are no longer capable of suppressing and sustaining an extinguished fire. UL 300 systems require wet chemical agents to suppress the fire, similar to how dry chemical systems worked. They also cool materials so they don’t reignite, which dry chemical agents cannot do.

Today, most states mandate that newly installed restaurant fire suppression systems are UL 300-compliant; however, there is inconsistency in enforcement when it comes to existing installations. Six states require UL 300-compliant fire suppression systems in all restaurants by a designated date. A majority of the country—35 states—require replacement of non-UL 300 systems when the cooking equipment is changed, repositioned, or replaced, or if the existing system can’t be maintained. Nine states have no statewide mandate, leaving compliance to be managed at a local level by the jurisdiction with proper authority.

In the absence of consistent mandates, restaurant owners often decide not to upgrade their fire suppression systems to be UL 300-compliant based on the perceived cost of doing so. In the restaurant industry, where profit margins are already thin, every dollar makes a difference. By not upgrading systems to be UL 300-listed, however, owners could face consequences—both financial and personal.

How do I know if a System meets Ul 300 Standards?

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According to Underwriters Laboratory, there is only one way to verify that a system meets UL 300. First, check with UL that the model number is listed as UL 300 compliant. Then, verify that all components have been installed as specified by the manufacturer’s manual.

Another indicator of a UL 300 system is the type of discharge nozzle. All UL 300 compliant systems use a wet extinguishing agent. Wet system nozzles are narrow ¾” to 1” in diameter and are typically covered with red, orange or yellow plastic caps to keep them clean. Wet chemical nozzles will be located directly over each cooking surface.

Discharge nozzles for a dry chemical system (not UL compliant) are fairly large, 2” in diameter and may cover more than one cooking appliance.

Non-UL-300 Compliant Nozzle
                  UL-300 Compliant Nozzle
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Obvious indicators that the system DOES NOT meet UL 300 include:
System installed before 11/21/1994

  • No UL label on cylinder
  • Dry chemical extinguishing media
  • Dry chemical discharge nozzles – large size – see above
  • System uses water spray to protect appliances
  • System uses single nozzle to protect multiple appliances or cooking surfaces