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UL-300 commercial cooking system

Understanding the proper application for a Class K extinguisher

What is a UL-300 System?

UL-300 is a fire testing standard administered by Underwriters laboratories (UL). In order for appliance companies to receive UL labels on their products, each individual model must be submitted to UL for testing. The appliances must meet specific requirements in order to be approved and certified as UL-300.

Why have a UL-300 System?

Before 1994, most commercial cooking involved animal fat. The deep fryers that were used were poorly insulated which made cooking temperatures inconsistent and inefficient. The extinguishing unit that protected those kitchens was a dry-chemical system which would smother the fire.

Today, vegetable oils are used in commercial cooking and they heat to cooking temperatures quickly. Deep fryers have excellent heat retention and are well insulated. Dry chemical systems are no longer capable of extinguishing and sustaining an extinguished fire. UL-300 systems use wet chemicals which serve two purposes: 1.) To smother the fire, similar to the way dry chemicals did; and 2.) To cool the liquids so they don't reignite, something dry chemicals systems couldn't do. Although a system might be labeled as wet chemical, it may not necessarily be rated to the UL-300 standard.

Fact: There are approximately 8,160 structure fires at eating and drinking establishments each year.  More than 50% of these fires were caused by cooking equipment.

Requirements for a UL-300 System:

  • Nozzles located in the hood and duct
  • Nozzles located over each cooking appliance
  • Manual pull station
  • Automatic fuel shut-offs for gas and electric
  • UL-300 compliant wet chemical extinguishing system
  • Wet chemical extinguishing system serviced semi-annually by an authorized licensed service company
  • Hood and duct maintenance and cleaning at least semi-annually by an authorized licensed service company
  • Weekly baffle filter cleaning recommended