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Why fire rigs, ambulances need portable extinguishers

In addition to the ABCDs, fire apparatus need to carry Class K extinguishers for residential and commercial response


The average piece of fire apparatus today is gargantuan when compared with its relatives of only 30 or 40 years ago. Especially impressive is the fire suppression capabilities (pump size, water carried and hose carried) that today’s Type I engine possesses.

So why do we still carry portable fire extinguishers aboard fire apparatus and other emergency service vehicles?

For starters, portable fire extinguishers are a form of risk management for your fire department. What are you going to do when faced with the situations like these?

  • Your fire apparatus or ambulance develops its own engine compartment fire.
  • You’ve parked your apparatus over a layer of dead leaves or tall dry grass and now you’ve got a fire under the apparatus caused by contact with the hot exhaust system.
  • You’ve parked your apparatus downhill from a motor vehicle crash; one of the fuel tanks of the involved vehicles ruptures and flowing fuel passes under the apparatus and ignites.

These are just a few reasons why we still carry portable fire extinguishers on fire apparatus. You can probably come up with three or four of your own scenarios without much thought.

Quick access to the portable fire extinguisher on your apparatus, or from another piece nearby, will be crucial in avoiding a catastrophic loss for your department’s fire apparatus.

NFPA 1901
NFPA 1901: Standard for Automotive Fire Apparatus requires that fire apparatus be equipped with a minimum of one approved dry-chemical portable fire extinguisher with a minimum of 80-B:C rating and one 2.5-gallon (9.5-liter) or larger pressurized water extinguisher.

I was unable to locate any specific portable fire extinguisher requirement for ambulances in NFPA 1917: Standard for Automotive Ambulances. The newly published Ground Vehicle Ambulance Standard, from The Commission on Accreditation of Ambulance Services lists the following requirement in Section C.15.1, Standard Mandatory Miscellaneous Equipment.

“Each ambulance shall be equipped with … fire extinguishers: two, (ABC dry chemical or carbon dioxide) minimum 5-pound unit, with a quick release bracket. One shall be located in the driver’s cab, the other in the patient compartment. This shall meet the requirements of SAE J3043 (Ambulance Equipment Mount Device or Systems).”

Classes A-D
UL classifies fire extinguishers by the type of fire that they will extinguish. Here’s a quick refresher on portable fire extinguishers before looking at the new kid on the block, the Class K portable fire extinguisher. It’s also a good cut-and-paste segment to include in your next fire and life safety presentation.

Class A fire extinguishers are used for ordinary combustibles such as wood, paper, some plastics and textiles. This fire class requires the heat-absorbing effects of water or the coating effects of certain dry chemicals. Extinguishers for Class A fires should have a triangle containing the letter A; if in color, the triangle should be green.

Class B fire extinguishers are used for flammable liquid and gas fires such as oil and gasoline. These fire extinguishers deprive the fire of oxygen and interrupt the fire chain by inhibiting the release of combustible vapors. Class B extinguishers should have a square containing the letter B; if in color, the square should be red.

Class C fire extinguishers are used on fires that involve live electrical equipment that require the use of electrically nonconductive extinguishing agents. Once the electrical equipment is de-energized, extinguishers for Class A or B fires may be used. Class C fires extinguishers should have a circle containing the letter C; if in color, the circle should be blue.

Class D fire extinguishers are used on combustible metals such as magnesium, titanium and sodium that require an extinguishing medium that does not react with the burning metal. Class D fires extinguishers should have a five-point painted star containing the letter D; if in color, the star should be yellow.

Class K
Class K fire extinguishers are used on fires involving cooking media like fats, grease and oils in commercial kitchens. Due to the higher heating rates of vegetable oils in commercial cooking appliances, NFPA 10: Standard for Portable Fire Extinguishers now includes a Class K extinguisher.

These fire extinguishers work on the principle of saponification, which takes place when alkaline mixtures such as potassium acetate, potassium citrate or potassium carbonate are applied to burning cooking oil or fat.

The alkaline mixture combined with the fatty acid creates a soapy foam on the surface that holds in the vapors and steam and extinguishes the fire. These extinguishers are identified by the letter K.

Newer, more efficient cooking appliances, plus the use of non-saturated cooking oils, require a fire extinguishing agent that will smother and cool a fire. Class K portable fire extinguishers are designed specifically to fight some of the toughest fires — hot grease, cooking oil and fat fires in the kitchens and food-prep areas.

Class K portable fire extinguishers now carry a UL rating of 2-A: K. This offers restaurant owners and other food preparation vendors a cost-effective portable fire extinguisher option that meets NFPA 10’s solid-fuel cooking requirements for a firebox size of 5 cubic feet or less.

Home fires burning
The upgraded 2-A rating also meets compliance with NFPA 10 fire extinguisher size and placement for Class A hazards, which means proprietors can protect their kitchen area without additional extinguishers.

Consequently, fire departments should be prepared for response to these types of fire with portable fire extinguishers that can carry on or complete the fire extinguishment effort initiated by the employees of such establishments.

And that means having a Class K rated portable fire extinguisher on your apparatus that is compatible with that used by those employees.

But don’t just think of food service establishments. Turkey deep frying remains a popular way to cook the holiday bird in many homes. Also, high temperature food preparation using non-saturated cooking oils has become more commonplace at outdoor venues such as fairs, carnivals and festivals.

It’s safe to say that many of these food service proprietors — and home chefs — may be unaware of the requirement or need to have a Class K portable fire extinguisher on hand or they may be knowingly noncompliant.

In either case, your fire department needs to be properly equipped to handle those types of fires regardless of the location.

Battalion Chief Robert Avsec (ret.) served with the Chesterfield (Virginia) Fire & EMS Department for 26 years. He was an instructor for fire, EMS and hazardous materials courses at the local, state and federal levels, which included more than 10 years with the National Fire Academy. Chief Avsec earned his bachelor’s degree from the University of Cincinnati and his master’s degree in executive fire service leadership from Grand Canyon University. He is a 2001 graduate of the National Fire Academy’s EFO Program. Beyond his writing for and, Avsec authors the blog Talking “Shop” 4 Fire & EMS and has published his first book, “Successful Transformational Change in a Fire and EMS Department: How a Focused Team Created a Revenue Recovery Program in Six Months – From Scratch.” Connect with Avsec on LinkedIn or via email.