Class K Extinguishers

[Guest alsfirefighter]

Being there was a discussion started about Class D extinguishers. I wanted to start a topic about who if anyone is now carrying a Class K extinguisher or anyone that has used one or been at a scene where a wet chemical hood system has activated. I have been to a couple and what a significant difference the Class K has made.

[ny10570 745]

We've just started with the K extinguishers. Haven't seen one used yet, but if its alf as effective as the systems installed in commercial kitchens it will be a very useful tool.

[Guest]

We have just added a Class K extinguisher to the new L2 truck, have not used it yet.

[Monty 35]

Being there was a discussion started about Class D extinguishers.  I wanted to start a topic about who if anyone is now carrying a Class K extinguisher or anyone that has used one or been at a scene where a wet chemical hood system has activated.  I have been to a couple and what a significant difference the Class K has made.

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I dunno, but maybe it would have made life easier at the recent Ossining fire? I understand it started in the hood / vent at a Restaurant.

Incidentally. I believe it is the third time it's happened in that location, although I'm not sure it's been the same business the whole time.

[WAS967 97]

Okay, I know Class A, B, and C. But whats the specifics of Calss K?

[Guest]

WAS967, I found this post from RES20CUE to be helpful to me :

NFPA 1901 requires the following on Pumpers, Aerials, Tankers, Initial Attack Vehicles and Service Vehicles:

(1)  2 1/2 gallon (or larger) water extinguisher- an "Indian Can" meets this requirement, as well.  - and -

(1) Dry Chemical extinguisher with a minimum rating of 80-B:C, so this extinguisher can be an ABC, BC, or PKP.

As ALS stated the Class "K" stands for Kitchen.  It is now required that ALL commercial kitchens have one of these portable extinguishers in them to supplement the WET CHEMICAL fire extinguishing system for the range, hood and duct.

The problem that has occurred over the last several years is that more us concerned weight watchers have shifted away from foods cooked in the traditional "animal fat" and gone to corn and canola oils.  These oils require a higher heating temperature and the equipment holds these higher temps longer.  The old "ANSUL" dry chemical systems and the normal BC extinguishers CANNOT extinguish these fires- thus comes the new "K" Class fire and extinguisher.

Different manufacturers may call the contents different names but essentially it's Aqueous Potassium Carbonate  or APC, better described as "liquid PKP".  This "wet chemical" was designed by Range Guard over 25 years ago and was and still is exclusively used by the US Navy onboard ships in the Galley's (kitchen's for you land lubbers).

Look for a County Course coming in 2005 relating to Commercial Kitchen Fires and extinguishing systems and the "K" class extinguishers.

As stated above- to all you fire inspectors out there, if you didn't know already-- NO more Dry Chemical Hood Systems or Dry Chemical Portable Extinguishers in those Kitchens!!

I know it's  alot of material- but I think I answered your questions- then some!!

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[Guest alsfirefighter]

The class K is actually more effective then the ansul hoods with its Class B agent. The problem with the Ansul with the powder was it would extinguish the fire, but with the use of hotter burning oils it wouldn't cool the oil below its ignition temperature. When the material clotted and sank to the bottom it would often reignite, as well as the powder hitting the oil would often cause oil to splatter. The class K is a wet chemical system that uses a fine spray of Potassium Acetate which in turns takes the fat in the oil and causes a saponfication process which the 2 unite and it forms a foam that is basically soap like. The fine mist also cools the oil below its ignition temperature. Additionally the clean up is half of that of the powder based agent, which is a win for the business owner as well.

For those of you that carry a portable extinguisher its important to know that the agent comes out in a mist. If you have a wand type you have to get it above and over the burning material. It may take some time for it to take effect, but it is safer with the mist, then using an ABC, it would blast the oil out of the fryer or container and also again stops from getting oil on the floor so there is no skating rink.