This Presentation Developed By Drew R. Smith

1. This Presentation Developed ByDrew R. Smith This presentation may be modified or reproduced by individual fire departments or training organizations provided it is not used to generate revenue or in any commercial manner.

2. The New Class Class K

3. Background In the past ten years or so there has been a major change in commercial cooking involving deep-fat fryers and cooking medias Class K Fires & Portable Extinguishers

4. Fryers • Older deep-fat fryers were either uninsulated or lightly insulated • Newer deep-fat fryers are well insulated Thus, older fryers cool faster than newer fryers Class K Fires & Portable Extinguishers

5. Cooking media • Older fryers used animal fat • Newer fryers use vegetable oil Vegetable oils cook at higher temperatures than animal fat Class K Fires & Portable Extinguishers

6. Unlike gasoline, paint thinner and other flammable liquids, cooking oils have a wide auto-ignition temperature range Class K Fires & Portable Extinguishers

7. When cooking oils heat beyond their auto-ignition temperature the oil changes composition resulting in an oil than now has an auto ignition temperature as much as 50°F lower before New AI Temp AI Temp ROOM TEMP HEATED Class K Fires & Portable Extinguishers

8. Unless the entire amount of oil cools below this new auto-ignition temperature the fire will reflash and burn Class K Fires & Portable Extinguishers

9. A new class of fire is born NFPA 10 defines Class K as Fires in cooking appliances that involves combustible cooking media (vegetable or animal oils or fats) Class K Fires & Portable Extinguishers

10. Dry Chemical Agents sodium bicarbonate or potassium bicarbonate, when applied to burning cooking oils create a chemical reaction known as saponification Class K Fires & Portable Extinguishers

11. All cooking oils, greases and fats contain free fatty acids (saturated fat) • When added to a free fatty acid, alkaline extinguishing agents (such as sodium bicarb or potassium bicarb) form a soap foam on the oil’s surface • This soap foam performs just like regular firefighting foam to secure vapors and extinguish the fire Class K Fires & Portable Extinguishers

12. When dry chemical is used to create this saponification it will not cool all of the oil in the fryer Class K Fires & Portable Extinguishers

13. Wet chemicals (liquids) that contain an alkaline agent are more effective • Agents may contain potassium acetate, potassium citrate and/or potassium carbonate • Applied in a fine mist the agents cool and form the saponification • These to action cool the oil to below its auto-ignition temperature Class K Fires & Portable Extinguishers

14. UL tests verify this • UL conducted dozens of tests comparing Class B-rated dry chemical portable fire extinguishers with these new Class K wet agent portable fire extinguishers • Tests showed that an 80B (20#) extinguisher that put out a 200-square foot pan fire could not put out a deep-fat fryer with only a 2& sq-foot surface Class K Fires & Portable Extinguishers

15. The Dry Chem knocked the fire down (with a big dust cloud) only to reignite • The Wet Agent fully extinguished the fire for at least 20 minute or until the oil’s temperature was below 60°F Class K Fires & Portable Extinguishers

16. As a side note... • Wet agents can be found in both permanent systems and portable fire extinguishers • They are applied using fine mist nozzles to reduce splashing • Most permanent kitchen extinguishing systems display a permanent making stating the equipment is UL300-compliant Class K Fires & Portable Extinguishers

17. NFPA 10 requires that a portable Class K fire extinguisher only be used AFTER the installed system is activated • When a Class K portable fire extinguisher is installed in a restaurant there is to be a sign above it stating this requirement Class K Fires & Portable Extinguishers

18. Class K Fire Extinguishers • Also carry a class A & B rating • Class K rating does not carry a number value such as class A & B ratings Class K Fires & Portable Extinguishers

19. Wet Agent units are available in both 1&1/2 and 2&1/2 gallon units Both the 1&1/2 and 2&1/2 gallon units carry 2-A:1B ratings While dry-agent Class K extinguishers are available, this program focuses on wet-agent extinguishers Class K Fires & Portable Extinguishers

20. Fire Department Operations • Recognize the situation and the need for the Class K fire extinguisher • Activate the installed system first • Wearing full protective gear, apply the wet agent from the portable fire extinguisher • Apply all the agent in the extinguisher EVEN if the fire appears to be out Class K Fires & Portable Extinguishers

21. REMEMBER Wet agents works by cooling AND saponification Class K Fires & Portable Extinguishers

22. References • “The New Class”, J. Craig Voelkert, NFPA Journal, July/August 1999 • NFPA 10 - Standard for Portable Fire Extinguishers, 1998 Edition Class K Fires & Portable Extinguishers

23. The End Class K Fires & Portable Extinguishers