Fire Extinguishers

[TowZone]

A fire extinguisher is the first line of defense against fires in our shops as well as on the road.  Extinguishers are grouped by the type of fires they can extinguish as well as their capacity.  Extinguishers can be for a single or multiple classifications.  Below are the various fire classes.
 

•  Class A: Wood, paper, cloth, trash or ordinary combustibles.

• Class B: Gasoline, oil, paint or other flammable liquids

• Class 😄 Electrical fires

•  Class 😧 Combustible metals and alloys

• Class K: Cooking oils such as vegetable or animal oils. 

 

The size of fire an extinguisher can extinguish is determined by the UL rating.  For instance, AW Direct p/n QR12, 5lb dry chemical extinguisher, has a rating of 2A:10B:C.  The A rating relates to the amount of water the dry chemical is equivalent too.  Each A unit is equivalent to 1-1/4 gallons of water.  So a 2A rating is the same as 2-1/2 gallons of water on a Class A fire.  The B:C rating relates to the square footage the extinguisher can cover in a Class B fire.  The 10B:C rating in our example will cover 10 square feet.  The C rating for electrical fires simply relates to the non-conductive nature of the extinguishing agent.

Fire extinguishers do need to be visually inspected monthly and the cylinder needs periodic hydro-static testing depending on the type of extinguisher.  A dry chemical extinguisher with an aluminum or brass cylinder needs to be tested every 12 years while a carbon dioxide extinguisher needs to be tested every 5 years.  Always follow the manufacturer instructions.

The Federal Motor Carrier Safety Administration of the DOT requires any truck transporting a placard-able hazardous material to have a minimum UL rating of 10B:C extinguisher.  Trucks that do not transport hazardous materials can use either a single 5B:C or two 4B:C extinguishers.  The extinguisher must be readily available and securely mounted to prevent sliding or rolling.  The extinguishing agent used must not need protection from freezing such a dry chemical extinguisher.  Verify local regulations that may be more stringent than federal regulations.