What are the classes of fire?

Class A Wood, Paper, Cloth, Rubber Class B Flammable Liquids Class C Electrical Class D Combustible Metals Class K Combustible Cooking Media

What is a six year maintenance?

An internal examination of an emptied dry chemical fire extinguisher to check for corrosion and any interior problems. Extinguishers that pass the six year maintenance are then recharged, reassembled, and receive a six year service label and a verification of service...

What is a hydrostatic test?

Pressure testing of a fire extinguisher to verify its strength against unwanted rupture performed by a facility that is approved by the D.O.T. to requalify cylinders.