Class A
Ordinary combustibles such as wood, paper, rubber, fabrics and many plastics
Class B
Flammable liquids and gases such as gasoline, oils, paint, lacquer and tar
Class C
Fires involving live electrical equipment
Some items such as electronics, including computers, are just too critical and deserve a less destructive extinguishing agent such as Halotron. Engine rooms in vessels might be better served with a Carbon Dioxide or Purple K extinguisher rather than the commonly used ABC dry chemical types. Investing a little more in the begriming might save you a lot of money should you ever have a fire.
Class A
ABC Dry Chemical provide protection against Class A fires.
These are the least expensive choice (other than water) but provide the most
mess afterwards.
Larger Halotron extinguishers provide Class A protection
with no residual mess, however this is the most expensive option.
Class B and C
Purple K dry chemical is the least expensive option in
specifically combating Class B and C fires. Unlike the ABC extinguishers which
also provide excellent protection, Purple K creates much less residual mess.
ABC Dry Chemical provides excellent protection at the
best initial cost. Also by covering all common types of fires it is the most
versatile.
Carbon Dioxide is a clean, non-contaminating gas. While
extremely effective its drawbacks are weight, size and cost. CO2 is a great
choice in an engine room.
Halotron is a "Clean Agent". It leaves no mess behind
and is the perfect choice for protecting electronic equipment, aircraft and
race cars. The only drawback is its cost.
Amerex manufactures fire extinguishers designed for long life in a hostile environment. All valves are brass or aluminum, not plastic, allowing the extinguisher to be recharged. Consider the investment you wish to protect and decide if you want a rugged, industrial grade tool or the less expensive "homeowners" model.