Fire Extinguishers

When does one size or type of product ever fit every application? In the case of fire extinguishers, the answer is never. Different types of extinguishers are required for different types of fires. Companies are required to provide an adequate number of the right type of fire extinguishers and to ensure that this equipment is inspected regularly.web photo 354

A more pertinent question is what is the right type of fire extinguisher are you required to have on hand. When I was asked this question after a speech, I couldn’t provide an answer?  So I called a friend, who had been the Fire Chief of his home town in New Jersey. Jack gave a little education on what fire is, the different classes of fires and which type of fire extinguisher is best for each class of fire.

What is Fire?

 The simple definition of fire is rapid oxidation of a material at a high temperature. At an elevated temperature the solid fuel turns to a gas and combines with oxygen. When heat is introduced, a chain reaction occurs and the fuel visibly ignites. The fire tetrahedron is a four-sided geometric representation of the four factors necessary for fire: fuel (any substance that can undergo combustion), heat (heat energy sufficient to release vapor from the fuel and cause ignition), oxidizing agent (air containing oxygen), and uninhibited chemical chain reaction (sufficient exothermic reaction energy to produce ignition). The fuel/air ratio must within flammable limits, which describes the amount of vapor in air necessary to propagate flame. Removing any of these four factors will prevent, suppress, or control the fire.

Types of Fire Extinguishers

 Everybody in your shop should know where the fire extinguishers are and how to use them. Screen printing plants are particularly vulnerable to a variety of different fire hazards that may require different types of extinguishers. Using the wrong extinguisher can be dangerous and in some cases deadly.

“Pressurized water is great for putting out wood, paper and trash fires,” said the fire chief. “Water works by cooling down the burning material below its ignition point” and is defined as a “Class A” fire.

“Class B” are defined as those fires which involve combustible liquids such as gasoline, grease and oils, water should never be used. Again, never spray water on an electrical fire. Water conducts electricity, which can cause the fire to spread and  you could also electrocute yourself in the process, a “Class C” extinguisher is the only safe approach. Usingpressurized water to extinguish combustible metal fires can also result in disastrous and explosive results.

 Dry chemical extinguishers can be used for wood and paper fires, electrical fires and combustible liquid fires and fall under the classification of “ABC Type Extinguishers”. These multi-purpose extinguishers, however, are only good for one use.  After that, you need to have them recharged.  Dry chemical extinguishers also have a limited shelf life and should be inspected annually.

 In a screen print plant, the multi-purpose dry chemical extinguishers are great for nearly every type of fire. Fires in a UV curing unit are a different story. The dry ammonium phosphate chemicals can screw up the electronics. For UV, a CO2extinguisher is the way to go.

The best advice in fighting electrical fires is to cut the power first.   Carbon dioxide extinguishers work best in quickly smothering the fire, replacing oxygen with CO2.  Be careful when using this type of extinguisher in tight confines.  Carbon dioxide can suffocate a fire, but in high concentrations it can also suffocate you.

In such cases where combustible metals are present, a “Class-D” extinguisher should be present. Combustible metals include, but are not limited to magnesium, titanium and potassium. These extinguishers contain a pressurized dry powder formulated to smother a burning metal and are designed to be operated differently that other types of extinguishers.  Before using a “Class-D” extinguisher, you must first open the value on the nitrogen cylinder to pressurize the tank.

Because there are different types of fires along with different firefighting procedures, your employees must be trained. You should put your fire safety plan in writing and review it regularly with your employees. Your plan should include periodic fire inspections.

When a fire starts, your first responsibility is to sound the alarm and call the fire department. After you do that, provide assistance to anyone in your immediate area who may be in need of help to exit the building immediately.

The next step is to contain the fire.  Closing doors, windows and exhaust vents as part of your exit procedures helps control the spread of fire to other parts of the building. At this point, those individuals trained in the identification and classification of fire and the proper usage of the appropriate extinguishment methods may proceed with the containment and suppression of the incident.


For more ideas on how you can prevent fires at work or in your home, read  ‘The Comprehensive Resource of Fire Safety Tips’:

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