Fire Extinguisher Ball

If you have taken the course CHEM1042, you had taken a safety talk provided by the University Safety Office before doing lab. It introduced some ways to put out a fire, including using water fire extinguisher, foam fire extinguisher and CO2 fire extinguisher. In addition to these, have you ever heard of fire extinguisher ball?

Fire extinguisher ball is a ball shaped fire extinguisher. Simply throw it into a fire and wait approximately three seconds, it will then self-activate and put out fire. Here is how it works:

There are two types of fire extinguisher ball using different chemicals inside. The first type of fireball uses sodium bicarbonate (NaHCO₃) as fuel. It decomposes when heated, forming sodium carbonate, water and carbon dioxide. (2NaHCO₃ → Na₂CO₃ + H₂O + CO₂). The large amount of carbon dioxide covers the fire and stops the contact between the fuel and oxygen. The other type of fireball uses Ammonium phosphate as fuel. The reactions are as follows:

    (1) 2NH₄H₂PO₄ → 2H₃PO₄ + 2NH₃
    (2) 2H₃PO₄ → H₄P₂O₇ + H₂O
    (3) H₄P₂O₇ → 2HPO₃ + H₂O
    (4) 2HPO₃ → P₂O₅ + H₂O

All of these reactions are endothermic, they have a cooling effect that helps kill and stop the re-ignition of a fire.

Advantages of using Fire Extinguisher Ball
It is light (less than 1.5kg) while the big metal one is heavy and may be little intimidating to operate. Special skills are not required to operate a fire extinguisher ball but the only skill is to throw the ball into a fire. It can be placed in a risk area and it will self-activate upon reaching certain temperature in absence of human.

Drawbacks of Fire Extinguisher Ball
This tiny fire ball may be a nightmare when you are just using it to put out a small fire, for instance, a kitchen fire on your stove. This would end up a mess with thick powders covering the kitchen entirely.

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