Chapter U5.106, Problem 8E

Interpretation Introduction

Interpretation: The reason of extinguishing a flame by carbon dioxide containing fire extinguisher needs to be explained.

Concept introduction: A fire extinguisher is a device that helps to extinguish a fire. It consists of gas like carbon dioxide. There are different types of fire extinguishers, namely, A, B, C and D and each put down different fire types.

Answer to Problem 8E

Carbon dioxide cuts the supply of oxygen to the fire and thus extinguishes the fire.

Explanation of Solution

Carbon dioxide extinguisher consists of a mixture of gaseous and liquid carbon dioxide (nonflammable gas). Carbon dioxide is in gaseous state at room temperature and pressure. To make it liquid, it should be stored in condition of high pressure. Releasing of pressure causes expansion of the gas and making of a huge white jet. The attack of carbon dioxide to the fire triangle occurs in two ways, it covers the fire and cut off the supply of oxygen to the fire during its changing of states from gas to liquid and sucks huge amount of heat from surroundings and causes cooling.

Conclusion

The supplying of oxygen to the fire needs to be cut down to extinguish it.