Explain how each of the following fire extinguishers work: i) carbon dioxide; ii) water and foam; iii) cartridge operated dry chemicals.(6 marks)June/July 2020

i) Carbon dioxide (CO2) fire extinguishers work by releasing a jet of CO2 gas from the nozzle, which helps to smother the fire by reducing the oxygen supply. The CO2 gas is also very cold, so it helps to cool the surrounding area and prevent the fire from spreading.

ii) Water and foam fire extinguishers work by releasing a mixture of water and foam onto the fire. The water helps to cool the surrounding area and the foam helps to smother the fire by reducing the oxygen supply. The foam also helps to create a barrier between the fire and the surrounding area, which can help to prevent the fire from spreading.

iii) Cartridge operated dry chemical fire extinguishers work by releasing a dry chemical powder from the nozzle. The dry chemical powder helps to smother the fire by reducing the oxygen supply, and it also helps to cool the surrounding area. The dry chemical powder is also designed to react with the fire, creating a barrier that can help to prevent the fire from spreading.