Fir
e extinguishers (four of those shown here are dry powdered). These extinguishers fall under the A.B.C class or otherwise known as multipurpose. These are coloured red in the photo. This type of extinguisher is designed to put out a small fire by means of a powder stored under high pressure within and can be recharged after use.
The black extinguisher in the photo is a Carbon dioxide (CO2) fire extinguisher. These dispense carbon dioxide which displaces the oxygen needed for combustion or blankets the material which is burning, thereby causing the fire to suffocate. The gas is expelled under high pressure stored within a cartridge in the cylindrical tube at very low temperatures thus aiding the process of extinguishment by cooling. Often times when in use frost can be seen forming on the outside of the cylinder when conditions are suitable.