Exam Question

### (a) 50 Litre Mechanical Foam Fire Extinguisher
A 50-litre mechanical foam fire extinguisher is a mobile, trolley-mounted unit primarily designed for tackling large Class B fires (flammable liquids like oil, petrol, paints) and is also effective on Class A fires (combustible solids like wood, paper, cloth). Its large capacity makes it suitable for machinery spaces, flight decks, and boiler rooms.
#### Construction
1. **Main Cylinder:** A welded steel cylinder with a capacity of 50 litres. The interior is lined with a polymer or other anti-corrosive coating to prevent reaction with the foam solution. The exterior is painted fire red with a distinguishing colour band indicating foam (cream coloured).