With bushfire season being just around the corner, it’s important everyone living in high risk areas to be fully prepared with a suitable fire fighting system. These systems are one of the most important of all building services, as their main goal is to protect human life and your property, exclusively in that order. The system consists of 3 basic parts: a fire storage tank, a specialised pump and a network of pipes or hoses.
The required storage tank size is determined by the hazard level. Typically, there are 3 hazard levels:
- light (residential buildings, schools and offices)
- ordinary (warehouses and factories)
- high (foam factories, paint factories, fireworks factories and other places that use and store flammable materials).
The amount of water stored is typically given in hours of pumping capacity. Building codes might require high hazard systems to have 4 hours capacity and light hazard systems to have 1 hour capacity.
The water is typically stored in underground tanks, and it’s essential the storage always remains full, so it should have no outlets except for those that lead to the pump. Quality tanks are designed to ensure the water inside them doesn’t develop algae or get stagnant, which can clog the pump and pipes, making the system completely useless.
Typically, high hazard systems involve 3 pumps. A main electric pump, a backup electric pump, and a second backup pump which is petrol-powered, in case of a power outage. The firefighter pump should be close to the water storage tanks, located just at a level below the bottom of the tank, so that the water from the tank can flow through the pump just by gravity.
The firefighter pumps are usually controlled by pressure sensors, so when an operator opens the sprinkler or hydrant, water comes gushing out the system and the pressure drops. When the pressure drops, the pumps are switched on. Some pumps can then only be turned off manually due to safety practices, and to prevent the pump from switching off in the middle of a dire situation.
The network of pipes and hoses ends either in sprinklers and hydrants. Fire hydrants are vertical pipes that feature an outlet onto which you can attach a fire hose and manually open to have water come gushing out. The amount of water that comes out and the high speed it comes out with, can knock the operator if he isn’t standing properly.
Sprinklers are basically nozzles attached to the network of pipes. They’re installed below the ceiling of the room and each and every one of them features a small glass bulb with liquid in it. When a fire starts, the liquid becomes hot, expands and breaks the glass bulb. The glass is the only obstacle that prevents the water to spray from the sprinkler, so once it’s broken, water automatically starts spraying. Sprinklers are ideal for preventing fires before they become large and problematic.