As the name suggests, a backflow preventer works to ensure that liquids do not flow back against the required direction of flow. When used in the context of a fire sprinkler system, a backflow preventer device is used to ensure that water does not flow from the sprinkler system back into the municipal water supply, or other source of drinking water. Unfortunately, water held in the sprinkler system can become contaminated. If allowed to re-enter the water supply, there is potential for the contaminated water to become a health hazard. The backflow preventer is intended to prevent water flowing back towards the main supply. Backflow preventers need to be checked regularly for effectiveness, as well as inspected annually by a fire inspection company in order to ensure they are working as they should.
How Does a Backflow Prevention Device Work?
A backflow prevention device responds to changes in pressure. When the water flows in the desired direction, the pressure of the flow pushes the backflow valve into the open direction, allowing the water to proceed as needed. When pressure builds up in the opposite direction (backflow), the pressure pushes the valve closed, meaning that water cannot flow back towards the mains. This simple procedure prevents contaminated water making its way back to the supply system. Backflow prevention devices normally require very little maintenance once in position, and do not need any external power supply in order to function correctly – their action is determined by the relative pressure on either side of the device.