Flood Alarm Case Study
Located on the banks of the Thames, just outside Dartford, this large supermarket have invested in a new regional distribution centre for their online capacity. The area is nominated as a sacrificial flood plain should the Thames Barrier be activated on the basis that a super- high tide was to occur. The site is located below river level and is protected by a large sea wall.
To wirelessly warn that the river level is 1000mm below the breaching point of the sea wall. The wireless unit must report; regularly, any fault, and must fail safe. No mains power supply available at probe location. The wireless link will be 500m. The receiver must link with the building BMS system, and also the fire alarm panel.
Using a wireless flood alarm probe housed in a UV, and marine proof enclosure, a battery operated bulk head unit with a five year lifespan overcame a lack of mains power. This wireless unit sends a health message every 5 minutes, along with readings every 2.5 seconds. Should readings not be received, the receiver will wait until 3 health messages are missed before failing safe, making the BMS aware that there is a potential fault. The receiver houses volt free contacts for linking with the fire alarm panel allowing for easy integration. The receiver provides an opportunity for text messages and emails to be sent to key staff so that management will know if a flood incident is occurring should they be off-site. This project saved the client thousands of pounds in unnecessary hard-wiring and design charges. The probes have no moving parts and can be serviced by the end user for the entirety of the product life.