Dry hydrants not new to Roselle fire officials

Dry hydrants aren't a new fire-fighting tool, but they're all but unknown in the Roselle Fire Department, and Peter Mitchell's own system is particularly innovative.

They're mostly found in areas without municipal hydrants but where adjoining lakes or ponds provide a non-drinkable water source.

The method of using water from a dry hydrant is referred to as "drafting water," Roselle Fire Marshal Thomas Biscan said. This works by using suction to bring the water from its source to the hydrant outlet.

Most dry hydrants are sited above the level of the water they draw from, Biscan said. Once the suction is released, the water drops back into the pond or lake it came from.

Biscan regards Mitchell's dry hydrant as particularly rare for the region as it uses a swimming pool as its source and because that source is on top of a hill higher than the outlet at street.

Mitchell said his backyard swimming pool is about 10 feet above street level, allowing it to use gravity to keep the flow going once it starts.

Biscan explained that to start the flow, his firefighters must fill the dry pipe with water first. This usually takes a few minutes.

While the pressure from Mitchell's dry hydrant is assisted by gravity, not just suction, the challenge of such a downhill system is stopping the flow.

But unlike the more traditional dry hydrants, Mitchell's has a valve to stop the flow and a drainage system to empty out the water already in the pipe.

Mitchell said his downhill design had to be thought up from scratch, using only the advice of a parts supplier for guidance. He didn't base the design on anything he came across elsewhere, though he considers a swimming pool an obvious water source.