AFFF Proportioner for Fireboat
What may be the nation’s first AFFF proportioner on a municipal fireboat went into service in Milwaukee last May. Completed in four months, the $15,000 system can deliver 10,000 gallons of 6 percent foam from a deck monitor or hose line—at the touch of a pilothouse button.
Said Milwaukee Deputy Chief Joseph Shanahan, “We needed something to deal with gas and oil fires along our waterways. Our land engine companies carry eductors, but the boat has had nothing since the old foam powder went off the market some years ago.”
Milwaukee’s fireboat is a 12,000-gpm, diesel-powered craft equipped with four monitors, fed by underdeck manifold lines along each side of the vessel. The AFFF supply system, located just beneath the pilothouse, is piped into one of these manifolds, forward of the main pumps, to supply the port bow nozzle.
Tank welded below decks
A stainless steel 550-gallon concentrate tank was too large to be installed below decks, so its parts were put on board and the tank was welded together in place. Foam can be projected at flows from 200 to 3000 gpm at any desired nozzle pressure. For working dockside or on shipboard, a hand line can be connected to the monitor barrel by removing the tip.
“We would expect to operate normally at about 550 gpm with a 1⅜ tip on the monitor,” explained Shanahan, “giving us 15 minutes of operation with a stream having a 200-foot reach.”
The boat will carry a backup supply of concentrate in pails which can be dumped into the tank through a deck fill pipe.
Added Shanahan, “The material lasts indefinitely in the tank. But every year we will probably drain and refill it, rotating the old concentrate out to other companies.”
Pressure balancing controls automatically match foam pump output to mainfold pressure (ideally 110 psi). Once started, the 10-hp electric foam pump drive runs for about three seconds to pick up solution and charge the system, then continues automatically until stopped or until the concentrate tank is empy, upon which a “no flow” red warning lamp lights up at the pilothouse control station.
The proportioner as designed for Shanahan’s Bureau of Construction and Maintenance by the Feecon Corporation, which supplied all the valves, fittings, and special controls. The bureau worked out the installation details, contracting out plumbing and tank fabrication to local firms.
“While we were planning this installation, Shanahan concluded, “we contacted by letter or phone a number of fire departments in other cities, such as New York, Houston, San Francisco, San Diego, Seattle—places with similar marine hazards. We found no one else with this kind of system.”