|HMA Fire’s UHP, shown on a custom built T6 delivered to Ellsworth Air Force Base in July, has been tested and validated at AFRL. The units can fit on a Polaris Ranger, on a pick-up truck or can be retrofitted into a larger vehicle.|
Editor’s note: This is the first of a multi-part series written to provide a comprehensive introduction to ultra-high-pressure firefighting.
Is it a fancy pressure washer or the ultimate new firefighting technology? That’s the latest question manufacturers of ultra-high-pressure (UHP) firefighting systems are getting at tradeshows.
Originally attempted in the late 1960s, high-pressure systems were built before the technology was mature enough to be used effectively for firefighting. Over the last 14 years, UHP has been developed and advanced in a simple and revolutionary way to efficiently and quickly extinguish fires with a fraction of the water and suppressant used by today’s standard firefighting techniques.
Working With Companies
Some firefighters have recognized the potential of increasing the water pressure capabilities of their systems and have experimented with the concept. But the scientists and engineers of the Air Force Research Laboratory (AFRL), Fire Research Group, with the aid of commercial manufacturing companies, such as HMA Fire, Oshkosh and Darley, have worked to optimize UHP into a firefighting powerhouse that may quickly become a firefighter’s favorite tool.
Years of research were instrumental in establishing the safe and most effective parameters of what is becoming known as UHP firefighting. The UHP method cut its teeth on aircraft rescue and firefighting (ARFF) situations at AFRL. It utilizes a system operating at 1,200 to 1,500 psi while initially pumping around 14 gallons per minute to extinguish 500 gallons of hydrocarbon fuel spread over 3,500 square feet in just over 45 seconds using approximately 10 gallons of aqueous film-forming foam (AFFF) solution through a handline. This psi is higher than the traditional European method of 800 psi, but it is still safely under the 1,850 psi that can inject water through human skin and cause severe injury.
Across the United States, military forces have been trying UHP in other testing and real life situations. Structural fire testing at Vandenberg Air Force Base in California led to the purchase of an 80-gallon system on a Polaris Ranger that has repeatedly proven valuable in structural and wildland situations. “It’s lighter (exponentially) and easier to maneuver, sucks the life out of the fire, does amazing hydraulic ventilation and uses about a tenth of the water to the same effect,” said Capt. Devin Misiewicz of the Vandenberg Fire Department.
UHP behavior is different from other forms of fire suppression currently in use in the fire service. Standard pressure systems follow a surround-and-drown mindset, requiring massive amounts of time, effort, resources and clean-up. Smaller water droplets created by UHP cover a much larger surface area than that of low-pressure droplets. This increased surface area translates to more contact with flames, higher heat absorption and faster extinguishment. Increased contact with flames also means much less water is wasted and much less water is needed.
After Cannon Air Force Base in New Mexico hosted AFRL personnel for UHP testing on its extensive range, base officials had an old M35 cargo truck holding a 600-gallon water tank successfully retrofitted with a UHP system.
The troops now have shoot-and-scoot capability with over 25 minutes of firefighting time to cover their massive wildland area. UHP ground penetration can be up to 7 inches deep, allowing clean up and maneuvering around the range quickly.
Going Where Others Can’t
More compact systems allow firefighting to reach where traditional trucks cannot go. Fort Leonard Wood in Missouri received a UHP system on a Polaris Ranger in May, just in time to respond to a train derailment. It was the only vehicle with firefighting capability that could reach the scene.
At Stone Mountain Park in Georgia, a Polaris mounted system responded to a wildland fire behind a new conference building this spring. With an 80-gallon tank of water, the unit went off-road and around the back of the building to corral and extinguish a wildland fire before it could spread into the recreational park or damage the building.
AFRL began testing in 2002 using JP-8 jet fuel in a large fire pit, with an aircraft mock-up, starting at 10 gpm and eventually scaling to 300 gpm. Testing with a variety of systems, including HMA, has shown that 15-20 gpm for handlines and 300 gpm for turret operations provide better ARFF protection than standard pressure 90-gpm handline and 500-gpm turret systems.
In 2006, AFRL converted five P-19s (air-transportable military firefighting trucks) to a large UHP system with the help of Darley, Elkhart Brass and Oshkosh. These trucks have been tested in the field and continue to provide ARFF protection at a number of Air Force bases, including Ellsworth in South Dakota, Davis-Monthan in Arizona, Tyndall in Florida, Mountain Home in Idaho and Dyess in Texas.
Currently, UHP data is being submitted to the National Fire Protection Association in proposals for standards and requirements review.
Jennifer Laine is the director of government sales for HMA Fire, which manufacturers and sells UHP systems. She worked at the Air Force Research Laboratory Fire Research Group, Tyndall AFB, for 5 years while this technology was being developed. Rory Groonwald is the chief engineer at HMA Fire and a pioneer in UHP technology.