Each authority has to decide if they have enough evidence and confidence to implement any new technology. Being one of the first to implement any new technology has some risks and the benefit in improved fire suppression performance is the reward for taking this risk. Each Authority having Jurisdiction (AHJ) makes their own assessment and decision about what is leading edge and what is bleeding edge in new technology. Some leading edge technologies in ARFF pumps that may be worth watching include the CAFS, Larger Pump Sizing, and UHP.
Compressed Air Foam Systems
Some of the first Compressed Air Foam units were built for the US Navy back in the 1940s and were utilized in the combat of shipboard Class B fires. Of course the technology and chemicals used were different back then, but the idea of adding air to the fire stream at the pump for better fire suppression is certainly not a new idea. In the early 1980s Compressed Air Foam began to prove its capability on Class A fuels in Wildland and Urban Interface Fires utilizing newer synthetic detergent based Class A foams. The US Forest Service and Department of Interior recognized the superior suppression capability of this new technology. More recently, Compressed Air Foam has been gaining more acceptance in Municipal or Structural Fire Suppression Applications. Municipal, Suburban, as well as rural fire suppression brigades have been using CAFS for Fire Suppression with some success. The most advanced applications for CAFS have built onto a few ARFF apparatus. The superior reach of CAFS is an obvious benefit as the additional energy in the compressed air foam stream can propel the fire stream further. Greater standoff distance is a clear advantage, especially with larger aircraft wingspan. One of the benefits of CAFS is that it produces a dense, consistent foam that adheres well to three dimensional fuels. The high quality bubble structure produced by CAFS is more durable and resists fuel pick up. These are some of the reasons that some authorities are considering CAFS as one potential fire suppression upgrade for use in Airport Crash Tenders. The major drawback for CAFS in ARFF applications is the same drawback faced by most new technologies. There is a lack of documented tests showing exactly how much more effective the CAFS Fire Stream can be on ARFF applications compared to traditional technologies. Hale and Godiva deliver a variety of Compressed Air Foam system solutions all over the world for various applications. As is often the case, a few intrepid and leading edge operators will need to attempt to qualify CAFS effectiveness so that the entire industry can see how good this tool might be.
Larger Pump Sizes
Airport Crash Tenders are being specified more often with larger pumps. To increase suppression capability, a larger flow suppression system is a low risk solution. The pump is at the heart of this larger flow capability, but the installation piping and foam systems as well as the discharge appliances should all match to take advantage of the capability. Larger tenders with pumps up to 10,000 LPM (2600 US GPM) are more common than in the past and some Tenders have been built with pumps as large as 11,000LPM (2900 US GPM). This has the distinct advantage of increasing suppression flows without technology risk. Some operators have decided bigger is definitely better. Of course larger pumps carry with them higher power requirements in addition to space and weight requirements. Hale has recently delivered these large pumps with a new configuration gearbox that uses less space in the truck installation and delivers extra performance in a more compact package. These larger pumps may not appear on every air field, but clearly some agencies are opting for this solution and it is a choice that should be considered.
Ultra High Pressure Pumping Systems
The US Air Force is experimenting with Ultra High Pressure in ACT vehicles. These units have pressures well above the traditional hose reel supplied high pressure 3D fog used in some structural applications. Since there is not typically an enclosed compartment for a large percentage of hazards encountered in ARFF evolutions, the theories of 3D high pressure fog using steam to displace oxygen do not necessarily apply to UHP. The Ultra High Pressure systems or UHP range from 75 to 100 BAR (1100 to 1500 psi) dwarfing the 30 to 40 BAR (400 to 600 psi) used in the manual fire suppression systems we typically term “high pressure”. The ultra high pressures used in fixed systems to protect enclosed compartments also run up to 100 BAR. Much like fixed systems, the flows in UHP systems are greatly reduced as the pressure is increased. A hand line with UHP may flow as little as 60- 120 LPM (15-30 US GPM). Rapid Intervention Vehicle (RIV) bumper turret flows might be in the range of 230 LPM (60 US GPM) while a full size ACT may have flows in the 1150 LPM (300 US GPM) range. These flows and pressures may change somewhat as the technology is developed, and the capability is further investigated, but it can be seen that this is a major change in Fire Suppression Flows and pressures. The Ultra High Pressure technology requires major changes in the suppression system on the apparatus and the USAF hopes to build smaller, more transportable ACT units with this technology. These much smaller flows could lead to smaller water tanks and smaller vehicles. Engine power requirements for pumping remain high as it still takes power to make extra pressure instead of flow. Hale has recently delivered a UHP skid system configured to be built into an RIV apparatus for additional testing of this suppression methodology. Military aviation protection services have a need to deploy the ACT by air and a smaller vehicle is obviously a huge benefit for military ARFF operations. Time, testing, and experience will show the capability of this newest fire fighting technology.
ARFF operators have a choice in terms of the next fire suppression system they utilize. Those choices vary between choosing what has been specified previously or this selection of newer choices that are becoming available. Whether the next new Aircraft Crash Tender you see has the same pumping system, or a larger high flow pumping system, these are very similar suppression systems with simply a difference in size and capability. Compressed Air Foam Systems add a dimension of difference and incremental risk of the leading edge, while Ultra High Pressure Systems remain the largest departure from the typical fire suppression package used in ARFF. The utility and acceptance of these technologies remains to be seen in ARFF applications. As noted, only the AHJ can decide if a technology is ready for their use. Staying on the leading edge and off the bleeding edge is how high performance organizations utilize technology effectively.
Michael A. Laskaris, PE is the Director of Research and Development for the Fire Suppression Division of Hale Products Inc headquartered in Ocala, Florida with Facilities in Warwick, UK, and Conshohocken, Pennsylvania. Hale is a worldwide manufacturer of Hale Fire Pumps, Godiva Fire Pumps, Class1 Electronics, Pump System Modules, as well as CAFSPro and FoamLogix Foam Systems. Hale produces a wide variety of equipment from small portable pumps to large industrial skid units and Hale vehicle mounted pumps are in service all over the world.