Airport protection: What's new in ARFF vehicles
Here's what you need to know before replacing, or buying your first, airport rescue and firefighting vehicle
By Robert Avsec
What if specifying your next piece of pumping fire apparatus were as easy as these three steps?
- What's the median square footage of commercial properties in your locality?
- What's the median fire flow for the square footage of those commercial properties?
- What's the size of the population being protected in your locality?
Sound a bit incredulous? Well it's not if your mission is to create specifications for the purchase of your department's next Aircraft Rescue Fire Fighting vehicle.
See, the Federal Aviation Administration has very specific guidelines for ARFF vehicles. The FAA's Advisory Circular 150/5220-10E, Guide Specification for Aircraft Rescue and Fire Fighting, provides an interactive specification tool for fire departments to use in procuring ARFF vehicles.
The guide addresses the three main phases of the ARFF vehicle procurement process including the:
- Description of the vehicle selection process.
- Selection of vehicle requirements.
- Production of a formal specification.
This information is based on the minimum ARFF vehicle requirements established by Title 14 Code of Federal Regulations Part 139, Certification of Airports. The guide is also based on the FAA additions, exemptions, or amendments made to NFPA 414 Standard for Aircraft Rescue and Fire Fighting Vehicles (2007 Edition), and NFPA 1901 Standard for Automotive Fire Apparatus (2009 Edition).
ARFF vehicle manufacturers do not have hard-and-fast rules as to when a vehicle must be replaced — neither does FAA. The manufacturers have developed forecast models based on life expectancy and life cycle operating and maintenance costs. ARFF vehicles typically last 10 to 12 years, longer for airports with less activity.
Here's a list of factors to help determine when its time to replace the ARFF vehicle.
- Reliability and serviceability becomes questionable.
- Parts for repairs (including after-market) are no longer available.
- Annual operating cost becomes excessive.
- Service life has been extended beyond the vehicle's normal field service life.
- Repair cost exceeds 75 percent of the current estimated value of the apparatus.
- Introduction of new and different aircraft that changes the airport index.
- Relative overall age of the ARFF fleet to allow for programmed replacement over a span of years.
The airport index — defined CFR 14 Part 139.315 — is determined by a combination of two factors: the length of air carrier aircraft, and the average daily departures of air carrier aircraft. There are five indexes labeled A through E beginning with aircraft less than 90 feet long and end at those more than 200 feet long.
CFR 14 Part 139.317 specifies the minimum levels of fire fighting agents by type and quantity within a vehicle system to support a specific airport index. The FAA classifies ARFF vehicles using five classifications — Classes 1 through 5.
These classifications segregate vehicles by what types of fire suppression agent and how much of those agents are carried on the vehicle. ARFF vehicles carry four types of fire agents (either as a single agent or in combination with another agent): sodium-based dry chemical, potassium-based dry chemical, halogenated (gaseous clean agents), and water and aqueous film forming foam.
Chassis design, drive train, axle capacity, fire-suppression systems and the manufacturer's ability to provide either a commercial or custom ARFF vehicle solution are some of the factors that come into play when determining how much fire suppression agent is carried and how it is delivered.
ARFFs by class
Class 1 is a four-wheel-drive diesel ARFF vehicle that must carry 100 gallons of water/AFFF and 500 pounds of sodium-based, 450 pounds of potassium-based dry chemical, or 460 pounds of halogenated agent. One example is Oshkosh's Stinger on a Ford Super Duty F-550, 4x4 chassis.
A Class 2 ARFF vehicle must carry 300 gallons of water/AFFF and the same dry chemical complement required of a Class 1 ARFF. Examples of this class include the Oshkosh’s Striker 1500 4x4 ARFF, E-One's Titan Force 4x4, and Rosenbauer's Airwolf Class 2.
A Class 3 ARFF vehicle must carry 500 gallons of water/AFFF and Class 1 ARFF dry chemical requirements. An example of this vehicle is Rosenbauer's Airwolf Class 3.
Class 4 ARFF vehicles are for an Index B, C, or D airport and must carry 1,500 gallons of water/AFFF and, depending on the airport, a complementary 450- or 500-pound dry chemical and a 460-pound halogenated agent system. Examples of this class include Oshkosh's Striker 1500; Rosenbauer's Panther 4x4; and KME's Force Series Class 4.
Class 5 ARFF vehicles are for Index D and E airports and must have a 3,000- to 4,500-gallon water/AFFF fire suppression system, a complementary 450- or 500-pound dry chemical and a 460-pound halogenated agent system. Examples of this class include E-ONE's Titan Force 6x6, Oshkosh’s Striker 3000 and 4500 models, Rosenbauer’s Panther 6x6, and KME’s Force Series Class 4.
ARFF vehicle manufacturers report that many customers want a high-volume low-attack turret they can lower to within 12 inches of the ground. This would allow the vehicle operator to attack low spots in an aircraft fire, such as under a wing or in the landing gear area.
Bigger airports — Index C, D, and E airports — have been specifying their new ARFF vehicles with high-reach extendable turrets, essentially a boom mounted on top of the ARFF vehicle. The vehicle operator can extend the boom, pierce the aircraft fuselage with a penetrating nozzle and deliver water, foam, dry chemical or halogenated agent.
Hydro-Chem has become a standard component of an ARFF vehicle's fire suppression complement. Typically there's a high-flow nozzle with a tube in the center of it that allows dry chemical to be discharged simultaneously into the foam-water stream.
Using the foam solution as the means to propel, enables the Hydro-Chem system to project dry chemical approximately three to four times farther than that of conventional dry chemical equipment. Firefighters get the knockdown of dry chemical agents plus the cooling and sealing effect of water and foam behind it.
Lastly, a growing number of fire departments have been requesting compressed-air foam systems. CAFS technology specialized for ARFF applications can enable foam throw distances of 250 feet or more.
A CAFS can also greatly increase the amount of finished foam that an ARFF unit can produce. For example, Rosenbaum's Flash CAFS AR system can take 1,585 gallons of water-foam mixture and convert it into approximately 12,680 gallons of compressed air foam.