Objective
The Battelle/Air Force Civil Engineer Center (AFCEC)-Tyndall Air Force Base Team has tested more than 20 fluorine-free foams (F3s) utilizing various foam delivery systems and nozzles, such as air-aspirated, compressed air foam (CAF), and Ultra-High Pressure (UHP). The objective of this effort is Demonstration/Validation (dem/val) of promising second and potentially third generation F3s and optimizing their performance by employing alternative nozzle designs.
The project will (a) establish performance of promising new (second and potentially third generation) F3s against key specifications in MIL-PRF-32725 (for Aqueous Film-Forming Foam or F3); (b) allow working with nozzle manufacturers to identify and select previously untested air-aspirating, CAF, UHP, and hybrid foam generation and delivery nozzles; (c) perform computational fluid dynamics modeling to guide alternative nozzle designs for effective and efficient foam delivery; (d) demonstrate selected nozzles with gasoline and Jet-A fuel fires at 962-ft2 scale; (e) correlate field-scale performance of new F3s using standard nozzles and alternative nozzles compared to the Mil-Spec nozzle; and (f) prepare a guidance document on selection of foam-generation/delivery nozzles for selected F3 chemistries.
Technology Description
Battelle/AFCEC plans to dem/val production level F3s and alternative design nozzles in operationally relevant firefighting scenarios. A few second generation PFF are soon expected to be qualified under the new Mil-Spec, and some new, potentially better F3s are maturing or emerging. Battelle/AFCEC have demonstrated standard aspirating, non-aspirating, CAF and UHP nozzles, but have learned from nozzle manufacturers that alternative-design nozzles exist or could be refined that might improve the performance of qualified as well as maturing and emerging F3.
Benefits
Alternative nozzles can potentially reduce the fire extinguishment time by a targeted 20% or more, compared to legacy nozzles for a variety of foam delivery systems, such as aspirating or non-aspirating nozzles, as well as CAF or UHP. This could then reduce DoD’s foam concentrate cost by 20% or more. The cost for wastewater treatment from firefighting, including training, will also be reduced roughly in proportion to foam quantity reduction, i.e., by 20% or more. The combined operational cost savings across DoD are estimated to be as much as $46M/yr, based on a recent Noblis life cycle assessment effort. It is believed that the alternative-design nozzles will cost about the same as standard Aircraft Rescue and Fire Fighting (ARFF) nozzles, which translates into a capital investment of less than $4M if all ARFF trucks were equipped with alternative-design nozzles. So, the potential annual cost savings are much more than the cost of installing new nozzles.
The testing at 35-ft diameter fire scale will also provide the following potential benefits to DoD and Federal Aviation Administration stakeholders. First, it will provide additional scale-up data for gasoline and Jet-A fires from 28-ft2 to 962-ft2 (34X) scale. It will also potentially provide a training site, for a variety of foam delivery equipment, including nozzles, at an intermediate scale of 962-ft2 rather than the currently used 6,504-ft2 fire size, which will greatly reduce the amount of F3s required to be discharged. The dem/val testing will further qualify maturing F3s and give more assurance that the F3s qualified under the Mil-Spec will also perform well at field conditions.