In accordance with the 1987 Montreal Protocol to Protect the Stratospheric Ozone Layer and the United States (U.S.) Clean Air Act as amended in 1990, Halon 1211 production in the U.S. ended on 31 December 1993. The U.S. Navy (USN) and the U.S. Air Force (USAF) use Halon 1211 predominantly in 150-pound fire extinguishers, which provide easy-to-use, effective, and clean first-response fire suppression on the flightline. Approximately 20,000 of these extinguishers are in use by the USN and USAF. Unless a non-ozone depleting alternative can be identified, under projected USN and USAF usage rates the Department of Defense (DoD) will run out of Halon 1211 stocks as early as 2012. In order to execute an orderly, economically feasible transition to a new agent, the USN and USAF need to demonstrate and validate a Halon 1211 alternative for this application within the next few years.
The objective of this demonstration was to identify and test commercially available, alternative agents and systems as potential replacements for the Halon 1211 150-pound flightline fire extinguisher.
Alternative agent and system Original Equipment Manufacturer (OEMs) were solicited to provide their commercially available technologies that meet DoD requirements. It was anticipated that submissions would include FK-5-1-12 (3M™ Novec™ 1230), HFC-236fa (Dupont FE-36™), and HFC-227ea (GLC FM 200®, Dupont FE-227™) as a minimum. Because all of these agents are available commercially as Halon alternatives in total flooding and streaming applications, no significant demonstration or validation issues were anticipated.
Extensive scientific test data are available on most of these agents from organizations such as Underwriters Laboratory, the National Institute of Science and Technology, the National Fire Protection Association, and various DoD research laboratories. Although all of these agents have been tested or are being used in fire extinguishing applications, application of these technologies to large flightline fire extinguishers has not been pursued in the commercial sector.
The hastening depletion of USN and USAF Halon 1211 reserves, the negative results of past DoD research and developments efforts in this area, and the larger set of commercial Halon 1211 alternatives available in 2005 all strongly suggested that the USN and USAF needed to take a demonstration and validation approach that, to the greatest extent possible, would leverage existing data and exploit mature, commercial technologies. The project built upon the knowledge base of flightline fire extinguisher performance requirements, the military and commercial partnerships built in previous efforts, and the demonstration and validation methodologies that were developed in previous projects.
Performance testing was conducted at Tyndall Air Force Base, Florida using a standard F-100 Engine-Nacelle Test Fixture. Fuel flowing from nozzles was ignited creating essentially three fires—a spray fire within the cylindrical fixture, burning fuel flowing out of the fixture, and a pool fire beneath the fixture—that candidate systems were expected to extinguish. A second test series, the stream-reach tests, measured candidate systems ability to extinguish small fires at distances of 20, 25, 30, and 35 feet. The main performance objective was for candidate agents/systems to match the fire-fighting performance of the existing Halon 1211 fire extinguisher against these fires. DoD would prefer a system with a stream reach of at least 25 feet with the ability to extinguish the test fire within 30 seconds using less than 285 pounds of agent. The tested units also had to meet requirements for safe fire-fighter standoff distance, relative size of the unit for typical use, environmental safety, and occupational health. Stream-reach tests showed that each of the combinations had a stream reach of at least 35 feet.
Following the testing of alternative agents, the Air Force Research Laboratory retested the 150-lb Halon 1211 fire extinguisher against the same test protocol and previously documented baseline performance requirements. None of the systems tested matched the extinguishing performance of the existing Halon 1211 system. Only 30 percent of the test fires were extinguished – compared to all fires being extinguished in the Halon 1211 baseline tests. There is insufficient data resulting from this testing to be able to consider whether use of one of the tested agents in larger quantities would result in greater success.
The concerns of several Air Force, Navy, and Marine Corps flightline fire protection stakeholders and end-users had to be considered in developing parameters for this testing. Key stakeholders are fire departments; aircraft, aircraft subsystem, and aircraft engine program managers; and ESOH professionals. Logistics maintenance organizations are the primary end-user for the 150-pound flightline fire extinguisher. In addition, Warner Robins Air Logistics Center, as the DoD supply item manager for the current Halon 1211 extinguisher, was involved in this project.
In response to one key end-user performance parameter, the project tested only “clean agents” that would not leave significant residue when applied to aircraft or equipment. In addition, through prior coordination with the firefighting communities, the project performers demonstrated the firefighting effectiveness of the tested fire extinguishers using the established protocol. With the conclusion of this project, it is expected that Air Force, Navy, and Marine Corps acquisition decision makers will use the test results and other existing information about the extinguishers to evaluate them against the full set of stakeholder and end-user requirements. These will include, but are not limited to, fire extinguishment performance, cost, logistics footprint, materials compatibility, ergonomics, Environment, Safety, and Occupational Health (ESOH), and industrial base considerations.