- Author
-
Verdonik, D. P.
|
DiNenno, P. J.
|
Williams, F. W.
- Title
- U.S. Navy Halon 1211 Replacement Plan. Part 4. Halon 1211 Replacement Program Plan.
- Coporate
- Hughes Associates, Inc., Baltimore, MD
Naval Research Laboratory, Washington, DC
- Report
-
NRL/MR/6180-99-8413
November 1, 1999
27 p.
- Keywords
-
halon 1211
|
halon alternatives
|
fire fighting
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fire fighting agents
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aircraft crash equipment
- Abstract
- The U.S. Navy currently uses five firefighting agents for suppressing fires on flight lines and flight decks: water, Aqueous Film Forming Foam (AFFF), Halon 1211, potassium bicarbonate (PKP), and carbon dioxide (CO2) [NATOPS]. While each of these agents is potentially effective for flammable liquids or other combustibles typically encountered on flight lines and flight decks, each has advantages or disadvantages for a particular application. AFFF and water are the primary agents while PKP, Halon 1211, and CO2 are secondary agents used with the primary agent or alone. The secondary agent is used alone in those situations where the primary agent is not effective and cannot completely extinguish the fire. It is often used in combination with the primary agent when increased effectiveness is required. For example, while AFFF is very effective in fighting pool fires and providing cooling, it is limited in fighting three-dimensional hidden, obstructed fires. The three secondary agents are better than AFFF in fighting three-dimensional fires and hidden fires but do not provide effective cooling or burnback protection. An important distinction between the five agents is the potential for causing collateral damage or damage caused by the agent to hot metal surfaces, electronics, or avionics. Halon 1211 is recognized as the agent that will cause the least collateral damage. While Halon 1211 and CO2 may both be considered 'clean,' CO2 may, in some extreme circumstances, cause collateral damage due to thermal shock or static discharge. In addition, Halon 1211 is significantly more effective than CO2, PKP and AFFF are not clean agents and may cause considerable collateral damage. For this reason, Halon 1211 has become the agent of choice in many aviation firefighting applications. The ability to reduce or eliminate collateral damage has been thought to be particularly important for engine fires and internal electrical fires. The aircraft may be placed back into service more quickly and at a lower cost when only Halon 1211 is used to extinguish the fire. Halon 1211 was not the first clean, halocarbon agent to be used for aviation firefighting. Chlorobromomethane (CB), also known as Halon 1011, was used by the U.S. Air Force (USAF) as a streaming agent as early as the 1970s for flight line firefighting. Halon 10 11 demonstrated the ability to limit collateral damage; however, it had corrosion and toxicity properties that were less than ideal. In the late 1970s the USAF sponsored testing of Halon 1211 as a replacement for Halon 1011 Halon 1211 was shown to possess the same positive attribute in limiting collateral damage but was much less toxic and corrosive than Halon 1011. The USAF sponsored work and the experience with Halon 1211 in Europe led to the recommendation to replace Halon 1011 in flight line extinguishers. Although no definitive literature source has been found that delineates how the 150 pound capacity was determined, there is a fair amount of anecdotal information available.