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The Pipeline and Hazardous Material Safety Administration and the Federal Aviation Administration (FAA) are proposing a new regulation for the shipping of lithium-ion and lithium metal batteries and cells. Much of the regulation involves record keeping, package markings, cell size, and lithium content. Part of the regulation may restrict packaging, shipping mode, and cell type for shippers who elect to ship their devices on transport category aircraft.
The tests described in this report were designed to increase knowledge of the flammability of lithium-ion and lithium metal cells generated in earlier test efforts. Based on the previous work of the FAA William J. Hughes Technical Center Fire Safety Team, tests were conducted with larger number of cells and simulated self-ignition (thermal runaway) conditions. The effectiveness of Halon 1301 was evaluated from the perspective of open flame suppression as well as the ability to halt the propagation of thermal runaway within a shipment.
Preliminary tests were also conducted to characterize the flammability hazard of lithium polymer batteries that are used in some laptop computers.
The capability of existing shipping containers to contain lithium-ion and lithium metal cell fires was evaluated. A proposed performance standard for a shipping container or overpack for lithium-ion cells was developed.
Some concerns have been raised about the flammability characteristics of personal hand sanitizer, which is presently being used in lavatories on many commercial airlines to mitigate the spread of the H1N1 virus. Personal hand sanitizer is a fluid, which is generally composed of approximately 60% ethyl alcohol by volume, and comes in two primary forms: liquid and gel. To examine the general flammability characteristics of alcohol-based hand sanitizers, a series of small-scale tests were performed at the William J. Hughes Technical Center by the Fire Safety Team. Both gel and liquid hand sanitizers were examined. Tests were also performed to determine if hand sanitizer spillage could pose a significant fire threat. The effect of burning hand sanitizer on typical aircraft materials was examined. Antibacterial liquid soap was also burned adjacent to typical aircraft materials to compare with the hand sanitizer results.
As expected, hand sanitizer is flammable and can easily be ignited with a common grill lighter when poured into a pan. It tends to burn relatively cool, compared to fuel, plastic, or cellulose fires with peak flame temperatures between 500° and 1000°F. The observed temperatures above the flame were higher for the liquid hand sanitizer compared to the gel. The vapor is flammable and can be ignited by heating the liquid from the bottom and then igniting the vapor. The hot liquid does not have to be present to ignite the vapor; however, the vapor could not be ignited at room or elevated ambient temperatures (up to 100°F) without bottom-heating the hand sanitizer. When a nearly full bottle of sanitizer was involved in a fire started by burning paper towels, it burned hotter and somewhat vigorously. At one point, a fire burning adjacent to a 12-ounce liquid bottle of hand sanitizer reached temperatures in excess of 1500°F. When the hand sanitizer was burned adjacent to typical aircraft interior panels oriented horizontally or vertically, the panel did not ignite and burn independently, and there was no significant damage to the panel. From the tests conducted, burning hand sanitizer presents no significant risk to commercial transport aircraft fire safety, given the present cabin material flammability requirements.
This study is based on 1036 accidents (of which 672 were survivable) that occurred between 1968 and 2007 involving large transport category turbojet and turboprop western-built aircraft operating in a passenger or passenger/cargo role.
Over the study period, there was a marked reduction in the total accident rate both for the world fleet and the combined U.S. and Canadian fleets. This reduction is apparent when the accident rate is measured on a per flight, per passenger, or per revenue passenger mile basis.
The survivability of accidents has also shown a marked improvement over the study period with a greater proportion of accidents being survivable and a marked increase in the proportion of occupants surviving an accident. These improvements are apparent in both the world fleet and the combined U.S. and Canadian fleets.
It would seem that fatalities attributable to impact represent a larger proportion of the total number of fatalities in survivable accidents than those that are caused by fire.
Micro fuel cells are an alternative to batteries as a portable source of electricity. Unlike a battery, which stores electricity, a fuel cell chemically reacts a base fuel with oxygen from the air to generate electricity. A fuel cell is recharged by simply replacing the fuel. The potential flammability of the base fuels is a concern when carried onboard an aircraft.
A series of tests were performed to evaluate the flammability hazard associated with fuel cell fuel cartridges. Tests were conducted with various fuel chemistries including methanol, formic acid, butane, hydrogen gas, and borohydrides. The response of each fuel cartridge to an external alcohol fire was evaluated.
Most of the fuels tested were flammable. The cartridge containing formic acid did not ignite under the test conditions. Butane produced the most vigorous fire. Heating hydrogen gas stored in a metal matrix caused breaching of the enclosure allowing the gas to escape and ignite. Borohydrides were difficult to ignite but gave off a flammable fume when heated and were capable of deep-seated exothermic reaction. It was found that the cartridge material can have a significant effect on flammability. Metal cartridges protected the fuel from an external fire better than plastic cartridges. Halon 1211 was effective against all but the deep-seated borohydride exothermic reaction.
Federal Aviation Administration