- Author
-
Marker, T. R.
|
Diaz, R.
- Title
- Evaluation of Oxygen Cylinder Overpacks Exposed to Elevated Temperature. Technical Note.
- Coporate
- Federal Aviation Administration, Atlantic City International Airport, NJ
- Sponsor
- Department of Transportation, Washington, DC
- Report
-
DOT/FAA/AR-TN98/30,
June 1999,
17 p.
- Distribution
- AVAILABLE FROM: Federal Aviation Administration William J. Hughes Technical Center's Fire Safety Section's Full-Text technical reports page (in Adobe Acrobat portable document format [PDF]): http//www.fire.tc.faa.gov/reports/report.stm AVAILABLE FROM National Technical Information Service (NTIS), Technology Administration, U.S. Department of Commerce, Springfield, VA 22161. Telephone: 1-800-553-6847 or 703-605-6000; Fax: 703-605-6900. Website: http://www.ntis.gov
- Keywords
-
transport aircraft
|
fire tests
|
temperature
- Identifiers
- pressurized oxygen cylinder; rupture disc; overpack
- Abstract
- Since the fatal in-flight fire accident on May 11, 1996, attributed to the improper shipment of chemical oxygen generators, the shipment of oxidizers and pressurized oxygen has been restricted. In early 1998, at Public Hearings convened by the Research and Special Programs Administration (RSPA), interested parties proposed that the transport of pressurized and medical oxygen cylinders be permitted in cargo compartments protected with fire detection and suppression systems (Class C cargo compartments). During the meeting it became apparent that appropriate test data did not exist regarding the performance of oxygen cylinder overpacks in cargo compartments. Consequently, the FAA committed to performing two different test protocols. One protocol entitled "Oxygen Enhanced Fires in LD-3 Cargo Containers" demonstrated the inadequacy of the LD-3 cargo container in controlling the spread of an oxygen fed fire. The second test protocol entitled "Evaluation of Oxygen Cylinder Overpacks Exposed to Elevated Temperature" evaluated the performance of various cylinder overpacks to determine whether a specially designed overpack would prevent a cylinder from overheating and releasing the oxygen into the cargo bin, thus creating a catastrophic fire. Two series of tests were undertaken in a large industrial furnace to examine the response on unprotected oxygen cylinders and cylinders encased in overpacks, when subjected to elevated temperatures representative of a suppressed Class C cargo compartment fire. In the first test series, unprotected oxygen cylinders were subjected to a furnace temperature of 400 deg F. When the surface temperature of the cylinder reached approximately 300 deg F, the pressure relief disc failed and the stored oxygen was discharged. In the second test series, several types of overpacks were tested in a similar manner to determine the degree of thermal protection that the overpacks might provide. The overpacks were designed to carry a 76.5-cubic-foot oxygen cylinder and were the largest size that could be tested in the convection furnace. These overpacks, which are designed mainly to protect oxygen cylinders against impact damage during shipment, prevented pressure relief activation for nearly 60 minutes. By contrast, an unprotected 76.5-cubic-foot oxygen cylinder experienced pressure relief in less than 10 minutes. Two overpacks designed specifically for thermal insulation provided significant additional protection. The tests demonstrated that oxygen cylinder overpacks, particularly when designed to provide thermal insulation, would prevent cylinder overpressurization during a suppressed cargo fire and the potential increase in fire hazards associated with the release of oxygen.