New Additions & Downloads

• Workshop Agenda
• Brief background, Rule extension, review of the test method
• Review of the Park burner and recent refinements
• Detailed review of the Next Generation burner
• Burnthrough Apparatus Set-up Using Calibration Tools
• Task Group Meeting Minutes from 3/03/04
• Burner Calibration Guidelines

Background

In a majority of survivable accidents accompanied by fire, ignition of the interior of the aircraft is caused by burning jet fuel external to the aircraft. Therefore, the integrity of the aircraft and its ability to provide a barrier against fuel fire penetration is an important factor related to the survival of aircraft occupants. Fuselage burnthrough resistance becomes particularly important when the fuselage remains intact following a crash, which occurs frequently in survivable accidents. The burnthrough resistance may be simplistically viewed as the time interval for a fuel fire to penetrate three fuselage shell members: aluminum skin, thermal acoustical insulation, and the sidewall panel/cabin flooring. Flame penetration may occur in other areas as well, such as windows, air return grills, and seams/joints. The burnthrough resistance of the aluminum skin is well known. It takes only about 30 to 60 seconds for the skin to melt, depending on its thickness. The thermal acoustical insulation becomes the next impediment to burnthrough following the melting of the aluminum skin. In recent years, the FAA conducted several outdoor fuel fire burn tests on surplus fuselages to determine the mechanism and time frame for burnthrough. It was determined that the fiberglass insulation provided an additional 1 to 2 minutes of protection, if it completely covered the fire area and remained in place. Thus, the method of securing the insulation to the fuselage structural members is important. Finally, the sidewall panels/flooring offer the final barrier to fire penetration. Sandwich panels comprised of honeycomb cores and fiberglass facings are effective barriers; however, full-scale fire tests also show that the fire can penetrate into the cabin through air return grills, seams/joints or window reveals. Moreover, some airplanes utilize aluminum sidewall panels that offer minimal burnthrough resistance.

Approach

As a result of the testing, the FAA has determined that the thermal acoustical insulation is the most potentially effective and practical means of achieving a burnthrough barrier. Comparative testing in the full-scale test rig has shown that several alternative thermal acoustical insulation materials/systems are capable of significantly delaying the burnthrough process.

After the completion of full-scale testing, development of a laboratory test for fuselage burnthrough was initialized. The new test needed to be realistic, yet simple enough to be conducted in a laboratory setting. The proposed test method utilizes an oil-fired burner, which is currently in use for other FAA fire test standards, including the seat fire block test and the cargo liner burnthrough resistance tests. The following document is a draft version of the proposed burnthrough test standard for aircraft thermal acoustic insulation. Because it is in draft form, it is possible that slight changes to the test rig, equipment, and test procedure may occur. Please view examples of results below:

Presentations

Additional Information

For information contact:
Tim Marker
(609) 485-6469
Tim.Marker@faa.gov