Cabin & Fire Safety Reports Search
|Title:||Stratification and Localization of Halon 1211 Discharged in Occupied Aircraft Compartments|
|Author:||Louise C. Speitel|
One goal of this analysis is to characterize the stratification and localization of Halon 1211 in aircraft compartments. A second goal is to provide a methodology to determine stratification and localization multiplication factors that can be applied to the safe-use halocarbon concentrations in Advisory Circular (AC) 20-42D to allow the safe use of higher concentrations than currently recommended. The current safe-use concentrations are based on pharmacokinetic-based assessments of gaseous halocarbon concentration decay histories in a ventilated compartment with perfect mixing and instantaneous agent discharge. The AC 20-42D refers to “an upcoming report” (this report) to provide guidance for setting safe halocarbon limits with consideration of stratification and localization. Separate analyses and guidance is provided for a B-737 aircraft and an unpressurized general aviation aircraft. General guidance is provided for application to non-test aircraft.
|Title:||Flammability Standardization Task Group—Final Reports: Federal Aviation Administration Policy Memo, PS-ANM-25.853-01|
|Author:||Scott Cambell, Michael Jensen, and Panade Sattayatam|
The Federal Aviation Administration (FAA) issued a proposed policy statement, PS-ANM-25.853-01, for the purpose of providing guidance on acceptable methods of compliance (MOC) for the flammability requirements of Title 14 Code of Federal Regulations Part 25 for commonly constructed parts, construction details, and materials. The proposed policy statement divides materials and design features into two categories.
Industry created the Flammability Standardization Task Group (FSTG) as an ad hoc action under the International Aircraft Materials Fire Test Working Group (IAMFTWG). The FSTG then initiated a 2-year substantiation activity to validate the contents of the policy in support of the FAA issuing a final policy in 2012. In September 2009, the FSTG organized a subteam to investigate the parts of the policy. Approximately 200 people were involved with this effort to standardize and simplify flammability compliance across industry. Many companies supplied data, materials, and testing.
The FSTG developed a process for substantiating each item in the policy memo. Test plans were developed and approved by industry and then made available to the FAA for concurrence. The test plan was then executed (occasionally with changes) and the data were gathered. The data were analyzed and a final report was posted for industry concurrence, followed by an FAA review. In the final report, the FSTG recommended using the MOC as written in the proposed policy; not using the proposed policy MOC; or, based on the data and analysis, using a modified approach to the MOC. The FSTG provided briefings of its activities to the IAMFTWG on a regular basis. The IAMFTWG participation is open to the public.
|Title:||Evaluation of Carbon Fiber Composite Flammability: Effect of Sample Thickness and External Ambient Conditions on Inboard Surface Flame Propagation|
|Author:||Robert I. Ochs|
A series of tests was performed to determine the relative effect of test sample thickness and external ambient conditions on the flame propagation potential of carbon fiber-reinforced epoxy airplane fuselage materials. A test rig was used to simulate an inaccessible cabin area, with a fire source placed at the bottom and thermocouples positioned along the length of the test panel. The test rig could vary the ambient conditions of the external, non-fire side of the sample. A scenario of minimal heat loss was simulated by placing a 1/2-inch thick ceramic fiberboard insulation panel directly on the exterior surface, whereas a scenario of high heat loss was simulated by flowing water along the exterior surface of the panel. Different solid laminate sample thicknesses and one sandwich panel with four plies on each side of a 1-inch thick honeycomb core were tested. Post-test burn length and width measurements were made to assess the level of flame propagation. Test results indicated that the relative flammability of a composite material is dependent upon the rate of heat dissipation from the flame-impinged surface, which varies depending on the panel thickness and the heat dissipation rate at the outboard surface. Thin panels (0.04- to 0.1-inch thick) were found to propagate flames under static ambient conditions, and were also more heavily influenced by the heat transfer at the outboard surface. Thicker panels (0.13- to 0.37-inch thick) were found to have enough thermal mass between the flame-impinged surface and the outboard surface to not propagate flames under static ambient conditions, and were relatively unaffected by the heat transfer at the outboard surface. The sandwich panel was found to behave like a thin composite panel fitted with an insulated outboard surface and was entirely unaffected by the heat dissipation rate at the outboard surface.