A previous study of polyetheretherketone showed that the ignitability of this high temperature engineering plastic is sensitive to the presence of absorbed moisture. The present research extends this work to include five other engineering plastics: polycarbonate, polyoxymethylene, polymethylmethacrylate, polyphenylsulfone, and polyhexamethyleneadipamide. Separate batches of each polymer were equilibrated in hot (80°C) water, 50% relative humidity at 20°C, or vacuum dried at 100°C and tested in a cone calorimeter at heat fluxes between 10–75 kW/m2. These hygrothermally conditioned samples were also examined by microscale combustion calorimetry to determine the effect of moisture on the decomposition and combustion properties. It was found that absorbed moisture did not change the thermal decomposition or ignition temperatures significantly, but was released as steam that formed microscopic surface bubbles at or above the softening (i.e., glass transition or melting) temperature of the polymer. The phase change from bound water to steam entrained in the polymer melt (i.e., foam) significantly reduced the ignition time as compared to dry samples. Attempts were made to account for the moisture-sensitive ignition delay in terms of thermal properties and chemical processes governing ignition and in a numerical thermokinetic pyrolysis model.

The use of electronic-tablets (e-tablets) as replacements for conventional in-flight entertainment systems has gained popularity among airlines globally. Innovative methods of storing and charging e-tablets in galley carts have been suggested or are already in service with some airlines.

The danger of thermal runaway in the lithium-ion-pouch batteries that are used in these e-tablets is well known, but the potential fire hazard resulting from e-tablets being stored and charged in galley carts or a similar enclosure has not been established. To examine this potential fire hazard, the Civil Aviation Authority of Singapore and the Federal Aviation Administration conducted a series of tests to investigate the behavior of e-tablet fires.

Tests were conducted within a galley cart and thermal runaway of the e-tablet lithium-ion-pouch battery was initiated by either a heat plate or an external alcohol fire. The arrangement of e-tablets inside the galley cart followed the typical methods of storage proposed by airlines and design organizations. The objectives of the tests were to determine a suitable storage configuration for the e-tablets, which would prevent the propagation of thermal runaway, and to determine the effect that thermal runaway would have on a typical galley cart.

Ten tests were conducted. The results of these tests showed the potential fire hazards associated with bulk storage of e-tablets in a galley cart or similar enclosure. Additional work is recommended to determine the desirable features of galley carts to contain a lithium battery fire and prevent the danger associated with fire, smoke intensity, and explosion.

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.

• Methods that are acceptable and can be used are as shown in Part 1 of the policy statement.
• Methods that are expected to be acceptable but require test data to support them are as shown in Part 2 of the policystatement.

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.

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.

The principles and practice of pyrolysis combustion flow calorimetry as embodied in the Federal Aviation Administration microscale combustion calorimeter (MCC) are reviewed to produce a technical basis for a standard set of operating parameters and procedures that produce accurate, repeatable, and reproducible thermal combustion properties of materials as codified in the American Society for Testing and Materials (ASTM) D7309 Standard Test Method for Determining Flammability Characteristics of Plastics and Other Solid Materials Using Microscale Combustion Calorimetry. The relationship between MCC thermal combustion properties of materials and the results of fire and flammability tests are presented and discussed.