Harold L. Kaplan, Jesse J. Beitel, III, Arthur F. Grand, Gordon E. Hartzell, Daniel S. Mitchell, Gary T. Moore, alter R. Rogers, Walter G. Switzer, Curtis D. White

For passengers to survive a postcrash aircraft fire, their escape capability must not be severely impaired by toxic combustion gases during the few minutes available for egress. Little information exists regarding the concentrations ay which human escape capability is impaired by these combustion gases, particularly the irritants. Most laboratory test methods have used loss of locomotor function or incapacitations of rodents as endpoints to measure the sublethal effects of the narcotic gases. In addition, respiratory rate depression of mice has been used as an index of incapacitation in studies of the irritant gases. However, the correlation between any of these effects in rodents ans escape impairment has not been established.

The primary objective of this research program was to assess the potential of representative combustion atmosphere irritant gases to impair human escape from a postcrash aircraft fire environment. For this assessment, a nonhuman primate model (the juvenile African savannah baboon) and an operant behaviorial task were used to measure the effects of acrolein and ydrogen chloride (HC1) on escape performance. Carbon monoxide (CO) was also included as a test gas in order to enable comparison of the sensitivities of the baboon and the rat to a narcotic combustion gas. The behaviorial task was designed to simulate human escape performance by requiring both mental functions (sensory recognition, memory, discrimination) and motor functions (locomotion, coordination) for successful escape of the animal. The animal was required, upon presentation of audio and visual cues, to select and operate an appropriate lever in order to open an escape door and then to exit through the door within a prescribed time. The escape perfomrance task was presented to the animal after 5-minute exposure to a steady concentration of the test gas as provided by a large recirculatin mixing chamber. A computer system was used to tain the animals to perform the task, to present the task for the exposure test and to record pertinent performance data, e.g., escape or failue, lever response time, escape time, number of correct and incorrect responses.

A sceondary objective of this program was to evaluate the relevance and validity of presently used laboratory tests with rodents to predict human escape impairment by narcotic and irritant combustion gases. For this assessment, the effects of CO and HC1 on the escape performance of the rat were determiined using a shuttlebox and behaviorial task similar in complexity to that used in the nonhuman primate studies. The results of these studies were compared with the primate escape performance data and human data (when available) to evulate the rat as a model for the baboon and man. These resulst were also compared with avialable data obtained with other laboratory methods for for methods with rodents to assess the predictive capability of these methods for human escape impairment.

Thor I. Eklund

The purpose of this analysis is the development of a model that relates polymeric material properties to ignitability. The model is developed for an idealized fire test for ignitability of large-scale aircraft honeycomb panels in a vertical orientation.

Transport relations for radioactive heat transmission and turbulent mass and energy transfer are applied to an idealized piloted ignition of a vertical aircraft panel. The incident radioactive energy required for panel ignition is related to thermal decomposition temperature from thermo gravimetric analysis. Effects of pyrolysis energy requirements and temperature dependence of flammability lean limits are incorporated in the analysis. The analysis is quasi-steady, in that transient effects are ignored and a slow ramp heating of the panel is assumed. State-of-the-art panel materials are dominated by radiative effects at the point of ignition. The analysis demonstrates that higher polymer degradation temperatures result in improved fire-worthiness, that surface emissivities and reflectivenss are the dominant factors controlling the incident radiation needed for ignition, and that the heat of pyrolysis becomes less significant in the energy balance as the polymer degradation temperature is raised.

Thor Eklund

The concept of the perfect stirrer is applied to smoke production and removal in ventilated compartments. The analysis results in simple relationships between the logarithm of the light transmission and the characteristic time for an air change in the compartment. In well mixed enclosures, the analysis demonstrates that the ability to improve visibility through smoke clearance is affected directly by the exponential of the negative of time divided by time for an air change.

George B. Geyer, Charles H. Urban

Information was obtained by conducting a series of representative fire modeling experiments of aircraft cabin window systems employing salvaged segments of a McDonnell Douglas DC-IO aircraft. Experiments were performed in which a thermally improved window system was installed adjacent to a standard window configuration and exposed to flame impingement from a Jp-4 fuel fire. The" results of test 1 indicated that the thermally improved DC-I0 window configuration, employing the stretched acrylic pressure pane and the new EX 112 fail-safe pane, provided an overall improvement in flame resistivity over the standard all acrylic window system of at least 79 seconds 0.3 minutes). During this experiment, the silicone rubber window gasket provided adequate thermal and mechanical stability toward preventing flame penetration into the cabin through the improved fail-safe (EX 112) window system for 225 seconds (3.75 minutes), which was the durat ion of fire exposure. The average failure time of the stretched acrylic and thermally improved (EX 112) fail-safe window panes in tests 2, 3, and 4 was 198 seconds (3.3 minutes) and 249 seconds (4.15 minutes), respectively, after fuel ignition. These data indicated that, on average, an improvement in fire resistivity of 51 seconds (0.85 minute) was obtained by the improved (EX 112) window configuration over the standard stretched acrylic window sys tem. Comparat ive tests performed with representative DC-I0 fuselage components employing the cabin interior honeycomb panel (test 3) and the aluminum panel (test 4) configurations, showed that the honeycomb panel provided a minimum inprovement in flame resistivity of 67 seconds over the aluminium interior panel.

John R. Hall, Jr., S. Wayne Stiefel

This report develops a generic model for analysis of the costs and benefits of fire-risk reducing strategies related to passenger airplanes. The model calculates incremental costs for installing and operarting these options. It also caluclates estimated lives saved and property damage avoided, and it provides rules for combining costs and benefits into a single measure of attractiveness for an alternative. This model is then applied to the strategy of fire-blocking seats on passenger airlines, either on U.S. airlines or on all world airlines.