R G W Cherry and Associates

The purpose of this Analysis is to evaluate the potential benefit, in terms of lives saved, from enhanced protection from fires within hidden areas in the aircraft cabin. For the purposes of this study, a "hidden area" is defined as any area inside the pressure shell, which is not readily accessible to the crew other than a dedicated cargo area.

An assessment has also been made of the benefits to be accrued as a result of enhancements to the flammability standards of Thermal Acoustic Liners attached to the fuselage skin.

The methodology of the assessment has been based on a Mathematical Risk Model. In order to validate the results of the Risk Model, a determination has been made of the number of lives that might be saved from enhanced protection from fires in hidden areas based on an analysis of past accidents.

The assessment of benefit has been based on data for the world fleet of Westernbuilt aircraft over the period 1991 to 2000.

Based on the developed Mathematical Risk Model, it is assessed that the number of lives to be saved from enhanced protection from fires within hidden areas in the aircraft cabin would be 52 per year. The 95-percentile range is 16 to 97 lives per year.

Whilst there are limited data available on hidden fire accidents the assessment of benefit over the period 1991 to 2000, of 48 lives per year, based on an analysis of past accidents, gives confidence in the model predictions.

It is assessed that the number of lives to be saved from improvements in the flammability standards of Thermal Acoustic Liners is approximately 34 per year over the period 1991 to 2000.

Richard M. Johnson

The purpose of this technical note is to document the results of fire tests conducted to examine the characteristics of fire that may occur in the cavity of an aircraft seat armrest and the fire-containment capability of the cavity. In all the tests conducted with actual seat armrests, the fire self-extinguished, the armrest materials did not ignite, and the fire was contained within the armrest cavity.

Harry Webster

One or more Halon 1211 hand-held fire extinguishers are specified in Federal Aviation Regulation (FAR) Part 25.851 as a requirement on transport category aircraft with 31 or more seats. Halon 1211 has been linked to the destruction of the ozone layer and production of new Halon 1211 has been halted per the Montreal Protocol in 1993. The phase out of Halon 1211, as the hand-held firefighting agent of choice, for civilian transport category aircraft has necessitated the development of a Minimum Performance Standard (MPS) to evaluate replacement agents. The purpose of the MPS is to insure that there is no reduction in safety, both in terms of effectiveness in fighting onboard fires and toxicity to the passengers and crew.

The MPS specifies two new tests that replacement agents must pass in addition to requiring national certifications such as provided by Underwriters Laboratories. The first test evaluates the "flooding" characteristics of the agent against a hidden in-flight fire. This test determines the ability of a streaming agent to function as a flooding agent. The second test evaluates the performance of the agent in fighting a terrorist fire scenario and the associated toxicity hazard. This test measures the agent's ability to extinguish a triple-seat fire in an aircraft cabin under in-flight conditions and the toxicity characteristics of both the neat agent and the products of decomposition.

This MPS will insure that the replacement agents will meet or exceed the performance of Halon 1211 both in fighting fires and maintaining a safe breathing environment in aircraft cabins.

Richard E. Lyon, Richard Walters and S. Gandhi

Flaming and nonflaming combustion studies were conducted on a series of polycyanurates to examine the effect of chemical composition and physical properties on the fire behavior of these cross-linked, char-forming thermoset polymers. Heats of complete combustion of the polymer and fuel gases were determined by oxygen bomb calorimetry and pyrolysis-combustion flow calorimetry, respectively. Fire calorimetry experiments were conducted to measure the heat released, the rate of heat release, and the smoke generation in flaming combustion. Fire response parameters derived from the data include the thermal inertia, heat of gasification, effective heat of combustion, and combustion efficiency. Halogen-containing polycyanurates exhibited extremely low heat release rate in flaming combustion compared to the hydrocarbon resins, yet produced significantly less smoke and comparable levels of carbon monoxide and soot.

Richard N. Walters

The cure chemistry, thermal stability, and fire behavior in a series of fire-resistant cyanate ester-epoxy blends were examined. The dicyanate and diepoxide of 1,1-dichloro-2,2-bis(4-hydroxyphenyl)ethylene (bisphenol-C, BPC) were combined in various molar ratios, and the reaction chemistry was monitored using Fourier Transform Infrared Spectroscopy (FTIR) and differential scanning calorimetry (DSC). Fire behavior of the BPC cyanate-epoxy blends was studied in flaming and nonflaming combustion, using fire calorimetry and pyrolysis-combustion flow calorimetry, respectively.