Richard E. Lyon

The thermal and chemical processes which occur in the solid state during flaming combustion are examined. A phenomenological model of fuel generation provides the relationships between macroscopic flammability parameters and polymer chemical structure and shows how the coupling of thermal diffusion and chemical kinetics occurs naturally in the pyrolysis zone. Fire behavior and flammability of solid polymers are predicted using the ignition temperature, heat of combustion, heat of gasification, and char yield calculated from the chemical structure; and the results are compared to experimental values. The objective of this work is to develop a consistent, solid-state physical chemistry of flaming combustion which bridges the gap between fire and material sciences to help guide the discovery of new, more fire-resistant polymers

Thomas Cleary and William Grosshandler

As part of the National Aeronautics and Space Administration (NASA) initiated program on global civil avaition, NIST is assting the Federal Aviation Administration in its research to improve fire detection in aircraft cargo compartments.

Timothy R. Marker and Ricardo Diaz

Tests were conducted inside a large industrial convection furnace to determine the temperature and time required to cause pressure relief activation of three different size oxygen cylinders commonly used in commercial transport aircraft. The cylinders were first emptied of gaseous oxygen for safety reasons and refilled with nitrogen to the original pressure. The furnace temperature was ramped to 400°F, which represented the temperature reached during a Halon 1301 suppressed deep-seated cargo compartment fire. Cylinder pressure relief activation typically occurred after the surface temperature had reached only 300°F.

Additional tests were conducted using a 76.5-cubic-foot oxygen cylinder placed inside several types of cylinder cases, commonly referred to as overpacks. The overpacks were available in a variety of constructions, all for the purpose of protecting the cylinder from impact damage that may occur during shipment. The tests were run to determine the level of thermal protection, if any, that the overpacks might provide when the cylinders are subjected to elevated temperatures. Two custom-made overpacks were also tested that contained insulating materials aimed specifically at providing thermal protection. Tests showed that some common overpacks have the ability to protect the cylinder from pressure relief activation for nearly 60 minutes while other types designed specifically for thermal insulation can provide significant additional protection.

Thomas R. O'Connor and Eric L. Hagen

This report presents the results of a series of tests performed on oxygen generators contained in cardboard shipping containers and packing materials to witness the probability of ignition in the event one of the generators was activated. Test results indicated that ion the presence of an activated generator, combustible materials will produce a fire.

Timothy R. Marker and Ricardo Diaz

Four tests were conducted inside a 169-cubic-foot LD-3 cargo container to demonstrate the hazards associated with the release of gaseous oxygen during suppression of a smoldering fire with Halon 1301. The cargo fires were allowed to burn for a short duration before Halon 1301 was discharged into the container. After the suppressant concentration stabilized to about 3%, the minimum design concentration for inerting, a quantity of oxygen was discharged to simulate the relief of oxygen from an overpressurized cylinder. During the first three tests, 11 cubic feet of oxygen was bled into the container from a remote cylinder. A fourth test was conducted in which 22 cubic feet of oxygen was introduced which produced a severe fire that destroyed the container. Temperature, toxic gases, and halon concentration were measured continuously inside the container and video cameras recorded the tests from three locations external to the container.