Constantine P. Sarkos

Seventy-five “self-extinguishing” materials used in wide-bodied aircraft cabin interiors were tested in the National Bureau of Standards Smoke chamber and analyzed for smoke and toxic gases in the combustion mixture. Concentrations of selected toxic gases were measured at regular intervals during the test, either directly from the chamber or from bag samples, using colorimetric detector tubes.

Data analysis was facilitated by grouping the materials into usage designations and comparing the peak smoke and toxic gas concentrations. Despite the unknown magnitude of interference effects in the combustion mixture, detector tubes appear to offer a convenient and inexpensive method for identifying the presence of selected gases and approximating the relative gas yield of similar cabin materials.

Fire Protection Branch

This test program studies the burning characteristics of titanium under air flow conditions. The flat plate titanium samples are ignited by molten titanium from an electrically heated igniter. Air flow conditions that support sustained combustion of a single sample are determined. The burn rate is measured on all tests with steady state burning.

Argon gas is shown to be a feasible extinguishing agent for titanium fire. Quick injection of a sufficient amount of argon gas to maintain a 60% concentration by volume of argon results in quick suppression by oxygen depletion. Carbon dioxide a common fire extinguishing agent, is shown to sustain titanium burning at an accelerated rate.

The ultraviolet (UV) radiation emitted by burning titanium is shown to be of a sufficient intensity for existing UV fire detectors to detect at reasonable distances.

Richard Hill

Flight tests were conducted on two self-generating overheats detection systems installed in the number tow nacelle of a Federal Aviation Administration (FAA) Convair CV880. The systems were mounted inboard and outboard in the nacelle paralleling the existing aircraft system. The outboard system logged 722.2 flight hours with no problems reported. The inboard system logged 615.0 flight hours. Shortly after the inboard system was installed, overheat warnings were obtained when the thrust reverses were used. The problem was found in the control box, which caused the system to alarm at a lower temperature than was set. The inboard system then operated flawlessly for 585.9 flight hours until another problem in the control box caused the system to cease operating completely. No false alarms were noted, at any time, from electrical noise. It is concluded that the self-generating system tested is an airworthy system, which should decrease the false fire-warning rate in engine nacelles.

Richard G. Hill

Flight tests were conducted on two self-generating overheats detection systems installed in the number tow nacelle of a Federal Aviation Administration (FAA) Convair CV880. The systems were mounted inboard and outboard in the nacelle paralleling the existing aircraft system. The outboard system logged 722.2 flight hours with no problems reported. The inboard system logged 615.0 flight hours. Shortly after the inboard system was installed, overheat warnings were obtained when the thrust reverses were used. The problem was found in the control box, which caused the system to alarm at a lower temperature than was set. The inboard system then operated flawlessly for 585.9 flight hours until another problem in the control box caused the system to cease operating completely. No false alarms were noted, at any time, from electrical noise. It is concluded that the self-generating system tested is an airworthy system, which should decrease the false fire-warning rate in engine nacelles.

James E. Brown

This report summarizes work for the period of February - August 1974 on a continuing program to characterize the chemical and physical parameters of importance in a flash fire and to develop laboratory scale methods for measuring the flash fire potential of materials.