The ignition hazard to urban interiors during nuclear attack due to burning curtain fragments transported by blast

Abstract

There exists some uncertainty at present, in the formulation of civil defense doctrine, as to whether it is advisable for window curtains to be closed or open during nuclear attack. Closed curtains would be in position to intercept some major portion, or all, of the thermal radiation pulse that would otherwise enter through the window and ignite kindling fuels within the room. But because they did so they would probably ignite and the flaming curtains, propelled into the room by the blast wave, could represent an even more serious ignition hazard than would occur if the window remained uncovered, and the curtains uninvolved. Because of this uncertainty, limited investigation, was undertaken to gain information concerning the ignition hazard represented by burning curtain fragments carried on a blast wave into typical urban interiors. The specific objective of the research described in this report was to investigate the propensity of burning curtains, carried into typical urban interiors by blast waves, to cause ignitions within the interiors capable of leading to flashover. The situation simulated in the experiments was one in which the closed curtains, having been ignited by thermal radiation from a nuclear weapon explosion, were carried, still burning, into a room in which none of the kindling fuels had been ignited owing to interception of most of the thermal pulse by the curtains. The blast wave, transporting the burning curtain fragments, was assumed to originate from the same weapon producing the thermal pulse, so that an appropriate delay time intervened, in each experiment, between curtain ignition and blast arrival.