Ignition of cellulosic and similar materials by the thermal radiation from the nuclear fireball largely determines the extent of fires resulting from a nuclear explosion in urban, rural, and wildland areas. Since the 1950s and 60s, it has been known and is well demonstrated that the ignition thresholds in materials exposed to the well-characterized thermal pulse of nuclear airbursts are controlled by thermal absorption and heat conduction. Remarkably, a full range of the ignitable materials subject to such exposure has ignition thresholds that can be forecast this way.This revisit of the pertinent technology from the last half of the twentieth century documents its findings in the open literature, some of it for the first time, while showing how it can be applied not only to computer modeling of nuclear fires but also to other nonnuclear pulsed heat releases for the twenty-first century. Beyond its originally intended purpose of forecasting the fire consequences of a nuclear war, the data correlation presented here can be used to examine a variety of threats associated with intense radiant pulses such as those in natural gas pipeline ruptures and in the class of flammable liquid storage accidents known as boiling-liquid expanding-vapor explosions (BLEVEs).KEY WORDS: pulsed radiant ignition of materials, nuclear fires, nondimensional correlation of ignition thresholds, computer codes for fire forecasts (GIS format).