Critical Radiant Exposures for Ignition of Tinder and Combustible Materials (Part I - Wood)

摘要

Wood in six different forms was exposed to thermal radiation from simulated nuclear weapons pulses in the range from 65 kilotons to 100 megatons. Sawdust from weathered wood was most readily ignited, glowing ignition occurring at 6.4 cal/sq cm for a 65 kt pulse, and at 21 cal/sq cm for a 100 Mt pulse. Clean, unseasoned douglas fir, one-half-inch thick, was ignited to sustained flaming at radiant exposures of 31 and 68 cal/sq cm for yields of 1.2 and 108 Mt, respectively. Weathered douglas fir could be ignited only to short-lived afterglow which extinguished itself shortly after exposure. Yellow poplar, clean, 1/16-inch thick, was ignited to sustained flaming at 33 and 71 cal/sq cm for pulses simulating weapon yields of 1.2 and 108 Mt, respectively; excelsior ignited at 29 and 53 cal/sq cm for the same pulses. Sustained flaming of the unseasoned douglas fir is a significant finding which is contrary to previous experience. The heavy resin content of the specimens studied in these tests is obviously a factor. (Author)