- Author
- Butler, C. P.
- Title
- Measurements of the Dynamics of Structural Fires. Annual Report.
- Coporate
- Department of the Army, Washington, DC
- Report
- OCD Work Unit 2561A; SRI Project PYU-8150, August 1970, 135 p.
- Contract
- DAHC20-70-C-0219
- Keywords
- structures | civil defense | wooden structures | scale models | wooden structures | scale models | weight loss | energy release rate | fire spread | barns | fuels | environmental effects | weather effects | irradiance | gas analysis | life hazards | flame detection | scaling | smoke | atmospheric composition | burn patterns
- Identifiers
- planned burning of 5 barracks sections; conduct of burns; barracks section burns; horse barn burns; fuel characteristics; fire spread between buildings; volumetric fire spread; scaling for energy release; time-irradiance plots; inflow winds; street-level fire environment; smoke attenuation
- Abstract
- A major effort has begun to evaluate experimentally the dynamic behavior of structural fires in the context of civil defense implications following nuclear attack. This report describes the accomplishments of the first year's effort which included (1) experimental measurements of the dynamic characteristics of fires in one-story wooden buildings, (2) methods used for correlating and interpreting the resulting data, and (3) attempts at reduced-scale modeling of such fires. For the most part, tests were conducted in single, uncollapsed structures in which fires were started in a single room at one end of the structure. In one full-scale test, a structure was partially collapsed to simulate moderate blast damage, and in another series, two long, parallel structures were burned simultaneously to observe effects of interactions. Measurements included weight-loss rates, energy-release rates, radiant fluxes, rates of fire propagation through structures, fire-induced inflow winds, CO and CO2 production, oxygen depletion, optical attenuation by smoke, and ignition of nearby fuel specimens. In spite of substantial differences in the conditions of tests, notably those due to weather variables, many consistencies in fire behavior characteristics and associated environmental factors were found. Radiometric measurements were shown to be a practical means for characterizing the burning rate of test fires in such structures. The pulse of radiant flux with time as measured at a distance in a suitably chosen direction correlates well with rate of weight loss as a function of time. Maximum burning rates in full-scale barracks sections occurred from 16 to 26 min after ignition, with corresponding energy release rates of about 2 x 109(9) to 4 x 10 (9) cal min-1. Fire appeared to spread through these buildings in a more nearly linear than exponential fashion. Rates of spread were estimated to be 12 ft min -1.