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NIST Report Urges Firefighters to Consider Wind Effects During Fire

Floor-to-ceiling temperatures rapidly increased where multiple crews were working.

Two NIST fire experts traveled to Houston shortly after the April 12, 2009, fire in a one-story ranch-style home located on the east side of the city. They examined the site and collected data about the behavior of the fire and the factors impacting that behavior—in particular, the wind at the time—in order to unravel the events that led to the deaths of the two men.

This was accomplished by creating sophisticated computer models of the fire and then visualizing them using two popular NIST software tools: the Fire Dynamics Simulator (FDS), which numerically characterizes the movement of smoke and hot gases caused by fire, wind and ventilation systems; and Smokeview, which displays the FDS calculation results as animations. The simulations portrayed two different scenarios of the Houston fire. The first demonstrated the actual conditions that firefighters experienced that day, including the contributing role of wind, while the second was intended to show how the fire may have behaved in the absence of wind. The wind-included scenario indicated that the fire followed a wind-driven flow path between the den and the front door after the failure of a large span of windows in the den. Floor-to-ceiling temperatures rapidly increased—in some areas, in excess of 260 degrees Celsius (500 degrees Fahrenheit)—in this flow path where multiple crews of firefighters were working. In the NIST simulation that excluded wind, the flow path was not created, and the temperatures and conditions where the firefighters were working were significantly less hazardous.