Fire Tests of Men’s Suits on Racks!

A series of fire tests were conducted to characterize the potential hazard from ignition of men’s suits hanging on racks. The fire test scenario was selected as part of a fire investigation being conducted by the U.S. Department of Treasury’s Bureau of Alcohol, Tobacco, and Firearms. Heat release rate was determined as a function of time from ignition using the oxygen depletionprinciple. In addition, the total heat flux from the burning suits and the mass loss were measured. Three tests were conducted with the suits placed in the open under a large calorimeter. The suits were ignited either in the center or at the end of the rack with a propane torch. Peak heat release rates obtained during the tests ranged from approximately 1 MW to 2 MW.

Introduction to the Fire Test:

Measurement of the rate at which a burning item releases heat is a critical parameter in fire protection engineering. The heat release rate can be used in the characterization of the hazard represented by a given fuel package. Heat release rate can provide information on fire size and fire growth rate. When used as input to a computer fire model, the heat release rate can be used to estimate available egress time and determine detection or suppression system activation time. Heat flux measurements can be used to estimate potential for ignition of adjacent fuel items.

As part of a fire investigation, the U.S. Department of Treasury’s Bureau of Alcohol, Tobacco and Firearms (ATF) was interested in determining the rate of heat release and burning characteristics from a rack of men’s suits. Photographs of the test arrangement showing the racks of suits are presented as figures 1 and 2. Figure 3 presents front and side views of the test arrangement with dimensions illustrating the location of the heat flux sensors.

Results:

The heat release rate curves obtained as a function of time from ignition for the three fire tests. In all three tests, a heat release rate of approximately 1 MW is sustained for about 5 minutes. The peak heat release rate for the first and third tests is about 1 MW while the obtained at the entrance to the exhaust

hood immediately above the center of the burning clothes is shown in Figure 18. During most of

the tests, the temperature above the burning clothes is 150 °C (302 °F). The temperature spikes

briefly to 200 °C (392 °F) during the early portion of the second test. The total heat flux data

obtained from the two sensors in the three tests are shown in Figures 19 and 20. There is good

agreement between the two sensors. Finally, the mass loss rate data for the three tests is presented in Figure 21. The initial mass of suits and racks was 55.8 kg (123 lb), 57.1 kg (126

lb), and 57.6 kg (127 lb) for the first, second, and third tests, respectively. The final mass at the end of the first, second, and third tests was 46.7 kg (103 lb), 48.0 kg (106 lb), and 49.0 kg (108lb), respectivelylb), and 57.6 kg (127 lb) for the first, second, and third tests, respectively.