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Simulating the Opening of Fusible-Link-Actuated Fire Vents.


pdf icon Simulating the Opening of Fusible-Link-Actuated Fire Vents. (3378 K)
Cooper, L. Y.

NISTIR 6227; 58 p. September 1998.

Fire Safety Journal, Vol. 34, No. 3, 219-255, April 2000.

Available from:

National Technical Information Service (NTIS), Technology Administration, U.S. Department of Commerce, Springfield, VA 22161.
Telephone: 1-800-553-6847 or 703-605-6000;
Fax: 703-605-6900.
Website: http://www.ntis.gov
Order number: PB98-177850

Keywords:

vents; building fires; compartment fires; computer models; fire models; mathematical models; plunge tests

Abstract:

Model equations, suitable for general use in compartment fire models, are developed to simulate the thermal response to arbitrary fire environments of fusible-link activated automatic fire vents. The method of analysis, which focused on a prototype three-element link-mount design, can be extended to arbitrary multiple-element link mounts. Also, the equations for the prototype three-element link mount are shown to include, and be directly applicable to the problem of simulating the response of single-element simply-supported links. A method was developed to determine the values of the set of parameters that characterize a particular multiple link-mount design. This involves: 1) the measured time-dependent thermal response of the link-mount design to exposure in a plunge test, the type of test used to characterize the thermal response of sprinkler links; and 2) an analytical means of determining values of the design parameters that yield an optimum fit between a solution to the model equations and the temperature data. The method takes account of the pre-fusing solder-melting phase of fusible-link response. The latter was shown to be very important for the link design used in this study. The method was carried out successfully for four plunge tests involving three link-mount systems and one or two system/flow orientations. In each case, the model equations, with the determined values of the system parameters and model equations were used successfully to simulate previously-reported time of link fusing and vent activation in a real fire environment.