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Triggered Barriers for the Suppression of Coal Dust Explosions.
Liebman-I; Richmond-JK; Pro-R; Et Al
NTIS: PB 80-134570 :24 pages
Two triggered barrier systems and several extinguishing agents were tested against coal dust explosion propagating in the main entry of the Bureau of Mines experimental mine at Bruceton, Pennsylvania. One system used a high-pressure cylinder to propel the extinguishant; the second system used pressurized nitrogen gas or halon 1301 (cf3br) in a low-pressure system to power the disperser. The relative efficiencies of the extinguishants were determined by comparing calculated concentrations of the extinguishant clouds present in the mine during suppressing of the explosions. Results showed the following trend of increasing effectiveness: purple-k (khco3) <water <hybrids consisting of foam or water combined with halon 1301 <halon alone. On a weight basis, water was two to three times as efficient as purple-k, whereas the hybrids and halon alone were only marginally superior to water. Maximum efficiency of an extinguishant is attained by high rates of discharge from the barrier and by minimizing the time interval between onset of discharge and flame arrival to that necessary for discharge. Both the high-and low-pressure barrier systems were demonstrated to be capable of suppressing coal dust explosions; however, because of the potential hazard of the former, the low-pressure system is considered to be the most attractive prototype.
IH; Report of Investigations
NTIS Accession No.
NTIS: PB 80-134570
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division