Impact of Air Velocity on the Detection of Fires in Conveyor Belt Haulageways

Abstract

A series of large-scale experiments were conducted in an above-ground fire gallery using three different types of fire-resistant conveyor belts and four air velocities for each belt. The goal of the experiments was to understand and quantify the effects of air velocity on the detection of fires in underground conveyor belt haulageways and to determine the rates of generation of toxic gases and smoke as a fire progresses through the stages of smoldering coal, flaming coal, and finally a flaming conveyor belt. In the experiments, electrical strip heaters, imbedded approximately 5 cm below the top surface of a large mass of coal rubble, were used to ignite the coal, producing an open flame. The flaming coal mass subsequently ignited 1.83-m-wide conveyor belts located approximately 0.30 m above the coal surface. Gas samples were drawn through an averaging probe for continuous measurement of CO, CO 2 , and O 2 as the fire progressed. Approximately 20 m from the fire origin and 0.5 m below the roof of the gallery, two commercially available smoke detectors, a light obscuration meter, and a sampling probe for measurement of total mass concentration of smoke particles were placed. Two video cameras were located upstream of the fire origin and along the gallery at about 14 m and 5 m in order to detect both smoke and flames from the fire. This paper discusses the impact of ventilation airflow on alarm times of the smoke detectors and video cameras, CO levels, smoke optical densities and smoke obscuration, total smoke mass concentrations, and fire heat release rates, examining how these various parameters depend upon air velocity and air quantity, the product of air velocity, and entry cross-section.

Evaluation of criteria for the detection of fires in underground conveyor belt haulageways

“…More detailed information on the effect of air velocity obtained in this study can be found in Ref. 10.…”

Chemical compounds released by combustion of polymer composites flat belts

“…The authors of the test results have jointly determined the flammability of rubber materials, which are common to conveyor tyres, conveyor belts and insulation of power cables, and have compared the thermal magnitude of the cargo quantities of these materials to other fuels that are publicly transported 27 , 28 . In turn, the smoke production of a material and the toxicity of the products of its thermal decomposition and combustion depend mainly on the chemical composition and combustion temperature of the materials.…”

Study on fire smoke flow characteristics in the ventilation network and linkage control system in coal mines

“…3 Owing to the underground tunnel environment, narrow spaces, and complicated ventilation network, serious secondary disasters can be caused by disasters combining with each other. [4][5][6][7] Jarosław Brodny revealed that numerical methods could be successfully used for analysing fire and ventilation phenomena in closed headings. 8,26 Aiming at the major safety demands for coal mines, many types of disaster smoke flow simulation software have developed by scholars to study the evolution laws and damage effects of smoke flow caused by fires.…”

“…The main factor for the heavy casualties is the spread of the smoke stream generated by the fire in the ventilation network 3 . Owing to the underground tunnel environment, narrow spaces, and complicated ventilation network, serious secondary disasters can be caused by disasters combining with each other 4‐7 . Jarosław Brodny revealed that numerical methods could be successfully used for analysing fire and ventilation phenomena in closed headings 8,26 .…”