A continuously recording atmospheric carbon monoxide monitoring system with fully automatic alarms in a blast furnace area.

A continuously recording carbon monoxide monitoring system with fully automatic alarms is described for use in blast furnace areas. The equipment comprised the Mines Safety Appliances Model 200 infra-red analyser, pumping system, recorder, extension meter, and alarm unit. Use of the apparatus showed that concentrations of carbon monoxide in the blast furnace area studied were mostly in the range of 0 to 49 p.p.m. Readings of 200 p.p.m. and over generally indicated that some abnormal and potentially dangerous incident had occurred. Examples of such incidents are given. A visual alarm was set at 200 p.p.m., a level at which work could safely continue for a limited period, and an auditory alarm at 500 p.p.m., at which level immediate action was necessary. The theoretical reasons for selecting these levels are discussed, and practical results are quoted to confirm their suitability.