PROJECT MANAGEMENT

Project Management



Project Management

Outline

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.

Introduction

The smelting of iron ore in a blast furnace is accompanied by the evolution of about six tons of blast furnace gas for every ton of iron produced (Memorandum on Carbon Monoxide Poisoning, 1951). The gas, which contains about 27 % of carbon monoxide by volume, is used as a fuel to provide heat and power for the blast furnace and subsequent steel-making operations. There is an ever-present risk of carbon monoxide poisoning to those engaged in the blast furnace process and in the handling and disposal of such enormous volumes of gas. Safe working practices and strict supervision on all jobs reduce the risk, but, as is shown in Table 1, fatal gassing accidents and others sufficiently severe to require reporting to the Factory Department continue to occur. It is difficult to obtain exact information concerning the number of cases which are not reported. However, from practical experience, it appears that for every reported case there are approximately 100 other cases of gassing of varying degrees of severity. (Thayer and Edward 2000 36) It is also known that even under 'normal' working conditions, the carboxyhaemoglobin levels of blast furnace personnel are significantly higher than the average levels found in the population as a whole (Farmer and Crittenden, 1929; Jones and Walters, 1962).

TABLE 1: GASSING ACCIDENTS DUE TO BLAST FURNACE GAS

Methods for detecting and estimating carbon monoxide may be chemical, chemico-physical or physical. Beatty (1955) described the various methods available, and since then the development of gas chromatography has provided the only basically new method. (Lewis 1995 231)

Monitoring Equipment

The necessary equipment consisted of an infra-red analyser, pumping system, recorder, extension meter, and alarm unit.

The infra-red analyser chosen was the Mines Safety Appliances Model 200. This was selective for carbon monoxide, had a response which was virtually instantaneous, and over a range of 0 to 1,000 p.p.m. had an accuracy and sensitivity of 1 % of full-scale deflection, i.e., 10 p.p.m. It was mounted on a panel (Fig. 1) located in a building conveniently sited in relation to the area to be monitored. (Kerzner 2003 68)

A pumping circuit fed the atmosphere to be analysed into the sample ...