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Oddziaływanie tlenków azotu na pracowników zatrudnionych w wyrobiskach kopalń węgla kamiennego (część II)

Sąsiadek R.

Bezpieczeństwo Pracy i Ochrona Środowiska w Górnictwie

2013

nr 10

13--17

W artykule przedstawiono istotne zagadnienia związane z występowaniem tlenków azotu w podziemnych wyrobiskach zakładów górniczych wydobywających węgiel kamienny. Ponadto zawarto analizę i ocenę wpływu szkodliwości tlenków azotu na organizm pracowników.

The tests of combustion units show that the nitrogen oxide content in combustion gases during the operation of idle running engine up to 500 ppm. This condition is not abnormal because Polish Standard enables the value of 750 ppm NOx in such work conditions but if the methane content in atmosphere exceeds 1.0%, the allowable value is 1000 ppm NOx. Taking into account the harmful effect of nitrogen dioxide, it can be stated that the risk level for personnel present in the location of non combustion gases is unacceptable. An example of a risk is leaving idle running combustion engine devices at passenger or material stations which is particularly harmful to personnel in the area of the station or involved transport tasks. Due to the specific character of the work environment, the existing legal status in underground mining facilities enables higher concentration of nitrogen oxides than in the other industry branches which cannot be used as the reason for ignoring this risk. The character of occurrence of nitric oxide is usually temporary and closely associated with the shot operations being carried out, the transfer of combustion engine drive units and welding activities (very rarely). Nevertheless the emission sources are very efficient. The completed analysis of nitric oxide emissions sources shows that the following measures may be used to limit the risk: correct selection of ventilation parameters and monitoring of the air ingredients, maintaining good technical condition of combustion drives, using explosives with low content of harmful elements in shot gases, using welding materials with low content of harmful ingredients in welding fumes, oriented medical examinations and periodic check-ups of the personnel health and the inclusion of the risk from nitric oxides in training programs.

Oddziaływanie tlenków azotu na pracowników zatrudnionych w wyrobiskach kopalń węgla kamiennego (część I)

Sąsiadek R.

Bezpieczeństwo Pracy i Ochrona Środowiska w Górnictwie

2013

nr 9

22--28

Nitrogen oxides are one of the most dangerous atmosphere pollutants. Among six such compounds, nitrogen monoxide and nitrogen dioxide are of importance. They tend to occur together and together they render work processes harmful. The source of emission of nitrogen monoxide and dioxide are high-temperature combustion processes with air inflow. Work processes subject to nitrogen oxides emission include transportation using fuel-powered drive units, blasting and welding works. Taking into account how widespread mine transport is, and the fact that it is ever more often based on fuel-powered drives, it becomes a substantial source of nitrogen oxides in mine workings. The portion of harmful substances in Diesel engine exhaust gases is very significant and can result in reaching the borderline value of nitrogen oxides concentration – 1000 ppm. In the mixture of aftergases, the borderline value of nitrogen oxides concentration is set at 800 ppm. Allowable nitrogen oxides concentration in the air supplied to workings is 2.6 ppm (MAC) and 5.2 ppm (STEL). Presented values indicate the importance of correct workings ventilation which must be capable of a very effective dilution of exhaust gases and aftergases to reduce concentrations as high as 1000 ppm to the allowable values of only a few ppm.