Abstract
The object of research is the welder safety during the repair and construction of underground pipelines. It is established that manual electric welding is characterized by significant influence on the human body, since the distance from the place of welding to the welder is 20–30 cm, the temperature in the pillar of the welding arc reaches 6500 K. It is contributes to the allocation in the surrounding space of a significant amount of metal vapor and fine particles (welding aerosol and toxic gases). Theoretical and experimental investigations of the initial part of the welding torch (at a height of 0.4–0.5 m) using manual, semi-automatic welding in the environment of protective gases and welding under a layer of flux have been carried out. Dependencies for determining axial temperatures and velocities are proposed. It is substantiated that the spreading of aerosols during welding of pipelines in the trench is determined by the physical processes of spreading the welding torch. The hygienic characteristics of the electrodes of the ANO type in the welding processes are investigated. It is established that the total amount of aerosol in the process of welding using ANO-4 electrodes with basic coating reaches 31 g/kg and toxic substances in aerosol up to 9 g/kg. The amount of gases in front of the welder shield during the welding of electrodes by ANO-8 reaches 20 mg/m 3 . Empirical equations for determination of aerosols concentration and gaseous concentration of harmful substances are obtained. In addition, an equation for determining the index of workplace pollution of welders, which made it possible to predict individual parameters of working conditions, is obtained. The mechanism of propagation of aerosols in the trench requires a special consideration, which can be carried out by the method of mathematical modeling, because such physical and chemical processes, as longitudinal and transverse dispersion, molecular diffusion play a role. The analysis of empirical formulas which can be recommended for determination of parameters in the initial section of a welding torch using flash welding of a pipeline in a trench is done.
Highlights
IntroductionThe main technological process in which a large amount of harmful emissions (nitric oxide, carbon monoxide, manganese oxide, fluoride compounds, ozone, dust and the heat associated with them) is released is welding
The main technological process in which a large amount of harmful emissions is released is welding.Hygienic studies of welding processes include experimental and industrial studies
Welding of underground pipelines during their repair is carried out in a half-open space, and since the distance from the place of welding to the welder is only 20–30 cm, there is a need to study the effect of welding processes when repairing underground pipelines on the safety of the welder
Summary
The main technological process in which a large amount of harmful emissions (nitric oxide, carbon monoxide, manganese oxide, fluoride compounds, ozone, dust and the heat associated with them) is released is welding. The subject of the study is to increase the level of hygiene and safety during electrical welding during the repair of underground pipelines. The main tasks of the work are the assessment of sanitary and hygienic working conditions, as well as studies of the allocation and spread of aerosols during the welding process. In this regard, it is relevant to conduct research to reduce the risk of occupational diseases working by increasing the efficiency of welding production. The aim of research is studying the effect of harmful substances on the human body when welding in half-open space (underground pipelines)
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