Improvement of Cast House Operator Work Posture with REBA Method at PT XYZ

Musculoskeletal disorders (MSDs) are diseases in the human muscular tissue system in the back, wrist, knees and shoulders caused by incorrect postur during work activities. This study was conducted to determine the level of risk MSDs on operator work activities at the cast house work station. Activities under study are activities; surface repair tap hole, checking temperature iron, and take iron sample. These activities are carried out repeatedly, incorrect work posture and the presence of heat from work environment factors that affect the whole body. This makes the operator complain of pain in parts of the body at risk of developing musculoskeletal complaints. This study was an observational study using the Rapid Entire Body Assessment method and the Nordic Body Map instrumen. The result of the Nordic Body Map instrumen for 20 operators at the cast house work station showed that there were 21 complaints against operator. Based on the measurement of cast house operators the surface repair activity of tap holes has a “high” risk value for MSDs (REBA Score 9), checking temperature iron activities have a “low” risk value for MSDs. Proposed improvement to prevent is to improve the procedur in the surface repair activities of tap holes, where when the process of sticking the dough is done in front of the tap hole is changed by attaching it to the mud gun nozzle tip. After the proposed improvement, the result of the Nordic Body Map instrumen showed no complaints and the measurement of the tap hole had a “low” risk value for the occurrence of MSDs (REBA Score 3).

РОЗРОБКА ЗАХОДІВ ПОКРАЩЕННЯ УМОВ ПРАЦІ ПРИ ВИРОБНИЦТВІ ЧАВУНУ

The article explores the causes of working environment pollution and identifies the sources of harmful and dangerous emissions in pig iron production, along with searching for rational measures to improve the blast furnace cast house aspiration system efficiency to remove toxic gases, dust and exhaust heat. A mathematical modeling methodology for transfer process of molten iron and slag from the blast furnace to the ladle has been employed. The best practice from Zaporizhstal Steel Works on a new aspiration system at blast furnace casting yard laid the basis for the research. An aerodynamic calculation method was used to detect deficiencies in the aspiration system. Statistical method to validate the results obtained was used for constructing of graphs and nomograms. The major causes of inefficiency of the current system of covering iron and slag troughs of a blast furnace casting yard have been revealed, in particular the bypass channel for slag from the main drain trough for molten iron and high local resistance losses on iron and slag distribution (the skimmers). Total and local resistance losses in various areas of drain gutters and aspiration systems have been calculated along with estimating the locations for additional exhaust hood installation, i.e. the special zones for skimmers, the main, transfer and bypass troughs for cast iron and slag. It is proved that by increasing the aspiration efficiency contamination of the working area is reduced, thus improving labour conditions significantly. It is proposed to use modern heat-resistant concrete troughs with higher resistance and longer life service. The proposed modification of trough slabs will facilitate their replacement when carrying out repair works on trough lining and cleaning. An aspiration system model for a typical blast furnace cast house has been developed and explored. The areas and reasons behind the loss of resistance in the exhaust system of hood covering for molten iron and slag troughs are identified. Recommendations to enhance the system efficiency to reduce contamination of the working environment and improve working conditions have been suggested.