Vol.22, No.3, 2022, pp. 339–346
UDC:

According to available literature, safety at work and productivity of cranes are a necessary and insufficiently researched topic. Both research directions are closely related because they depend on the number and type of stoppages that occur during operation of these construction machines. The focus of research should be on identifying the stoppages that can have fatal consequences for employees on-site, or unintended consequences in terms of production loss, means of work, or environment. In the present research, an attempt is made to create a methodology for identification, analysis, assessment, classification, and calculation of stoppage risk in cranes (classified by categories and causes). Criteria used for analysis, assessment, and calculation of stoppage risk: degree of stoppage danger, frequency of stoppage classified according to stoppage categories/causes, and downtime according to the adopted classification. Experimental research on a sample of 1,091 stoppages recorded on several cranes over a longer time interval has confirmed the hypothesis of generating a 3-criterion matrix for stoppage risk assessment sensitive enough to prioritise key crane stoppage in terms of risk. Results of experimental research indicate mechanical downtime of 16.22 %, a frequency 45.35 % in downtime, and RPN number 80, at hazard level 10. Selectively, according to the cause of stoppage, the results indicate that the hoisting brake (6.48 % downtime at hazard level 10; 2.14 % stoppage frequency) and hoist gear/tooth breakage (5.29 % downtime at hazard level 10; 3.58 % stoppage frequency) are key mechanical causes of stoppages and crane risk generators. By mitigating the given risks, it is possible to improve safety and increase productivity.

Keywords: crane, risk assessment, stoppages, downtime analysis, risk matrices