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In order to prepare a research project a study was conducted in the pulp and paper industry. The identified problems were around the risks associated with the design of control systems. The investigation suggested that a training program was the best mean to improve the design in order to reduce the risks associated with the considered machinery. This training program would be oriented toward personnel who design or prepare specifications for control systems. This paper will present the result of the study, which will be materialized in the project currently carried out throughout the pulp and paper industry in Quebec.

Performance of experienced crane operators in stopping rotational movements of a crane platform was compared with that of an automatic braking system. Sixteen certified crane operators performed boom movements towards a segment of a typical power line using a 100 tons lifting capacity crane equipped with a fixed-length 18 m long boom, a single lifting cable, and hard ball hook. The 18 m boom was later replaced with a 49 m boom to vary crane geometry and motion response. In all trials, a 1500 kg (3500 lb) load was hooked to the lifting cable. In critical operating conditions, the control input strategy used by the experienced crane operators could yield a stopping angle comparable to that of the automatic braking system. However, when compared with the automatic braking system, the operators had a better control on the oscillations of the load during the stopping maneuver. The data collected in this experiment were used to specify two key parameters in the design of a crane movement limiting device.

Sixteen certified crane operators performed several series of boom movements toward a segment of a typical power line using a 100-ton lifting capacity crane equipped with an 18-m boom, a single lifting cable, and a hard ball hook. The operators were instructed to stop the crane movement when the lifting cable reached the edge of the danger zone located 3 m from the power line. To achieve each maneuver, they evaluated the distance between the nearest wire and their crane using two methods: free sighting and the use of highly visible markers delineating the edge of the danger zone. The dependent measure was the distance between the lifting cable and the edge of the danger zone. Results showed that operators were generally unreliable when judging the distance between their crane and the power line when sighting the power line directly, but the use of markers proved to be much more precise and reliable in targeting the edge of the danger zone.

Limit switches are present throughout process control systems. Being classical components, their operation is taken for granted. However, an inappropriate choice may jeopardize the reliability and the safety of a production process. To achieve maximum safety and reliability, selection criteria for limit switches can be defined which go beyond simple operational criteria. This is possible mainly because of techniques and standards originating in Europe which deal with such things as positive opening of contacts, fail-safe condition and automatic monitoring.

Reports or summary accounts of accidents by electrocution occurring when machines come in contact with powerlines have been analyzed from several aspects. These accidents occurred in Quebec, Ontario, the United States and France. The type of involved equipment could be classified into 8 recognized types. Other analyses were carried out that considered mainly the occupation of the workers affected, the severity of the accident, the part which came in contact with the powerline and the voltage of the powerline. Based on this analysis, some specific factors have been recognized in six categories of equipment which have helped to describe some typical accidents for each category of equipment. This study can be used to define a priority for the prevention of, and the strategy against accidents resulting from contact between machines and powerlines. This prevention should take into consideration the technology of the machines involved.

Several means are known to improve the safety of PLC-controlled machines or processes, but no comprehensive standards exist, and safety is often left to system designers. Here are some basic measures that can be taken to minimize the risks of accidents or system failures.

To assess and plan future risk-analysis research projects, 275 documents describing methods and tools for assessing the risks associated with industrial machines or with other sectors such as the military, and the nuclear and aeronautics industries, etc., were collected. These documents were in the format of published books or papers, standards, technical guides and company procedures collected throughout industry. From the collected documents, 112 documents were selected for analysis; 108 methods applied or potentially applicable for assessing the risks associated with industrial machines were analyzed and classified. This paper presents the main quantitative results of the analysis of the methods and tools.