2017-02-01 12:00 - Messages

Safety of industrial machinery in reduced risk conditions

Industrial machines are known to possess many hazards. One machine safety design requirement found in the machinery directive in Europe, national or provincial legislation in North America, as well as national and international safety of machinery standards is the control mode for maintenance when guard or protective device has to be displaced or removed. One of the conditions is that the control mode permits operation of the hazardous elements only in reduced risk conditions. This condition presents some challenges to designers and users alike. What are considered reduced risk conditions is open to interpretation. The objectives of this study were to identify values for safe reduced speed, safe kinetic energy and safe contact pressure from the literature and from enterprises and to identify the factors influencing the choice of values. It was found that values for reduced speeds, force, energy, contact pressures varied widely. Industrial visits showed that enterprises use reduced speeds by switching to the reduced speed mode of operation without applying the other required conditions. Machines were modified to incorporate this mode of operation indicating some design problems. Some factors were identified which could guide the choice of values when the information is missing from standards or other documents. When a safety standard exists for a particular machine and that the values are specified in the standard, designers and users can use those values. However, if the machine has no safety standard, a risk assessment is needed before deciding which values to use.

Source: Chinniah, Y., Aucourt, B., & Bourbonnière, R. (2017). Safety Science, 93, 152-161.

Forklift truck reverse sensor systems assessment

Counterbalance forklift trucks (FLTs) are widely used in a variety of industry sectors for material handling. Incidents involving FLTs are typically vehicle/pedestrian, vehicle/vehicle, or vehicle/structure collisions. Of these, vehicle/pedestrian incidents have the most potential for reportable injury and around 500 incidents a year involving moving FLTs are reported to HSE.
Measures to improve or augment the operator's field of vision can include: mirrors and CCTV systems (which rely on the operator's observations) and sensor systems (including ultrasonic, radar, and Radio Frequency Identification (RFID)), similar to those commonly fitted to passenger vehicles; or simply improving the driver's operating position.
This report describes work undertaken to assess the active sensor systems (ultrasonic and radar) commonly used to reduce the risk of collisions. The systems tested appeared to provide a useful function in mitigating the risk of collision by stopping the truck when an obstruction was detected. However, certain configurations produced blind spots in the detection zones that could allow a pedestrian to approach the truck without being detected. The sensors also needed to be mounted to give an appropriate detection zone without producing a large number of false detections.

Source: http://www.hse.gov.uk/research/rrhtm/rr1084.htm

Exploring the human and physical factors associated with telescopic handler overturning risks

A combination of machine instability and various human factors elements are important precipitating factors in telescopic handler overturn incidents. Industry guidance makes a number of assumptions about the impact of operator “knowledge gaps”, however the link between operator knowledge gaps and overturn risk is, at present, hypothetical and remains empirically untested.
This study was done to identify:
- the full range of human factors issues that might potentially contribute to telescopic handler overturn incidents;
- the human factors issues that appear to be most important in terms of overturn risk and
- key operator knowledge gaps that could increase the probability of an operator overturning a machine.

Source: http://www.hse.gov.uk/research/rrhtm/rr1085.htm

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