HSE Research reveals key factors in preventing telehandler overturns
Research report RR1085 Exploring the human and physical factors associated with telescopic handler overturning risks has been published by HSE. The report reveals that a combination of machine instability and various human factors elements are important precipitating factors in telescopic handler overturn incidents.
The HSE authors state that 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”.
The research was undertaken to identify:
- Potential factors – the full range of human factors issues that might potentially contribute to telescopic handler overturn incidents;
- Most important factors – the human factors issues that appear to be most important in terms of overturn risk and
- Knowledge gaps – key operator knowledge gaps that could increase the probability of an operator overturning a machine.
Key messages identified by researchers
The researchers summarise the key messages of the research as follows:
- Boom position – a telescopic handler overturn is more likely to occur when a machine boom is raised and / or extended. Operating a telescopic handler with an extended/raised boom, regardless of whether loaded or not, presents a risk, particularly when a machine is used on uneven or unstable ground;
- Lateral stability – incident data shows that overturn incidents related to lateral instability have a higher probability of occurrence than overturns due to longitudinal instability. Telescopic handlers are, therefore, more likely to overturn in a sideways direction (lateral instability) rather than tipping forwards (longitudinal instability) because of a shift in a machine’s centre of mass;
- Operator knowledge – as some operators were not aware of the overturn risk related to lateral instability, this implies the possibility of a knowledge gap among operators;
- Ground conditions – challenging ground conditions (e.g. soft, sloping and uneven ground) are associated with lateral overturns;
- Training and supervision – weaknesses in training and site management/supervision are likely to increase the risk of an overturn incident; and
- Technical solutions – the installation of lateral instability warning technology, and improving or supplementing visibility from the cab, could reduce overturn risks by warning operators of dangerous situations before a critical threshold is reached.
See HSE Guide The safe use of vehicles on construction sites: A guide for clients, designers, contractors, managers and workers involved with construction transport which contains practical guidance on how to prevent on-site vehicle accidents.