Mobile Elevated Work Platforms (MEWPs) are used in a range of industries for working at height activities. Entrapment of the operator between part of the MEWP basket and a fixed structure is a significant hazard which can lead to serious injuries or death unless effective control measures are in place.
Manufacturers have developed a range of secondary guarding devices designed to supplement the machines primary safeguards and further reduce any entrapment risk and/or raise the alarm of entrapment events. The two most common types of secondary guarding devices available are: pressure sensing devices, and physical barriers to create a protected zone. However, as of 2022, there is no common standard to assess their performance.
This HSE report describes a study to analyse MEWP entrapment incidents and carry out an engineering and ergonomic appraisal of the protection provided by the main current types of secondary guarding devices.
The researchers analysed 58 incidents and used these to create and validate potential incident scenarios using computer modelling. The researchers identified that the level of protection for the operator depends on the incident scenario. For some scenarios, physical barriers would be likely to protect an operator standing within the potential protective zone: for other scenarios, little or no protection would be given.
Additionally, there may be entrapment scenarios where a pressure sensing device may fail to activate, for example the operator may get into a trapped position over the controls without making contact with the pressure sensing device.
Pressure sensing devices are unlikely to protect a second occupant in the platform, says the report. However, some of the physical guards may do so in some scenarios.
This report will be of interest to MEWP manufacturers, MEWP hire companies, MEWP users, and individuals with an interest in MEWP use. It is based on studies carried out between 2015 to 2020.
HSE December 2022
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