HSE is issuing this safety alert to highlight the dangers of using top cutting machines in trench preparation without appropriate safety devices. The information is aimed at dutyholders within the construction and utilities industries and is intended to raise awareness of the potential risk of entrapment when accessing the cutting drum.
HSE is investigating an incident where a worker was fatally injured when he became entrapped between the cutting drum and housing. As part of the investigation it has come to our attention that a number of the safety devices used on the machine to prevent access to the drum while in motion may not be working in the manner originally intended by the manufacturer. The EN standard for trench cutters (EN 474-10) requires a deactivation device which “shall stop machine travel and attachment movement when the operator leaves the operator's station" - for mobile trench cutters this device is generally linked to the drivers' seat.
Provision and Use of Work Equipment Regulations 1998 give employers a legal duty to ensure that work equipment is maintained in an efficient state: this includes all safety devices attached. Any safety device fitted to the machine should be checked to ensure that it is in full working order and brings the rotation of the drum to a standstill within an appropriate time to prevent access and injury. If it does not, the device should be adjusted or repaired.
In addition operators should ensure that the power is disconnected and movement has stopped before approaching the machine to carry out any maintenance on the cutting wheel and pick attachments.