McArdle trials machine proximity alarms on M25 contract

Earthworks contractor and plant hirer McArdle is trialling the use of proximity alarms on machines working on a major contract on London's M25 orbital motorway.

The ZoneSafe system, supplied by mobile automation specialist OnGrade and developed by RFID company Avonwood Developments, comprises antennae located on machines that detect RFID tags carried by workers. If a worker gets too near an excavator or dozer it triggers an audible warning inside and outside the cab.

John Wellard, general manager, McArdle Contracts, told IRN that the trial - on 20 machines on the M25 road widening contract - had demonstrated that "the system changes attitudes to the proximity to machines within days."

"We're on a trial at present, but managers are fully in favour of expanding it. We are getting interest from our clients, the ultimate clients, who are tired of plant and human accidents. I think this is a big step towards changing behaviour."

McArdle has fitted the RFID tags to all of its employees working on the project. The system, as well as warning staff and the operator that they are too near the machine, also logs when and where alarms were set off, and identify the worker involved. This can help identify where further training is required.

Gary Escott, director at OnGrade, said ZoneSafe will cost around £3500-5000 per machine and will be appropriate for excavators and other machines above 12 t in size.

McArdle's John Wellard told IRN that the investment was worthwhile; "The system may last for two machines. And if it prevents one man from being injured then all the costs evaporate." He said the ultimate plan would be to fit ZoneSafe on all 70 of the company's fleet of large earthmoving equipment.

OnGrade showed the system at a recent two-day demonstration event organised by the Construction Equipment Technology Alliance (CETA), a group of four UK mobile automation companies, Moba UK, OnGrade, GKN Technik and Halomec.

See the July-August issue of IRN for a full report on the CETA days event.