Kimberly critisises HSE Genie Z-135/70 boom safety alert

Kimberly Access has said a safety alert released by the UK's Health & Safety Executive (HSE), stating that all Genie Z-135/70 booms should be calibrated correctly or taken out of service, does not go far enough.

The UK rental company said HSE's advice that the machine's secondary boom angle sensors need to be correctly calibrated does not rule out the possibility of human error. It said it had received expert advice that the addition of an electromechinical safeguard, at minimal cost, could eliminate the risk of error.

"Kimberly has shared this expert advice with the HSE and with Genie during recent months", said the company, "As matters stand neither the HSE nor Genie have indicated formally whether they agree or disagree that additional equipment safeguards are required."

The statement follows a continuing investigation into the collapse of one of Kimberly’s Genie Z-135/70 booms at its depot near London in June last year, in which the operator was killed.

Kimberly said the HSE had not released any specific safety guidance despite the fact that its own investigaton indicated that the boom's stability “may be compromised by the incorrect measurement of the boom angle sensors".

The company said; “It is the opinion of both Kimberly and its independent engineering expert that the installation of the proposed modification is vital in the prevention of further similar accidents involving Z-135/70 machines."

Kimberly said it had still to be established who had calibrated the sensors "incorrectly" on the machine that collapsed last year and under what circumstances.

Genie’s safety notice on 29 July 2013 emphasised the importance of ensuring that the secondary boom angle sensors are calibrated correctly.

The rental firm grounded all of its Z-135/70 machines immediately following the accident, and said they will be kept grounded until the company’s concerns over safety issues have been addressed and the machines have been suitably modified.

The Kimberly statement adds, “Calibrating the secondary boom angle sensors incorrectly is a human error, which Kimberly’s independent engineering expert considers can compromise the machine’s overturning stability.

“In short, calibrating the secondary boom angle sensors incorrectly can allow the secondary boom to start to extend before it has elevated fully, which can take the machine outside its stability envelope.”