25.03.2008

BHP introduces dead man check

Australian mining company BHP Billiton Iron Ore has introduced a new quarterly check list for any aerial lifts that are used on its sites.

Any boom or scissor lift used on a BHP project must we fully inspected according to the company’s own checklist. Once a machine has been signed off as complying with the check list a dated sticker is applied with a three month duration.

The check list has been implemented following incidents at its locations in Nelson Point and Area C in the Pilbara region, where operators struck an overhead obstacle and were pressed against the control panel and unable to stop the lift from crushing them.

One incident involved a boom, while the other was a scissor lift that also trapped the second occupant between the guardrails and the overhead structure.

BHP is insisting that all machines are fitted with a protection bar above the controls to help prevent an operator’s body being pressed into the controllers in such a situation. It is also checking the dead-man controller – whether this be a foot pedal, locking detent or trigger mechanism.
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A top bar suich as this one on a JLG Boom, is what BHP is looking for

In addition to the inspection sheet BHP has introduced a set of operating procedures for its staff which includes the insistence that those working at ground level where aerial lifts are being used are knowledgeable about the ground based emergency descent controls.

Vertikal Comment

When individual companies begin to implement their own inspection criteria it is a sign that the industry has failed.

Each year a few accidents such as the above occur and all too often they are fatal. BHP would have been exceptionally unlucky to have experienced two such incidents in a short space of time. However while they are relatively rare they do occur on a consistent basis, usually when an operator drives into an overhead obstacle behind him which then presses him against the controls which either keep the machine moving or even raise it into the obstacle.
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Aichi's new boom includes both a top bar and separate covers over each controller

At the same time those working on the ground rarely know how to bring the machine down quickly so any chance of saving the individual are lost.

Controls such as those with only a timed enable button which leaves the controls live as long as the operator has been using them within the previous few seconds. With such controls there is no easy instinctive way for the operator to stop the machine.

A foot pedal, joystick trigger or separate side mounted button that must be applied at all times would seem to be better, however the foot pedal with a cover has also been criticised in the past.
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A rare cover over a scissor lift controller on Aichi's new global range

Some form of bar above the controls also makes good sense and most, if not all manufacturers of boom lifts do now incorporate them.

Surely it is time for the industry as a whole to look at this subject in more depth and propose some solutions? Perhaps the controls need to be tested their ability to avoid such accidents when they are submitted for regional certification such as CE marking?

In fact the EU Machinery Directive calls for such risk assessments and while most manufacturers have now incorporated such protection into their boom lifts, few have done so with their scissors where it can be argued the risk is greater.

This should be the subject for an industry wide review perhaps under the auspices of IPAF?

If the EN280 vertical and review committees would not allow themselves to be high jacked by overzealous inspectors with wild and irrelevant agendas, it could be concentrating on useful subjects such as this one.