Statistics from the USA’s Occupational Safety & Health Administration (OSHA) show that the construction industry suffers more fatalities than any other industry and that crane deaths are the most significant, accounting for 20% of all fatalities. Of these, death by electrocution is the number one killer, accounting for almost 40 percent of the 500 plus crane-related deaths in the ten years to 1994.
Data since that survey was completed indicate that the pattern remains unchanged.
Until recently there was no reliable protection against electrocution by power line contact because insulating links could not withstand power line voltages when exposed to rain or dirt, their electrical protection deteriorated over time, and they were unable to endure lifting loads common in the industry.
However, recent advances in insulating techniques and the use of microprocessors to monitor their effectiveness has enabled us to overcome these conventional shortcomings.
Computer simulations allow a unit to be designed to give levels of protection never previously available. Power devices ensure that testing, recording and alarm features remain 100% functional for two years beyond their permitted warranty period.
Load Monitor, working with some of the leaders in the lifting industry, believes that it is now appropriate to make the use of insulating links mandatory in the construction industry in any circumstance in which a crane may be working in the proximity of overhead power lines.
We have submitted a proposal to the ASME B30 committee which governs legislation for cranes in the USA.
In summary, this is what we have proposed: “In a job site which includes a Danger Zone, all cranes operating within the Danger Zone or which the site manager determines have the capacity to operate within that Danger Zone(s), shall be fitted with insulating links. This requirement extends to all mobile cranes at that job site. The insulating link must have the capacity to self-check at any time during the lift. It must have been tested under conditions that simulate the expected lift environment including appropriate current, voltages and possible contamination. Any current leakage during such tests should not exceed 0.5mA. Furthermore, it shall meet the structural requirements of ASME B30.9.” Should that proposal be accepted the use of insulating links would become mandatory. Even now, operators of lifting equipment near power lines should be asking themselves:
• Do jobsites on which I work have danger zones? Is lifting occurring in a danger zone or could an unforeseen movement cause it to be so?
• Is the site manager aware of his/her responsibilities with reference to power line contact?
• Have we as a company decided whether or not to respond to the change in the state of the art which will be expected by accident investigators, insurers or litigants?
• What can I do to further enhance safe working practices in my company?