Crane boom collapses while lifting turbine nacelle at Swedish wind farm

What happened

The boom of a 750 tonne Liebherr LG1750 mobile crane, reportedly owned by Polish company Viatron, collapsed while lifting the nacelle of a Vestas wind turbine at the Solberg wind farm near Åsele, in Västerbotten, Sweden. The nacelle had only been raised a short distance off the ground when the boom went over the rear of the crane, reportedly after a loud noise and a sudden recoil. The crane operator jumped clear of the cab and suffered minor leg injuries.

Two other workers on the ground also sustained minor injuries; one was taken to hospital for a precautionary X-ray. The crane base itself remained stable after the collapse. The incident occurred around 10:00 am. The wind farm, which will comprise 22 turbines, is being developed with funding from Skelleftea Kraft and Fortum, with Vestas and Arise providing project management services during construction.

Contributing factors

Not officially reported. The crane was working with main boom, regular counterweight and a suspended counterweight, but no confirmed cause such as wind speed, load weight, ballast configuration or lift radius has been published.

Lessons learned

1. A mobile crane boom can recoil over the rear during a nacelle lift, so the operator must have a clear escape path from the cab.
2. Boom failure can occur even with main boom, regular counterweight and suspended counterweight fitted, so each configuration needs independent verification.
3. Ground workers can be hit by a falling boom, so exclusion zones must extend beyond the load drop area to the full boom reach.

More lessons on structural integrity and turbines, worker safety and safe systems of work, from every incident on the register.

Not yet known

• Confirmed cause of the boom collapse
• Wind speed during the lift
• Load weight and lift radius used
• Downtime and repair cost

This entry is updated when these are reported. Get an alert for the next one like it.

Source

vertikal.net