By following basic procedures and using the right equipment and safety features, safe working at heights can be achieved.
Access is usually gained by climbing up the inside of the turbine, and the worker abseils from outside the nacelle. Rope-access workers must be specially trained and kitted out with suitable clothing, full body harness and fall-arrest lanyards. A rescue kit should be carried, with pulley or winch and telescope rescue pole. At least one other person should be on the ground, to be able to call for help or come to the rescue. Ideal for intricate work or inspection of blades or tower.
Mobile elevated work platform
A purpose-built, guarded platform that extends on the arm of the aerial lift vehicle. Aerial platforms, like the one below, include controls that the personnel on board can use to manoeuvre around. The operator should wear a body harness or restraining belt with lanyard attached to one of the harness points, and be properly trained.
Aerial lift vehicle
These vehicles provide the base for the mobile elevated work platforms. The extended arms, often telescopic, or articulated, lift the work platform up the side of the turbine to the nacelle or the blade. Limited by the height they can reach - currently around 110 metres. Outriggers extend from the vehicle base to increase load and reach capabilities. Hard-standing is often required to ensure level and stable siting.
Man basket for crane
When a crane is already on site for lifting heavy equipment, it is often considered an option to use a separate cage for lifting personnel high on the turbine. These baskets are hooked to the crane and hang free. But, it is not such a simple solution, says Julian Hubbard of developer RES. "Cranes are primarily designed for lifting materials, components, etc, and different certification may be applicable when lifting personnel." Man baskets have no controls for the personnel on board, can be more at risk from the vagaries of winds, and are therefore better suited for simple personnel transfer than for work.