Environmental Engineering Reference
In-Depth Information
of the turbine. He then positioned all three blades to the maximum wind-resistance
position and closed all three energy isolation devices on the blades. The devices are
designed to control the mechanism that directs the blade pitch so workers do not get
injured while they are working in the hub. Before leaving the confined space, the
worker did not return the energy isolation devices to the operational position.
As a result, when he released the service brake, wind energy on the out-of-position
blades created an “overspeed” condition, causing one of the blades to strike the tower
and the tower to collapse, the Oregon OSHA investigation found. Chadd Mitchell,
who was working at the top of the tower, died in the collapse. William Trossen, who
was on his way down a ladder in that tower when it collapsed, was injured. The third
worker was outside the tower and unharmed.
During the investigation, Oregon OSHA found several violations of safety rules:
• Workers were not properly instructed and supervised in the safe operation
of machinery, tool, equipment, process, or practice they were authorized
to use or apply. The technicians working on the turbine each had less than
two months' experience, and there was no supervisor onsite. The work-
ers were unaware of the potential for catastrophic failure of the turbine
that could occur as a result of not restoring energy isolation devices to the
operational position.
•
The Company's procedures for controlling potentially hazardous energy
during service or maintenance activities did not fully comply with Oregon
OSHA regulations. Oregon OSHA requirements include developing, doc-
umenting, and using detailed procedures and applying lockout or tagout
devices to secure hazardous energy in a “safe” or “off” position during ser-
vice or maintenance. Several energy isolation devices in the towers, such as
valves and lock pins, were not designed to hold a lockout device, and energy
controls procedures in place at the time of the accident did not include the
application and removal of tagout devices.
•
Employees who were required to enter the hub (a permit-required confined
space) or act as attendants to employees entering the hub had not been
trained in emergency rescue procedures from the hub.
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As shown in Case Study 2.1, wind energy employers need to protect their workers
from workplace hazards. Workers should be engaged in workplace safety and health,
and they need to understand how to protect themselves from these hazards. Even
though the wind energy industry is a growing industry, the hazards are not unique,
and OSHA has many standards that cover various worker on-the-job activities and
exposures. The hazards (along with controls) that workers in wind energy may face
are provided in this section.
Working around, with, or on wind turbines and associated equipment presents
many hazards to the installers, operators, and maintenance personnel. The hazards
along with applicable OSHA standards and controls include the following:
