Although there have been relatively few major incidents – such as a blade flying off in North Dakota last year –a lot more come under the category of falls and electric shocks such as those caused by arc flashes. According to Wally Tinsley, lead power systems engineer at diversified power management company Eaton Corp, OSHA investigated over 30 arc flash accidents in US wind farms in one year.
Understandably, the industry is giving far more attention to safety. OSHA and the American Wind Energy Association (AWEA) have formed an alliance to improve safety standards. Its purpose is to develop consensus on standardising safety practices, to ensure compliance and to establish training programmes. AWEA has agreed to help OSHA inspect US wind facilities region by region.
Most wind turbine OEMs have joined the AWEA Safety Committee. And with good reason – a rise in accidents could lead to soaring insurance costs and expensive worker's compensation claims. And a poor safety record would fan the fire of the anti-wind lobby.
"The safe operation of wind turbines will be a significant factor in promoting the wind industry," says Grayling Vander Velde an environmental health and safety expert at US utility Duke Energy's wind energy production division in Charlotte, North Carolina. "As companies recognize hazards, they have worked together to reduce or eliminate that hazard. This has allowed the overall safety of the wind industry to continue to improve."
While OHSA efforts will cover the spectrum of possible safety issues, two issues attracting attention are minimising arc flash and at-height rescue procedures.
An arc flash is essentially the release of electrical energy due to an electric arc. It has the potential to cause serious injury or even death.
"Arc flash is a concern for wind turbines due to the limited area in the base of the tower and nacelle, as well as when operating pad mount transformers," says Vander Velde. "For example, the restricted area within the tower would confine any energy produced to that area and to any individuals within the tower."
What is to be done about arc flash? Tinsley highlights the importance of an arc flash hazard assessment to isolate trouble spots so mitigation measures can be instituted. Possible areas of high risk include squirrel cage induction generators, doubly fed induction generators and direct-drive turbines.
"A smart way to mitigate arc flash hazard is through remote access and remote switching," says Tinsley.
Vander Velde concurs. His company has adopted a remote operator design for some of its wind-related electrical equipment to allow the employees to reduce the need to go inside the tower.
"We have also developed computer access that allows the switches to be operated remotely," says Vander Velde. Training is another important facet of any safety programme related to arc flash. Duke Energy, for instance, requires National Fire Protection Association's NFPA 70E training, a standard to promote electrical safety in the workplace, to along with an employee qualification programme.
There is also plenty of arc-flash rated equipment around including headgear, coveralls, gloves, rainwear and even beard nets. But it takes training for employees to recognize the need for it.
By the very nature of the business, most accidents are likely to happen off the ground. So what do you do when a worker is injured a hundred metres up?
"OSHA requires that employers not only protect works from fall hazards, but also have a rescue plan in place for workers who may be suspended from a fall arrest system," says Kevin Denis, training manager at Gravitec Systems Inc. of Poulsbo, Washington, a company that provides fall protection equipment and equipment. "Although there is a regulatory requirement for the employer to provide rescue, there are no specific guidelines for wind industry rescue programmes."
Denis explained that a well-designed fall protection programme would go a long way towards preventing the need for rescue. This begins with personal protective equipment such as hard hats, gloves and safety harnesses and continues into good housekeeping practices like not cluttering up the nacelle with tools, replacement parts or personal items.
Another step in at-height safety is teaching workers to evacuate dangerous areas under their own power. There are many situations where use of the ladder is not an option. For example, a worker may already be suspended below the hub to do blade repair/inspection when high winds make a rapid descent imperative. In those cases, competence is called for in using the various descent control devices available on the market.
Standards are also evolving concerning what is known as high-angle rescue, defined as terrain that has a slope angle of 60 and higher where rescuers are dependent upon ropes. This might involve other wind technicians or emergency personnel and a variety of safety systems. Denis stresses the need for the writing of proper procedures for every wind farm including a fall protection code that clearly outlines the required action for all possible events.
Currently, OSHA rule 1910:66 (f) is fairly general: "The employer shall provide for prompt rescue of employees in the event of a fall or shall assure the self-rescue capability of employees."
The only way to ensure this is by establishing effective training programmes for new and existing employees. "Even though the incidents are infrequent, the potential for high angle rescue is a concern for everyone," says Vander Velde. "Most sites now require all their employees to be trained in a high angle rescue system."
Medical help at height
Some go beyond high angle rescue training and require additional emergency management training such as support for injuries that occur in remote areas. Duke Energy reports great success with the implementation of an Elevated Emergency Management (EMM) programme.
Each year, the company holds an emergency response drill that involves all site personnel and may include off site personnel. This drill is to practice emergency response skills as well as assess existing levels of knowledge. During one of the first such drills, several wind technicians said they felt they needed more emergency medical treatment training. That led to a new safety programme involving one of Duke's wind site managers who was an Emergency Medical Technician (EMT) and a company called Tech Safety Lines of Carrollton, Texas that supplies rescue training and equipment. This team worked together to develop training to address a range of injuries.
The company now provides annual EMM retraining for all employees. This programme deals with such situations as victims being suspended in their harness and needing relief before being lowered to the ground. It is all very well to call a medic. But what if you are 50 miles from the nearest doctor and in a location that can only be accessed along a dirt track? And in any case, rural emergency response teams do not typically have the training or tools to reach a patient dangling from a rotor.
"Emergencies involving a post-fall suspended victim get most of the attention but the larger percentage of up-tower injuries involve soft-tissue or bone and joint injuries," says Brent Wise, a partner at Tech Safety Lines. "Victims suspended in their harness need relief and lowering as quickly as possible, however many up-tower accidents would benefit greatly from medical care before being assisted to ground."
He says that some wind industry safety programmes failed to achieve adequate patient assessment in their procedures for responding to an emergency aloft. A fellow worker might overlook what might be indistinct signs of a serious internal injury such as a broken arm.
"The fractured bone could potentially puncture an artery in the process of a haphazard evacuation attempt — making a relatively serious but manageable injury into a critical if not fatal event," says Wise.
Those completing the EMM programme are able to: ensure scene safety for both the rescuer and the victim; prioritise care for life-threatening injuries; recognize and care for traumatic injures including burns, severe bleeding, electrocution, and amputation; apply moldable splints for injured bones and joints; apply patient packaging and stabilisation; and evacuate a victim with minimal disruption of care.
"Best practices would include an understanding that trained medical help is most likely remote if not altogether unavailable up-tower," says Wise. "Each climber should be capable of assessing a medical event, providing appropriate treatment, and stabilising the injured member until turned over to a medical professional."
The subject of "packaging" was continually stressed by Duke and Tech Safety Lines. What they mean is how to safely harness the person to be lowered to the ground. Tech Safety Lines recommends a device known as a Spec-Pak, which is a combination of a Class III harness and a backboard. It is designed to immobilise a victim and facilitate evacuation with minimal disruption of care.
Wind turbine design
Worker comfort is not necessarily a priority in wind turbine design. Consequently, the wind turbine technician spends much of his or her day in tight spaces. Additionally, many of the components are heavy and have to be lifted in awkward positions. This is added to the repetitive motion of climbing ladders.
"Ergonomics is a very prominent issue within wind turbines," says Vander Velde. "Further studies need to be done in order to determine what action should be taken."
With OSHA scrutinising wind farms all around the US, expect that the next generation of wind turbines will be called upon to improve ergonomics and provide greater built-in safety mechanisms and practices. And older models will probably be required to retrofit improvements or risk being phased out.
Having a wind safety programme is one thing, but it is quite another to get it used by personnel. After all, it is often easier and quicker to do without a harness or don the required electrical gear to avoid arc flash. So how do you get around the urge to cut corners or ignore safety rules for a quick trip up top to perform a two-minute maintenance task?
Todd Karasek, Vice President of EHS at Suzlon Wind Energy Corp, sums it up nicely. "The overwhelming numbers of policies are procedures can sometimes cause staff to ignore the rules or be slow with compliance," he says. "In many cases, complying with safety procedures is difficult, inconvenient, slow and uncomfortable."
His solution is to lay out clear consequences both positively and negatively. This goes beyond just saying that following a procedure will keep you safe and failing to follow it could get you hurt. The way to make such a programme work is to concentrate on the positive.
"Catch them doing something right," says Karasek. "Concentrate on recognizing the right behaviours." But where there is a carrot, there must also be a stick. In this case, Suzlon has created a series of levels of safety violation which have different actions and penalties associated with them. This ranges from written reprimands all the way up to suspension and even termination. Failure to wear arc flash-protective equipment or working under the influence of drugs or alcohol, for example, are grounds for dismissal.
This article originally appeared in Wind Stats magazine