Wind-turbine technicians face unique hazards, natural and man-made, on worksites that have caught the attention of safety professionals worldwide. Fine-tuning commonplace Personal Protective Equipment (PPE) to the work environment and educating techs on strategic climbing techniques that reduce fatigue have been solidifying factors in reducing injuries. A combination of fall protection, ergonomics, head protection, and targeted hand protection can make wind-turbine maintenance less harzardous.
Jennifer Choi / Vice President of Marketing / Cestusline Inc
Wind-turbine technicians are at times subjected to unusual occupational safety hazards. While fall protection is a top concern, the industry is taking a second look at why techs initially lose their grip, hand positioning while climbing tower ladders, and recent developments in wind-energy safety practices to reduce worksite injuries.
Natural wind-energy hazards
While working at height, turbine operators face many hazards beyond fall protection. For instance, the wind itself is a natural hazard. “Wind gusts in the nacelle have the potential to affect balance in severe wind environments,” said Russell Cook, EHS Training Manager at the Siemens Wind Service Training Center in Orlando. “Wind speeds may vary anywhere from a five to 20 meters per second, depending on site, weather and terrain.”
For workers servicing the nacelle, there is little shelter from the wind. “Wind speeds at the top of the towers can double that at the base,” said Vernon George, a seasoned wind-energy professional. “The towers are designed to sway a little to prevent cracking the structure. Most days, wind inside the tower is not a factor, however, if the winds are gusting at 35 to 45 MPH, you can feel the tower moving from the inside.”
Ambient temperatures also pose a threat. Working in the field, technicians see temperatures range from below freezing up to 110°F. Harsh cold temperatures can cause numbness, slower reaction speeds, and a limited range of motion, which affect the safety of a worker despite any safety precautions. Towers are not subject to the elements themselves, but most are not climate controlled. “All sites have a heat index gauge. If the temperatures are too high or too low, maintenance workers are restricted from climbing, barring an emergency situation,” adds George.
Standard wind-turbine towers stretch to heights up to 100m, without a platform or netting. George noted recent changes in OSHA standards that require securing tower ladders farther from the tower wall than before. Technicians in the past would lean their backs against the tower walls to steady themselves when adjusting wires or to rest. This change to the inner tower design and the way ladders are secured in the new standard forces techs to adjust their hand positioning as they climb.
The design of the ladder rungs is a blessing and a curse. The grooves in the aluminum rungs can withstand greater weights and allow for superior traction for feet as workers ascend and descend. They are, however, unforgiving to hands over the course of 293 rungs to the top.
Climbing tips to maximize grip
Over his 15+ years in the industry, George has found that rung climbing causes a lot of fatigue, especially on the pinky and ring finger. Prolonged exposure to this repetitive outer palm impact can have effects ranging from bruising and tenderness, to carpal tunnel syndrome. Many technicians find it less tiring to hold the side rails of the ladder as they climb. The new way the ladders attach to tower walls can break up a climber’s rhythm, but they will notice a reduction in palm impact injuries.
Both George and Cook agree that the key to safely climbing is to maintain a steady pace without rushing or trying to skip rungs. In summer months, technicians are advised to watch out for sweaty palms and to try to keep their hands dry, even when wearing gloves.
Fall protection saves lives
In the U.S. construction industry, falls are the leading cause of worker fatalities. On average, between 150 and 200 workers are killed and more than 100,000 are injured each year as a result of falls at construction sites. Fall protection is a safety concern for any jobsite where workers are at elevations. According to OSHA standard 29 CFR 1926.501(b)(1): Each employee on a walking/working surface (horizontal and vertical surface) with an unprotected side or edge which is 6 feet (1.8 m) or more above a lower level shall be protected from falling by the use of guardrail systems, safety net systems or personal fall arrest systems.
In response, fall-arrest systems have become the norm in this industry. These systems require a substantial amount of training for newcomers and attention to detail before initiating any maintenance work. Human fall arrests involve a series of slide traps that give workers a back-up plan should they lose grip at height. The advent of magnetic bottomed bolt bags, tool lanyards and other safety innovations additionally protect workers at ground level from tools dropped from height. The force of a 1.8 pound wrench dropped from a height of 175 feet can be lethal by the time it hits the ground. The development of fall protection for people and tools has saved many lives.
Wind-energy outsiders are often overwhelmed at the new products the safety industry has developed to prevent not only human falls but the equally dangerous drops of equipment and tools from height. According to the U.S. Emergency Department records and Bureau of Labor Statistics, in the U.S alone it has been reported that 36 people died in 2010 from falling objects and about 28,000 injuries are reported each year from fallin
Head protection that is looking up
Hard hats are synonymous with any maintenance industry to protect against objects impacting the head from above. Turbine techs spend a good portion of the day looking up. When they do so, a hard hat with a full rim can impede the natural range of vision. A worker tends to compensate for this blockage by tilting his head further back or leaning further away from the ladder. This can lead to reduced grip or neck strain.
The initial solution to preventing hard-hat drop hazards was installing uncomfortable chinstraps. However, wind-energy technicians have been quick to embrace bump caps as a reasonable compromise for head-impact protection. This reduces the potentially uncomfortable chinstrap and reduces neck strain because of its better visibility when looking up.
The top rung of hand protection
Many wind-turbine towers feature climb assists for safety and ease, but in the end, no one wants to lose grip and rely on these secondary protections. While fall protection is the number one safety device people think of when working on towers, the loss of grip that leads to falls is often not explored. Climbing gloves are growing in wider use for good reason, as safety managers realize that preventing the loss of grip originates from the hand.
A substantial amount of grip is needed when ascending a vertical climb of 200 to 300 feet. Despite the wind turbine’s development over time, the gloves that maintenance workers wear at sites around the world have remained almost unchanged. To date, there are no OSHA standards for hand protection in the wind-energy industry.
Currently, wind-turbine operators use two types of gloves during their climb and maintenance. To keep a strong grip while climbing, operators will use a heavy- duty, non-slip glove that aids in climbing the ladder. Once in the nacelle, techs will switch to high-dexterity, dipped-style gloves that allow for maximum tactile sensitivity between thumb, forefinger and middle finger. This aids in using tools, handling small parts such as nuts and bolts, and lets the operator feel what they are doing.
The latest developments in hand protection have been overlooked by the wind-energy industry because many gloves in the market today tend to focus on the wrong side of the glove. “The guys use gloves to climb. They need a padded palm and warm hands,” said Dale Coyle, Wind Asset Manager at the Bigelow Canyon Wind Farm. “The ladders are aluminum, and they have grooved rungs. We have noticed flat-palmed gloves quickly wear out.” The latest glove trend in dorsal impact protection does not address the impact and abrasion workers face while climbing to the top.
When shopping for gloves, look for a high dexterity glove to reduce hand fatigue on the journey up and down the tower. The flexibility of the glove can directly impact the level of grip a worker exerts. Many accidents tend to occur toward the end of shifts when hand strain is at its worst.
The addition of palm padding helps reduce vibrations from the aluminum ladder and bruising on the heels of hands from the repetitive impacts of the climb. There is a delicate balance between the thickness of the palm padding required to dampen impact and vibrations, and the thinness required to comfortably flex fingers to maintain grip control.
Another important factor is breathability. Sweaty hands slipping within the glove can lead to loss of grip. A breathable glove will keep hands from growing numb in cold weather or growing slick from sweat in warm conditions.
A snug fit will do a better job of keeping hands warm, reduce slipping and provide increased dexterity than a loose fitting glove. The light insulation and compression of a snug fitting glove is a main recommendation from healthcare practitioners when discussing Hand-Arm Vibration Syndrome (HAVS) prevention. This should be combined with rotating job duties when possible and taking regularly scheduled breaks.