A Safe Descent

Building or maintaining a wind farm can be a tall
order, especially when crew members need to scale
soaring turbines. When working on a wind project,
preparations should be made in the event a rescue
situation occurs. A single rescue system cannot
efficiently handle every scenario an authorized
rescuer may encounter in the wind energy industry.

A Safe Descent: Selecting a Rescue System
for the Wind Energy Industry

By William Wright

Building or maintaining a wind farm can be a tall order, especially when crew members need to scale soaring turbines. When working on a wind project, preparations should be made in the event a rescue situation occurs. A single rescue system cannot efficiently handle every scenario an authorized rescuer may encounter in the wind energy industry. One system may perform well for one application but not another. Some rescue systems are easy to use for one application, while others require more skill but can be adapted for use in multiple situations. Wind turbines in North America simply come in too many different styles and designs to have a one-unit-fixes-all rescue solution. In this way, rescue systems are analogous to vehicles; the basic function is similar, but depending on the road, some outperform others.

Regardless of the turbine “road” you must travel, all turbines require technicians to climb them to perform maintenance. In the event of a fall, OSHA (1926.502(d)(20) of Subpart M) mandates a “prompt” rescue of the victim. Choosing a suitable rescue system for different types of turbines can be a daunting task for employers.

Instead of asking, “What is the best rescue system for the wind industry?” consumers should ask, “What is the best rescue system for my turbine?” Regardless of your choice, the system you choose should have the ability to raise, lower, drag and evacuate. It should also be operational by one person because many turbine rescues will involve the rescuer and the rescue subject only.

Examining the functions and capabilities of various rescue systems on the market, along with anchor point recommendations for these systems, is important in the selection process. The complexity of training required to operate a rescue system is also a factor. Regardless of the manufacturer, type, operation, color or construction method, the vast majority of rescue systems can be divided into two categories: automatic descent control devices and manual descent control devices.

AUTOMATIC DESCENT CONTROL DEVICES

This family of automatic descent control devices is also known as rescue wheels. Tractel’s Derope Up E, SKYLOTEC’s MILAN, DBI-Sala’s Rollgliss R500 Descender and ResQ’s REDPro all fall into this category. These devices usually have a fixed mechanical advantage with a 4-to-1 lifting ratio. They are typically operated by turning a wheel toward the direction of travel intended, indicated by “Auf” and “Ab” stamps on the wheel, which simply mean “up” and “down,” respectively. Automatic descent control devices excel in scenarios where the evacuation and rescue is linear, so that there is always a line of sight to the anchor point. Simple to use and operate, the pre-loaded 3/8-in. rescue rope is strong enough to support one- or two-person descents from 300 to 1,300 ft.

Automatic descent control devices allow an automatic descent rate between 2.8 and 5 ft per second, depending on the manufacturer. If overhead anchor points are available, automatic descent control devices are typically the quickest, most effective and simplest rescue devices on the market for emergency evacuation and rescue. The cost of these automatic descent control devices generally ranges from $1,300 to $3,200.

MANUAL DESCENT CONTROL DEVICES

Manual descent control devices make up the second family of rescue systems. They usually include rope, pulleys and progress capturing devices. Some also have short haul systems used for lifting heavier loads. Manual descent control devices require a higher level of user participation from the rescuer. Unlike the automatic descent control devices used during self- or assisted-lowering where the user can rely on the automatic braking mechanism for descent control, the manual devices require an authorized rescuer to continually control the rate of descent.

Manually operated rescue systems for the wind energy industry fall into one of two categories: block and tackle systems or pre-rigged rope systems. Products such as Miller’s Series 70 universal rescue system, MSA’s Suretyman rescue utility system and DBI-Sala’s Rollgliss Top R350 are block and tackle systems. They generally operate in either a 2-to-1, 3-to-1, 4-to-1 or 5-to-1 configuration and are only practical for distances under 100 ft. The higher lifting ratio allows for easier lifting compared to automatic descent control devices.

However, they can require up to five times the length of rope. They also require an overhead anchor point and do not work well over edges. The advantage of block and tackle rescue systems is that lifting and lowering are accomplished without an add-on pulley kit, reducing the possibility for user error when lifting — making it the likely choice when performing suspended pick-offs. The cost for block and tackle systems ranges from $600 to $2,000 and is usually determined by the working length of the system and the lifting ratio.

Pre-rigged rope systems are distinctly different from block and tackle systems. They typically consist of a single rope used for lowering and a compatible lowering device. Most systems of this variety have an additional short haul (pulley) add-on for an increased mechanical advantage when lifting. Unlike block and tackle systems, pre-rigged rope systems can navigate corners more easily. The single line also prevents rope entanglement and length requirements are less than those for a block and tackle system.

Gravitec’s G4 Wind Turbine Rescue and Evacuation System is one of a handful of systems that use pre-rigged rope.

These systems are an assemblage of components from a number of different manufacturers and may come equipped with edge rollers or protectors for navigating rope over sharp edges. They may also include descent devices with anti-panic features, industrial quality anchorage connectors and a host of other accessories. This category of rescue systems generally is the most versatile, lowest in price ($800 to $1,800) and best-equipped for more technical rescues. They do, however, require a higher level of training.

RESCUE SYSTEM TRAINING

Wind turbine technicians typically do not have the same caliber of training as an emergency rescue response team, therefore the duration and complexity of rescue system training needs to be considered. Because a rescue event creates a high level of anxiety and apprehension, the rescue techniques should be effective, yet easy enough to remember. A rescue system is useless if the rescuer is unable to operate it.

There is no magical equation to determine the appropriate length of rescue system training. Competent rescuers can begin to make this determination during the initial rescue assessment when they identify all the possible locations where a worker might require rescue or evacuation. Identifying these locations will also help competent rescuers determine the necessary functions of their rescue system.

Rescue system training should instruct the user on the system’s components and capabilities and include scenarios that closely simulate the real-life rescue event. Training should always include an observation of performance. On average most rescue training lasts between two and five days. The ANSI/ASSE Z359.2 standard provides direction on the content of authorized and competent rescuer training.

A PROACTIVE APPROACH TO RESCUE

Unlike emergency responders who must react to the situation at hand, employers in the wind energy industry have the opportunity to be proactive if they engage in pre-planning for rescue and evacuation. During the work planning phase, competent rescuers should perform detailed hazard surveys and write rescue procedures for those areas where hazards exist in an effort to address and abate all fall hazards. This will give them the upper hand in a rescue event.

The nature of the work, the anchor location, the working load and limit and ease of use should be factors in determining the appropriate rescue system. Relying on an internal competent rescuer to make an informed choice based on these factors is a much more effective way to protect workers than basing the decision on the purchasing habits of other consumers. There’s simply no such thing as the “best” rescue system for the wind energy industry. Individual companies should always select rescue systems that best address their specific needs.

ABOUT THE AUTHOR

William Wright, Training Coordinator for Gravitec Systems, Inc.