Exposure to fall hazards can lead to serious injuries and fatalities.
The Occupational Safety and Health Administration (OSHA) standards for fall protection require that workers be protected from falling 4 feet or more in general industry (1910.28(b)(4)(i) and 6 feet or more in the construction industry (1926.501(b)).
There are four primary strategies used to prevent fall-related injuries and fatalities. These strategies comprise what is known as the Hierarchy of Fall Protection.
The strategies at the top of the hierarchy are more effective than those at the bottom.
Each step down the hierarchy is a less favorable method.
Personal fall arrest is the least effective method for addressing fall hazards. This does not mean that it is not effective in situations where the other methods are unfeasible.
Elimination, passive fall protection, and fall restraint use methods to eliminate or prevent a fall while fall arrest stops a fall that has already occurred.
A personal fall arrest system has three main components: an anchorage, body-wear, and a connecting device.
OSHA requires that anchors used for fall arrest are capable of supporting at least 5,000 pounds per employee attached or designed, installed, and used, under the supervision of a qualified person, as part of a complete personal fall protection system that maintains a safety factor of at least two.
Finding a suitable anchorage point can be challenging in many situations, often leading workers to make a judgment on whether an anchor point is suitable or not.
Preventing swing falls. In addition, many situations make it difficult for the anchor point to be located directly above the head. In the event of a fall, the worker may be subjected to swing fall hazards.
Swing fall is a pendulum-like motion that occurs when a worker moves in a horizontal direction away from an anchorage. This pendulum effect may cause workers to swing into adjacent structures and equipment, resulting in serious injury.
Body harnesses. Body wear, such as a body harness, is a critical component of personal fall arrest. During the arrest phase of the fall, the body harness distributes the fall arrest forces over the thighs, pelvis, waist, chest, and shoulders. The forces associated with a 200-pound worker falling 6 feet can result in up to 1,200 pounds of force across the body.
Avoiding suspension trauma. Use of energy-absorbing connectors can reduce this amount significantly, but the risk of injury still exists. In addition, suspension trauma may occur when a worker falls while wearing a body harness.
After the fall is arrested, the worker’s body will be supported in an upright position with the legs dangling. The body harness straps compress the leg veins, reducing blood flow back to the heart. Without muscle contraction in the legs, blood flow to the heart will slow and a person may lose consciousness.
Prolonged suspension can result in serious physical injury or even death within as little as 30 minutes. For this reason, it is important that companies have a defined fall rescue plan requiring that workers using personal fall arrest never work alone.
Connectors, such as energy- or shock-absorbing lanyards, reduce the amount of energy transmitted to a worker’s body as well as provide deceleration distance.
Deceleration distance must be accounted for when using a personal fall arrest system. Consider a 6-foot-tall worker using a 6-foot energy-absorbing lanyard with 3-1/2 feet of deceleration distance and a safety factor of 3 feet. The connector is attached to the dorsal D-ring and an anchorage above the head.
This results in a total fall distance of 18-1/2 feet. To safely arrest the fall and prevent the worker from contacting the lower level, the fixed anchor point must be at least 18-1/2 feet above the lower level. If this calculation is performed incorrectly, a worker may come in contact with dangerous equipment or a lower level.
Conclusion. This article discussed several of the challenges associated with personal fall arrest. When employees are tasked with working at heights, consider using the Hierarchy of Fall Protection to identify the best option for protecting employees.
If the fall hazard cannot be eliminated, consider alternatives such as guardrails and fall restraint systems to prevent fall-related injuries and fatalities.
Joe Mlynek is president and safety and loss control consultant for Progressive Safety Services LLC, Gates Mills, OH; 216-403-9669; and content creation expert for Safety Made Simple, Olathe, KS.
- From the November/December GRAIN JOURNAL