Most North American fall protection standards specify that the dorsal attachment shall be used as the connection point for fall arrest systems. This article outlines a logical safety justification for using the sternal (chest) attachment on specific harnesses for some fall arrest applications. The use of the sternal attachment may be safer in some circumstances because it improves the opportunity for self-rescue, minimizes the risk of suspension trauma, may protect the face in some types of falls, and shortens the potential fall distance.
While Ropeworks harnesses are compatible with both sternal and dorsal attachment, our technicians frequently use the sternal attachment point for their back-up safety line in rope access and some fall protection applications, especially when climbing towers.
Current Fall Protection Standards:
Most North American fall protection standards are similar to OSHA 1926.502(d)(17): “The attachment point of the body harness shall be located in the center of the wearer's back near shoulder level, or above the wearer's head.” Standards in Europe allow for both sternal and dorsal attachment for fall arrest systems. The ANSI Z359 Committee is considering including the sternal attachment in addition to the dorsal attachment in the next revision of the standard.
When? Ropeworks technicians use the sternal attachment under these specific conditions:
- Technicians have been trained in the use of the fall protection system.
- The Ropeworks harness is designed for suspension and fall arrest from the sternal attachment point.
- The sternal attachment point has been tested using the ANSI Z359.1 drop test procedure specified for the dorsal attachment point.
- The lanyard assembly will not allow a free-fall of more than 6 feet (2 m).
- The technicians are trained to limit the free-fall potential to less than 2 feet (60 cm), and a shock-absorbing lanyard is used in any situation where a greater fall may be anticipated.
- Using the dorsal attachment would increase the distance of fall, increase the severity of the consequences of a fall, or limit the ability of the technician to self-rescue.
Why? Ropeworks technicians use the sternal attachment point for some of their fall protection needs for the following reasons:
- Self-rescue: In most cases, it is easier to self-rescue from a fall when connected to the sternal D-ring. As shown in Figure 1, it is very difficult to reach connections or move productively while suspended from the dorsal D-ring. The dorsal D-ring connection tends to pitch the worker forward and restrict movement in the legs. While it is not necessarily obvious and simple to self-rescue while suspended from the sternal D-ring, the position does not restrict movement of the legs and it is easier to connect a foot-loop or ascending device to the lanyard assembly. Ropeworks technicians use dynamic rope lanyards (and shock absorbers as needed) to help facilitate a rescue using ascending equipment.
- Suspension Trauma: In simple terms, suspension trauma is caused by the pooling of blood in the legs which in turn does not return to the vital organs. This can result in life-threatening circulatory failure in as little as twenty minutes while hanging upright and motionless in any harness. It appears that this condition can be held off indefinitely as long as the legs can be moved freely. It is clear from our field testing that most fall arrest harnesses that rely exclusively on a dorsal attachment for fall arrest severely restrict the mobility of the conscious worker in addition to causing great discomfort while hanging in suspension. The worker may also be at greater risk from suspension trauma because it can be more difficult to self-rescue while suspended from the dorsal D-ring. It is much more comfortable and easier to move the legs while hanging from the sternal D-ring in a harness designed for suspension.
- Protecting the Face: In many environments, arresting a fall using the dorsal D-ring may cause the user to strike his or her head and face on the structure or slope. This is especially obvious when climbing a tower or descending a slope because the head and face are positioned between the connection point and the structural hazard. After the initial strike to the head or face, the user will then likely spin away from structure further exposing the back and the head to additional trauma without the benefit of the arms and hands for protection.
- Distance of Fall: Attaching the fall protection lanyard into the sternal D-ring allows the user to use a shorter lanyard while structure climbing. Most technicians will need a lanyard that is at least 12 inches longer if the lanyard is attached to the dorsal attachment.
Dorsal Attachment - There are good reasons for using the dorsal attachment point in many fall arrest situations.
- System compatibility: Some fall arrest systems are more compatible with the dorsal attachment point. A steel cable self-retracting life line (SRL) is a good example. The overhead cable is usually best clipped to the dorsal attachment point because the cable is less likely to run across the face and nose during the course of work.
- Does not interfere with work: Using the dorsal attachment point can keep the connection and lanyard out of the way while working with tools. Interference with tools can be a safety hazard.
- Harness compatibility: Many fall arrest harnesses do not have a sternal D-ring, and many that do are not specifically designed for suspension and fall arrest from the sternal D-ring. If your harness is not designed for suspension from the sternal D-ring, then certainly do not use it in this way!
- Potential Legal Liability: Most North American standards and legislation specify the dorsal attachment point for fall arrest applications. While the logic behind this legislation may not lead to the safest techniques for all applications, some risk managers may understandably choose convention to avoid the potential legal liability exposures. Ropeworks has chosen to endorse the use what we consider to be the safest technique for our specific application.
Disclaimer: Ropeworks has chosen to use a specific fall protection technique that is not consistent with current legislation. While we believe that under these circumstances, the sternal attachment point affords a higher level of protection for our technicians, falling from height is always dangerous and injury can occur. This justification has never been tested in the legal system. Every organization must decide on its own specific procedures. |
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Figure 1: Arresting position using the dorsal D-ring (top) and using the sternal D-ring (bottom)
Figure 2: Recommended lanyard length for sternal attachment. Standard six foot lanyard is not recommended.
Drawings used by permission from the North American Working at Height Handbook published by NSL and distributed by Ropeworks. |