This week we are going to discuss the D-Rings on harnesses and which ones are safe to attach my lifeline to.
What are D-Rings?
D-Rings get their name from the fact that they are generally D-shaped, although their exact shape can vary. These D-Rings are sewn into the harness webbing and serve as loops to which other components, such as lanyards and self-retracting lifelines (SRLs), attach.
How to Use Harness D-Rings Safely
It is important to know how to use each D-Ring that you might encounter on a full body harness. In this section, we’ll introduce the most common types of D-Rings and ways to use them correctly and safely:
· Dorsal D-Ring: The Occupational Safety and Health Administration (OSHA) requires all fall protection safety harnesses to include a D-Ring on the back, also known as a dorsal D-Ring. This is the required safety harness attachment point for a fall arrest harness. Connecting a personal fall arrest system to a back-ring harness helps keep the body upright during a fall and lets the harness do what it was meant to — distribute the forces of a fall arrest throughout the body.
· Side D-Rings: A personal safety harness may include extra D-Rings on the sides by the hips. These are not attachment points used in fall arrest, but rather useful points to connect devices to during work positioning. When an employee is held in suspension, common in tower applications and rebar construction, a positioning device can be attached to the side D-Rings. These positioning systems give more flexibility to workers in suspension, although they must be used together with — and cannot replace — standard fall protection connected to the dorsal D-Ring.
· Chest and shoulder D-Rings: A fall arrest body harness sometimes comes with chest D-Rings, which can serve as points of attachment for climbing applications. Again, these are not proper points of connection for fall arrest systems. Some other harnesses, such as those used for confined spaces or rescue operations, may feature shoulder D-Rings, which are excellent for safely lowering or hoisting a worker but are not meant to arrest an uncontrolled fall.
D-Rings not only act as the connection point to a fall protection harness, but help ensure the body stays in an upright position during a fall. Other situations that require the use of specific D-Rings include:
· Fall restraint: Like with fall arrest, you must use the dorsal D-Ring.
· Positioning: Use the D-Rings on the chest, hips, or waist.
· Fixed ladders: D-Rings on the waist and chest should be used.
· Fall arrest rescue: The D-Rings on the waist and chest should be used.
· Confined space rescue: Use the shoulder or dorsal D-Rings.
As fall protection equipment contains lots of parts, this leaves room for many mistakes, especially when you’re not fully versed on the basics of using body harnesses and D-Rings for safety harnesses. However, there are a few particularly common mistakes we’d like to mention so you can avoid them. These include:
The most effective method for mitigating possible misuse of the rebar snap hook is to make sure the anchorage connector D-Ring is bigger than the snap hook to prevent side loading of the hook. As this is hard to achieve, we encourage users to utilize a smaller anchor snap for attaining the right geometry.
If an employer chooses to use these hooks, they should know the hooks’ gate strength and be aware that certain hooks have two stress points aligning with the hook’s strongest points.
Another common mistake regarding anchorage is people anchoring under their feet. When they do this, it increases free fall, which may exceed the equipment’s permissible limits. If a worker pushes a piece of equipment to its limit, this may cause the anchorage or lanyard to fail or exceed the permissible force on the body, which will increase the chances of a severe injury.
It’s critical to remember that, even if the fall is arrested, the longer the fall, the more forces on the body. In turn, serious injuries could occur. For this reason, it’s a good idea to avoid anchoring under the dorsal D-Ring. If you have no choice but to do so, use an SRL rated for extra free fall or a 12-foot free fall energy-absorbing lanyard. Keep in mind these lanyards have an arresting force greater than that of standard versions, so you must design the anchorage accordingly.
To mitigate the problem, do the following:
While these two devices look alike and function similarly, many workers make the mistake of assuming they’re interchangeable. These two devices are tested in different conditions and applications, meaning you shouldn’t use them for things they haven’t been tested for.
Furthermore, people tend to misuse both lanyard types by anchoring under the dorsal D-Ring, which can increase the arresting force by several thousand pounds.
To avoid this problem, follow these tips:
Even if the harness’s condition is good, wearing it improperly can be hazardous. For instance, wearing a harness loosely creates a higher level of potential energy, which converts to kinetic energy when a fall occurs.
Other problems, like the position of the chest retainer strap or back D-Ring, could be seriously hazardous. A back D-Ring that’s too high could hit a worker’s head when falling, and one that’s too low could cause the worker to face the ground following the arrest, which increases the risk of suspension trauma. A chest retainer strap that’s too high could choke a worker, and one that’s too low could pull apart, allowing the worker to come out of the harness.
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