Standard belay devices and their loading-handling capabilities, by Richard Delaney

This graphic represents the results of a series of tests by Richard Delaney to "test the capacity of various devices to hold a load—not the ability of a load (or abseiler/rappeller) to belay itself." 

Notes: The "hand" applied tension was an attempt to apply a tension similar to what could normally be applied with one hand on the rope, and the other hand at one's side—as if behind a belay device when belaying/abseiling/rappelling. The"max" applied tension was an attempt to apply a tension similar to what could normally be applied holding the belay rope with two hands, standing behind the device with good footing. Richard also measured these subjective approximations and got 10kg for one hand, 10-20kg for two hands at the waist height behind a device, and 50kg for the max/two hands standing pulling out in front effort. He used 11mm Edelrid super static rope, says all "figures should be viewed as +/- 20kg or so," and described the test process as an "example of experimentation and interpretation."

The setup Richard used for this test.

To read the exchange of comments, questions, and answers between the author of this graphic and other rope enthusiasts on the Rope Test Page, point your Internet browser here.

Source: This article was adapted from Standard belay devices and their loading-handling capabilities, by Richard Delaney, Copyright © 2014. All Rights Reserved. Excerpted with expressed written permission. To learn more about rope access work, climbing, and rope rescue, visit Richard's Rope Test Lab.

Richard Delaney has worked professionally with ropes since 1992. Initially, this was as a multi-pitch, rock-climbing guide, but this soon morphed into specialized rescue instruction and rope access work.

He is currently an accredited Vertical Rescue Instructor/Assessor, a Level 3 Rope Access Technician, a Technical Director of the Australian Rope Access Association, and the administrator of the Rope Test Lab group on Facebook.

Understanding and teaching the Physics of Rigging is a core passion of Richard's, one based on his experience, and his prior professional life as a qualified engineer.

Train with Richard: An internationally-recognized expert in rope rigging, Richard is coming to North America—the United States and Canada—to instruct several 3- to 5-day Rigging Physics Courses during 2014. To learn more about these courses, point your Internet browser to the Rescue Response Gear Rigging Lab.
• To follow Richard on Facebook, 'like' the Rope Test Lab group page.