Thomas Cocchiola, P.E., CSP, Mechanical Engineer
Case Synopsis: A school purchased a portable rock-climbing wall for summer camp sessions. For safety purposes, a belay rope is typically used to prevent climbers from slipping and falling. Most rock walls require a partner to hold a belay rope for each climber, but the manufacturer equipped the subject rock wall with an automatic belay fall protection system that eliminated the need for climbing partners.
The automatic belay system utilizes hydraulic cylinders to absorb forces and gently lower climbers to the ground if they slip and fall. In the second camp season, a counselor slipped while climbing near the top of the wall and plummeted to the ground. The automatic belay system did not protect the counselor due to a failure of the hydraulic cylinders.
Engineering Analysis: The manufacturer claimed the rock wall was rated for 250-pound climbers and that the automatic belay system was fully redundant. An engineering analysis demonstrated the manufacturer’s claims were false. The analysis proved that a climber weighing as little as 100 pounds could overload the hydraulic belay cylinders; clearly the belay system was not redundantly designed. To complicate matters, the manufacturer learned that the belay cylinders were failing because of casting defects. In fact, some belay cylinders failed more than 1.5 years before the counselor was injured. The manufacturer knew that defective castings severely weakened cylinders and compromised vital fall protection, but failed to recall the rock wall of the belay cylinders, and did not warn the school to stop using the rock wall.
Result: The case went to trial and the jury returned a verdict for the plaintiff.
Thomas Cocchiola, P.E., CSP, Mechanical Engineer with DJS Associates, Inc., can be reached via email at experts@forensicDJS.com or via phone at 215-659-2010.
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