Over the last few months I’ve been collecting a few bits of retired equipment from stores checks and ‘isolation’ bins with a view to looking at loss of strength due to wear. Nothing here constitutes a scientific test and this is purely for my own satisfaction, but I’m writing it up anyway. I used my home made breaking rig with the Hilti HAT-28 anchor tester to provide the pull force. Each item was pulled up to the maximum possible load of the Hilti, 20kN, and the results were recorded.
Petzl Omni SL
Pulled to 20kN – No breakage, gate / lock working correctly.
I suspect that the wear on this item had not yet reached a sufficient depth to form a significant weak point. The connector was certainly retired at an appropriate time, i.e. with visible wear but before strength loss occurred.
Petzl M33 OK Oval SL
Rated to 24kN main axis. Wear visible at both ends of the connector. Large radius wear from twin cheeks of a steel pulley and small / deep radius wear from a long term connection to a steel 7mm Maillon Rapide.
Pulled to 20kN – No breakage, deformed beyond elastic recovery. Gate no longer closes and shape is visibly distorted. This item deformed at 15% below its rated strength. This shows that wear had already reduced the strength of this connector and it should really have been retired before reaching this level of wear.
Petzl Vertigo Twist Lock
Pulled to 20kN – No breakage, deformed heavily under test but recovered almost completely after. Connector permanently deformed and the gate locking mechanism does not function correctly. This item deformed 20% below its rated strength. This shows that wear had already reduced the strength of this connector and it should really have been retired before reaching this level of wear.
Do not take this test as advice to use kit beyond it’s manufacturer stated working life. Get a qualified person to advise you if unsure or go and do a PPE/FPE inspector course. If you have any retired gear you want to send to me to test in this manner then please get in touch.