The support point capacity for a Rope Access anchor is 15 kN (almost 1500 kgf, or about 1.5 tonnes), in the direction of the likely load. This has been the case for many years (check BS7985, or the IRATA code, annex F). This year I have come across a “spate” of otherwise competent RA “advisors” using all manner of much lighter loads to define capacity for both permanent and temporary anchor points. They are dangerously wrong. Many simply use 150 kgs, which is totally inadequate, and some are using 250 kgs which is equally inappropriate.
The maximum “permissible” load in a fall situation is referenced consistently within the EN Standards as 6 kN. Arrest forces above this load will result in significant injury. IRATA recognise that the energy absorption of the support rope increases with rope length, and that there is the potential for equipment failure at the top of a support rope. In this position there is very little rope to absorb fall energy.
- IRATA apply a factor of safety of 2.5.to this 6 kN maximum load to reach the load capacity of 15 kN.
- IRATA justify this with reference to the need to potentially use the support anchor for rescue.
- The engineering is this simple. We need to start specifying 15 kN capacity anchors,and nothing else.
Please note, as mentioned in an earlier Height Safety News .. EN 795 anchors require a structural capacity of 12 kN now .. and therefore at least two should be used for RA works. EN 795 is the wrong reference for RA support.