2.11.3.1.11 Anchor lines should be configured so that a rope access technician cannot inadvertently descend off the end of them. Where the anchor line is free hanging, this may be achieved by the use of a simple stopper knot (see Figure 2.9). The stopper knot should be properly dressed and then set (i.e. hand tightened). After the knot has been set, the length of the tail below the knot should be at least 300 mm. In use, care should be taken to ensure the knot cannot become snagged with potential obstructions (see the examples given in 2.11.3.3). It should be understood that a simple stopper knot is unlikely to arrest an out-of-control descent, e.g. when the user has lost control of their descending device and the descent is effectively a fall. If it is thought necessary to protect against such a possibility, a proven stopper system, e.g. one incorporating a stopper disc that has been tested with the descending device being used, should be fitted to the anchor line.
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