The 10 year 'expiry date' on all Petzl products which are either predominantly textile or plastic is mainly an arse covering excersize on the part of the manufacturer due to the possibilities of degradation through UV. I know we don't get much UV in the UK let alone underground but it would be inadvisable to extend the life expectancy of any product beyond what the manufacturer recommends. Most other manufacturers would apply a 5 year life expectancy for textile products.
In the industrial rope access industry, extending the life of any product beyond the manufacturers recommendations would render any insurances invalid in the unlikely event of an accident which can be directly attributed to the failure of the e.g. harness. I would imagine the BCA insurance policy would be the same. If you were an insurance provider looking at a potential ?5M claim being made you would be making every effort to get out of it. Using a 20 year old harness would be an ideal way for our insurance providers to 'get out of it' and don't think for one minute that this wouldn't happen.
In response to caving_fox, the only way to know how safe the harness is, is by carrying out a thorough visual and tactile examination in accordance with the recommendations of the manufacturer. A 20 year old harness would fail this examination regardless of its condition.
Apart from it not being practical to do a drop test of a caving harness on the BCA drop test rig it wouldn't provide any useful information. As with any type of destructive testing, it has to be scientific and above all else, repeatable. None of the testing carried out on the BCA drop test rig is scientific or repeatable.
Cheers,
Mark
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