The main reason why textiles and/or predominantly plastic items of PPE are given a usable lifespan is due to the possible negative effects of UV degradation.
A number of years ago an energy absorbing lanyard was tested to destruction and it was found that the tear-ply element of the lanyard failed at an alarmingly low force. It was found the material the tear-ply element was manufactured from was considerably weaker than the main lanyard webbing. The current minimum strength requirements for lanyards is 22kN and this should include all elements of the lanyard. The tear-ply element of the one which failed was found to have a minimum breaking load of only 15kN when new and UV degradation had caused this figure to fall well below this level, thus significantly reducing the required Factor of Safety.
Following this testing the EN standards for manufacturing such products were changed to ensure all elements of the lanyard met the 22kN strength requirement.
There has been plenty of testing done on ropes to show that extending the manufacturers recommended lifespan does not necessarily mean they are more likely to fail. If however, such ropes are being used in a high UV environment then this should be a cause for concern.
Most of my work over the past few years has been onboard very large motor yachts working in very high UV environments and the effects of the degradation are clearly visible after only a few years with significantly faded webbing and stitch patterns. Elasticated components also suffer significantly by completely losing their elasticity.
Large commercial sailing yachts take UV degradation of their sail rigging very seriously and completely change out the rigging every 5 years.
Luckily for us there isn't an awful lot of UV down a cave, or anywhere else for that matter, looking out of my window, so we would be better off paying more attention to the actual condition of the rope through visual and tactile examination.
Only yesterday I re-introduced one of my old Petzl Erin Best helmets back into service which was manufactured in December 2003 and, knowing its history, I have no issues with this. If it fails then this will be entirely my own fault and won't affect anyone else. We have to be careful though that textiles and/or plastics used beyond their recommended life expectancy in a club environment is very different.
If somebody tried to make a claim on the BCA insurance due to a club ignoring the recommendations of the manufacturer and as such significantly increasing the premiums for the rest of us then I think I would be encouraging our insurers not to make any pay out. Having said that, I would imagine our insurers would be looking for any way they can of getting out of paying out ?5M.
Mark
