Just caught up with this posting. Any SRT rope made to BS EN 1891:1998 is required to have an external marking, an instruction leaflet and an internal marking. The problem with the external marking and the leaflet is that the standard does not require them to be available for each length of rope sold. So the first purchaser from a new reel of rope gets one end with an external marking as does the last purchaser from that reel. I suspect the leaflet just gets thrown away. The internal marking is required to have repeated at least every 1000mm and show the:
â€¢ manufacturers name,
â€¢ number of the standard (ie 1891),
â€¢ type of rope (ie A or B - Please note that a Type B rope is made to a lower spec than Type A and to quote the standard â€œrequire greater care in useâ€!),
â€¢ name of the materials(s) which the rope is made of, and
â€¢ year of manufacture.
So if you cut along a rope you should find a tape inside with the info on it. The problem is that after some use of the rope, the tape has been rubbed and the letters become indistinct. I understand that prior to 1998 some manufacturers used interior threads of different colour to indicate information; but what the information was, is unknown to me. I also have found that exterior markings (coloured threads in the sheath) are no guide to manufacturer; I have 3 different exterior markings from one manufacture for the same type of rope!
If you are fortunate to get hold of the leaflet, then you will be dismayed to read that some the manufactures recommends a life of 5 years. (And yes, one shop did sell me a rope which was nearly 5 years old.) All I can say about life time for use (disregarding wear) is that Pat Schubert (President of UIAA Safety Commission) stated in an article on dynamic ropes printed in 2000 thought life times of 10 or more years were not unreasonable (see http://www.uiaa.ch/article.aspx?c=312&a=566 ).
I suspect that rope life is related to â€œwearâ€ and â€œabuseâ€ but I can't prove it. By â€œwearâ€ I mean the elongation and relaxation that a rope undergoes when a weight is hung from it. By â€œabuseâ€ I mean damage to the sheath. But this simplistic approach provides no neat way to include a fall, or even a heavy handed start to an abseil. I have been mussing over setting up a fatigue test for rope which would just cycle a weight on a rope until the rope broke (like they do for metal). But mussing is as far as I have got.
In the mean time I am still working on seeing how ropes perform after some degree of usage with only 300 metre left to break. Owen Clark's records from the BCA Rope Test Rig suggest that one can â€œwearâ€ a rope down within a year or so without any obvious effect, other than when you test it. Worryingly in 2005, nearly 30 percent of the ropes I tested only managed to survive 2 drops. Clearly some cavers are taking their ropes to near their limit of performance.
Sorry for so long a response, I must get back to preparing to take the rig to Hidden Earth and break a few meter of rope.