Pitch fibre

Today I found some pitch fibre drainage pipes. These are potentially not good! The material was a by-product of the oil industry in the 1960/70's. Whilst it worked it had to be laid correctly and be adequately protected from any compression forces. If not then it would compress and 'go oval' with the problem then that blockages would occur. The only way to find out if the pipe has distorted is by way of a camera survey. There is no remedy apart from replacing the affected length of drain.
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Not an exciting blip but the best I can offer today and perhaps informative for those that might have nothing better to do than think about drains!