Compressible Pitch Fibre Pipes were fitted principally in properties built between 1950-1970 and are becoming an increasing problem as they fail through de-lamination, blistering and general collapse/pinching.
1.) Reform the pipe work by winching through a bullet shaped reforming tool.
2.) By pulling through a Reamer to cut out the high and low spots in the deformed pipe work followed by a low pressure jet wash.
3.) A cutter can be used when only one man hole is present followed by a low pressure jet wash
Once the pipe work is reformed or cut back into a circular shape and a liner covered in resin is pulled through (which is filled with compressed air and left to cure) then finally trimming off the ends.
This would seem to be a less disruptive repair and often comes with a ten year guarantee from reputable contractors.