NOTE: Since all lining tubes are usually equipped with an outer membrane (foil) made of PE (polyethylene), PP (polypropylene), PUR (polyurethane), PA (polyamide), PVC (polyvinyl chloride), it is questionable whether a leak tightness test of the CIPP liner in situ makes sense at all. It can be assumed that even if there are leaks in the composite, the test will be passed due to the outer membrane.

For this reason, a leak tightness test of the composite in the laboratory is mandatory.

The following pictures show a CIPP liner sample. The CIPP liner was tested in-situ leak tight, in the laboratory the sample was not leak tight at all 3 test points.