Leaks have been observed on finished liners. They range from small drips to water pouring or jetting in.
Causes: Reasons for the formation of leaks on seams are associated with the initial formation of a hole in the seam brought about at some stage during installation.
Prior to this, any holes would have been apparent during impregnation. Once water/air/steam during cure has a route out through the liner, groundwater can then follow the same route producing the features in the Figures below.
A stress raiser at the edge of the seam tape may induce a split under excessive load.
Figure 1: Small leak. (Click photo to view video.)
Figure 2: More extensive leak. (Click photo to view video.)
Figure 3: Severe leak with water jetting through seam. (Click photo to view video.)
Solutions: Leaks on seams can be avoided, where they are brought about by damage to the seam through careful handling. Damage can occur by allowing the liner to run over rough surfaces.
During impregnation and installation ensure that all rollers and elbows (where a bottom inversion is used) are clean and smooth.
After impregnation and storage for transport, the seam area can swell making the seam more vulnerable to damage.