Unfortunately accidents happen.  Accidents can happen to flexible PVC tank liners as well.  Sometimes an operator can drop something sharp on a liner, or a liner can be unfolded when still cold, or something heavy with a sharp edge can be dragged across a floor liner, or a heater could burn a hole in a liner.  No matter what the cause of the damage, one of the benefits to a Witt drop in PVC tank liner is that it can be quickly and easily repaired.