Containment system for storage systems having discontinuities

A system for sealing a liner about a discontinuity at a structural envelope for containing fluid, the liner forming secondary containment between the liner and an inner surface of the structural envelope, the system comprising:

• an opening in the liner for forming a first edge about the discontinuity;
• a mechanical seal circumscribed at an outer perimeter about the discontinuity and located between the liner's first edge and the structural envelope for forming secondary containment between the structural envelope and the liner;
• and
• a secondary seal attached at a perimeter attachment to one of the inner or an outer surface of the structural envelope at the discontinuity, the perimeter attachment being outside the outer perimeter of the mechanical seal for forming a continuous envelope extension from the liner to the discontinuity and for forming secondary containment between the continuous envelope extension and the structural envelope.