The concept of developing the Dual Contained Pipe Test Plug comes from many years of installing these systems for contractors and owners of landfill facilities throughout the northeast... For these systems to be accepted by our regulatory agencies they have to be tested to insure that as a dual-containment system they are 100% effective. Testing of the carrier (inner) pipe was never an issue since there is access to the pipe for flanges or other mechanical terminations. However, providing the means of closing the annulus of a Dual-contained pipe system in preparation for the containment (outer) pipe test of 15 psi can be a safety issue, time consuming and expensive challenge for the contractor or facility maintenance personnel. In the past we have employed the use of elastomeric couplers, expandable links or welded rings to seal off the carrier-containment terminals, followed by drilling and tapping the containment pipe for the pneumatic test. All of which are time consuming, labor..