Abstract: A double containment piping system for securing a primary pipeline in position within and enabling pressure testing of a surrounding secondary pipeline which interconnects two or more sump chambers. Centralization seals are affixed to the interior surface of opposite ends of the secondary pipeline and to an adjacent exterior surface of the primary pipeline to form an airtight wall and seal the space between these surfaces. An air insertion fitting allows pressure testing of the sealed spaces between the primary and secondary pipelines. Air bridge hoses can interconnect air insertion fittings within a sump chamber to permit simultaneous pressure testing of more than one secondary pipeline in the secondary pipeline system. The seals further provide a centralization function to limit the radial movement of a primary pipeline within a secondary pipeline to reduce the risk of impact damage caused by pressure spikes in the primary pipeline system.