Pipe lap joint with improved collapsible sealing zone

A pipe lap joint is disclosed with an improved sealing zone and which comprises a pair of end-to-end intersecting slots in the outer pipe which allow the sealing zone to be collapsed against the inner pipe by a band clamp around the outer pipe. The outboard slot extends inwardly from the end of the pipe and the inboard slot is circumferentially offset and extends inwardly from the outboard slot. A frangible bridging segment of the wall of the pipe extends between the adjacent walls of the two slots and is deformed or fractured and maintains isolation between the slots when the pipe is collapsed. To facilitate collapse of the outer pipe, the length of the inboard slot is maximized for increased leverage of the clamping force.