Abstract: Systems and methods for cutting an existing pipe carrying a fluid under pressure include using a cutting assembly having first and second linear cutters spaced by a lateral width. The cutters are moved from a retracted position to an extended position thereby to cut a coupon from the existing pipe. An insertion valve may then be installed on the existing pipe at the location where the coupon was removed. The insertion valve includes a valve element that is movable between open and closed positions. In some examples, the systems and methods include a check valve that moves from an open position to a closed position as the valve element moves from the closed position to the open position, thereby to facilitate repair and/or replacement of the insertion valve.