A tool for closing and sealing the open end of a pipe, the tool having front and back ends and comprising, in combination: an external front plate for extending across and abutting the open end face of the pipe, to form an annular interface therewith; the front plate having a central aperture extending therethrough and a peripheral flange for projecting radially beyond the pipe outer surface; an axially movable back plate for transversely positioning with clearance within the bore of the pipe, said back plate carrying at its front end an annular, resilient, deformable seal means for sealing the interface by contacting with the front plate and the pipe inner surface; the back plate being connected at its front end with a forwardly projecting stem adapted to slidably extend through the aperture, whereby the back plate and stem may move as a unit to deliver the seal means to the interface and compress it against the front plate and pipe; a first clamp means for positioning around the pipe and means (26, 27) for tightening said clamp means so it may frictionally engage the pipe to anchor the first clamp means in place thereon; a second clamp means for positioning on the pipe at the rear end of the first clamp means and abutting the first clamp means, said second clamp means comprising a ramped compression ring mounted on a ramped segmental gripper ring, said second clamp means being operative to frictionally engage the pipe upon actuation thereof; bolt means for connecting the front plate and compression ring, whereby said bolt means biases the front plate against the pipe end face and actuates the second clamp means by pulling on the compression ring; and means, associated with the stem, for drawing the back plate toward the front plate to thereby bring the seal means into compressed sealing engagement with the front plate and inner surface of the pipe along the length of the interface and for disengagably locking the stem in place. an external front plate for extending across and abutting the open end face of the pipe, to form an annular interface therewith; the front plate having a central aperture extending therethrough and a peripheral flange for projecting radially beyond the pipe outer surface; an axially movable back plate for transversely positioning with clearance within the bore of the pipe, said back plate carrying at its front end an annular, resilient, deformable seal means for sealing the interface by contacting with the front plate and the pipe inner surface; the back plate being connected at its front end with a forwardly projecting stem adapted to slidably extend through the aperture, whereby the back plate and stem may move as a unit to deliver the seal means to the interface and compress it against the front plate and pipe; a first clamp means for positioning around the pipe and means (26, 27) for tightening said clamp means so it may frictionally engage the pipe to anchor the first clamp means in place thereon; a second clamp means for positioning on the pipe at the rear end of the first clamp means and abutting the first clamp means, said second clamp means comprising a ramped compression ring mounted on a ramped segmental gripper ring, said second clamp means being operative to frictionally engage the pipe upon actuation thereof; bolt means for connecting the front plate and compression ring, whereby said bolt means biases the front plate against the pipe end face and actuates the second clamp means by pulling on the compression ring; and means, associated with the stem, for drawing the back plate toward the front plate to thereby bring the seal means into compressed sealing engagement with the front plate and inner surface of the pipe along the length of the interface and for disengagably locking the stem in place.