An apparatus for sealing an open end of a pipe includes a clamp for frictionally being secured to the exterior of the pipe, a sealing plate for covering the open end of the pipe and being connectable to the clamp, and an urging mechanism for urging the sealing plate towards the clamp and for forming a seal between the sealing plate and the open end of the pipe. In one aspect, the clamp comprises an annular body formed by at least two sections that are radially tightened over the pipe exterior. In another aspect, the clamp comprises cooperating annular bodies, one capable of radially narrowing the other for frictionally engaging the pipe outer surface. In another aspect the method provides a method of sealing an end of a pipe. According to the invention, once the open end is sealed, the interior of the pipe may be pressurized, for example for testing the integrity thereof.