an apparatus for connecting two flanged pipes comprises at least one piston arrangement having a pair of opposed pistons slidable within a hydraulic cylinder . each pair of pistons has a rod extending therefrom and is adapted to receive a threaded fastener at its end remote from the piston . each rod extends through an aperture at the respective cylinder end and is adapted to pass through a respective aperture in the flange of a flanged pipe . each piston has an associated biasing means in the form of a spring or similar which urges the piston away from its respective cylinder end . pressurization of the hydraulic fluid in the cylinder causes the piston to move towards its respective cylinder end against the urging action of the biasing means , to allow the hand tightening of the threaded fastener . when the pressure is removed the action of the spring biases the flanges of the flanged pipes together to energize the ring seal between each flange and the apparatus .