What happened: During the air pressure testing of 16” HDPE liner for a line section and while the PTW holder and Helper were attempting to carry out pressure verification check on the gauge attached to the manifold, the ball valve attached to the gauge suddenly failed and caused the manifold to detach and hit the Helpers’ left leg resulting in a fracture Initial Findings: -The whip lock arrestor between the test plug and manifold section was missing. -No support was provided for the manifold section during the air filling time. -Anchoring wasn’t done for the manifold section to prevent whipping in case of valve failure. -MTC or rating certificate were not available for the ball valve and the test plug.