A locking cover plate can be selectively locked in position on a stortz pipe end fitting or can be unlocked and removed for access to the open pipe end. The cover plate includes a sliding plate that is driven laterally outward into a deployed state by rotating a drive bolt. The drive bolt is coupled to the sliding plate through a torque limiting coupling that transfers the rotation of the drive bolt to translating movement of the latch bar with a cam plate. Movement of the sliding plate is indicated through a front of the cover plate such that the user can identify whether the cover plate is locked on a fitting or simply placed on the fitting without the lock engaged.