ATLAS rapid pressure relief control valves are installed perpendicular to the pipework in pressurised water networks. When the pressure in the pipeline rises to an undesirable level, the valve’s disc opens to release water into the atmosphere, thereby reducing the pressure in the pipeline; once the pressure returns to normal, the valve closes slowly to ensure a complete seal. The slow closing mechanism prevents water hammer effects from occurring in the system. In pumped booster lines, the valve activates when water pressure rises due to pumps cycling on and off, releasing water into the atmosphere to reduce the pressure.