Safety Pressure relief or pressure release valves are designed to stay closed until the inlet or upstream pressure reaches the maximum set safe limit at which point the pressure relief valve will quickly open releasing the excess pressure downstream. When the upstream pressure has dropped back to the set safe limit the safety relief valve will slowly close preventing any back pressure spikes or pressure hammer effects, the back pressure is displayed by an external pressure gauge. In the way the pressure relief valve automatically protects the upstream process systems at all times. Each pressure relief valve can be chosen according to a fully adjustable minimum and maximum pressure range, size and material of construction to suit just about any media application. All pressure relief valves are factory function, pressure and leak tested.