Safety valve is designed to protect equipment and people. In potentially dangerous situations, it will open at a predetermined set pressure. The compressed-spring force that keeps the valve closed is overcome when pressure builds up at the inlet of the safety valve, and the valve is forced open. As the forces balance out, the valve will discharge and decrease pressure, reclosing as the system returns to normal. Models in the line include the SB pressure-relief valve, SB anti-vacuum valve and SB anti-vacuum house. The safety valves protect against overpressure in tanks and pipelines and against implosion.