The back pressure regulators enable, by a direct mounting on a pipeline system, a pressure vessel or a gas container, the evacuation of any accidental overpressure. Its main advantage with respect to a standard relief valve is to relief at a constant upstream pressure whatever the downstream counter pressure. The back pressure regulators enable high discharges in case of overpressure. They are compatible with all non corrosive gases, oxygen and acetylene included but excluding ammonia and carbon monoxide.