RELIEF VALVE Relief valve is used to limit the pressure in a system within set limit. Opening of the relief vale is directly proportional to the increase in the vessel pressure. The relief valve open when pressure reached the specific set pressure limit and it is operated by operator. It activate at above the 10% of working pressure SAFETY VALVE A safety valve is used to release the excess pressure automatically. Safety opens immediately to release overpressure. It is used to release the excess pressure without the operator The set point of the safety valve is usually set at 3% above the working pressure.