Under what circumstances is it necessary to install a safety valve?

There are many situations in which safety valves must be installed; for example, when the pressure in a system exceeds the capacity of the containers or pipes, safety valves should be installed to protect equipment and personnel from danger. The manufacturing and operation of advanced process equipment require the addition of safety measures within specified pressure ranges, to ensure the safety of both equipment and personnel under all circumstances. There are also many situations in which rupture disks must be installed; for example, when abnormal pressure fluctuations occur in a piping system, it can lead to an explosion within that system, so rupture disks need to be installed to mitigate the damage caused by such pressure fluctuations. In certain specific situations, it is necessary to install both a safety valve and a burst disc simultaneously to ensure the safety of the system. For example, in high-risk systems or when it is necessary to ensure the absolute security of the system. When a safety valve and a burst disc are installed together, they should be connected in series or parallel depending on the specific system requirements. Series and parallel connections are used to achieve different safety objectives respectively. In a series configuration, blast valves typically serve as the first line of defense to prevent minor pressure fluctuations, while safety valves are more suitable for handling large pressure changes. In parallel operation, the burst disc and safety valve can function simultaneously to ensure the complete safety of the system. As for why a safety valve and a burst disc should be installed simultaneously, it is because the two have different functions and roles. A safety valve is a pressure release device that releases pressure when the pressure in the system reaches a set value, thereby protecting the equipment and personnel inside the system. A burst disc is a pressure buffering device that helps to reduce the risks when abnormal pressure fluctuations occur within a system. The combined use of these two measures can ensure the security of the entire system to the greatest extent possible. .

SHT 3210-2020 Code for Process Design of Safety Pressure Relief Devices in Petrochemical Plants

Appendix B of GB150 on overpressure relief devices should be able to answer some of your questions