Does a safety valve need to be equipped with a root valve?
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I would like to ask whether a root valve is required for safety valves on pipelines or equipment
It’s possible; be careful when opening the seal… Theoretically, it’s better to have no valves… In practice, valves offer convenience (though this convenience can be harmful in extreme situations)
It is convenient to install a root valve, as it eliminates the need to shut down the system during annual safety valve inspections. When installing a root valve, make sure that its diameter is not smaller than the diameter of the safety valve discharge pipe.
The requirements of Article 9.1.3(4) of TSG21-2016 shall be met
According to the standards, it is generally not recommended to install a root valve on safety valves; however, one can install it for easier replacement, provided that it remains in an open state during use
It can be added; the safety valve can be easily inspected, but it is necessary to ensure that the lead seal remains in an open state.
In accordance with Article 10.2.10 of the Code for Design of Layout of Metal Piping in Petrochemical Industries, when isolation valves are installed on the inlet and outlet pipes of safety valves, they shall be sealed with lead or locked open； When the shut-off valve is a gate valve, the valve stem should be installed horizontally. When a safety valve is equipped with a bypass valve, the valve stem should be sealed or locked in place. Based on this provision, it is possible to install a root valve, but it should be sealed with lead or unlocked.
It can be installed, but it needs to be opened with a seal, and a written opinion from the safety department of the operating unit is required. It can’t be added casually.
Received. Thank you all. I just saw a clause in the chemical industry standard HG/T20584 stating that safety valves on equipment must not be equipped with root valves