Storage tank inlet and outlet isolation valves
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Generally, double valves are installed on storage tanks where material is added or removed from the bottom. Should double valves also be installed on storage tanks where material is added or removed from the top? Is there a regulatory basis? I need experts’ advice!
Not everything has regulations; it depends on the risk.
We have two valves: one is the root cut-off interlock valve (which remains open under normal conditions) and is used for emergency shutdown. In the control room, there is an emergency stop button for each tank; by pressing it, all the root valves for that tank are closed. There is also the ordinary cut-off valve, which is used for material inlet and outlet of tanks.
Whether to install dual valves is determined based on the requirements of SIS/ESD and the process itself; generally, it is necessary to have separate control for SIS/ESD and the process. Since many valve and instrument control systems need to be operated independently, this leads to the use of dual valves.