What is the relationship between the set pressure of a safety valve and the design pressure of the equipment it protects?
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Is it accurate to say that the set pressure of a safety valve equals the design pressure of the equipment being protected?
Also seeking the answer to this question. Some say that the set pressure of a safety valve should not be greater than the design pressure, while others claim it should be slightly higher than the design pressure. Which is correct?
The set pressure of the safety valve is 1.25 times the design pressure
No, according to Article 146 of the regulatory standards, when only one safety valve is installed on a fixed-pressure vessel, the opening pressure of that safety valve shall not be greater than the design pressure of the vessel, and its closing pressure shall be greater than the highest operating pressure of the vessel； When multiple safety valves are installed on a fixed pressure vessel, the opening pressure of one of these safety valves shall not be greater than the design pressure of the vessel; the opening pressure of the remaining safety valves may be increased appropriately, but must not exceed 1.05 times the design pressure.
When a fixed-pressure vessel is equipped with one safety valve, the setting pressure of this valve is less than the design pressure but greater than the maximum operating pressure; it is generally 1.1 times the maximum operating pressure. When two safety valves are installed on a boiler simultaneously, the set pressure of one is 1.04 times the operating pressure, and that of the other is 1.06 times the operating pressure. The set pressure of the safety valve on the economizer is generally 1.1 times the operating pressure.
The set pressure of the safety valve = 1.05 times the design pressure; this is fixed! !
Reply to 4# hcwang12345: Could you explain the relationship between the relief pressure and the design pressure?