Is the installation of the safety valve done before the hydrostatic test (air-tightness test)? After?
Thread Content
Should the safety valve be installed before or after the hydrostatic test (or pneumatic test or airtightness test)? If the equipment requires a gas-tightness test and the test pressure is higher than the opening pressure of the safety valve, what should be done? If the safety valve is installed after performing these tests, how can the sealing between the safety valve and the flange be ensured?
Generally, it is definitely after testing (safety valves are usually not supplied by the equipment manufacturer). The equipment is released from the factory only after testing; after it leaves the factory, once installation is complete and before trial operation, a safety valve can be installed. All equipment must undergo trial operation before being put into use, so there is definitely an opportunity to check the sealing integrity of the valve and the flange – no need to worry. :lol
Safety valves are not involved in the pressure testing process; they are usually calibrated by specialized agencies. When the equipment leaves the factory, it is delivered to the customer either with or without such a valve, depending on the customer’s choice, who is then responsible for its installation. During the equipment’s operation and debugging phase, online debugging is carried out.
Our factory ships the equipment in skids, but during pressure testing, pressure relief devices such as safety valves and rupture disks cannot be installed
Generally, this is done after pressure testing, as the opening pressure of the safety valve must be slightly lower than the test pressure
The safety valve should be installed after the equipment’s hydraulic pressure test; during the testing phase, a blind flange is used as a substitute. Pressure vessels go through a pressure testing procedure before each use, and it is at that time that the safety valve can be installed. After installation, the safety valve must undergo additional tests before it can be put into use, and these tests certainly include the items you mentioned. Moreover, the safety valve must be calibrated by a qualified inspection agency before it can be used. Depending on its level of use, it also needs to be inspected regularly. The installation, removal, and testing of safety valves are carried out quite frequently.
According to the regulations, when conducting a airtightness test on pressure vessels, the safety accessories should generally be installed in their entirety (Article 102, Point 5 of the regulations; I have some doubts regarding this point and am not sure how to resolve them – safety accessories such as system isolation devices that would activate in the absence of a pressure test). But nothing was mentioned about the hydrostatic test; it should be installed after the hydrostatic test.
Article 102, Point 5 of the Code: When conducting a airtightness test on pressure vessels, the safety accessories should generally be fully installed. If it is necessary to install safety accessories on-site prior to commissioning, the leak test report included in the pressure vessel quality certificate should indicate that a further on-site leak test is required after the installation of those safety accessories.
The safety valve should be installed after the hydrostatic test and before the airtightness test, because 1. the opening pressure of the safety valve is lower than the hydrostatic test pressure. 2. The airtightness test is generally conducted at the operating pressure; therefore, the opening pressure of the safety valve is higher than the pressure used in the airtightness test.
The safety valve should be installed after the hydrostatic test and before the airtightness test, because 1. the opening pressure of the safety valve is lower than the hydrostatic test pressure. 2. The airtightness test is generally conducted at the operating pressure; therefore, the opening pressure of the safety valve is higher than the pressure used in the airtightness test. The answer is absolutely correct :)
It is usually done after pressure testing, because 1) the opening pressure of the safety valve must be slightly lower than the test pressure, which affects the testing process. 2. The safety valve and the equipment are not supplied by the same manufacturer. 3. The safety valve needs to be adjusted separately.