Set pressure of the safety valve

1. It should be remembered that the factory-quality certification documents did not include a calibration report; upon arrival at the site, the user entity must provide the safety valve register approved by the manufacturer, along with the relevant calculations, and submit them to a qualified safety valve calibration facility for calibration, which will then issue a calibration report. One of the selection criteria for safety valves is the setting pressure; for safety valves of the same nominal pressure, model, and manufacturer, there are various specifications for the springs used, and the final choice is made based on the setting pressure. 3 No specific ratio was noticed; it is likely that the safety valve manufacturer has already included a safety margin during design and manufacturing. It’s not clear exactly how much was left

When the safety valve is disassembled, the spring has a specific pressure range within which the pressure can be adjusted; if the pressure exceeds this range, the safety valve needs to be replaced. Taking Swagelok’s proportional relief valve (R3A high-pressure valve) as an example: blue spring, set pressure range of 3.1~24.1 barg; red spring, 275~344 barg.

1. Determine the setting pressure of the safety valve based on the operating pressure of the container; it is generally set at 1.05–1.1 times the operating pressure. When the setting pressure is less than 0.18 MPa, it is possible to increase the ratio of the setting pressure to the operating pressure appropriately. 2. The design pressure of the container should be equal to or slightly greater than the set pressure.

1. Determine the setting pressure of the safety valve based on the operating pressure of the container; it is generally set at 1.05–1.1 times the operating pressure. When the setting pressure is less than 0.18 MPa, it is possible to increase the ratio of the setting pressure to the operating pressure appropriately. 2. The design pressure of the container should be equal to or slightly greater than the set pressure.

1. Determine the setting pressure of the safety valve based on the operating pressure of the container; it is generally set at 1.05–1.1 times the operating pressure. When the setting pressure is less than 0.18 MPa, it is possible to increase the ratio of the setting pressure to the operating pressure appropriately. 2. The design pressure of the container should be equal to or slightly greater than the set pressure.

It is specified in rows 1-3 on page 19 of GB150.

The set pressure at the time of manufacture is given as a range value (different springs are used for different pressures); ultimately, the device must be taken to a qualified inspection agency by the end-user for verification before it can be used. Safety valves fall under the category of pressure vessels and are subject to strict inspection requirements

Factory inspection cannot replace verification during use; in fact, verification during use serves as a form of supervision. Moreover, verification must be carried out by qualified entities; manufacturing plants generally do not possess such qualifications. Even if they do have the necessary qualifications, their efforts are usually recognized only if approved by the regulatory authorities in the location where the product will be used. The set pressure of the safety valve shall not exceed the design pressure or the maximum allowable operating pressure.

Regarding the setting pressure of safety valves, many people have some rather unusual ideas, such as adjusting the operating pressure of equipment based on that setting pressure. A safety valve is a type of safety accessory, and it is also the most common and important such accessory; it functions as a release device. A safety valve is the last line of defense for equipment safety, designed to release pressure inside the equipment before it reaches its maximum tolerance level. Setting of the safety valve: 1. Determine the required setting pressure ； -2. Determine whether the required setting pressure falls within the range of the safety valve ； -3. Does the safety valve manufacturer have the necessary qualifications? ； -4. Whether the appearance meets the requirements and other aspects ； -5. Adjust safety valves, etc. The setting of safety valves is completely disconnected from the actual equipment, which results in a mismatch with reality in many cases; this requires the user to possess the appropriate professional knowledge and a high level of responsibility. Determination of the set pressure for the equipment’s safety valve: It is determined in accordance with the requirements specified in the design drawings, including the model, diameter, and set pressure. These two tasks are often carried out by different people, which often leads to mistakes in assigning them to the right persons; as a result, the equipment is equipped with safety valves that do not meet the required standards, thereby eliminating the last line of defense for safety protection.