Can a fixed-pressure vessel be equipped without a safety valve?

Whether a safety valve should be installed on a fixed-pressure vessel depends on the specific operating conditions and design specifications. Generally speaking, to ensure safety, most pressure vessels need to be equipped with safety valves, especially those devices that are at risk of experiencing excessive pressure. This is because the main function of a safety valve is to open automatically when the pressure inside the container exceeds the designed pressure, thereby releasing that pressure and preventing dangerous situations from occurring due to excessive pressure in the pressure vessel. The design and safety requirements for pressure vessels are primarily based on the following specifications and standards: 1. **“Regulations on the Safety Supervision of Pressure Vessels”**: This is the basic **standard** for pressure vessel safety, outlining requirements regarding the design, manufacturing, installation, inspection, and use of such vessels. 2. **GB 150-2011 Pressure Vessels**: This is a detailed standard for the design and manufacture of pressure vessels, which includes specific requirements regarding the installation of safety valves. 3. **Industry standards and local standards**: Certain specific industries or regions may have additional regulations. If safety valves are not installed throughout the production area of the natural gas transmission station you described, from the inlet ball tank and horizontal filters to the pipeline outlet, there could be several explanations for this: – **Design permission**: Certain designs may allow the omission of safety valves based on operating conditions (such as pressure and temperature) and risk assessments. For example, there may be other forms of pressure relief or control mechanisms in the system. - **Special provisions**: Certain specific applications or industry standards may permit the omission of safety valves under particular conditions. - **Monitoring and control systems**: Modern pressure vessel systems may be equipped with advanced pressure monitoring and automatic pressure adjustment systems that can effectively control pressure, thereby possibly eliminating the need for traditional safety valves. It is recommended to check the relevant design documents and engineering specifications to determine whether there are any special design rationales that permit the omission of safety valves. Additionally, you can also consult design firms or testing agencies to understand the specific design rationale and safety measures. The absence of a safety valve, without sufficient reasons and supporting measures, may pose safety risks. .

The pipes entering and leaving the station are equipped with emergency shut-off valves and vent valves; it is estimated that only the pressurization section will have safety valves, while the equipment in other sections will only have manual vents.

Section 3.4.3 of GB 50251-2015 stipulates that pipelines, equipment, and containers subject to overpressure must be equipped with safety valves or pressure control devices. Used in natural gas stations.

It is generally installed on pipes, but a safety valve is not necessary if the pressure from the pressure source is lower than the device’s designed pressure.

A relief device is necessary, but it doesn’t have to be a safety valve; it could also be a burst disc or a fusible plug. In the case of mobile units used at gas stations, I’ve never seen any units without safety valves, nor have I seen any use of burst discs or fusible plugs. Determine whether a safety valve is needed: Locate the as-built drawings; if safety accessories are specified in those drawings, then a safety valve must be installed, regardless of whether the designed pressure is higher than the pressure from the source. If the as-built drawings require the installation of a valve in the system, it is necessary to check whether the system is equipped with a safety valve, and whether that safety valve can withstand the design pressure of the equipment; it is not acceptable if it cannot.

There are also specific requirements for installing safety valves: 1. The set pressure of the safety valve should be 1.05 to 1.1 times the operating pressure, and must not exceed the maximum allowable operating pressure. 2. The discharge capacity of the safety valve must also be greater than that of the container’s leakage rate; this is not easy to determine. Generally, safety valves do not specify their discharge capacity, and even if the container does provide such information, it is still difficult to determine the appropriate value. Therefore, the safety valve should be selected based on its diameter – use a safety valve with a diameter corresponding to that of the container. If the leakage rate is insufficient, it is a design issue. If the design specifies a minimum throat diameter for the safety valve, then that specification should be followed. 3. The safety valve must be installed vertically; don’t keep making excuses by saying that the designed outlet is inclined – the fact that the outlet is at an angle does not mean it can be installed in that way; you need to address this issue later on. 4. Generally, for safety valves, full-opening type is used for steam, gases, and liquefied gases, while a slightly-opening type is used for liquids, unless the design drawings specify a particular type. 5. If you see wording on the drawings stating that safety accessories are to be provided by the user, don’t take it lightly. Allowing users to handle this themselves does not mean they are exempt from complying with laws, regulations, and standards.