What is the definition of a pressure vessel?
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We were inspected by the Quality Supervision Bureau today, and the staff said that anything over 1 kilogram is considered a pressure vessel. Are they trying to deceive our company?
A pressure vessel is a sealed container that is subjected to gas or liquid pressure from within or outside, and requires high standards in terms of safety. Classification of pressure vessels: Classified by pressure level, pressure vessels can be divided into internal pressure vessels and external pressure vessels. Internal-pressure vessels can also be classified into four pressure grades based on their design pressure (p), as follows: Low-pressure (code L) vessels: 0.1 MPa ≤ p < 1.6 MPa; Medium-pressure (code M) vessels: 1.6 MPa ≤ p < 10.0 MPa; High-pressure (code H) vessels: 10 MPa ≤ p < 100 MPa; Ultra-high-pressure (code U) vessels: p ≥ 100 MPa. So, it is correct that the staff from the Quality Supervision Bureau say that anything weighing more than 1 kilogram is considered a pressure vessel.
The scope of application of LS’s pressure vessel regulations is determined by the operating pressure of the equipment; as long as the operating pressure is greater than 1 kilogram, it is considered a pressure vessel
Working pressure is greater than or equal to 0.1 MPa
The Regulations on the Safety Supervision of Special Equipment specify three conditions for defining pressure vessels: 1) the operating pressure must be 1 kilogram or more; 2) the product of pressure and volume must be 2.5 MPa·L or more (in other words, if the pressure is 1 kilogram, the volume must be greater than 25 L); 3) there must be a gas phase space (the medium is either a gas or a liquid whose temperature is above its boiling point).
The Regulations on the Safety Supervision of Special Equipment specify three conditions for defining pressure vessels: 1) the operating pressure must be 1 kilogram or more; 2) the product of pressure and volume must be 2.5 MPa·L or more (in other words, if the pressure is 1 kilogram, the volume must be greater than 25 L); 3) there must be a gas phase space (the medium is either a gas or a liquid whose temperature is above its boiling point). The one upstairs is more comprehensive.
The working pressure must be 1 kilogram or more, and the product of pressure and volume must be 2.5 MPa·L or more (in other words, if the pressure is 1 kilogram, the volume must be greater than 25 L). There must also be a gas phase space (with the medium being a gas or a liquid whose temperature is above its boiling point).
The revised Regulations on the Safety Supervision of Special Equipment provide a definition: A pressure vessel is a closed device used to hold gases or liquids and capable of withstanding certain pressures. It refers to fixed or mobile containers in which the maximum operating pressure is 0.1 MPa (gauge pressure) or higher, and the product of pressure and volume is 2.5 MPa·L or higher, for gases, liquefied gases, and liquids whose maximum operating temperature is equal to or higher than their standard boiling point； Gas cylinders, liquefied gas cylinders, and cylinders for liquids with a standard boiling point of 60°C or lower, whose nominal working pressure at full charge is greater than or equal to 0.2 MPa (gauge pressure), and whose product of pressure and volume is greater than or equal to 1.0 MPa·L ； Oxygen chambers, etc.
Standards: Low-pressure (code L) vessels: 0.1 MPa ≤ p < 1.6 MPa; Medium-pressure (code M) vessels: 1.6 MPa ≤ p < 10.0 MPa; High-pressure (code H) vessels: 10 MPa ≤ p < 100 MPa; Ultra-high-pressure (code U) vessels: p ≥ 100 MPa. It can be seen that when the pressure inside the container is greater than 1 kilogram, it already belongs to a low-pressure container.
In addition to pressure, there are also requirements regarding volume and the gas-liquid phase.
Very comprehensive. The staff member mentioned by the original poster seems to consider you guys as experts as well; it’s probably not some kind of deception. There is no need to list all these conditions when inspecting pressure vessels. As an example, for the atmospheric tower in our atmospheric-pressure units, if the design pressure is 0.1 MPa, then it is considered a pressure vessel; if it is less than this value, it is not. The difference is that the former is under the supervision of quality oversight departments, while the latter only requires maintaining equipment records.
The Regulations on the Safety Supervision of Special Equipment provide a comprehensive definition of pressure vessels, and using this as a reference is absolutely correct!