The classification of pressure vessels
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Currently, there is a type of pressure vessel with a relatively small volume—less than 1 cubic meter. It is typically used to contain volatile liquids. Such equipment must be transported via freight vehicles before being delivered to customers for use; after use, it is returned. May I ask how such equipment should be classified? I believe it might not be appropriate to classify it as a stationary pressure vessel. But should it be classified as a mobile pressure vessel, or as a gas cylinder? This involves various stages such as design, manufacturing, transportation, and usage; therefore, I would appreciate guidance from professionals.
A stationary pressure vessel refers to a pressure vessel that is installed and used in a fixed location. Pressure vessels that must meet all of the following conditions: 1. The operating pressure is greater than or equal to 0.1 MPa
A stationary pressure vessel refers to a pressure vessel that is installed and used in a fixed location. Pressure vessels must meet the following conditions simultaneously: 1. The working pressure is greater than or equal to 0.1 MPa. 2. The volume must be ≥0.03 m3, and the inner diameter must be ≥150 mm. 3. The medium filled is a gas, a liquefied gas, or a liquid whose maximum operating temperature is higher than or equal to its standard boiling point. This is a requirement in the Safety Technical Supervision Regulations for Stationary Pressure Vessels.
It depends on whether you’re transporting with a medium or empty. In the latter case, it should be a fixed type.
Currently, this device definitely needs to contain a medium, and it must also be delivered to the customer. In other words, the device serves as a container. However, this container is meant to be reused. Based on this understanding, shouldn’t it be classified as a gas cylinder? However, according to the relevant regulations regarding pressure vessels, gas cylinders generally contain inert gases such as nitrogen, argon, and carbon dioxide, or easily liquefiable gases like liquefied petroleum gas. They may also contain dissolved gases such as acetylene, as well as toxic gases like chlorine. Mobile pressure vessels typically include tank trucks and rail tank cars. In my case, the medium is a liquid that can easily vaporize; therefore, there must be pressure inside the container. The pressure is below 0.2 MPa, and the volume of the container ranges from 200 to 1,000 liters. It’s clear that this constitutes a pressure vessel. The problem is determining whether it should be classified as a mobile pressure vessel or a gas cylinder. This classification affects procedures such as registration and annual inspections. If it were a gas, issues related to gas filling would also come into play.
If the transportation is by road (national or provincial highways), it must be considered as a mobile container.
Personal opinion: If the equipment is filled with a medium before transportation, it definitely falls under the category of mobile pressure vessels. However, if the empty equipment is transported to the user, filled with the medium, and then the medium is drained after use before being shipped back, it should be classified as a stationary pressure vessel