Regarding the classification of containers when the drawing indicates a “maximum allowable pressure”

1. The classification of containers should still be based on the design pressure. 2. The indicated maximum allowable working pressure is only for short-term use. 3. No description classifying by the maximum allowable operating pressure can be found in standards and specifications either.

I agree with your view. Classifying based on the maximum allowable operating pressure raises a series of problems. For example, if the wall thickness allowance of the equipment is large, the maximum allowable operating pressure assigned will likely be high as well, which may result in an equipment that should originally be classified as category two being classified as category three instead. Different classifications lead to varying requirements regarding materials, manufacturing processes, non-destructive testing, and so on, ultimately resulting in a significant increase in costs.

The purpose of classifying containers is to enable regulated oversight; of course, from a safety perspective, it is an artificial administrative regulation, and there’s no need to dwell on this issue – experts are just that, experts!

The maximum allowable pressure is intended solely for use with safety valves when ensuring airtightness; such high pressures are not normally required. The classification is determined by the design pressure, but whether it complies with regulations is specified by laws and standards. For example, if the design pressure is 1.6 MPa, it falls under Category 2, but if the actual operating pressure is 0.01 MPa, which is atmospheric pressure, then no regulatory oversight is necessary

1. The classification of containers should still be based on the design pressure. 2. The indication of the maximum allowable operating pressure is solely intended to ensure that, during a leak test, the safety regulations are not triggered, allowing for a proper setting of the safety valve pressure. 3. Operating pressure is the highest pressure that can be reached at the top of the vessel. 4. There is no literal connection between the maximum allowable operating pressure and the operating pressure.

Don’t experts say that it is the maximum allowable operating pressure that determines whether it falls under fixed-volume regulation? The classification is clearly based on the design pressure

Don’t experts say that it is the maximum allowable operating pressure that determines whether it falls under fixed-volume regulation? The classification is clearly based on the design pressure

Don’t experts say that it is the maximum allowable operating pressure that determines whether it falls under fixed-volume regulation? The classification is clearly based on the design pressure

The expert meant that it is determined whether it falls under the fixed-volume regulation based on the maximum allowable operating pressure, right?

Theoretically, I don’t quite understand it. Let me explain how I carried out the operations on site. Take the pressure testing of the heat exchanger before it started operating as an example: the design pressure is 4.0 MPa, while the operating pressure is 2.6 MPa. The head generated by the pump for the liquid passing through this heat exchanger is 276 meters, corresponding to a theoretical pressure of 2.76 MPa. So what should be the pressure used for the water test? Should it be the design pressure or the operating pressure? I used a pressure of 3.0 MPa for the testing; I didn’t use either of these two values. Instead, I relied on my experience. First of all, my power source can only reach 2.76 MPa without any losses. The design pressure refers to the fact that the equipment is designed to operate at 4.0 MPa, and it can handle such a pressure. The operating pressure means that the equipment can function properly when exposed to this pressure over a long period of time. Why didn’t I use 4.0 MPa? I was worried that applying such a high pressure for 30 minutes would cause fatigue in the sealing gaskets (which are made of metal and graphite), leading to leaks once the equipment starts operating at higher temperatures. Heat tightening also wouldn’t be effective in such cases. Theoretical matters can be expressed in writing, but practical matters need to be determined based on experience. After all, it’s a factory that has been in operation for over 50 years, and it has experienced numerous accidents; the experience gained from these incidents is certainly more practical than theory.