Is the half-tube subject to regulatory oversight?

The diameter is not 150 millimeters or more as specified in the tolerance rules; to meet the requirements for a container, all the conditions outlined in those rules must be satisfied simultaneously

I think this statement is also correct; vacuum containers are not subject to dimensional tolerance inspections. In my opinion, vacuum vessels suffer from instability-induced failure, and their hazard level is much lower than that associated with strength failures in vessels under internal pressure; therefore, regulatory standards do not apply to them.

OP, I personally think the answer is incorrect, as the question is too vague. Coils certainly fall outside the scope of regulatory oversight because they don’t meet the requirement specified in clause 2 of the regulations – namely, an inner diameter of >=150 mm. As for vacuum vessels (with Dg=2500 L-2900), it’s impossible to determine whether they are subject to such regulations. First, the pressure difference between the inside and outside isn’t specified; is it greater than 0.1 MPa? Second, it’s not clear whether the maximum operating temperature exceeds the standard boiling point of the medium contained within them. Since these points aren’t clearly stated, it’s impossible to determine whether such vessels are subject to regulatory oversight. But stating outright that they aren’t subject to such regulations is incorrect. These multiple-choice questions often use such tricks to deceive people; OP must have fallen for it..:L

:The L... vacuum vessel is also under scrutiny; you can take a close look – there’s a note 1 in its second section, which states that for vessels subjected to external pressure, a maximum operating pressure of >=0.1 MPa refers to the maximum working pressure difference between the inside and outside of the vessel...

It should be subject to regulatory oversight. Refer to the \"Training Manual for Pressure Vessel Design Engineers\"

:'(Vacuum cannot be reduced to -0.1 Mpa; therefore, the requirement regarding the maximum operating pressure specified in the regulations cannot be met. Note 1, item 2 of the regulations applies mainly to vessels under external pressure (jacketed vessels), based on my personal understanding.)

Based solely on the question, I think the answer is “correct”. Reason: 1. The half-pipe does not meet the requirement in Article 2, Paragraph 1 of the Code for Containers, which stipulates a diameter of 0.15 m or more ； 2. The interior of the container is under vacuum, that is, the pressure is negative, which fails to meet the requirement specified in the Container Regulations that the maximum operating pressure should be greater than or equal to 0.1 MPa. As for the issue of pressure difference, there is no need to elaborate; the container wall is subjected to the combined effect of vacuum and jacket pressure, which constitutes an external pressure design and is not covered by the Container Code. As for other conditions, such as the medium, there is no need to consider them, because this is just a true/false question; if even one condition is not met, it is not applicable to the Pressure Vessel Regulations.

Note 1 on pressure differences in the Code of Practice is not clear enough, and many industry professionals have misunderstood it, resulting in the classification of many jacketed vessels that are not covered by the Code of Practice. Regarding the pressure difference mentioned in Note 1, it results in a negative pressure for the inner cylinder; it is important to note that this value is negative. Article 2 of the Pressure Vessel Regulations requires that the maximum operating pressure be greater than or equal to 0.1 MPa, and since the value is negative, it is certainly less than 0.1 MPa. Please do not take the absolute value of this negative number before comparing it with the requirements specified in the Pressure Vessel Regulations.

Vacuum vessels with outboard heating coils (Dg100, P=0.8MPa, V=0.3m3) (Dg=2500 L-2900) are not subject to vessel code supervision. It is incorrect. I remember the teacher saying that it is subject to tolerance monitoring; specifically, the diameter of the half-pipe cannot be considered as DN100 – the diameter of the container must also be taken into account. In other words, the diameter of the outer half-pipe is DN2600, and as long as the medium meets the relevant classification criteria, it should be classified accordingly.

After hearing you explain it, I’m also confused, because I’ve always thought that such containers are not regulated； If you are right, then such containers must be regulated and regularly inspected.

After hearing you explain it, I’m also confused, because I’ve always thought that such containers are not regulated； If you are right, then such containers must be regulated and regularly inspected. Could you provide an authoritative explanation? Thank you.

Dg is not needed now; use DN instead