Everyone, take a look: how many categories can we classify these jacketed tanks into?

I understand this discussion now! Currently, the classification of special equipment is carried out in accordance with the requirements of TSG 21-2016. It’s sufficient to understand a few key points: classification is indeed based on design parameters rather than operating pressure; training institutions are correct in this regard, but the actual classification also takes into account the medium and the PV value ； This jacketed tank consists of an inner cylinder and a jacket, representing two separate pressure-bearing systems: the inner cylinder is designed for a pressure of 0.1 MPa and has a volume of 10 m³. Formaldehyde is a flammable/moderately hazardous substance; its PV value amounts to 1 MPa·m³, which is below the PV threshold for class II low-pressure vessels. The inner cylinder itself actually belongs to class I ； However, the design pressure of 1.5 MPa for the jacket corresponds to medium pressure; medium-pressure vessels themselves fall under Category II pressure vessels ； In the case of a comprehensive inspection, the overall category is generally determined based on the highest-rated pressure-bearing component among the equipment, so it is reasonable to classify it as Category 2. For accuracy, please refer to the relevant regulations and verify the parameters accordingly.

This post was last edited by Siege Lion_peyWD on 2026-7-16 10:10 ------------

If the working pressure of the inner cylinder is less than 0.1 MPa, it does not fall under the regulations for solid containers; so how can it be classified?

This post was last edited by Engineer_peyWD on 2026-7-16 10:11 ----

The prerequisite for this classification is compliance with Article 1.3 of TSG21, before classification can be carried out

Right, only pressure vessels are classified

Multi-chambered containers need to be classified separately, with the highest category determining the classification of the entire container