[ask for help] what is the classification of a class of pressure vessels and two categories?

It is classified according to the pressure inside the container.
Three types of containers. One of the following cases is three types of containers:
(1) high pressure vessel;
(2) medium pressure vessels (toxic to extreme and highly hazardous medium);
(3) medium pressure storage container (inflammable or toxic degree is moderate hazard medium, and design pressure and volume PV≥ 10MPa· m3;
(4) medium pressure reaction vessel (inflammable or toxic degree is moderate hazard medium, and PV≥ 0.5MPa· m3;
(5) low pressure vessels (toxic degree is extreme and highly harmful medium, and PV≥ 0.2MPa· m3;
(6) high pressure, medium pressure tube shell type waste heat boiler;
(7) medium pressure glass lined pressure vessel;
(8) use pressure vessel with high strength level (lower limit of tensile strength specified value ≥ 540MPa);
(9) mobile pressure vessels, including Railway Tankers (liquefied gases, cryogenic liquids), tank cars (liquefied petroleum gas)
Body, cryogenic liquid or permanent gas carrier) and tank containers (medium for liquefied gases, cryogenic liquids);
(10) spherical tank (volume V≥ 50m3);
(11) cryogenic liquid storage container (V≥ 5M3)
Two types of containers. One of the following two categories is not in the first paragraph:
(1) medium pressure vessel;
(2) low pressure vessel (toxic degree is extreme and highly harmful medium);
(3) low pressure reaction vessel and low pressure storage container (inflammable medium or toxic degree is moderately hazardous medium);
(4) low pressure tube shell type waste heat boiler;
(5) low pressure glass lined pressure vessel.
A class of containers. Low pressure vessel and not within first and second paragraphs.
The degree of toxicity of chemical medium and the classification of flammable medium in pressure vessels can be referred to the relevant provisions or the following
Then:
The maximum allowable concentration is < and 0.1mg/m3 is extremely dangerous (grade I).
The maximum allowable concentration is 0.1 ~ < 1.0mg/m3 is highly harmful (grade II).
The maximum allowable concentration is 1 ~ < 10mg/m3 is moderate hazard (grade III).
The maximum allowable concentration is &ge, 10mg/m3, which is a slightly hazardous toxic medium (grade IV).
The lower explosive limit of mixture of medium and air is < 10% or the difference between the upper and lower limits of explosion is > the 20% is flammable medium.
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