Is there any rule stating that manholes cannot be installed on the side of tanks that hold highly hazardous substances or flammable liquids?

When designing and manufacturing pressure vessels that hold extremely or highly hazardous media, the following points should be taken into account: 1) For ferritic and low-alloy steel plates with a thickness of 12 mm or more (excluding the layers of multi-layer pressure vessels), used to construct the vessel shell and in cases where the toxicity level of the medium is extremely or highly hazardous, each plate must undergo ultrasonic testing in accordance with JB/T4730.3, with the inspection result having to meet a grade of at least II. —TSG R0004 (P6) 2.5 2) Cast iron shall not be used in pressure vessels containing extremely hazardous, highly hazardous, or moderately hazardous media. —TSG R0004(P6)2.6.1 3) The joint design between the nozzle (flange) and the shell, as well as the joint design of jacketed pressure vessels, shall adopt a fully penetrated weld design. —TSG R0004 (P15) 3.14.2 (1) 4) For pressure vessels designated in the design drawings to contain media with extremely high or high toxicity, it is necessary to prepare product welding specimens. —TSG R0004 (P20) 4.3.1 (4) 5) After passing the pressure test, pressure vessels with a medium toxicity level that is extremely or highly hazardous, or those for which minor leaks are not permitted according to the design, shall undergo a leakage test. —TSG R0004 (P27) 4.8.1 (1) 6) For pressure vessels containing explosive media or those that pose an extremely high, high, or moderate level of toxicity, ducts shall be installed at the discharge outlets of safety valves or rupture discs to direct the discharged media to a safe location where it can be properly disposed of; it is not allowed to discharge them directly into the atmosphere. —TSG R0004 (P38) 8.2 (3) 7) Level gauges are used on liquefied gas pressure vessels containing explosive and highly toxic media; they are equipped with protection devices to prevent leaks. —TSG R0004 (P39) 8.5.1 (5) 8) For containers whose medium toxicity level is extremely hazardous or highly hazardous, or for those in which even trace leaks are not permitted, a leakage test shall be conducted after the pressure resistance test is passed. —GB150.1 (P15) 4.7.2 9) For containers holding explosive media or media with extremely high, high, or moderate toxicity, a conduit shall be installed at the outlet of the relief device to direct the released medium to a safe location where it can be properly disposed of; it shall not be discharged directly into the atmosphere. —GB150.1 (P18) B3.10 10) Pressure relief disc safety devices cannot be used alone in situations where the toxicity of the medium is extremely high, highly hazardous, or where explosive substances or liquefied petroleum gas are involved; in such cases, they can be used in combination with safety valves. —GB150.1 (P19) B.5.3 11) The method for determining the design pressure of containers specified in Appendix C of GB150.1 via verification blasting tests shall not be used for the design of containers containing extremely hazardous or highly hazardous materials. —GB150.1 (P19) C.1.5 12) Steels 10, 20, and Q345D specified in GB/T8163 shall not be used for media with an extremely high or high degree of toxicity. —GB150.2 (P53) 5.1.3 e) 13) Steel pipes of Class III and Class IV as specified in GB/T12771 shall not be used for media with an extremely high or high degree of toxicity. —GB150.2 (P54) 5.2.4 b) 14) Steel pipes specified in GB/T24593 shall not be used for media with an extremely high or high degree of toxicity. —GB150.2 (P54) 5.2.5 c) 15) Steel pipes of Class IV as specified in GB/T21832 shall not be used for media with an extremely high or high degree of toxicity. —GB150.2 (P54) 5.2.7 c) 16) According to GB/T3274-2007 \"Hot-rolled heavy plates and strips of carbon structural steel and low-alloy structural steel\", 235B and Q235C steel plates shall not be used for media with an extremely high or high degree of toxicity. —GB150.2 (P87) D.1 g) 17) Carbon steel and low-alloy steel vessels used to contain media with extremely or highly hazardous toxicity shall undergo post-weld heat treatment. —GB150.4 (P332) 8.2.2.3 18) For containers holding media with extremely or highly hazardous toxicity, and those with Class A longitudinal weld joints, product weld specimens shall be prepared for each individual container. —GB150.4 (P333) 9.1.1.1 a) 19) For vessels containing media with extremely or highly hazardous toxicity, all Class A and Class B weld joints shall be subjected to radiographic or ultrasonic testing in accordance with the methods specified in the design documents. —GB150.4 (P335) 10.3.1 e) 20) For forgings whose medium is extremely or highly toxic, as well as those with a cross-sectional dimension greater than 300 mm, the requirements of Grade III or Grade IV shall be met. —HG/T20581 (P57) 6.4.3 21) For flanges connecting pipes inside containers that contain flammable or explosive media, or media with moderate or low toxicity (the classification of toxicity and explosion risk levels of such media is based on the standard HG20660-2000 \"Classification of Toxicity and Explosion Risk of Chemical Media in Pressure Vessels\"), the nominal pressure rating of these flanges should be at least 1.6 MPa; for flanges connecting pipes inside containers that contain media with extremely high or high toxicity, or media with strong permeability, the nominal pressure rating should be at least 2.0 MPa. —HG/T20583 (P437) 7.2.4 22) When the media inside the container are extremely hazardous, highly hazardous, or moderately hazardous due to strong permeability, or when the medium is liquefied petroleum gas, wafer-type butt-welded pipe flanges should be used for the connection pipes. —HG/T20583 (P437) 7.2.4 23) For vacuum vessels, vessels that store media with extremely high or high toxicity, and vessels using liquefied petroleum gas, those with medium to high nominal pressure should preferably be equipped with manholes of smaller nominal diameter. —H/T20583 (P441) 8.5.4 24) In cases where the toxicity of the medium inside the container is extremely high or highly hazardous, overall reinforcement (i.e., increasing the wall thickness of the shell) or the use of local overall reinforcement elements should be employed. —HG/T20583 (P443) 9.2.2 25) When the container holds flammable and explosive hazardous materials, as well as materials with moderate, high, or extremely high toxicity, the use of glass tube level gauges and glass float level gauges is not permitted. —HG/T20583 (P447) 10.1.3 26) When the medium contained in the container is extremely hazardous, highly hazardous, or moderately hazardous due to its strong permeability, fully penetrative welds should be used. —HG/T20583 (P489) 18.9.2 27) For low-temperature pressure vessels that are flammable or toxic and pose extremely high hazards, or those with a pressure of 1.6 MPa or higher, T-shaped connections should be made using seamless extruded tees or by welding thickened pipes after making openings in them. —HG/T20585 (P596) 7.0.6 28) For low-temperature pressure vessels that contain extremely or highly hazardous toxic media, or those with a design pressure of 1.60 MPa or more and that contain flammable media, butt-welded flanges shall be used for the vessel flanges and pipe flanges. —HG/T20585 (P597) 7.0.10 29) NB/T47003.1 \"Welded steel pressure vessels\" is not applicable to vessels used for containing extremely hazardous or highly hazardous media; the design, manufacture, inspection, and acceptance of welded steel pressure vessels shall be carried out in accordance with GB150. —NB/T47003.1 (P5) 1.3, Interpretation of NB/T47003.1 standard 30) NB/T47003.2 \"Solid Silos\" is not applicable to silos used for storing materials that are extremely or highly hazardous. —NB/T47003.2 (P185) 1.3

You can refer to this post at https://bbs.hcbbs.com/thread-1106963-1-1.html. In my opinion, it’s better to avoid swerving if possible, as doing so increases the risk of leakage

What criteria are used to classify the hazard level of media?

In Article 21 of the reply on the 2nd floor, there is