Discussion on designing propylene oxide storage tanks as spherical tanks

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According to the scope requirements of AQ3053-2015, it does not apply to vertical cylindrical welded steel storage tanks with storage media of extremely toxic or highly toxic toxicity. Indeed, in this project, there are two 3000 m³ propylene oxide tanks that are not covered by this standard; however, this does not mean that they need to be designed as spherical tanks. Because in Section 4.2 of SH/T3007-2014, the Design Code for Storage Areas in Petrochemical Storage and Transportation Systems, under the subsection on tank selection, Article 4.2.10 stipulates that liquid storage tanks used for storing substances of Category A and B with toxicity levels of Grade I (highly toxic) and Grade II (highly toxic) should not have a capacity exceeding 10,000 m³, and such tanks must be equipped with a nitrogen or other inert gas-based sealing protection system ； At the same time, clause 4.2.4 also specifies that for Class A B liquids with a boiling point below 45°C or a saturated vapor pressure greater than 88 kPa at 37.8°C, pressure tanks, low-pressure tanks, or atmospheric-pressure tanks with cooling systems should be used, along with appropriate protective measures. Furthermore, according to the HG20660-2017 Standard for Classification of Toxicity Hazards and Explosion Risks of Chemical Media in Pressure Vessels, propylene oxide is classified as a highly toxic medium (Grade II). (Among them, propylene oxide is a new addition.) 1. For storage tanks containing extremely toxic or highly toxic substances that are not covered by AQ3053-2015, it only indicates that this standard does not apply; therefore, there must be other standards to regulate such situations. Are there any other safety-related standards that can be used as references? 2. If not, SH/T3007-2015 can be used as a reference standard. Designing propylene oxide storage tanks as vertical cylindrical welded steel tanks should not raise any issues regarding design responsibility, right? 3. For most projects in China at present, I don’t think any company has designed propylene oxide storage tanks as spherical tanks yet Dear sea friends, please share your own opinions. It would be best to have experts in safety or standards available to provide clarification! ! ! Thank you! ! ! :P