4. Excellent seismic performance; the seismic requirement for general buildings is to crack under specified loads but not collapse. To ensure the safety of the storage tank under unexpected loads, it must have good seismic performance. For LNG tanks, it is required that they neither collapse nor crack under specified loads. Therefore, the selected construction site generally avoids fault zones, and seismic tests must be conducted on the tank before construction to analyze the structural performance of the tank under dynamic conditions, ensuring that the tank does not sustain damage under given intensities. 5. LNG tanks can withstand low temperatures; the boiling point of liquefied natural gas at normal pressure is -160°C.

Lng tank design should accommodate top and bottom filling
ASME Storage Tank
Basic Design Requirements
The using unit should specify the maximum allowable working pressure, including the range above the normal operating pressure; and the maximum allowable vacuum degree.
Components and materials that are frequently in contact with LNG in LNG storage tanks, as well as those that come into contact with LNG or cryogenic LNG vapor [vapor at temperatures below -29°F (-20°F)], should be compatible with LNG in terms of physical and chemical properties, and suitable for use at -168°C (-270°F).
All pipeline systems as part of the LNG tank shall comply with the provisions of Chapter 6. These tank pipeline systems should include all pipelines inside, within the insulated space, and within the vacuum space of the tank, as well as the external pipelines attached to or connected to the tank up to the point where they connect to the pipeline. This provision does not include the entire inert gas blanketing system located within the insulated space. For ASME tanks, all pipeline systems that are part of the tank, including the pipelines between the inner and outer tanks, shall comply with Volume VIII of the ASME Boiler and Pressure Vessel Code or ASME B31.3 Process Piping. Compliance with the standards should be indicated or attached to the Table U-I of the "Pressure Vessel Manufacturer Data Report" in the Appendix W of the ASME Boiler and Pressure Vessel Code.
All lng storage tanks should be designed for top and bottom filling, unless other effective measures to prevent separation are in place (see 11.3.7).
The outer surface of the lng storage may accidentally come into contact with a substitute temperature due to leaks of lng or low-temperature vapor at flanges, valves, seals, or other non-welded joints. Therefore, it should be operated at an appropriate temperature or protected from such contact.
Within a shared dike, there are two or more storage tanks. The foundation of the tanks must be capable of withstanding contact with the national LNG or be equipped with protection to prevent the accumulation of LNG from compromising the structural integrity.
The density of the liquid should be set as the mass per unit volume at the low storage temperature, except for densities greater than 470 kg/m³ (29.31 lb/ft³).
lng tank design should accommodate top and bottom filling

1.2.6 LNG Storage Tank Maintenance and Maintenance Procedures
LNG station operation technicians must be familiar with the structure and principles of the storage tanks and strictly adhere to the operational procedures for all LNG-related activities.
2. Operators of Liquefied Natural Gas must be familiar with the performance and principles of the storage tank accessories (pressure gauges, level indicators, temperature gauges, vacuum degree testing valves).
3. The outer shell of the liquefied natural gas tank is an externally pressurized vacuum vessel; welding operations are strictly prohibited under negative pressure.
4. Regularly inspect the outer shell of the storage tank for signs of icing or frost. Upon detection, promptly report to the on-duty supervisor and station master. The on-duty supervisor or station master should immediately contact the manufacturer to identify the cause and initiate immediate action. During the process, closely monitor the changes in icing or frost. If there is a tendency for the accident to escalate, immediately proceed with tank draining or cease filling operations, and close the relevant emergency shut-off valves for inflow and outflow.
5. Regularly inspect the storage tank's connecting pipes, valves, etc., for frost formation. Report any issues to the on-duty supervisor immediately, who will then arrange for personnel to address the situation.
6. Regularly inspect the tank's pressure gauge, level gauge, and thermometer to observe if the readings are normal.
7. Regularly inspect the sealing performance and operation of the connecting valves to ensure normal functioning.
8. Regularly inspect and calibrate safety valves, pressure gauges, level gauges, and thermometers according to regulations, ensuring proper operation and timely updating of equipment inventory.
9. Regularly perform anti-corrosion treatments on the outer shell of storage tanks and maintain the appearance by cleaning and maintaining the pressure gauges, level gauges, and thermometers on the tanks.
10. Regularly perform rust removal and anti-corrosion treatment on the easy-to-rust areas of storage tanks, such as pressure gauges, level control instruments, and three-way valves.
11. Perform annual or as-needed vacuum level inspections on the storage tanks to monitor their operational status.

If temperature, pressure, and other parameters fluctuate, the ability to determine the cause of the fluctuation based on the equipment's principle and changes in other parameters is essential. Analyze each parameter individually. For instance, if there is a significant difference in the temperature between the first and second cylinders of the compressor, after comparing past records and confirming abnormal parameters, accurately analyze the cause and promptly contact the equipment manufacturer for resolution. In addition to parameter fluctuations, the ability to promptly identify and address other abnormal equipment conditions, such as excessive vibration, gas leaks, or unusual noises, is crucial. Failure to address these issues promptly could lead to increased losses. It requires experience accumulation and continuous improvement in equipment management during our daily work.