Problems with buried storage tanks
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I learned this from discussions with colleagues: in a factory with limited space, if Class A and B storage tanks are placed on the ground, the required safety distance is not sufficient. So they came up with a solution by burying the tanks, which allows the required safety distance to be reduced. But I’m not sure whether storage tanks of Class A1 (such as liquefied gas, natural gas) with a capacity of under 200 m3 can be buried If possible, what standards should be followed for the design?
I. Standards for horizontal oil tanks: 1.1 Designed in accordance with the R11 and R112 catalogues for horizontal oil tanks, and used in industrial oil depots, gas stations, and other facilities for storing fuel oils； 1.2 Scope: Constant pressure, temperature ranging from -19°C to 200°C; the medium is fuel oil (diesel, gasoline, etc.). 1.3 “Steel Pressure Vessels” GB 150-1998; “Welded Steel Pressure Vessels at Constant Pressure” JB/T 4735-1997. 1.4 “Welding Procedures for Steel Pressure Vessels” JB/T 4709-2000; “Non-Destructive Testing of Pressure Vessels” JB 4730-9. II. Types of horizontal oil tanks: 2.1 The flow diagram of the fuel supply system is shown in the chart; 2.2 Above-ground horizontal oil tanks and underground horizontal oil tanks: manufacturing drawings for capacities of 5–100 M3, installation diagrams, and tables of basic parameters; 2.3 Diagrams of the operation wells for underground horizontal oil tanks, diagrams of the welding methods for tank connections, and diagrams of the internal ladders in horizontal oil tanks. III. Volume of horizontal oil tanks: The total volume should be determined based on factors such as the mode of transportation and the fuel supply cycle; for transportation by train or ship, it should be at least equal to the maximum consumption over a period of 20–30 days ； For road transport, the maximum consumption over a period of 5 to 10 days or more ； Pipelines should transport an amount equal to at least 3–5 days’ maximum consumption. For office buildings, the daily operating time of fuel-powered equipment is taken as 12 to 16 hours ； For high-end residential and hotel buildings, the daily operating hours are 16 to 24 hours. IV. Installation of horizontal oil tanks: 4.1 The thickness of the soil covering the top of the buried oil tank should be no less than 0.5 m. Fill the surrounding area with clean sand or fine soil, with a thickness of not less than 0.3 m ； 4.2 The selection of ladders for the oil tank operation platform is determined in a unified manner; the buried operation well is designed for buried horizontal oil tanks, and the two are designed to work together effectively ； 4.3 In areas with high groundwater levels, the selector should adopt anchoring measures to prevent floating of buried horizontal oil tanks ； 4.4 Oil tanks can be used for heavy fuel oils; the heaters require separate design. The installation of bottom valves and connections at the material outlet of buried tanks is something that the user should consider ； 4.5 Apply lightning protection, anti-static, and fire prevention measures. Internal corrosion protection should be determined based on the storage medium, while external wall corrosion protection should be determined based on the quality of the soil in which the tank is buried ； 4.6 The outlet of the vent pipe shall be at a height of 4 m or more above the ground level; the nominal diameter of the vent pipe shall be not less than 50 mm, and a flame arrester shall be installed.
Storage tanks that can generally be buried are usually horizontal tanks or similar types; those that do not require insulation or cooling measures on the outside can be considered for burial. However, once buried, appropriate safety measures must be put in place, otherwise it may become even more dangerous.