Design of fire dike in the hottest storage tank ar

2022-09-27
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Design of fire dike in storage tank area - material selection of fire dike (9)

the building code and the stone code stipulate that the fire dike should be made of non combustible materials. Common materials include soil, block stone, reinforced concrete and clay brick, which meet the requirements of the specification, and each has its advantages and disadvantages:

1. Soil embankments are mostly seen in the fifties and sixties of the last century, and their cross sections are trapezoidal. According to the requirements of the specification, the width of the top of the embankment should not be less than 0.5 meters to ensure its stability. The advantages of earth embankment are very obvious: economy; The disadvantage is that the earth volume is large, the floor area is large, and it is necessary to plant turf on the surface of the earth embankment to prevent soil loss. The cost of sea transportation is low. Large oil depots are mostly set up by wharfs, and every inch of land and money in the port area is scarce; In addition, it is difficult to survive by planting turf on the seashore. Therefore, the use of earth embankments is not ideal

2. Block stone embankments are mostly used in the oil depot area near the mountain, with thick appearance. Their advantages are local materials, economic and reliable, and good strength and sealing at room temperature. Its disadvantage is that under the high temperature after the oil port is on fire, due to the thermal expansion and thermal dispersion, the block stone is easy to crack and collapse, and even if necessary, it will be handled in detail according to the instructions, which will affect the accuracy; The latter uses servo electromechanical with high cost and complete destruction; In addition, when fighting a fire, the fire extinguishing agent is sprayed on the hot stone, causing the surface to cool sharply. Under the action of high temperature, the CaCO3 decomposition products of the rock are hydrated into Ca (OH) 2 in quicklime Cao, which intensifies the rock damage and loses the function of fire dike. This unfavorable factor is often ignored by designers

3. The reinforced concrete embankment is relatively common, which is mostly found in small and medium-sized oil tank areas. Its advantages are high strength, good sealing, and less floor area; Its disadvantages are uneconomical, complex construction and poor high temperature resistance. Under the action of high temperature, the concrete will dehydrate and crack, and the strength and tightness will be affected. In addition, when the concrete is suddenly cooled by water gun spraying at high temperature, its compressive strength is lower than that in hot state; The strength of the reinforcement is based on the high temperature of 500 ℃ to avoid the loss of electric shock. According to the test of Sichuan Fire Research Institute, the strength of concrete decreases by half at the temperature of 500 ℃. A common solution is to spray a suitable fire retardant coating on the inner side of the concrete embankment

4. brick dike is an ideal fire dike with good fire resistance. Its strength and sealing performance do not change significantly under high temperature conditions, which can ensure the stability of fire dike under fire conditions. It is worth pointing out that clay bricks have good resistance to rapid cooling and heating, and are not easy to be damaged by water injection under high temperature. Its disadvantage is high cost. In order to bear the static pressure of the oil products, there are certain requirements for the cross-section size of the brick dike, which is mostly trapezoidal cross-section. With the foundation, the amount of bricks used in the whole brick dike is relatively large

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