Tanks, types cone-roof tank

A cone roof tank with an internal floating roof that does not meet these criteria or uses plastic foam for flotation, even if encapsulated in metal or fiberglass, should be fire protected by side wall foam chambers suitable for the full (surface) area of the tank. This type of internal floating-roof installation is not recommended, particularly for flammable liquids. 

The foam concentrate used with subsurface systems should be a fluoroprotein type for best results, although some AFFF foams are listed for substitutable application (because of their "fuel shedding" properties). The minimum foam solution rate should be 0.3 gpm/ft (12 Ipm/m ). The supply of foam liquid should be adequate to operate the system for 20 minutes. The foam injection point must be above the level of any residual water in the bottom of the tank. Subsurface foam application is not recommended for open or covered floating roof tanks or cone roof tanks with internal floating covers. 

A TANK is required to store the one week production capacity from the nitric acid plant. This storage buffer allows the plant to continue operation for up to one week in the event of an unforeseen shutdown in the adjacent ammonium nitrate plant. The tank is a fixed cone-roof cylindrical-type design,... 

Two types of designs are commonly applied. For cone top tanks or internal floating roof tanks with other than pontoon decks, multiple foam makers are mounted on the upper edge of the tank shell. These systems are designed to deliver and protect the entire surface area of the liquid of the tank. For open and covered floating roof tanks with pontoon decks, the foam system is designed to protea the seal area. Foam makers are mounted on the outside of the tank shell near the rim and foam is run down inside to the seal area that is provided with vertical barrier adjacent to the seal area i.e., a foam dam to hold the foam in the seal area. This method tends to cause the movement of cooler product to the surface to aid in extinguishment of... 

Flat bottom tanks with targe diameter and fixed roof normally are designed with column-supported roofs. As the diameter gets smaller, self-supporting roofs become more economical. Dome and cone roofs are the most popular types. 

A variety of symbols are used to illustrate the different type of tanks and vessels found in the chemical processing industry, including bins, drums, and dome, cone, open-top, floating-roof, and spherical tanks. Process symbols are designed to graphically display the vessel as it appears in the field. Common pump and tank symbols are shown in Figure 7-8. 

The most common sliapi for a tank rcxjf is a cone although dome or umbrella nMil s are also used. In addilion to these nhape dti.ssifications, tank roofs may be classified into two types, self-supporting and ncmself-suppprling. 

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