Fixed cone roof tanks

Fixed (cone) roof tanks Vent fire Overfill ground fire Unobstructed full liquid surface area Obstructed full liquid surface fire if frangible roof remains partially in tank For volatile liquids, the rich vapor space typically prevents ignition within the tank. Environmental regulations typically prevent storage of Class 1 flammable liquids in larger fixed roof tanks. 

C37) 4 No foam system recomrrrended, Fexed foam system for seal fire may be provided if desired. Yes Tank desi provides lightning p(ttectk>n Yes Same requirement as fix cone roof tanks. Vere according to API sdbsa... 

Fixed cone roof vertical cylindrical tanks in diameters larger than 30-50 feet (9-15 m), should have a weak seam or weak seam roof. These are intended to respond to an internal overpressure by being blown off and allowingthetankto retain its integrity of content containment. Design of an effective weak seam roof becomes increasingly difficult as the diameter decreases. 

Table 8-12 summarizes the protection measures that should be provided for vertical atmospheric storage tanks to protect them against fire risks. Fixed or semi-fixed fire protection for cone-roof tanks should be provided as follows ... 

Cone roof tank—an atmospheric storage tank with a fixed cone-shaped roof. 

Cone roof tank with internal floatingcover—an atmospheric storage tank with a fixed cone-shaped roof and an internal floating cover of one of the following designs ... 

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,... 

Cone-roof tank This is a low-pres >ure storage tank that has a fixed, cone-shaped roof. 

Fig. 4. Fixed-roof tanks (a) self-supported cone roof (b) center-supported cone roof (c) column-supported cone roof and (d) dome or umbrella roof...

Open Tanks These may be used to store materials that will not be harmed by water, weather, or atmospheric pollution. Otherwise, a roof, either fixed or floating, is required. Fixed roofs are usually either domed or coned. Large tanks have coned roofs with intermediate supports. Since negligible pressure is involved, snow and wind are the principal design loads. Local building codes often give required values. 

Fixed-Roof Tanks. The effect of internal pressure on plate structures, including tanks and pressure vessels, is important to tank design. If a flat plate is subjected to pressure on one side, it must be made quite thick to resist bending or deformation. A shallow cone-roof deck on a tank approximates a flat surface and is typically built of 3/ 16-in. (4.76-mm) thick steel (Fig. 4a). This is unable to withstand more than a few inches of water column pressure. The larger the tank, the more severe the effect of pressure on the structure. As pressure increases, the practicality of fabrication practice and costs force the tank builder to use shapes more suitable for internal pressure. The cylinder is an economic and easily fabricated shape for pressure containment. Indeed, almost all large tanks are cylindrical. The problem, however, is that the ends must be closed. The relatively flat roofs and bottoms or closures of tanks do not lend themselves to much internal pressure. As internal pressure increases, tank builders use roof domes or spheres. The spherical tank is the most economic shape for internal pressure storage in terms of required thickness, but it is generally more difficult to fabricate than a dome- or umbrella-roof tank because of its compound curvature. 

Fixed Roof Tank—These consist of a cylinder shaped base with a permanently attached typically cone shaped roof. They normally store high flash point liquids. The cone shaped roof reduces environmental emissions and provides additional strength... 

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. 

Vertical cylindrical tanks can be categorized as fixed roof tanks, with either a cone or dome roof construction, or floating roof tanks. 

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