Pipe racks vertical arrangement

In the case of pipe loops it is sometimes possible to arrange all the hot pipes on one side of the rack, and to accept that all the hot pipes will be looped at the same point along the piperack, in which case the loop may be in the same plane as the rack pipes. Otherwise, and if there is any doubt about possibly conflicting design development or future needs, the loops should be stationed in a horizontal plane above the rack pipes, and the pipes connected vertically to the loops. 

Pipe racks within vertically structured or housed facilities cannot be defined as easily as for inline arrangements, because the equipment is usually located on several levels. The venical units are usually fed by conventional pipe racks at established elevations entering the structure at a designated area. Once inside the structure, piping should be routed in an orderly manner according to economic, constructibility, and support requirements. Exhibit 3-22 displays a typical process structure. 

EXHIBIT 3-22 Typical Pipe Rack in a Vertical Arrangement... 

Pumps 3A, 3B, 4A, and 4B are partially loc aied under the pipe rack, with the casing set outside the column line. In this arrangement, the cli.scharge piping can rise into the vertical slot that is usually provided... 

Exhibit 11-14 shows a typical arrangement for a hose station. Battery limit valving for a single-level pipe rack is shown in Exhibit 11-15. The valves are staggered on either side of the catwalk, and handwheel extension stems are furnished when necessary to facilitate operation. Exhibit 11-16 also displays a single-level rack. Here, however, an elevation change is required between the process unit and the off-site pipe rack. This design has the block valves installed in the vertical portion of the line, which allows for relative ease of operation. 

When complex equipment (e.g., a converter and fractionator in a fluid catalytic cracking unit) is designed, a stair structure with a vertical pipe rack must be located between both vessels, as shown in Exhibit 12-26. Although elevators are often used, diem approval must be obtained before they are included. The optimum layout includes arranging the vessel platforms for easy access from the structure. Clearance between the vessel and structure platforms must accommodate die growth of the vessels, which should be calculated to satisfy safety concerns. This structure eliminates the... 

A suction bell on the inlet of a vertical pump (or the inlet pipe of the suction side of a horizontal pump) is not necessary as far as pump or sump operation is concerned. If a bell is omitted, the entrance losses due to flow will be higher ith only a straight pipe, and this must be considered in pump operation. An economic comparison vsill help decide the value of the bell. Strainers should not be placed on suction bells unless this is the only arrangement. Inlet water should be screened with trash racks, bars and screens to keep the sump free of debris. 

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