Equipment elevations

Towers, drums and exchangers can be elevated for the following reasons. 

Pump Net Positive Suction Head. A pump with a high OTSH requirement pushes equipment to a higher elevation, increasing the cost of piping and supports. On the other hand, a pump with a lower NPSH may cost more. The difference in support and piping costs must be considered in the selection of a more expensive pump with a lower NPSH. 

With turbine surface condensers, it often pays to choose a pump with a low NPSH, especially when die condenser is directly below the turbine. The compressor house floor can be lowered. With the lower elevated condenser, operation and maintenance access is improved. Vertical pumps are usually specified with a minimum height from grade to equipment because their suction inlet nozzle is below grade. 

If for some reason equipment is elevated above the required NPSH, a reduction in line size and pump differential is often possible. 

Grade Location. The most economical and common location of process equipment is at grade. Supporting structures and platforms are not required. Construction is easy. Most valves and instruments can be made accessible firom grade. Operation and maintenance are convenient. Elevated equipment with its structures, platforms, handling beams, etc. means cost increases in several design areas. 

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Maintenance shops—electric, piping, sheet metal, machine, welding. Raw-material and finished-product handling equipment—elevators, hoists. 

Auxiliary Equipment Elevating conveyors must be equipped with some form of holdback or brake to prevent reversal of travel and subsequent jamming when power is unexpectedly cut off. Ratchet and wedge roUer-type holdbacks are commonly used. Solenoid brakes and spring clutches may also be employed. 

Building or structure, including heating equipment, elevators, dock, windmill, wharf and jetty... 

Confirm hydraulic calculations on all pump circuits and establish pump NPSH and minimum equipment elevations. 

DetailedLayout The detailed layout specifies the locations of main equipment and equipment elevations. 

The piping designer needs three essential source documents engineering flow diagrams, nomenclature, and equipment elevations. These documents are usually furnished by the piping analyst. 

Engineering flow diagrams do not present all the essential information for the piping designer. They do not include equipment elevations and insulation specifications, which may be obtained from the equipment elevation summary and from the nomenclature list. 

Liquid Flow Measurement. The requirement of accurate liquid flow measurement can also elevate process equipment (see Figure 7-8). If liquid is near the boiling point, a static head is required in the front of the control valve to overcome pipe friction losses and avoid flashing in the line. Minimum equipment elevation, orifice range and minimum line size can be used if the orifice is as close to the equipment as possible and the piping has only one elbow up to the control valve. 

Hoisting devices have some of the same hazards as other materials handling equipment. Elevated materials can fall on people or items below. Structural failure can occur when loads exceed equipment capacity. Hoisting equipment may become unstable and tip over under certain loading or environmental conditions. Equipment or load failures are likely to cause damage, injury, or death. Operators may have limited visibility and need help to lift and position loads. 

Hoisting Equipment Elevators Regular inspections completed and recorded In good operational condition Suitable of objects lifted Rigging is proper Proper training in operation ... 

Building and Equipment (Elevation View). . . Building and Equipment (Plan View). 

Figure 19 is a cutaway view of the reactor building and equipment elevation and plan are shown in Figs. 20 and 21, respectively. 

If equipment elevation is 25 ft above fire source, it is assumed that it will not be exposed to fire. 

Riding hazardous moving equipment. Moving equipment poses a hazard by its very nature. Trucks, trailers, powered equipment, equipment elevators, and conveyors can cause injury to someone who decides to ride on them. The rule of no riders is essential in any list of warehouse safety rules. Employees can easily fall off of the moving equipment or become trapped between machines, rollers or moving parts. 

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