Pipe racks 90° turns

Multielevation piperacks are usually needed to handle all the required services for piping, electrical, utilities, and instmmentation. The two-level rack is one of the most common but three-level ones are also used. The utility lines are usually mn in the upper level and the process lines in the lower levels. The larger-diameter lines are located to the outside of the rack to be closest to the column supports. Access platforms are required at the battery limit to provide operators access to the block valves and blinds. If long mns of hot pipe are required, a portion of the pipe rack needs to be dedicated to an expansion loop. A horizontal space in the piperack is provided for a set of lines to be flat-turned into a set of expansion loops with the large pipes located on the outside. AH of the pipe turns are in the same horizontal plane, which is an exception to normal piping practice. A flat turn takes up and blocks space for other pipes. Flat turns are generally only made from the outside of the rack to minimize this blockage. 

Determine distance from each motor to motor control center, follow pipe racks routing and allow at least 10% for miscellaneous turn and deviations from the shortest route. The maximum distance should not exceed 500 ft., otherwise several transformers and/or motor control centers at separate locations may be required. 

Air hoists are commonly used on rigs and during production activities rig hands can be struck-by swinging objects such as drill pipe or casing as it has been hoisted up the pipe rack. As the load is lifted, the pipe may swing, twist, or turn. The traveling block that moves up and down inside the mast can also strike the derrickman or the casing stabber. 

Occasionally, a situation arises in which a flat-turn pipe rack may be employed. This often happens near a dead-end area where Ae potential for problems is minimal. As shown in Exhibit 11-28, the line sequence... 

Figure 12 shows the plan and elevation views of a process unit piping (9). A dmm is supported off the piperack. Heat exchangers are located far enough back from the support columns so that they are accessible and their shell covers can be removed. Pumps are located underneath the piperack, but sufficient room is provided for maintenance equipment to access the motors and to remove the pump if necessary. The motor is always oriented away from the process equipment and located on that side of the piperack. Instmment valve drops are shown supported from the columns. The instmment trays themselves mn on the outside of the support columns. Flat turns are only made from the outside position of the piperack. Nozzle-to-nozzle pipe mns are made whenever possible. Larger lines are located on the outside of the piperack. Connections to nozzles above the rack are made from the top... 

Figure 7-57. This is a typical elevation for yard piping intersection. Notice that the 14-foot elevation of the lateral rack permits turning up or down at the intersection.

Allow for proper turning and positioning clearances when moving loads. The stacked product can easily strike other product, racking, electrical equipment, sprinkler pipe, or parts of the building structure. 

---