PLANT PIPE RACK GUIDELINES

PLANT PIPE RACK GUIDELINES FOR PLOT PLAN

 

1. In general, pipe racks for process Units and pipe sleepers for the off-site facilities shall be considered as the principals support of the pipe way. Run pipe lines overhead should be grouped in pipe racks in a systematic manner.

2. Pipe rack runs oriented in the same direction shall be at consistent elevations. Pipe rack runs oriented opposite to these runs shall be at other elevations to accommodate crossing of lines at pipe racks junctions and to accommodate branch line intersections.

3. Single level pipe racks are preferred, if more than one level is required, the distance between levels oriented in the same direction shall be adequate for maintenance but not less than 1.25 meters.

4. Maximum pipe rack widths shall be 10 m. If widths larger than 10 m are required, the pipe rack shall be designed to be of two stages. Actual widths shall be 110% of the required widths or the required widths plus 1m. In cases where air fin coolers are to be placed on the pipe racks, the pipe rack widths shall be adjusted based on the length of the air coolers.

5. Avoid flat turns. When changing directions, change elevation.

6. Allow ample space for routing instrument lines and electrical conduit. Provide 25% additional space for future instrument lines and electrical conduit adjacent to that required.

7. Provide 20% additional space on the pipe rack for future piping. This space shall be continued and clear on each level for the full length of the rack. The width allocation may be split in two sections but not more than two.

8. Allow a continuous clear area of 4 meters high by 4 meters wide below main racks in process Units for maintenance access ways.

9. Pipe racks outside process areas shall have the following minimum overhead refinery/plant clearances: main roadway: 5 meters, access roads: 4.5 meters, railroads: 6.7 meters above top of rail.

10. Typical layout of pipe rack, for process plants depending on the number of process Units incorporated and the process complexities are given in Figs. 1 through 4 with reference descriptions as follow:

a. "Single Rack Type" layout, in Fig.1 is suitable for small scale process complex consisting of two-three process Units. It is economical without requiring any large area.

 

b. "Comb Type" layout shown in Fig. 2, is recommended for use in process, complex consisting of three or more process Units. "Single Rack Type" in  this case will not be suitable since separate maintenance and utility administration in normal operation will be difficult because of the utility and flare line which are placed on the common rack.

c. "Double Comb Type" layout is an expansion of the "Comb Type" which is recommended for the use in large scale process complexes where five to ten process Units are to be arranged. This layout as shown below in Fig. 3, can be conveniently utilized.

d. "U Type" layout shown in Fig. 4 is recommended to be used in case of process Units whose maintenance cannot be conducted separately, within the complex. This type can be regarded as an expansion of the "Single Rack Type". Even process complexes of this nature, can be regarded as one process Unit in the planning of their layout.

11. Location of pipe racks shall be in general agreement with the plot plan.

12. Overhead racks may contain more than one level. For steel pipe racks, the height of levels shall have one of the following elevations:

a. Main pipe racks: 4.60, 6.20, 7.80 m

b. Individual or secondary pipe rack: 3.80, 5.40, 7.00 m. In special cases for large size pipes or concrete pipe racks, the distance between the various floors may be increased.

13. Except for special cases, minimum width of pipe rack shall be 6 m. The width of pipe rack shall be designed to accommodate all pipes involved plus 20% space for future expansion or modification. Where the pipe rack supports air coolers, the preferred width shall be the width of air coolers.

14. In multi-level pipe racks, pipe carrying corrosive fluids shall be on the lower level, and utility lines should be at the upper floor. Large size or heavy weight pipes shall be located at the lower level and on extreme sides.