December 2013 - Piperacks

The end of another year and things in the Plant Design business is starting to look promising in the New Year as a number of major projects should get the green light.
The Third Edition of 'Detail Engineering and Layout of Piping Systems' is about to be published. We have gone to a larger 10.5 x 8.5 format rather than the 10 x 8 size. This makes a significant improvement including an increase in the text size. Also added are a number of sections and graphics all of which have been as a result of feedback from users mainly in my piping seminars.
A Merry Xmas and a Happy New Year to all.

This months’ tips


  1. Use line spacing chart to ensure that all lines can be contained within rack.
  2. Determine piperack elevations, normally bottom level of rack is 15 ft (5000mm) above grade, depending on mobile equipment used to access pumps and equipment located under rack.
  3. Flat turns for branch lines are not permitted. If the rack runs North/South then all East/West branch lines running to and from equipment etc. must run, usually, 3 ft (1000mm) above or below.
  4. Allow space for cable trays and instrument lines.
  5. Check with adjacent areas to determine if they have any lines that run along your section of piperack.
  6. Allocate sections on rack for certain lines e.g. steam and other hot lines that may require loops to be located on one side of the rack.
  7. Group utility lines.
  8. Group process lines.
  9. Process and relief lines are placed next to the large bore lines and utility lines are positioned in the centre of the rack. The positioning of individual utility headers will depend on what side of the rack most of the branch connections are running to.
  10. Cooling water lines should be located to one side of the rack, that side being where there are more branches to and from equipment.
  11. Locate lines with orifice taps on the outside of rack for maintenance/accessibility.
  12. Large bore lines should be located on the outside of the rack to reduce the bending moment on the beam. Check if future piperack expansion is planned before using flat turns.
  13. If flanges are located in the line make sure that any flanges on neighbouring lines are staggered to minimize spacing.
  14. All insulated lines must sit on shoes (see company spec. for height of shoes, normally 4” (100mm)
  15. Small bore lines that may not span the distance between bents (columns) may be supported from larger bore lines if acceptable to client.