Piperack Design Guidelines

Piperacks - General

whenever possible the Piperack shall be single level. On single level pipe racks, process piping shall be placed outsides with utility and service piping on the middle. Where multilevel racks are required, generally process lines shall be placed on the lower rack levels, and utility and service piping shall be placed on the upper rack level. However, draining considerations shall be taken into account when placing process lines on multilevel racks, by applying the following rules of thumb:

· If both ends of a process line are lower than the lower level, the line should be run in the lower level.

· Process lines that connect two nozzles elevated higher than the top level should be located in the top level.

· Process lines having one end lower than the lower level can run in either the lower or upper level.

Specific elevations shall be established and maintained for lines running the north/south direction, and different elevations for lines running east/west. North/south and east/west pipe racks shall intersect midway between deck levels. At every change of direction the piping should change elevation, but care should be taken to minimise pockets.

Sloping lines may be supported on the side of rack.

Piping should enter from above or below the rack level. Piping should not flat turn on or off the rack closing out space for installation of future lines. Lines requiring expansion loops should be located close to piperack columns and should be grouped together to enable use of common supports.

Onshore piping laid on sleepers at grade shall have minimum clearance of 400mm between bottom of pipe and finished grade.

Piping carrying caustic materials, chemicals, acids or similar services shall not be located near equipment or other piping with service temperatures exceeding 95°C and where avoidable should not be run over escape routes.

Piping smaller than DN50 shall not be run in pipe racks or sleeper ways. Where pipe sizes on racks require a support spacing which is less than the bent spacing, intermediate support beams shall be installed. Generally, small piping shall not be supported from larger piping. On sleeper ways, sleepers shall be spaced to suit the pipe requiring the smallest support span, but should not be spaced less than 3000mm apart.

Hot insulated lines should be grouped together and separated from cold lines.

Electrical and Instrument Cable trays will normally be run in or off the side of the piperacks. Piping Designers shall liaise with these disciplines to allocate these areas. Cable trays systems shall be kept away from hot lines.

SEE ALSO:

Piping Arrangement Around Piperack