Piping Layout : General Considerations


Piping Layout must be carried out with Process requirements, economy, orderliness, stress and supporting requirements in mind. Following points shall be adhered to for optimum pipe routing.


Piping shall be arranged in an orderly manner and routed as directly as practical, preferably in established banks or pipeways.

Thermal Expansion and Stresses

Arrangement shall provide for natural loops and offsets to compensate for thermal expansion and contraction of lines. Reactions or moments causing excessive stresses in piping or equipment shall be avoided by proper design.

Dynamic Loading

Where dynamic loading, limited pressure drop, or other severe service conditions apply, particular care shall be used in routing the piping. Dynamic loading may be expected when pulsating flow such as at reciprocating compressors and high velocity flow, flashing fluid, fluctuating temperature or pressure, or mechanical vibration (including wind) conditions exist. Piping subject to possible dynamic loading shall be carefully designed and checked to ensure that its size, configuration, mechanical strength, supports and restraints will prevent excessive stresses, vibration or noise.

Pressure Drop Restrictions

Limited pressure drop conditions may be expected in large vapour lines, heater transfer lines, reboiler circuits, pump suctions and gravity flow lines. Such piping shall be routed as directly as practicaL.

Costly Materials

Other severe services include erosive, corrosive and high or low temperature or pressure conditions.  Many such services require alloy or other special materials. Piping in these services shall be routed to minimize the effects of service severity and make most practical use of required special materials.

Pipe Racks

Pipeways shall be sized for present needs plus 15%. As far as practical, piping shall run at different elevations in north-south and east-west banks, and shall change elevation when changing direction. Combined changes of direction and elevation in pipeways ordinarily shall be made with 90° elbows. Where necessary, a 90° and a 45° elbow can be used.  Inside buildings, piping may run in vertical banks and flat turns may be used.

Chemical Injection Piping

All injection points into hazardous lines (i.e. high pressure, sour or dangerous) shall have a block valve and check valve located as close as practical to the injection point.

Liquid Sulfur Piping

All flanged connections shall have two sockets on threadolets, installed in the jackets as close to the flanges as possible on flange centerline. All piping bends shall be made with welded crosses, installed complete with flanges and plugs for cleaning. All runs of pipe shall contain a sufficient number of breakout flanges and all laterals shall be connected to mains through pipe crosses with flanges on onnecting ends of laterals with flanges and blinds on opposite sides. Suffcient connections for steaming, blowing, draining and rodding shall be provided on all sulphur lines. All liquid sulphur lines shall be sloped to the sulphur pit and shall be drainable.

Sample Connections Piping

Sample stations shall be provided with 3/4″ main valve on the feed and return. Where liquid samples are taken in a bottle, the sample outlet shall be located above a drain funnel to permit free running of the liquid before sampling. Liquid sample connections shall be taken off the side of the pipe.


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