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Economics of Grooved Piping Systems


An economic evaluation shall be performed prior to selecting a piping system.  If it is found that corrosion conditions require the use of an internally plastic-coated steel pipe, then a financial comparison of flanged versus grooved systems shall be performed.  The cost and availability of valves and material shall be included in the evaluation.   Some Victaulic gasket materials (Viton) are very expensive and could alter favorable economics.  A thorough and accurate evaluation is required in order to avoid false economics.

Advantages

  1. Grooved piping systems may be disassembled and reassembled for portability purposes.  This is not usually a requirement for oil and gas production facilities.
  2. Grooved systems allow internally plastic-coated steel pipe to be connected.  If IPC is not required, screwed fittings shall be considered since they can be utilized at a much lower cost.
  3. Grooved systems do not require hot work.

Disadvantages

  1. It is difficult to provide corrosion protection to the coupling area of grooved systems.   Even with end seal type gaskets, fluids sometimes reach the groove area causing failure type corrosion.  Gasket lubrication and placement are critical to maintaining the total integrity of a grooved system.
  2. A grooved system does not have the structural qualities of a flanged and welded system.   There are special requirements to be considered in the support system for grooved piping.  These requirements are covered in the Victaulic manual referred to in Section 1 of this Appendix.
  3. Pipe grooving, whether cut or rolled, damages the internal coating, which requires the coating to be repaired.  The repaired coating area is somewhat susceptible to corrosion.



Tags: grooved-piping