API Plan 99

API Plan 99

Engineered piping plan not defined by other existing plans.

P&ID according to API


  • Typically an engineered system – as per API 682 guidelines or at times beyond the scope of the standard.


  • May be applied to any duties – non-hydrocarbons, non-flashing or flashing hydrocarbons.
  • May be applied to horizontal as well as vertical pumps.

Remarks, checkpoints

  • This plan always needs detailed engineering as well as detailed discussions between the seal manufacturer and client.


Pump media characteristics

  • Depends on the application.

Location, function

  • Depending upon the application, may be applied on the process side or the atmospheric side.
  • Depending upon the application the function may be flushing, cooling, lubrication or leakage detection or leakage collection or alarm.


  • May be applied to any of the configurations defined in the API 682.