Here is the compiled list of Piping Abbreviations.  This is not an exhaustive list and is updated regularly.

  1. ASME: American Society of Mechanical Engineers
  2. ASTM: American Society for Testing and Materials
  3. AWS: American Welding Society
  4. AWWA: American Water Works Association
  5. BBE: Beveled Both Ends
  6. BBP: Bottom of Base Plate
  7. BLE: Beveled Large End
  8. BOM: Bill of Material
  9. BOP: Bottom Of Pipe
  10. BSE: Beveled Small End
  11. BW: Butt Weld
  12. CI: Cast Iron (Material)
  13. CONC: Concentric (Reducer)
  14. CS: Carbon Steel (Material)
  15. DRL: Double Random Length (Pipe Length)
  16. ECC: Eccentric (Reducer)
  17. FC: Fail Close (Valve)
  18. FF: Flat Face (Flange)
  19. FO: Fail Open (Valve)
  20. FOB: Flat On Bottom (Eccentric Reducer)
  21. FOT: Flat On Top (Eccentric Reducer)
  22. FPT: Female Pipe Thread
  23. FRP: Fiber Reinforced Pipe
  24. LR: Long Radius (Elbow)
  25. MTO: Material Take Off
  26. NC: Normally Closed (Valve)
  27. NO: Normally Open (Valve)
  28. PE: Plain End
  29. POExTOE: Plain One End Threaded Other End (Pipe Nipple)
  30. RF: Raised Face (Flange)
  31. RTJ: Ring Type Joint (Flange)
  32. Sch: Schedule (Thickness of Pipe)
  33. SMLS: Seamless
  34. SO: Slip On (Flange)
  35. SPWD: Spiral Wound (Gasket)
  36. SR: Short Radius (Elbow)
  37. SRL: Single Random Length (Pipe Length)
  38. SS: Stainless Steel (Material)
  39. STD: Standard Weight (Thickness of Pipe)
  40. WN: Weld Neck (Flange)
  41. WRC: Welding Research Council