Compressor exchange in Ex zone, with compressor leaking

Example task: Exchange the semi-hermetic compressor operated with A2L refrigerant R454C. The compressor is located on a rack in a machine room. The room has some ventilation. A leakage has appeared, possibly on the compressor, so flammable refrigerant is in the room air.

Special tools or preconditions:

First goal: get rid of Ex zone and after that do the work with A1 equipment!

Working steps or preconditions:

  1. Educated worker
  2. Read / inform for risk assessment of system
  3. Have A2L fire extinguisher ready
  4. Put warning sign to notify work in progress, especially where refrigerant might be released
  5. Power off compressor / system
  6. a. All systems in the machinery room
  7. b. Leave gas warning system on
  8. Ventilation on
  9. a. Install extra fan
  10. Check if outlet of ventilation is safe for people
  11. a. Put warning sign to notify work in progress, especially where refrigerant might be released
  12. Go in with gas detector / check regularly with gas detector or machinery room detector
  13. Find the leak, stop the leak!
  14. a. If leak is on compressor: Close compressor shut off valves
  15. b. If leak is at other place: shut off this system part
  16. Go out and wait until Ex atmosphere is gone
  17. Start your work in no Ex zone
  18. If leak was at other place in the system
  19. a. Charge this part with nitrogen
  20. b. Close leak
  21. c. Evacuate this part of the system
  22. d. Open the valves to this part again
  23. Close compressor valves
  24. Release pressure
  25. a. Small gaseous amount to marked outside area
  26. Oil heater on
  27. Evacuate compressor
  28. a. Release vacuum pump outlet to marked outside area
  29. Charge compressor with Nitrogen
  30. Remove compressor
  31. a .Leave valves on pipes
  32. b. Check valves for tightness with leak detector
  33. c. Close compressor connections pressure tight with flanges or valves
  34. d. If leak was on compressor, close leak, at least well enough to keep air out
  35. e. Evacuate removed compressor
  36. f. Put nitrogen holding charge in removed compressor
  37. Put sticker for flammable gas on return compressor
  38. Install replacement compressor
  39. Evacuate replacement compressor
  40. Open compressor shut off valves
  41. Take compressor into operation again
  42. Adjust refrigerant charge
  43. Remove warning signs