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:

• Mobile A2L gas detector
• A2L leak detector
• A2L fire extinguisher
• A2L recovery equipment
• Vacuum pump with external switch, outside room
• Extra fan
• A2L anti-sparking tool – not necessary
• Avoid Ex zone! Avoid / check for leakage!

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
6. Ventilation on
7. a. Install extra fan
7. Check if outlet of ventilation is safe for people
8. a. Put warning sign to notify work in progress, especially where refrigerant might be released
8. Go in with gas detector / check regularly with gas detector or machinery room detector
9. Find the leak, stop the leak!
10. a. If leak is on compressor: Close compressor shut off valves
11. b. If leak is at other place: shut off this system part
10. Go out and wait until Ex atmosphere is gone
11. Start your work in no Ex zone
12. If leak was at other place in the system
13. a. Charge this part with nitrogen
14. b. Close leak
15. c. Evacuate this part of the system
16. d. Open the valves to this part again
13. Close compressor valves
14. Release pressure
15. a. Small gaseous amount to marked outside area
15. Oil heater on
16. Evacuate compressor
17. a. Release vacuum pump outlet to marked outside area
17. Charge compressor with Nitrogen
18. Remove compressor
19. a .Leave valves on pipes
20. b. Check valves for tightness with leak detector
21. c. Close compressor connections pressure tight with flanges or valves
22. d. If leak was on compressor, close leak, at least well enough to keep air out
23. e. Evacuate removed compressor
24. f. Put nitrogen holding charge in removed compressor
19. Put sticker for flammable gas on return compressor
20. Install replacement compressor
21. Evacuate replacement compressor
22. Open compressor shut off valves
23. Take compressor into operation again
24. Adjust refrigerant charge
25. Remove warning signs