I have debated this many times and finally just gave up on the industry to do the right thing. And yes, there is a line item in NFPA 350, that I have requested the NFPA to address. But for me, in all my years, we would evacuate the NH3 from the condenser coils and lock out the fan(s) in order to reclassify the condenser to a Non-PRCS. Case in point… condenser tubes FAIL and release NH3. And we rarely know (sarcasm as we NEVER know) when the failure is going to occur.
The refrigeration system that was shut down for the summer season developed a crack in an internal tube in the 26-year-old condensing unit.
The ammonia refrigeration system, including the condensing unit, is 26 years old. When the licensed contractor arrived on scene to contain the leak on the system, it was noted and informed that the leak was noticed to be coming from the area of the condensing unit internally, where there are many small diameter tubes.
Source: https://safteng.net/wp-admin/post.php?post=34992&action=edit