I am currently busy with a 2 stage casacde system (LT & MT) that utilises Ammonia as the main refrigerant. A swing screw compressor is piped between the two system.

What protect do I require for the swing machine to the wrong flow of discharge gas? (i.e. specila valves, piping, ?)
Any other swing compressor protection required?

Key information:
LT = Low Temperature with -36/-13
MT = Medium Temperature with -13/35