Just a word of caution !
Yes the cause and effect:
In regards to the reduction of the IA system receiver pressure
(original listed as 200 psig) and the final line pressure (still in table 5.1.11 listed as 169-185 psig) for a Instrument Air ( IA ) Medical Support Gas.
The NFPA 99 Edition 2018, provides a statement that allow, a reduction in the source and final line delivery pressures. In my opinion the wording is weak .
Section 5.1.13.3.4.3 & 5.1.13.3.4.5.
This change still refers us back to Table #5.1.11
which has IA pressures between 160-185 psig.
But no matter what you do / the system still has to provide the following requirements .
1) Quality of IA Source (i.e. up-stream of the final line regulator)
a pressure Dew-Point of -40 C ( -40 F)
2) Master and Local Alarms, if the IA system delivery pressure exceeds a pressure Dew-Point of -30 C ( -22 F )
The above is just a short listed of all the items or conditions still required.
(see the full section #5.1.13.3.4)
Also for those with existing IA systems with the intent of just turning down the final line pressure to less than the listed (160-185 psig), remember to replace the pressures relief valves to meeting the code.