At least one manufacturer that I know of ships zone valves with the individual valve labels that read "Air" for medical air and "Vacuum" or "Vac" for Medical Vacuum.  

Table 5.1.11 (I reviewed the 2012, 2015 & 2018 edition, all read the same) gives two names for each of these:

• Medical air or Med air
  
• Medical-surgical vacuum or Med vac
  

I am curious as to what the consensus of the group here is on how you would treat this during verification (or an annual).  Do you bring this up as a deficiency since TJC / DNV / CMS / HFAP are all obsessed with the exact wording in NFPA 99 now?

This also exists on pipe labels, many times I see pipes labeled with simply "Air" or "Vacuum"

Agree:

O2 or Oxygen

NOT

OXY 

We just completed a job where the differences among the types of air was quite relevant.  There were a few different air systems in the facility that the AHJ were hell-bent on being labeled a specific way, and I can't blame them.  They needed to be clearly identified and differentiated in their pipeline and valve labeling .  There was MEDICAL AIR, DENTAL AIR, and INSTRUMENT AIR and all were requested to be labelled exactly so.  We did come across a labeling mix-up with these systems at one point and it created some problems that took a while to resolve during the verification process.  

Long story short - The AHJ has the ultimate say in what they want to see, so if it's at all possible to get an answer from them on what they will accept for labeling terminology, it's worth asking the question.  

I do believe that all outlets, valves and pipe should have the appropriate name on them for the med gas they manage, the code is specific on this matter

For example, in a hospital there may be med air and an another Air piping  (for other use different than medical use), each of them should be label properly, for medical air they should be label as the code specify on 5.1.11, there is no doubt on my mind