I recently saw a post on another social media site from a medical gas installer showing their latest medical gas installation.

In reviewing those photos, I noticed that the facility had Waste Anesthesia Gas Disposal inlets, and the zone valve box only showed medical vacuum, along with the other pressure gases for that room. I would then assume that the designer and contractor took advantage of the code allowance to combine the medical vacuum tubing with the waste anesthesia gas disposal tubing.

I commented that the zone valve and area alarm panel should be labeled for the combined system (Med Vac/WAGD). One of the replies that I received is that the NFPA 99 - 2012 does not require this combined system to be labeled for both gas systems, the person that replied went on to say that this is now required in NFPA 99 -2021. I agree that the NFPA 99 - 2021 does add additional clarification that the combined system is to be labeled for both gas systems.

Our reading of NFPA 99 - 2012 5.1.11.1.1, 5.1.11.2.1(1), 5.1.11.4 would imply that the correct labeling of the tubing, valves, and alarms is to indicate the gas or vacuum that is served by that device. In a combined system the system gas is both medical vacuum and waste anesthesia gas disposal, so each component would need to be label for both gas systems.

My question is this.

What does everyone else enforce on your verification projects?