According to NFPA-99, every valve in the medical gas system must be identified with the following phrase:
CAUTION: < name of gas> VALVE
DO NOT CLOSE OR OPEN EXCEPT IN EMERGENCY
THIS VALVE CONTROLS SUPPLY TO:
These valve tags are 3" wide x 5-¾" long and come with a tie wrap to secure to the valve.
They come in a pliable plastic coated paper and a seim-rigid vinyl (recommended for wet locations)