All valves except zone valve box assemblies shall be __________.

• A. located in a secure area
• B. all of the above
• C. locked or latched in the operating position
• D. labeled indicating contents and location served

Answer: (B)

Safety and proper operation of medical gas systems rely on three practices: valves should be located in a secure area to restrict access, they should be locked or latched in the operating position to prevent unintended movement, and they should be labeled to indicate what they contain and the location they serve. This combination reduces the risk of tampering, misoperation, or misidentification during normal use or emergencies, ensuring staff can quickly and correctly control the correct valve. Zone valve box assemblies are treated as exceptions to this full set of requirements, which is why all of these conditions apply to the other valves.