The check valves in an Emergency Oxygen Supply Connection are required to be constructed of which of the following materials?

• A. Brass, bronze or stainless steel
• B. Brass or bronze
• C. NFPA 99 does NOT establish any material requirements for these check valves
• D. Materials per the EOSC manufacturer's recommendations

Answer: (B)

Material choice for EOSC check valves is driven by oxygen compatibility and safety. NFPA 99 specifies that these check valves must be constructed from brass or bronze. These metals have a long, proven track record in medical gas systems: they resist corrosion in oxygen service, are reliable under pressure, and help minimize ignition risks in oxygen-rich environments. The standard does not rely on stainless steel for this component, nor does it leave the requirement to manufacturer recommendations. saying the standard doesn’t establish material requirements is incorrect, and leaving the choice to the EOSC manufacturer’s guidance isn’t what the standard requires.