NFPA-99 Practice Exam 2025 – The All-in-One Guide to Exam Success!

The minimum size requirement for factory-installed tubes on station inlets with a minimum inside diameter of 0.4 inches aligns with the specifications established by safety and industry standards. Given that 0.4 inches is equivalent to 10.16 millimeters, the 1/4 inch N.P.S. (Nominal Pipe Size) option matches this requirement effectively.

In practical terms, 1/4 inch N.P.S. tubing has an internal diameter that is slightly larger than the minimum inside diameter specified, allowing for adequate flow rates and ensuring compliance with safety regulations. Maintaining appropriate sizing helps prevent potential issues such as pressure loss or inadequate gas delivery, which could impact patient care in medical settings.

The other sizes do not match the minimum inside diameter requirements as directly as the 1/4 inch N.P.S., either falling below the needed specifications or offering more diameter than necessary, which might not be efficient for the specific applications required in medical gas systems.