When using NFPA 54 sizing tables, what should you do to find the correct pipe size for a certain CFH value?

When utilizing NFPA 54 sizing tables to determine the appropriate pipe size for a specific cubic feet per hour (CFH) value, it is crucial to reference the correct length of pipe that corresponds to your installation. By using the row in the table that matches or exceeds the actual length of the pipe you will be using, you account for potential pressure drops due to friction in the system over that distance.

This method ensures that the pipe is adequately sized to maintain sufficient gas flow and pressure, regardless of any applicable factors like bends or fittings that might affect the performance. Therefore, selecting a length that is equal to or greater than what is proposed allows for a more conservative and practical approach to system design, ensuring safety and efficiency in the gas piping system. The other options do not achieve the same level of reliability because they either disregard the importance of accurate length or misinterpret the criteria for pipe sizing.