Which of the following is not a standard requirement for piping systems?

Color coding is not a standard requirement for piping systems in the same way that material quality, distance between hangers, and pressure ratings are. Material quality is crucial to ensure that the piping can withstand the operating conditions and potential corrosive environments. The distance between hangers is essential for maintaining the structural integrity and support of the piping system, preventing sagging or undue stress. Pressure ratings are critical for determining the maximum operating pressures that pipes can safely handle, which is fundamental for ensuring the safety and functionality of the system.

Color coding, while beneficial for identifying different types of fluids or systems and enhancing safety during maintenance or in emergency situations, is not universally mandated as a standard requirement across all piping systems. Its implementation may depend on specific industry practices or organizational policies rather than being a foundational requirement. Hence, it stands out as the option that does not align with the core technological standards for piping systems.