In which measurement format are pipe sizes expressed within the Building Code?

The correct format for expressing pipe sizes within the Building Code is using nominal pipe size dimensions in inches. This standard is widely adopted in North America for plumbing and piping systems, ensuring consistency in communication and application throughout the industry.

Nominal sizes facilitate a common understanding among manufacturers, engineers, contractors, and inspectors, allowing for easier matching of pipes with fittings and accessories, which are often designed and cataloged based on these nominal dimensions.

Using inches as the measurement for pipe sizes also aligns with traditional practices in North American construction, where other systems of measurement, such as millimeters, centimeters, or even feet and yards, are not typically used for this specific application. This focus on inches helps maintain standardization in material specifications, installation practices, and system design, reducing confusion and increasing efficiency in construction projects.