What is the standard unit of measurement for water supply pipe sizing in the National Plumbing Code?

The standard unit of measurement for water supply pipe sizing in the National Plumbing Code of Canada is in millimeters (mm). This choice is correct because the code specifies the use of metric measurements to ensure consistency and accuracy in plumbing installations. The adoption of millimeters aligns with Canada's metric system, making it easier for professionals in the plumbing industry to communicate and work with specifications that reflect international standards.

Other units, such as inches, centimeters, and feet, are not used for water supply pipe sizing in this context. While inches might be familiar in some areas of construction, the National Plumbing Code emphasizes the metric system for standardization. Centimeters are too small a unit for practical pipe sizing, and feet are a larger measurement often reserved for other types of dimensions or larger scale measurements rather than specific pipe sizes. Thus, using millimeters ensures precision and clarity, which is essential for effective plumbing design and installation.