The terms PEX pipe and PEX tube have been used interchangeably, however some manufacturers distinguish beween the two by manufacturing to different inside/outside diameters. For example, PEX pipe may be manufactured to IPS-ID (iron pipe size, inside diameter controlled) sizes with varying thickness to meet pressure requirements, while PEX tube may be manufactured to CTS-OD (copper tubing size, outside diameter controlled) sizes, commonly with a standard thickness of SDR-9 (standard dimension ratio).
The PEX tube manufactured to CTS-OD sizes is the most common, with available sizes including 3/8", 1/2", 5/8", 3/4" and 1". On this website, "PEX tube" refers to this common CTS-OD product.
Before extrusion, HDPE can be colored to produce color-coded pipes. Common PEX pipe colors are "natural" (hazy and clear, no pigment), white, black, red and blue. Red and blue are used to help plumbers and homeowners distinguish hot and cold water supply pipes. There will be marks on the outside of the pipe to show which standards it meets.
During the production process, PEX is wound on reels for storage and transportation. A typical 1/2-inch PEX shaft can hold 1,200 feet of tubing.
