What is a "full port" ball type valve?

" A full port ball valve has an oversized ball so that the hole in the ball is the same size as the pipeline resulting in lower friction loss. Flow is unrestricted, but the valve is larger. "When you say, 'Approved PEX pipe must meet ASTM F876/F877 specifications with a non-external oxygen barrier,' what does that mean exactly?" ASTM was originally known as the American Society for Testing and Materials, and is one of the largest organizations that tests and helps develop the standards by which products are manufactured to. ASTM F876/F877 is the standard specification (or level of quality) by which cross-linked polyethylene (PEX) tubing and cross-linked polyethylene (PEX) plastic hot- and cold-water distribution systems are made to comply with. Non-external oxygen barrier PEX, is PEX tubing without an EVOH oxygen diffusion barrier applied to the exterior of the tubing. "What is PEX-AL-PEX?" PEX-AL-PEX is a unique five-layer pipe consisting of inner and outer layers of PEX and ...  more