Non-metal flexible polyvinylchloride (PVC) pipes used in municipal water, municipal sewers, irrigation, agricultural irrigation, agriculture, and mining applications and systems for liquids, wherein the ends of such PVC pipes are specifically manufactured so that the pipes are connectable to each other by a restrained-joint locking system, but wherein such pipes expressly do not include PVC pipes for gas and natural gas transmission, and also expressly excludes PVC repair or maintenance pipes for gas and natural gas transmission