Pre-insulated crosslinked polyethylene-based pipe (PEX) has gained acceptance as a cost-effective alternative to ferrous pipe in direct-bury applications for certain heating hot water systems. These systems can also be used on cooling systems and there are many other non-ferrous cost-effective solutions. However, while steel pipe can deliver unmatched temperature and pressure service levels, properly designed PEX pipe can deliver corrosion-free and leak-free operation.