- Uponor AquaPEX® tubing is used in hot and cold water distribution systems and AquaSAFE™ residential fire safety systems. Uponor AquaPEX® tubing is suitable for use in hydronic heating applications where the system contains no ferrous corrodible components or where any ferrous components are isolated from the tubing. Uponor AquaPEX® tubing coils and straight lengths come in red, white and blue for potable-water applications, and purple for water-reclamation applications.