PP-R is smooth and causes less friction than other, more commonly used materials, so the incidental beads that may form during the heat fusion process are not consequential. Larger beads, caused by excessive heating and pressure, may cause restrictions and block the pipe. Blocked connections should be removed and replaced. The installer’s technique should be corrected if he or she is regularly leaving large beads. Beads will not cause pin-holing, nor will the beads break off and damage equipment or filters.

The beads that form during outlet fusion are not a problem. The friction loss caused by a fusion outlet is approximately 75% less than what is caused by a tee. Information on pressure loss through the fittings can be found on pages 5.34 – 5.39