This article summarizes about 20 years of experimental studies on the durability of cross-linked polyethylene (XPE) extruded pipes for hot water transport. The time to failure was determined against hoop stress and temperature (in the 20-120degreesC range). The XPE samples (16 distinct materials) were compared to classical PE ones (6 distinct materials). It appears clearly that cross-linking suppresses the ductile-brittle transition (average coordinates: t(C) = t(C)0 exp(Q/RT) with In t(C)0 = -24.2 and Q = 84.6 kJ mol(-)1 but does not modify significantly the behavior in ductile regions. It can be assumed that, for XPE, the ceiling conditions are determined by the oxidation embrittlement of which the (tentative) coordinates could be given by t(E) = t(E)0 exp(H-E/RT) with In t(E) = -24.45 and H-E = 116 kJ. Thus, XPE performs better than PE in the (t(C) - t(E)) interval. On this side of t(E), the lifetime t of XPE is linked to the hoop stress sigma and the temperature by an equation of which a simplified form could be: sigma = alpha(T-M - T)(beta - log t) where alpha = 4 x 10(-)3 and beta = 30 for T less than or equal to 80degreesC and alpha = 6 x 10(-)3 and beta = 20 for T greater than or equal to 80degreesC, sigma being in MPa, t in hours and T-M being the melting point (137degreesC).