# 1992 Eindhoven
Eight excavated HDPE pipes of the 1st generation along with 3 modern PE types have been investigated. Comonomer content as a function of molecular weight of the old HDPE pipes appeared to be nonoptimal with respect to the modern PE types. Further unwanted effects in the old pipes were : particles, oxydation, inhomogeneity. Premature failures were due to previously unexpected effects of external point loadings.