Patent ID: 7069772

Claim:
A method for assessing the life expectancy of a polymer lined pipe which transports fluids, comprising the steps of: positioning pre-aged polymer witness coupons in said polymer lined pipe, each of said pre-aged polymer witness coupons being made of the same material as a polymer in said polymer lined pipe, and each having a molecular weight, which can be the same or different for each pre-aged polymer witness coupon, which is less than an initial value for said polymer in said polymer lined pipe and more than a threshold replacement value for said polymer in said polymer lined pipe; determining an equilibrium molecular weight for said polymer based on changes in the molecular weight of said pre-aged polymer witness coupons over time; and comparing the equilibrium molecular weight to said threshold replacement value, and, based on the comparison determining whether (i) said polymer lined pipe will need to be replaced, or (ii) when said polymer lined pipe will need to be replaced.