Pipe & Manhole Materials for a 100+ Year Design Life

New Castle County operates a sanitary sewer collection and transmission system in Delaware consisting of approximately 1,600 miles of gravity sewers, 200 miles of force mains, and 165 pump stations. Several interceptors have failed well before the standard “50 Year Design Life” and as part of a Secretary's Order from Delaware's Department of Natural Resources and Environmental Control, these interceptors are being replaced and an additional interceptor is to be constructed. The goal is to find interceptor pipe and manhole materials that have a useful life of at least 100 years under adverse or severe duty interceptor applications, are readily available and relatively easy to install, are cost effective, and are maintainable by traditional methods.This presentation addresses the methodology used by the County to evaluate the ability of various pipe and manhole materials to meet the above goals and to address the problems that led to the cited failures.