The engineering community is well aware of the long service lives of composite equipment in a variety of harsh environments. It would take no more than a brief tour of any modern pulp bleaching or chlorine–alkali facility to realize the importance of composites in services where metal corrosion is a major issue. However, after many years of good service, there is still no reliable method to predict the durability of the corrosion barriers in such cases. The many studies and test methods developed over the years to evaluate laminates immersed in aggressive chemicals, while certainly useful to establish suitability, are not adequate to quantify the durability. This is understandable in view of the overwhelming complexity of the problem. The many combinations of resin types, working temperatures and other process variables, coupled with a myriad of aggressive chemicals make the prediction of laminate durability in aggressive environments a most daunting endeavor.