Pitting corrosion is one of the most dangerous corrosion types for zinc roofs. The theory of extreme-value statistics is a powerful tool to quantitatively analyze pitting corrosion. For obtaining reliable results, it is very important to know how to collect small samples correctly and effectively. The method proposed by JSCE (1988) is discussed. This method considers only the influence of the number of small samples on the estimated maximum pit depth over a large area and not the influence of the number of pits per small sample. An improved method, which takes both influences into account, is presented in this paper. Two examples are given to demonstrate the application of the improved method in zinc roofs.

Authors: Rongjin Zheng; Jan E. Carmeliet, Ph.D.; Hugo Hens, Ph.D.; Walter F. Bogaerts, Ph.D.

Citation: Thermal Performance of the Exterior Envelopes of Buildings VIII

Keywords: December, Florida, 2001