Three dimensional mapping of corrosion pits in cast iron pipe using the remote field effect
: The remote field effect is an electromagnetic method for inspecting pipes and tubing. It has recently been commercialised as a technique for inspecting gray cast iron and ductile iron water mains. How-ever, commercial tools provide information on pits depths in the pipe and overall wall loss. Models of the mechanical behaviour of cast iron pipe also require information on pit width and length. This paper discusses remote field effect apparatus and experimental techniques used in the laboratory to produce three dimensional electromagnetic field maps. The maps shown in the paper indicate that sizing corrosion pits in three dimensions is possible using the remote field effect. Further research needs are also discussed.
The phantom exciter: high resolution measurements of RFEC slit defect interactions
In order to obtain a better understanding of defect interactions associated with the Remote Field Eddy Current technique, a new exciter/detector geometry has been used. The Phantom Exciter geometry uses a single through-wall transmission and allows high resolution measurements to be made in the region of a defect. Strong response to axial slits in nonferrous pipes due to eddy current interaction has been demonstrated. Magnetic interactions in ferrous pipe has lead to good responses to circumferential slits
Comprehensive review of structural deterioration of water mains: physically based models
Abstract This paper provides a comprehensive (although not exhaustive) overview of the physical/mechanical models that have been developed to improve the understanding of the structural performance of water mains. Several components have to be considered in modelling this structural behaviour. The residual structural capacity of water mains is affected by material deterioration due to environmental and operational conditions as well as quality of manufacturing and installation. This residual structural capacity is subjected to external and internal loads exerted by the soil pressure, traffic loading, frost loads, operational pressure and third party interference. Some models address only one or a few of the numerous components of the physical process that lead to breakage, while others attempt to take a more comprehensive approach. Initial efforts were aimed mainly towards development of deterministic models, while more recent models use a probabilistic approach to deal with uncertainties in defining the deterioration and failure processes. The physical/mechanical models were classified into two classes: deterministic and probabilistic models. The effect of temperature on pipe breakage is discussed from three angles; the first deals with temperature effects on pipe-soil interaction, the second deals with frost load effects and the third provides a brief review of various attempts to statistically quantify influence of temperature on water main failure. This paper complements the companion paper “Comprehensive review of structural deterioration of water mains: statistical models”, which reviews statistical methods that explain, quantify and predict pipe breakage or structural failures of water mains.