A water corrosivity sensing system is currently under development that combines the strengths of rate
measurement techniques such as linear polarization resistance with longer-term cumulative damage measurements
typically provided by electrical resistance probes. This sensor technology is applicable not only to water pipeline
systems, but a broad range of liquid and gas piping systems used in military facilities as well as electric power,
chemical, pulp and paper, and fossil fuel industries.
The corrosion sensing system operates on a diaphragm-based principle, where the diaphragm is a
sacrificial element that corrodes similarly to the pipeline. Small changes in diaphragm thickness can be detected
by monitoring the diaphragm response to the applied pressure intrinsic to the pipeline process. Diaphragm
response, as with traditional pressure sensors can be measured using any of several instrumentation strategies. To
date, diaphragm corrosion sensors that operate using optical interferometric techniques as well as more traditional
electrical foil strain gages have been designed and tested, each of which has inherent advantages depending on the
intended application. This paper contains details of the sensing element design and representative corrosion data
for optical and resistive strain gage sensor variants. The prototype system currently under development will be
field demonstrated in a trial Army water system.
Keywords: corrosion sensing, optical sensors, pipeline corrosion, accumulated corrosion, corrosion rate