Using our own specially developed equipment, James Fisher Strainstall provides a below ground corrosion assessment service as an alternative method to traditional excavation techniques.
Understanding the performance of metals when buried in soils and the rate of corrosion enables structure service life to be determined with reasonable accuracy.
Traditional excavation methods can be a very costly and time consuming assessment of underground corrosion. JF Strainstall's alternative technique, using our own specially developed equipment provides a more efficient and less intrusive way to evaluate corrosion rates.
Below ground corrosion assessment methodology
Corrosion of a steel element embedded in the ground is a chemical reaction, whereby iron, oxygen and water react. Using our BGCMap system, the below ground corrosion assessment operates by applying a current and recording the change in electric potential occurring between the systems half-cell and the corroding sample.
An electrode spike is driven into the ground within 1 meter of the component, to the depth of at least 200 millimetres. The BGCMap unit is connected to the component and the electrode using heavy duty steel clips. Any surface coating at the point of contact is removed.
The copper / copper sulphate half-cell is then inserted firmly into the ground, in a small hole excavated alongside the test component. The test is automatically conducted by the BGCMap, which applies the current and records the voltage. The GPS coordinates, date and time of the test are all also recorded.