Importance of Mapping
Digital soil mapping allows one to analyze the relationships between soil corrosion properties and ancillary data (e.g. topographic attributes and remote/proximal sensing data) through several techniques.
Our corrosion maps can be used for corrosion risk assessment, DC/AC interference risk and mitigation, identifying areas where shielding/coating dis-bondment can potentially cause localized corrosion, leaks, and possible explosions.
The Technical Approach to Constructing A Below-Grade Corrosion Risk Map
Matergenics’ unique approach to soil mapping considers the following:
1) Examination of spatial patterns associated with the physical and chemical properties of soil. This evaluation leads to insights on overall corrosion risk, and answers questions on where to locate a new pipeline and substation infrastructure.
2) Identification of the least or most corrosive sites and possible sources of stray current for corrosion mitigation
Sources of Data
1) Matergenics Soil Database
2) Client’s Database (if available)
3) United States Department of Agriculture
4) Soil Survey Geographic Database (SSURGO) – the most detailed level of information for resource management, county planning, etc.
5) National Resource Conservation Service
Soil Data Layers
Soil properties contributing to corrosion are individually mapped and a proprietary weighting system is used to compare the layers and develop an overall corrosion risk assessment map identifying areas of high, medium and low corrosion. A few of the properties are listed below. Field surveys are then made to confirm the accuracy of the map. The key to this technology is finding accurate data and the development of an accurate weighting system.
Matergenics will also include maps for gas pipelines and transmission towers (if available), either of which may be a source for stray current corrosion.
Corrosion Risk Assessment Map
A proprietary method is utilized by Matergenics to create a final corrosion risk assessment map for the area of interest. The method includes an algorithm to assign a corrosivity index to each location on the map based on soil properties, geological data, and external corrosion factors. The accuracy of this algorithm has been field tested and proven in several projects.
Some Layers Incorporated into Corrosion Maps
Soil properties play a crucial role in the overall corrosivity of soil. Physio-chemical properties describe the corrosivity of liquid phase in soil while the geological properties estimate moisture content and the ability of the soil to retain that moisture. Matergenics considers both to estimate corrosion risk. A few of the properties that are included in our corrosion maps are listed below.
SOIL TYPES, INCLUDING CLAY CONTENT
STRAY CURRENTS FROM NEARBY GAS PIPELINES OR PROTECTED AREAS
The following demonstrate various examples of soil corrosion mapping for utility structures and pipelines.