Plan reliable corrosion control for critical assets. Enter area, current density, coating, and resistance values. Download clear reports and share sizing with your team.
| Scenario | Area (m²) | Current Density (mA/m²) | Coating Eff. (%) | FT | FS | Result I (A) |
|---|---|---|---|---|---|---|
| Buried coated pipeline | 450 | 20 | 92 | 1.00 | 1.20 | 0.21 |
| Soil, moderate coating damage | 450 | 20 | 85 | 1.05 | 1.25 | 0.44 |
| Splash zone steelwork | 120 | 150 | 60 | 1.10 | 1.30 | 10.04 |
The calculator estimates required protection current using: I = A × (J/1000) × CF × FT × FS × GF
Rectifier voltage is estimated as V = I × R + Vback, and power as P = V × I.
Cathodic protection design starts by defining the structure, exposure, and acceptance criteria. Coated steel in soil targets protective potentials confirmed during commissioning. The calculator estimates current using exposed area and a selected current density. Coating efficiency converts coating quality into an exposed fraction, representing holidays and damage. A safety factor adds margin for variability in soil resistivity, moisture changes, and construction tolerances.
Current density is the primary driver of required amperage. Seawater and splash zones demand higher values due to oxygen availability and aggressive chloride exposure. Fresh water and average soils generally need lower current densities, especially when coatings perform well. Use site data when available, such as resistivity and temperature. If commissioning surveys show underprotection, current density or exposed area assumptions should be updated.
Coatings reduce demand, but performance changes over time. The growth allowance factor represents deterioration, new holidays, and damage during operations. For long pipelines, small percentage changes can materially increase current. Use inspection history, holiday testing results, and expected mechanical stresses to set realistic values. When coating efficiency is uncertain, select a conservative efficiency and document the basis.
Rectifier sizing depends on voltage as well as current. The calculator uses circuit resistance with an added back EMF term to estimate required voltage. High resistance may indicate poor anode placement, insufficient groundbed design, or dry, high resistivity soils. Power follows from voltage and current, informing transformer and electrical supply requirements. Field adjustments should keep output within equipment ratings while maintaining protective potentials.
Anode count is estimated by dividing required current by expected output per anode and rounding up. Output depends on anode type, electrolyte, and spacing, so manufacturer data should be validated with site conditions. The amp-hour estimate helps compare demand against anode capacity and design life. Use it to plan groundbed size, replacement intervals, and monitoring frequency for critical assets.
Use the exposed metal area that contacts soil or water. For coated assets, include only the protected surface, then apply coating efficiency to represent holidays and damage.
Yes. Select an environment for guidance, then enter a project-specific current density based on standards, soil testing, or commissioning feedback.
It is the percentage of surface effectively insulated by coating. The calculator converts it to a coating factor, which is the remaining exposed fraction that drives current demand.
After polarization, many systems require slightly less current to maintain protection. The calculator uses a simple planning reduction to estimate maintenance demand.
Voltage is estimated from current, circuit resistance, and losses. If required voltage seems high, review groundbed design, resistance assumptions, and connection quality.
No. It is a current-based estimate. Final life depends on anode capacity, utilization, environment, and monitoring. Confirm with manufacturer data and detailed design checks.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.