b'Review of Results of Example 2 & 2ADiscussion of the Results of Design Examples 2 & 2A:Theresultsobtainedbythe Quick -Solve design analysison Example2A underestimatesthecorrosion life expectancy slightly compared to the calculated results for corrosion life.The inaccuracyis due to attempting to read between the boxes in the corrosion tables to determine a life expectancywhen the soil at the project has a soil resistivity between the lines of the boxes.The values, 700ohm-cm and pH = 5.5, do not appear in the tables.The inaccuracy occurred in or prediction becausethe change in life expectancy between boxes is not linear. This clearly demonstrates a flaw in theQuick -Solve design method of corrosion life estimating when it is necessary to extract datafrom between the boxes. In this case both results exceeded 40 years and it is Safe Use design toround down.Design Example 2A was designed as a complicated problem.The goal was to be able to demonstratea simple method of linear interpolation to extract data from between the boxes on the tables.Thelinear interpolation method demonstrated in Design Example 2A caused some discrepancies betweenthe two methods of corrosion life expectancies. Point of interest is that one must SUBTRACT life wheninterpolating between boxes because the corrosion life decreases between pH = 5 and pH = 8.This issomething to keep in mind when using Quick -Solve design tables. We are dealing with complicatedrelationships when using the tables.There are three parameters involved that one can appreciate bylooking at Graph 3, shown above and in Chapter 8.This table was used to determine the Weight ofSteel Loss by Corrosion for the steel support products installed in corrosive soils.Looking at Graph 3,notice that the resistivity data are logarithmically plotted on the left axis and the curved pH boundarylines in the body of the graph are not linear.The interpolations used in Design Example 2A assumedthat the changes in life expectancy between boxes in Tables 5 and 6 are linear. The values are notlinear and making the assumption of linear relationships created variances in the life expectanciesestimated by the Quick -Solve design method.The advantage in using Quick -Solve design tables isthat determining a corrosion life estimate is faster.Thereaderiscautionedtobe verycarefulandconservativewhenreportingcorrosionlifeexpectancies thathavebeeninterpolatedbetweentheboxeswhenoneusesthe Quick -Solve design method demonstrated here. ALWAYS ROUND DOWN THE RESULTS.Review of Results of BonusAlternate Product:The bonus solution was provided to illustrate that substituting a larger diameter pier pipe with a thickerwall and with a thicker galvanized coating will result in a substantial increase in corrosion life of the pierpipe with very little increase in cost.In the calculated result for Design Example 2, the corrosion lifeincreased by 75% simply by changing from the PPB-350-EPS (3-1/2 diameter) to the PPB-400-EPS(4 diameter - HDG) pier system. This recommendation method to extend corrosion life by substitutinga larger pipe and using the same foundation bracket is simple.This solution is less expensive thanspecifyingandinstallingcathodicprotectionateachpierplacementtoincreasethecorrosionlife.Offering a product substitution can save the customer money.It is also a valuable tool to use when theengineer is not satisfied with the result obtained for the corrosion life estimate for the first system.* Onemustbecautionednottoconsidertheresultofeitheranalysisas anexactanswerbecause the formulas were derived from empirical data.Both corrosion lives determined intheexamples areaccuratewithintherangeoferror,andwereroundeddowntobeconservative.** Important Note: Keep in mind that the corrosion life results are only the average corrosionlife estimate. ECP recommends rounding down the results of the analysis, especially when thepredicted corrosion life results with an estimate EXCEEDING 40 YEARS, and use extra cautionwhenreportingresultsthat wereobtained frominterpolation using the Quick -Solve designsystem.The best suggestion is always round down the results for Safe Use design.EARTH CONTACT PRODUCTSDesigned and Engineered to PerformECP Technical Design ManualCorrosion Life Design Examples2021 Earth Contact Products, L.L.C.2021-09 Chapter 9Page 166 All rights reserved'