b'requireacontinuousexternalpowersourceto economical approach for corrosion protection.provide corrosion protection. AllcorrosionprotectionsystemsrequireThemajorityofapplicationswherefoundation technicalexpertiseandtrainingtodesignandunderpinningisinstalledwillnotrequirean installtheproductsforthespecificjobsiteactivecorrosionprotectionsystem.Inmost conditions.Aslongasthesystemisproperlycases where there is corrosive soil and/or adverse designed and installed; and the system remainselectrolyteconditions,thesacrificialanode inoperation,theundergroundsteelwillhaveprotectionsystemwilllikelybethemost unlimited corrosion life.Corrosion Life AnalysisTheestimatedcorrosionlifeisbasedonthe Corrosion Life of Steel Pier or Pile:Once thefollowing factors: protection offered by the galvanized coating has1. The life of the galvanized coating, (CL G ) been exhausted, the steel begins to corrode and2. The life of a limited amount of steel loss in lose thickness.Safe Use Design states that athepierwallwithoutlosingstructural factorofsafetyof2.0or greatershallbeusedintegrityofthepile,(CL P )(The when designing foundation supports.Experiencerecommended allowance is 10 %.) has shown that the structural integrity of the steel3. The life when cathodic protection is present, piersystemisnotbecompromisedaftera(Usethelifeanalysisprovidedbythe corrosion loss of steel not exceeding ten per cent.sacrificial anode manufacturer.) Thisisbecausegreaterstrengthisneededforproductinstallationthanforsupport.TheThereisahighdegreeofvariabilityinthe formulaforestimatingaveragetimefortenperformance life of steel piers and helical piles in percentcorrosionlossinsteelwallthicknessthe soil.Including, but not limited to: (10%of W S ) isgiveninEquation2, which multiplestratasoilsthroughthedepthof estimates corrosion loss per year.installation, Equation 2 - Corrosion Loss Steel Shaft: soil variations within a given stratum CL P= W S-10% / K C variabilityofthewatercontentofsoilboth Where:vertically and seasonally CL P = Life expectancy of steel tube (years) presence or absence of salt ions in the soil due W S-10% = 10% shaft weight loss(oz/ft 2 )to leaching, etc. K C-1 yr = Corrosion loss per year - oz/ft 2 non-uniformityofthegalvanizedcoating W S-10%can be determined by Equation 3.thickness and areas of stress concentration Equation 310% Loss of Steel: imperfections in the steel W S-10%= 10% x t ft x 489.6 lb/ft 3 x 16 oz/lb damage to the steel or the galvanized coating presence or absence of stray currents Where:t = Tubular shaft wall thickness or one-half theCorrosionLifeofGalvanizedCoating:The thickness of the solid bar - ft.observedrates ofcorrosionforthegalvanized K C-1yrcan be estimated from the data in Graph 3,coating were found to be less than that for bare which estimates of corrosion loss per yearsteel in Romanoffs NBS study.Equation 1 can based upon the resistivity and pH of the soil.be used to estimate the corrosion (weight loss) Attheendofthecalculatedcorrosionliferate for galvanized coatings. determined by these equations, there will beEquation 1 - Corrosion Life Zinc: no loss of structural integrity.CL G= G / [0.25 - 0.12 log 10(R/150)] ItisimportanttorememberthatcorrosionlifeWhere: 2 predictionsprovidean averagelifeexpectancyCL G = Weight loss (oz/ft ) 2 forthefoundationsupportproductwhenG = Amount of galvanize coating (oz/ft ) installed under the given conditions.R = Soil resistivity (ohm-cm)ECP Technical Design Manual Corrosion Life2021 Earth Contact Products, L.L.C.2021-09 Chapter 8 - Page 154 All rights reserved'