b'If specific information on a soil is available to the to the AWWA system was developed by ECP thatdesigner(soiltype,pH&resistivity),a provides guidance for steel foundation products inpreliminaryestimateformetalcorrosionlossof soil.The numerical corrosivity score is designedbaresteelcanbedetermined.TheNBS only as a Quick-Solve design method to warn ofpublication can also be used to find a comparable a possible corrosive environment in which the lifesoilandconditionforestimatingtherateof of galvanized steel product may be accelerated duecorrosion.Itshouldbenotedthatwhenhot- to aggressive corrosion conditions.dipped galvanizing is used as a form of corrosion Using the information gathered from a specific jobprotection,theresultingcorrosionrateforsteel site, an indication of the likelihood of corrosion is(oncethegalvanizedcoatingislostdueto suggested based upon point values that is assignedcorrosion) will be lower than the rates shown in tothethreesoilparameterslinkedtoincreasedGraph3onthepreviouspage.(Theestimated corrosion rates.Notice in Table 3 that the threereduction rate of corrosion is in the 20% to 100% elements that influence the rate of corrosion mustrange). be known before an assessment of soil corrosivitySpecialCorrosionConditions:Soilresistivity can be predicted from Table 4.and pH are strong influencing factors on corrosion The sum of these point values gives the numericalrates;however,thereareotherspecialsoil corrosivity score for the site.The score suggestsconditions which may increase the corrosion rate the likelihood of slight, moderate or high corrosionsuchas:1.)excessivesaltcontentofwater potential of the soil.As the score approaches 10,(seawater),2.)velocityofwaterflowand3.) the soil becomes more aggressive.atmosphericconditions.UhiligsCorrosionHandbook,EditedbyR.WinstonRevie,2 nd When the numerical corrosivity score equals 10, orEdition, provided the following reference material: higher,itisstronglyrecommendedtoseektheadvice of a corrosion engineer who can evaluate1.Corrosion Rates in Seawater the project to determine what additional corrosion (Pipe Piles, H-Piles, Etc.) protective measures (in addition to galvanization)a. Splash Zone (Average) = 6.9 oz/ft 2 / yr are might be required for extended service life.b. Tidal Zone (Average) =2.0 oz/ft 2 / yrc. Immersed (Average) =2.3 oz/ft 2 / yr Table 3. Numerical Corrosivity Scored. Immersed Zone (Range) = 0.5 to 9.0 oz/ft 2 /yrSoil Parameter2.Influence Of Velocity In Fresh Water Soil Resistivity (ohm-cm) PointsVelocity (m/s)Corrosion Rate Multiplier 500 101/2 to 3 4 500999 83 to 15 1.2 to 0.8 1,0001,999 53.Atmospheric Corrosion Rates 2,0004,999 2(Pipe Piles, H-Piles, Etc.) 5,00010,000 1Atmospheric = 3.2 oz/ft 2 /yr (Average) 10,000 0 ( 500 Meters to Seashore) pH PointsSoilCorrosionRatings: Inover90%of 24.5 6foundation underpinning projects corrosion is not 56 0a problem, but one needs to recognize the warning 79 2signsofproblemsoils.TheAmericanWater 10.5 12 6WorksAssociationdevelopedanumerical rating Moisture Pointsto determine the severity of corrosion for cast iron Tidal or Salt Water Exposure 5pipes.WhileECPproductsarenotconstructed Poor DrainageAlways Wet 2from cast iron, a numerical rating system similar Fair Drainage - Moist 1Good DrainageUsually Dry 0Table 4. Soil Corrosion PotentialUnlikely Slight Mild Moderate Aggressive Severe0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20ECP Technical Design Manual Corrosion Life2021 Earth Contact Products, L.L.C.2021-09 Chapter 8 - Page 151 All rights reserved'