... soil resistivity along the subject pipeline, for portions of line that show strong AC interaction; Assume that AC-induced corrosion is aggravated by low soil resistivities, including what may be high soluble ion concentrations, and by the presence of good-quality fusion-bonded epoxy (FBE) or similar...

... Alternating Current (AC) Current Density Mitigation Interference Fusion Bonded Epoxy (FBE) Coat Tar Enamel (CTE) Fault Currents and Voltages Barnes Layer Soil Resistivity PROJECT OVERVIEW The pipeline operator decision to model the new mix of older pipe CTE coating with short segments of replacement...

...Abstract The AC interference between High Voltage AC (HVAC) power lines and pipelines has been modeled with various software programs, all of which have a variety of input data which creates various results and outputs. Important aspects such as the soil resistivity along the pipeline route can...

... Examination Dig Selection Cathodic Protection ACVG DCVG ACCA Cathodic Protection Soil Resistivity Indirect Inspection Cost Pipeline Integrity Management Program INTRODUCTION According to NACE SP0502-2010 ¹ , ECDA is a four-step process that involves pre-assessment, indirect inspection...

... conditions. BACKGROUND AC Interference It is well known that soil resistivity is a key factor in the assessment of AC interference on pipeline infrastructure. Therefore, it is common practice to perform extensive site surveys to measure soil resistivities along areas of powerline/pipeline collocation...

...Abstract This paper covers various methods for dealing with sources of errors affecting the accuracy of the Direct Current Voltage Gradient (DCVG) coating defect identification and sizing tool. Topics reviewed in detail include: eliminating the influence of local soil resistivity and varying pipe...

... associated with coatings that shield cathodic protection. cathodic protection shielding by coatings, stress corrosion cracking (SCC) pitting corrosion corrosion risk assessment soil resistivity soil corrosivity mapping coating dis-bondment cathodic protection Cathodic Protection Shielding A well...

...(1) ρ E = 4 · π · a · R w 1 + 2 · a a 2 + 4. b 2 − a a 2 − b 2 Where, ρE = measured apparent soil resistivity (Ωcm) a = electrode spacing (cm) b = depth of the electrodes (cm) R_W...

...-of-way, this may require 1,000 to 2,000 or more segments. Generally, because of right-of-way uniformity over large regions, data input requirements can be significantly reduced, i.e. manual data input for each individual segment is usually not necessary. Soil Resistivity Models www.electrosci...

...(1) i ac = 8 U / ρ s πd Where: i_ac = AC current density (A/m²) U = AC voltage potential ρ_s = soil resistivity (ohm-m) d = coating holiday diameter (m) Abstract The corrosion effects of high AC current density on pipelines are known. The installation...

..., the induction on the pipeline changes as well. Field monitoring records the AC pipe-to-soil potentials at test stations and areas of concern along the pipeline. These AC potentials can be used in conjunction with field measured soil resistivity to predict the theoretical current density for a given flaw size...

... embedded on the sand pad as shown in Figure 2 & 3 . Cathodic protection of ASTs tank external bottom plates soil resistivity grid anodes MMO ribbon anode distributed anode criteria current distribution containment liner distributed anodes INTRODUCTION Corrosion failure of Above Ground...

... specimens were those overprotected. An inverse relationship between corrosion potential and corrosion rate is demonstrated using a linear regression model. A mechanism involving moisture content, soil resistivity and oxygen content is proposed to explain this inverse relationship. Similarly, this mechanism...

... the performance of a normal tank bottom CP system are as follows Soil Properties Soil resistivity of tank bottom cushion constructed with washed sand are normally observed to be varying from the time of construction towards the end of the design life due to seasonal changes, water ingress to the bottom surfaces...

... of predicting coating holiday size from common ECDA survey tools. The results of previous simulations performed using a University of Florida model called CP3D were reduced to simple expressions that allow correction for soil resistivity, depth of cover, pipe diameter, CP level, and DCVG signal strength. ECDA...

... to search for corrosion. After specific site locations were excavated, additional pipe-to-earth potential measurements were conducted. At all excavations the in situ soil resistivity was measured. Representative soil samples were also obtained and tested for resistivity, pH, and oxidation-reduction...

...) relate above-ground measurements of potential or current to the pipeline coating and corrosion condition. This relationship is based on the distribution of current and potential around pipeline coating flaws and is affected by many factors. These factors include CP level, soil resistivity, coating...

...External Corrosion Direct Assessment ECDA corrosion close interval surveys CIS close interval potential surveys CIPS Direct Current Voltage Gradient DCVG soil resistivity AC Current Attenuation surveys ACCA coatings direct assessment in-line inspections ILI pipeline integrity...

... in locating corrosion concerns on this pipeline. ECDA liquid CO₂ Guided Wave Ultrasonic Test corrosion CIS DCVG soil resistivity current attenuation INTRODUCTION In-line Inspection of pipelines can be constrained by issues relating to the ability of flow conveyed tools to navigate tight...

... on. Results indicate that CP does not interfere with the measurement of corrosion rate and pitting factor using EN, LPR, and HDA techniques. corrosion natural gas corrosion probe electrochemical noise harmonic distortion linear polarization resistance gas transmission pipeline soil soil resistivity...