Northeast Gas Operation School Thursday June 5 th Recognition and Assessment of Atmospheric Corrosion Presented by Donald A. Doubleday Jr. National Grid New England Corrosion Engineer & Team Lead
Contents Applicable Codes and Regulations Types of Environments Forms of Corrosion Coatings & Remediation Inspection Process Photo s, Photo s and more Photo s
Codes and Regulations CFR 49, Pipeline Safety Regulations Section 192.479 Atmospheric corrosion Control: General Section 192.481 Atmospheric Corrosion Control: Monitoring Your Companies Operations and Maintenance Manual
Atmospheric Corrosion Control: General 192.479 Each operator must clean and coat each pipeline or portion of pipeline that is exposed to the atmosphere. Coating material must be suitable for the prevention of atmospheric corrosion. Except portions of pipelines in offshore splash zones or soil to air interfaces, the operator need not protect from atmospheric corrosion any pipeline for which the operator demonstrates by:
192.479 goes on to say For which the operator demonstrates by Test, Investigation, or Experience appropriate to the environment of the pipeline that corrosion will: a) Only be a light surface oxide, or b) Not affect the safe operation of the pipeline before the next scheduled inspection.
Atmospheric Corrosion Control: Monitoring 192.481 During the inspection the operator must give particular attention to: Pipe at soil to air interfaces Under thermal insulation Under disbonded coatings At pipe supports Splash Zones At deck penetrations Over spans of water
Atmospheric Corrosion Monitoring Part 192.481 (cont.) Each operator must inspect each pipeline or portion of pipeline that is exposed to the atmosphere for evidence of atmospheric corrosion as follows: - Once every three calendar years but not to exceed 39 months
Atmospheric Corrosion Monitoring: 192.481(cont.) If atmospheric corrosion is found during an inspection, the operator must provide protection against corrosion as required in 192.479
Atmospheric corrosion is defined as: Corrosion which causes deterioration or pitting of the pipe surface resulting from a reaction with the atmospheric environment
Types of Environments Industrial Acid Rain Marine Rural Salt Spray or Splash Zones Ocean or Road Salts Fertilizers w/ condensation Indoor - High Relative Humidity
Factors Affecting Atmospheric Corrosion Moisture Condensation Relative Humidity Dew Rain Temperature Cycling Hot/ Cold Contaminants Acidic Contaminants Alkaline materials (limestone) Chlorides affect corrosion rates
Forms of Corrosion Uniform Surface Rust or Pitting - General Pitting - Localized Fretting Corrosion Crevice - Intergranular Exfoliation Dissimilar Metals - Galvanic
Uniform Corrosion
Pitting
Fretting Corrosion
Crevice Corrosion
Exfoliation
Coatings Wax Tapes (primer) Minimal surface prep Paints (rust protective enamel) Minimal to medium surface prep Epoxies (curing times) Medium to extensive surface prep Cold Applied Tapes Minimal to medium surface prep Shrink Sleeves Medium to extensive surface prep Handling and storage should be in a dry place, ventilated and above freezing temps
Coatings Coatings are applied to protect the steel pipe from the environment. Reasons why Coatings Fail. The installation was never coated. The pipe surface was not properly cleaned prior to coating application. Initial Improper Selection of Coating for the Environment or Application. Poor workmanship NOTE: Proper SURFACE PREP is KEY to any successful application of coatings
Surface Preparation Minimal Surface Prep: Remove all dirt, loose mill scale, loose paint, loose rust, any other loose foreign matter Extensive Surface Prep: Suitable anchor pattern, the surface when viewed without magnification shall be free of oil, grease, dirt, mill scale, corrosion products, oxides, paint and foreign matter All Coatings must be applied in accordance with Manufacturers Specifications
Tools Wire brush Brushes, gloves, rags Knife, hammer, chisel Torch with regulator, hose and propane tank (shrink sleeves) Tape Wrapster machine (cold applied tapes) Power cleaning tools Abrasive blast equipment: NACE SSPC-SP2 Hand Tool Cleaning NACE SSPC-SP3 Power Tool Cleaning NACE SSPC-SP5 White Metal Blast (NACE 1) NACE SSPC-SP6 Commercial Blast Cleaning NACE SSPC-SP10 Near White Blast (NACE 2) Coating inspection tools like: Jeep (electrical test, correct settings) Wet film gauge Dry film gauge Visual
Inspection Process In some companies leak survey techs, customer service techs, meter readers, contractors, ect. performs the atmospheric inspections. At National Grid we utilize Walking Survey is our Primary Inspection Process, with CMS as our secondary: Soil to Air Interface Buried Meter Shut-Off Buried or Corroded Meter Piping (to outlet of meter) Coating Disbondment Never Been Painted Poor Corrosion Foreign Contacts Foreign grounds Metallic (pipe to pipe)
Inspection Process Fittings -Dissimilar Metals -Insulated Fitting's -Electrical or Lightning Burn Marks Meter Bar (integrity, corrosion) Splash Zones Deck Penetrations Supports (integrity, corrosion) Meter Protection (needed, poor condition) Foundation Wall (exfoliation) Hidden or Concealed Piping (inspection not complete if we don t see the wall penetration)
Inspection Process ADDITIONAL INSPECTION REQUIRED Need to document when addition resources are required Inspection goes beyond standard inspection Deck or Building in way Special Equipment needed. Bucket Truck, Ladder, ect. Ultrasonic Thickness Tester
Inspection Classification Each Company has there own set of classifications Good, Fair or Poor Satisfactory, Mild, Slight or Severe I d like to argue we need an: IMMEDIATE Spalling
Inspection Classification Satisfactory - a state where the component does not show signs of corrosion and/or any noticeable structural or mechanical defects. Mild (cosmetic) - degree of corrosion in which rust stains are beginning to appear and are causing cosmetic concerns. Minor cleaning and re-coating will mitigate future concerns. Applying a paint and primer system normally is sufficient to resolve mild corrosion issues. Slight - a condition in which pitting or scaling is beginning to take place. Scrapping and/or wire brushing the area to remove loose corrosion deposits and then applying a paint and primer system normally mitigate future concerns. Severe - a condition in which sufficient metal loss creates a concern for the integrity of the pipe or structural component. Corrective action may require replacement or structural reinforcement of the affected component. Nondestructive examination may be used to determine the degree of corrosion and serviceability of the component.
Record Keeping NEAT NEAT NEAT NEAT PLEASE
Soil to Air Interfaces
Soil to Air Interface
Soil to Air Interface
Soil to Air Interface Wet Bark Mulch
Buried anodeless riser, meter shut-off and meters
Buried Shut-offs & Anodeless Risers
Buried Shut-off
When we dug it out we found an improperly buried anodeless riser
Perfection Mold Shot Anodeless Riser Here is the manufacture s recommended transition point that must be above grade Here is the location of the Max Bury Depth Do Not Bury sticker
Perfection Service Head (Servisert) Anodeless Riser Here is the manufacture s recommended transition point that must be above grade
Manufacture s recommended transition point Manufacture s recommended transition point
Buried/Corroded Meters
Buried Meter
Buried Meter
Buried Meter & Shut-off
Buried Meter & Soil to Air interface is difficult to conduct
Corroded Meter
Foreign Contacts??
Tracer Wire
Tracer Wire
Is it ours? Or Foreign
Illegal Ground
Illegal Ground
Illegal Ground
Foreign contacts Would be OK here Illegal Ground
Arc Burns/Lightning Strikes
Arc or Lightning Burn
Supports
Support
Support
Support looks broken Big meter to be hanging???
2x4???
Support Potential Foreign Contact or Dissimilar Metal
Support Required???
Support Dissimilar Metals Dissimilar Metals Support
Concrete Pad is a Support NO Spaulling
Dissimilar Metals Support
Support
Support Support
Anodeless Riser?? Dissimilar Metals Support Concrete Pad is a Support
Meter Protection Just because you see it does it mean it performing it s function?
Meter Protection
Concealed Piping
Satisfactory The pipe does not show signs of corrosion or any noticeable structural or mechanical defects
Mild (cosmetic) A degree of corrosion in which rust stains are beginning to appear and are causing cosmetic concerns.
Slight A condition in which pitting or scaling is beginning to take place
Severe A condition in which sufficient metal loss creates a concern for the integrity of the pipe or structural component
Before and After
Non Locking Shut-off Open Pipe?
Crazy but True?