PRESENT CONDITION EVALUATION (PCE)

KNOW YOUR COATINGS

KNOW YOUR SUBSTRATES

INFORMATION IS KEY

Department Manger | Coatings Services NACE Certified Coatings Inspector # 9625SSPC PCS Protective Coatings Specialist # 472-427-0833

A liquid, liquified, or mastic composition that, after application to a surface, isconverted into a solid protective, decorative, or functional adherent film.

The deterioration of a material, usually a metal, that results from a reaction with its environment.

What is the cause of corrosion??

2020 estimate is… With little fanfare, cost of corrosion in the US exceeds $1 trillion annually.

Cost worth addressing issues with Corrosion???

Corrosion and Corrosion ControlWhat is CorrosionHow/Why Does Corrosion OccurCorrosion CostsForms of CorrosionCorrosion Control MethodsHot-dip Galvanizing (HDG)ProcessCoating CharacteristicsPerformance in Corrosive Environments

The Galvanic Series

ZINC - Anode

STEEL – Cathode

This arrangement of metalsdetermines what metal willbe the anode and cathodewhen the two are put in aelectrolytic cell (arrangementdependent on salt water as electrolyte)

Corroded end Anodic or less noble

MagnesiumZincAluminumCadmiumSteelLeadTinNickelBrassBronzesCopperNickel-Copper AlloysStainless Steels (passive)SilverGoldPlatinum

PROTECTED END

Microscopic anodic andCathodic areas exist on a

single piece of steel.As anodic areas corrode,new material of differentcomposition is exposedand thus has a different

electrical potential

GeneralIdentified by uniform formation of corrosion products that causes a even thinning of the substrate steelLocalizedCaused by difference in chemical or physical conditions between adjoining sitesBacterialCaused by the formation of bacteria with an affinity for metals on the surface of the steelGalvanic/Dissimilar MetalCaused when dissimilar metals come in contact, the difference in electrical potential sets up a corrosion cell or a bimetallic couple

Barrier ProtectionProvided by a protective coating that acts as a barrier between corrosive elements and the metal substrate

Cathodic ProtectionEmploys protecting one metal by connecting it to another metal that is more anodic, according to the galvanic series

Corrosion Resistant MaterialsMaterials inherently resistant to corrosion in certain environments

Paint

Galvanizing

What can be used to stop corrosion of a substrate??

Coatings / Paint

Create a barrier of protection between a substrate and it’s environment.

Coatings are designed for a multitude of applications, imperative to know your substrate.

What coatings are applicable for what substrates??

Where to obtain the correct answer for applications of coatings?

Broken Down Into Four Steps

1. Background Information 2. Safety items (OSHA)3. On site evaluation 4. PCE Report

Provides Specific information for infrastructure design

1. Existing conditions2. Current condition of coatings and type3. OSHA Requirements 4. Repairs and modification 5. Defects6. Report provides projected date for

rehabilitation and coatings system

Information Gathering

1. Age 2. Size3. Last rehabilitation4. Coating Type5. Empty / full6. Condition Fair ?? Poor!!7. Are all substrate surfaces accessible8. Tanks? Is there a ladder for access9. Is there an access hatch

1. Handrails / Height 2. Safety Climb? Condition 3. Venting 4. Lighting 5. Hatches 6. Ladders 7. Manways8. Catwalk

1. Paint Samples 2. Measure all items3. Structural Condition 4. Coating Condition 5. Anchor Bolts 6. Foundation / Spalling?7. Piping Condition / type of stored material 8. Pipe Vault 9. Valves 10. Pipe material / stored product temperature

11. Roof Rafters 12. Interior Floor 13. Coating Adhesion Testing / Method14. Ultrasonic Thickness Gauge (UTG) Readings 15. Conductivity Testing for salts

1. Photos with date time stamp 2. Per Item Graph 3. Checklist 4. Written evaluation for all items listed 5. Recommended repair rehabilitation date6. Coatings systems for rehabilitation 7. Construction Cost Opinion

Why is design important in the discussion on corrosion?

80% of all coating's failures are due to poor surface preparation.

NACE International:National Association Coatings Engineers

SSPC Society for Protective Coatings

Both of the standard organization above have a wealth of informationthat spans all industries if there are questions about what to use, thisis a great place to start.

Impressed Current

Galvanic Sacrificial Anode

Galvanic Zinc ApplicationZinc Metallizing

Zinc-rich Paints

Hot dip Galvanizing

Impressed CurrentExternal source of direct current power isconnected (or impressed) between the structureto be protected and the ground bed (anode)

Ideal impressed current systems use ground bedmaterial that can discharge large amounts ofcurrent and yet still have a long-life expectancy.

Galvanic Sacrificial Anode

Pieces of an active metal such as magnesium orzinc are placed in contact with the corrosiveenvironment and are electrically connected to thestructure to be protected

Example: Docked Naval Ships

Galvanic Zinc ApplicationZinc Metallizing (plating)Feeding zinc into a heated gun, where it is melted and sprayedon a structure or part using combustion gases and/or auxiliarycompressed airZinc-rich PaintsZinc-rich paints contain various amounts of metallic zinc dustand are applied by brush or spray to properly prepared steelHot-dip GalvanizingC f / f

DegreasingRemoves dirt, oils, organic residue

PicklingRemoves mill scale and oxides

FluxingMild cleaning, provides protective layer

Degreasing/Caustic cleaningZinc-iron metallurgical bond only occurs on clean steel

1. Does environment / location of a substrate play a part in coatings selection?

2. What is the cause of corrosion?

3. What coatings are applicable for what substrate?

4. What can be used to stop corrosion of a substrate?

5. When and where does corrosion take place?