Water Tank Coatings Management: The Life-Cycle Approach

Water Tank Coatings Management:

The Life-Cycle Approach

Christopher ScannellRon Christian

AWWA Water Distribution SeminarJuly 10, 2018

Safety Moment: Fall Protection

“Caterpillar Machine Gun Destroyer”“Land Ship”“Water Carrier”

“Tank”

ElevatedStandpipe

Reservoir

Outline

• Introduction to Coatings• Coatings Systems• Inspection of Existing Coatings• Coatings Lifecycle• Recoating Projects• Project Inspection• Q&A

Introduction to Coatings

Definitions• SSPC – Society for Protective Coatings• NACE – National Association of Corrosion Engineers• DFT – Dry Film Thickness• Mil – 1/1000 inch• Exterior• Interior Wet• Interior Dry• Sweat-in• Pot Life

Why Coatings?• Corrosion Control• Waterproofing • Sanitation• Weatherproofing / UV Protection• Appearance / Aesthetics• Fireproofing / Fire Retardant• Decontamination• Color Coding (Safety colors)• Friction Reduction• Friction Enhancement• Wear Resistance

Main causes of Coating Deterioration

• Inadequate / Insufficient coating thickness• Poor Edge Coverage / Edge Retention• Pinholes / Voids / Holidays• Premature Chalking / Fading

Source: Sherwin Williams, Protective & Marine Coatings, Infinitank market information

Coatings Systems

What is “Paint”?

SolidsLiquid

% Solids: @100%, 1604 SF @ 1 mil thickness (sheet of paper is ~3 mil)

Generic Coating Types

• Acrylic: Polymer-based binder in water emulsion• Alkyd: Synthetic oil-based paint• Epoxy: Resin + hardener• Polyurethane: Resin + curing agent• Zinc-rich primer

oOrganic & InorganicoMIOoOAP

Source: http://www.titankogyo.co.jp/products/cosmetics_ti/cosmetics_mio/

Generic Coatings Systems

• Primer: Adhesion• Intermediate: Barrier• Surface: Resistance & Weathering

*Good practice to always use a “stripe coat” for seams and welds

AWWA D102: Standard Coating Systems

• Each system corresponds to a differing conditions for:oAmbient Environment oWater chemistryo Temperature variations

• Specifies:oNumber of coatingsoGeneric coating typesoDFT thicknesses

Outside Coating Systems (OCS) - #1-7• Standard: #6

o Zinc-rich primero Epoxy intermediateoAliphatic Polyurethane finisho Total DFT: 6.0 mil

• Extended-Life: #4o Zinc-rich primeroAliphatic polyurethane intermediateo Fluoropolymer urethane finisho Total DFT: 6.5 mil

Inside Coating Systems (ICS) - #1-5

• Standard Dry: #5• Zinc-rich primer• Epoxy intermediate• Epoxy finish• Total DFT: 10 mil

• Standard Wet: #4• Zinc-rich primer• High-Build fast-set Polyurethane• Total DFT: 25-50 mil

Inspection of Existing Coatings

Washout AND inspection• They are separate but related things

• Sanitary integrity• Structural longevity

• Required by EPA every 5 years• Recommended interval of 3 years• As Needed

• Anniversary inspection• Repair work• Tank Maintenance

Wash Outs

• A minimum of 7 people• 1 Electrician• 1 Pumper Operator• 1 Ground Man• 1 Condensate Man• 2 Hose Operators• 1 Supervisor

• An average wash out takes 4 hours

Inspection Certification Programs

• NACE Coatings Levels 1-3www.nace.org

• SSPC QP I & IIwww.sspc.org

Coatings Conditions: Expected Service Life Remaining• Excellent – 20+ years• Very Good – 15-20 years• Good – 10-15 years• Fair – 5-10 years• Poor - <5 years

Helpful Tips• When negotiating cell towers or anything else

mounted on tanks put in the contract that the company will disassemble when it is time to paint

• Painters rings mounted to ceiling 20 ft apart• New design beams with flat seams• Seam weld not stitch welding • Spec fiberglass grating

• Have the paint representative give a good estimate of the amount of paint needed and request that the contractor keep all empty containers

• Ladders are for climbing. Do not attach anything to them

• Ask landscape crew to blow off the tank when they blow off the driveways

Helpful Tips

Coatings Lifecycle

Information Management

• Tank Inventory• Coatings Conditions Reports• Tank Project Records• Project Inspection Records• Annual Washout Reports

Tank Inventory• Name• Location• Capacity• Type• Dimensions• Existing Coatings• Mixing Systems• Elevations

Columbus:37 Tanks500,000 to 10 Million Gallons

Project Prioritization & Budgeting

• Evaluations-based Prioritization• 5 Year CIP Budget• Longer-term Outlook• Cost Estimation

o Square footageo Tank Typeo Interior / Exterior

Dimensioning

Recoating Projects

Overcoat

• Existing system not extensively deteriorated• Additional Barrier Required• Test for adherence (SSPC-TU 3)• Clean and scarify with light water jet or blast

cleaning (SSPC SP-7)

Recoat – Specification Considerations

• Containment• Surface Preparation• Surface Profile• Coating System• Application method

• DFT range• Dehumidification• Ventilation• Lighting

Surface Preparation

Surface Profile

• Per coating manufacturer’s recommendation• Finer sized blasting media = smaller profile (1-2

mils)• Coarser sized blasting media = larger profile (3-6

mils)

• High performance coatings are NOT paint jobs• Prequalification

• Safety Programs• Certifications – NACE / SSPC• Plural component training

• Consider the life cycle benefit• Pre-bid site meeting

Bid Process

Project Inspection

Project Inspection“The best warrantee is inspection”

Independent Inspector – Avoid the “fox guarding the henhouse”

Full Time vs Hold Point – You get what you pay for• Mixing technique• Thinning• Sweat-in• WFT/DFT measurement

Authority to stop workInspector needs to climb!

Environmental Conditions

Surface Temperature

Humidity

Air Temperature

Profile and Cleanliness

Mixing, Sweat-In, Film Thickness

Holiday Detection

Anniversary Inspection

• Peeling, bubbling, cracking

• Rust spots• Rust stains from

inaccessible surfaces are acceptable

Questions?

Christopher Scannell – [email protected] Christian – [email protected]

References

• AWWA D102• 10 State Standards

• Sherwin Williams, “Generic Classifications of Coatings,” March 2018, Protective & Marine Coatings Group.

• Sherwin Williams, “Is That Really What I Wanted,” May 15, 2018, presentation by Kevin Morris and Don Berry.