API 652/653 – How it Apply’ s to Internal Tank LiningsPresented By: Darryl CorbinNov. 18, 2016

Agenda

• Introduction• Who is API and how can it influence a lining selection• What is AP I652 and how does it apply to linings• Tank Bottom Lining Selection (New & Existing)• Advantages and Disadvantages of these lining systems• Summary of API 652• What is API 653 and how does it apply to linings• Inspection Intervals• Summary

The longer interval between lining and planned inspection the better for the owner

• Tank is in use

There are no additional costs • Emptying• Cleaning• Inspection • Repair

Safety – less time required in confined spaces in contact with hazardous chemicals

Environment - less hazardous waste

Saving $$$ to Customer – Inspection interval

Who is API?

American Petroleum Institute(API guidance)

Who is API?

- National Trade Association representing the America’s Oil and Natural Gas Industry.

- API has over 400 corporate members.- API is involved in Advocacy to governments, negotiating with

regulatory agencies. - API is also involved in Research and statistics, Certifications,

Education and what we are going to discuss to day Standards.

- There are two API standards that are commonly used in the Oil and Gas Industry for above ground storage tanks and they are API 652 and API 653.

American Petroleum Institute (API)• API gives guidance on protection of Above Ground Steel

Storage Tanks Bottoms utilizing the following standards:

• API 652 – Linings of Aboveground Petroleum Storage Tank Bottoms: gives guidance on the selection and use of linings for protection of Aboveground storage tanks. Revised in 2014 and a ERRATA in Aug. 2016.

• API 653 – Tank Inspection, Repair, Alteration, and Reconstruction: gives guidance on inspection intervals and how linings can assist. Newest version November 2014.

• One other that is mentioned some times is: API 651 gives guidance on use of Cathodic protection. But we will not discuss this standard other than reference it in terms of how it effects the inspection interval.

API 652 Overview

API 652 (September 2014) is a “Recommended Practice” and not a “Standard” and therefore compliance with this document is voluntary. However, parts of API 652 are referenced within API 653, and therefore when an owner/operator is complying with these sections of API 653, the compliance with the referenced section of API 652 becomes mandatory.

Section 5 – Determination of the need for Tank Bottom Linings and Section 6 – Tank Bottom Lining Selection. In Section 5 of the specification discusses the need for lining above ground carbon steel tanks based on the following considerations:

• Corrosion Prevention; Tank Design; Tank History; Environmental Considerations; Reduce Time and Effort for Future Tank Cleaning; Federal, State and Local Regulations; Product Quality and Considerations under API 653 with respect to next inspection interval.

API 652 Overview• It defines or outlines the different options the customer has in

selecting an internal tank lining. It also goes on to say tank bottom linings can generally be divided into two classes; Thin Films (< 20 mils/ <500 microns DFT) and thick films (> 20 mils DFT/ > 500 microns DFT).

• Thick films is also divided up into two groups; Thick Film, Thick Film fibre re-enforced

• In Section 6 it states that thin films may be applied to new tanks and to bottoms of storage tanks that have experienced minimal corrosion. However the standard does not define what minimum corrosion is but we would say general corrosion with no pitting.

API - Lining Selection Based on Steel Condition

API 652 – Overview of Thin Films• States that most systems or linings are based on epoxy or epoxy-copolymer

resins, and goes on to state that selection of a lining should be based on resistance to water and NACE No. 11/SSPC-PA8 should be considered should be considered when design and installation of a thin-film is used.

• Advantages of Thin- Film Linings;

• Initial cost is typically less than thick film reinforced linings• Most are easier to apply than thick-film reinforced linings• Experience has shown that if properly selected and applied can have a life

expectance greater than 20 years.• Most have good flexibility• Generally more accurate magnetic flux leakage (MFL) Floor Scans• Easier to remove at end of life.

API 652 – Overview of Thin FilmsDisadvantages of Thin-films: • API 653 allows a minimum of 0.053 in (1.3mm) remaining bottom plate

thickness at the next internal inspection if a thick-film is used. However, if a thin film is used than API 653 will only allow 0.100 in (2.5 mm) at the end of the next interval because thin films don’t offer hole bridging capabilities.

• Thin-films linings are more susceptible to mechanical damage.• Hard to cover or coat rough welds and weld spatter • Most thin-films require multiple coats• Most thing film linings are solvent-borne therefore VOC regulations can affect

selection.• Most have longer recoat and cure times than thick film Also noted in section 6.2; Inorganic zinc (zinc silicates) are used as tank linings but are not considered thin-film linings for the purpose of API 653 calculations.

Edge Retention of Thick and Thin Films

Thick film Coverage over Sharp edges like Welds, Flange faces, etc.

VSThin Film Coverage over the same

sharp edges

Thick Film

Thin Film

API 652 – Overview of Thick Films (un-reinforced)

• States: Thick-film, unreinforced linings may be used for both new construction and corroded or existing/old storage tanks. It also specifically states that only fibber-reinforced lining are well proven to have hole-bridging capability. Important; There is also no testing procedure within API to test the hole-bridging capabilities.

• Advantages of Thick- Film Linings;• Can be applied as thick as 100 mils/2500 microns DFT in a single

coat• Better coverage over rough welds or surfaces• No overlap or intercoat contaminating, blushing issues if applied

in a single coat.• High volume solid coatings have better edge retention then thin

films due to reduced material shrinkage.• Typically thick film coatings cure faster at ambient temperatures,

some in as little as 24 hours.• Fewer holiday to repair

API 652 – Overview of Thick Films (un-reinforced)

Advantages of Thick- Film Linings;• Promotes as faster return to service • Have a long term service record, can be over 20+ years resulting

in a lower life-cycle cost.

Disadvantages: 

• Most require high pressure airless pumps or even heated plural component equipment.

• Hard to coat complex internals• Contractors have to a higher level of experience• MFL (magnetic Flux Leakage) Inspection technique maybe

limited on thick films applied at very high film thickness.• Some thick-film coatings may crack due to flexure of the plates.

Pit Filling Ability of Thick FilmsHigh Solids, Solvent Free

Open

Omega

Pitting Types

API 652 – Overview of Thick Films(Reinforced –Laminate & Chop Glass & Fiber)

API 652 states there are only two systems specified to be used to restore heavily corroded or pitted tanks. • Fiberglass reinforced plastic (FRP) laminates – Hand Layup & Chop Glass

(1.5 oz. mat or chopped glass); Typically Vinyl Ester, Polyester, Epoxy resins.• Reinforced Thick-film linings (Errate1 Aug. 2016). Typically Epoxy, Vinyl

Ester

Advantages Reinforced Systems:• Excellent coverage of welds and seams• Excellent pitting coverage, maximum allowable before floor replacement• Hole bridging capabilities (laminates up to 8 inches)• Excellent Impact and Abrasion resistance• Reinforced Epoxy’s have reduced labour costs and are quicker than FRP

laminate systems

API 652 – Overview of Thick Films(Reinforced –Laminate & Chop Glass & Fiber)

Disadvantages Reinforced Systems:• Special equipment, experienced contractors• multiple layers and the importance of proper fibber to resin

proportions• FRP systems take longer to install• MFL Inspection techniques maybe limited on films applied at

very high DFT

Cross Section View of a FRP laminate system

652 Summary• API 652 is a Recommend practice and not a regulated standard unless API

653 is used.• API outlines the different types of linings that can be offered:

• Thin Film• Thick Film Un-Reinforced• Thick Film Reinforced

• API does not give any standard for assessing the hole – bridging capabilities of a coating.

• API can be used for both New Construction as well as M&R

• API 652 does NOT tell you which product or lining is suited for the environment.

API 653 API 653 – (November 2014) is the API Standard for Tank Inspection, Repair, Alteration and Reconstruction. It provides a minimum standard for maintaining the integrity of tanks after they have been placed in service. It does not cover the design and construction of new tanks – this is covered by API Standard 650. API 653 covers or address the maintenance inspection or interval in which a tank must be. API 653 requires an owner/operator to monitor the corrosion rate of the tank bottom plate. Once a corrosion rate of the bottom plate is established, the owner/operator may use the remaining steel thickness, together with the known corrosion rate to establish the next interval when they must conduct a tank bottom inspection. The next inspection interval is based on the calculated minimum bottom (steel) thickness at next inspection.

Who uses API 653?

Compliance with the standard is the responsibility of the owner/operator of the storage tank. This is an industry standard. It has, however, been adopted by a number of Federal and State regulatory agencies as the basis for Federal and/or State Regulations governing the operation of storage tanks. Compliance with the standard may also be a requirement of Insurance Companies that write policies for aboveground storage tanks.

API 653 Inspection Frequency Considerations

Several factors must be considered to determined inspection interval:• Nature of the product stored, Visual Maintenance Checks, Corrosion Allowance and

rates, Corrosion prevention systems, materials of construction, location of tank (isolated high risk areas), leak detection systems etc.

• Interval between inspections of the tank (both internal & external) to be determined by its service history unless special reasons. Inspections can be scheduled with the frequency commensurate with the corrosion rate of the tank.

• Jurisdictional regulations, in some cases control the frequency and interval of the inspections.

• The minimum thickness of a steel tank bottom should be determined accordance to API 653. An internal tank bottom lining may be deemed necessary if corrosion is expected to proceed so that the steel thickness may reach this minimum thickness, generally 0.100 inches (2.5mm), prior to next scheduled inspections. If you use a RBI assessment per API 653 to determine if a floor needs to be lined, repaired, replaced, or the interval to the next internal inspection shortened.

API 653 Bottom Plate Minimum Thickness;(Related to next inspection)

Minimum Bottom Plate Thickness at Next Inspection

Tank Bottom/ Foundation Design

0.10 Tank bottom/foundation design with no means for detection and containment of bottom leak

0.05 Tank Bottom/foundation design with means for provide detection and containment of a bottom leak

0.05 Applied tank bottom reinforced lining, >0.05 in thick, in accordance with API 652

API 653 Next Inspection Interval Calculations

Tank Safeguard Incremental Addition to Inspection Interval

OR Fiberglass- reinforced (FRP) lining of the product side of the tank as per API 652

5 years

OR Reinforced lining of the product side of the tank as per API 652

5 years

OR Installation of a Thin Film lining of the product side of the tank as per API 652

2 years

Plus Cathodic Protection of the soil side of the tank bottom installed as per API 651

5 years

Plus Release Prevention barrier installed as per API Std 650 10 yearsOR Bottom constructed from Stainless steel material that meets requirements of API 650

10 years

API 653 Summery regarding - Lining selection and Inspection Intervals

• API 653 is the specification used by end users to determine the current condition of the tank via NDT testing.

• API 653 is also used determine or predict corrosion rates to help select which coating is suitable for desired inspection interval

• API 653 give the adjusted inspection intervals based on Tank Safeguards

• API 653 does NOT tell you which product or lining is suited for the environment.

API 653 – Inspection Summary• If a functioning lining scheme and a method of preventing

under plate corrosion (e.g. cathodic protection) are in place, API 653 allows tank owners to assume zero corrosion rate

• No simple method of fully assessing the condition of the floor and liner short of emptying, cleaning, and inspecting the tank

• Non destructive testing possible through linings up to 118 mils/2950 microns

• If the corrosion rate is known internally and externally

• INSPECTION INTERVALS CAN BE SET TO A MAXIMUM ACCORDING TO A RISK BASED ASSESSMENT

Summary of API 652/653 together• There are a lot of things that are not covered by API 652/653

when it comes to coating suitability, therefore it is very important that the end user maintain a good relationship with not only the contractor but also the coating manufacturer to assure that the right coating is selected for the job.

• The next few slides will show some other considerations that need to be looked at outside API 652/653.

• Inspection intervals can be set at the maximum 20 years with a simple coating selection process.

• Therefore there are lot of other things to consider outside API 652/653 when selecting a lining. For Example:

Product Chemistry General Comparison of Chemical Resistance vs. Product Type

Vinyl Ester

Epoxy

Phenolic Epoxy

Novolac Epoxy

Novolac Vinyl EsterChemical

Resistance

Technology

Polycyclamine cured Novolac Epoxy

$

Product Chemistry General Comparison of Chemical Resistance vs. Product Type

Standard Leaded

Gasoline

Gasoline with MTBE

Gasoline with Ethanol

Gasoline with Methanol

Epoxy

Phenolic Epoxy

Novolac Epoxy

Gasoline Changes

Technology

BIO FUELS

Methyl tert-butyl ether

Crude Oil Storage Temperatures

40ºC

60ºC

80ºC

100ºC

Epoxy Phenolic epoxy

Novolac epoxy

Epoxy Phenolic epoxy

Novolac epoxy

Thin film systems Thick film systems

Light crude

Heavy crude

API 652/653 summery

API 652 Lining

CategoryThin Film Thick Film

Un-Reinforced Reinforced FRPChop/Laminate

Min Steel Thickness next Interval

0.1 inches(2.54 mm)

0.1 inches(2.54 mm)

0.05 inches(1.27 mm)

0.05 inches(1.27 mm)

API Point of UseNew Construction with some M&R with light pitting

New construction & M&R with light to Medium pitting

New construction & M&R with light to Heavy pitting

New construction & M&R with light to Heavy pitting

Incremental Inspection Interval Influence

2 years 2 years 5 years 5 years

Any Questions?