RINA INTERNATIONAL CONFERENCE ADVANCED MARINE MATERIALS & COATINGS 22 23 February 2006 2006: The Royal Institution of Naval Architects The Institution is not, as a body, responsible for the opinions expressed by the individual authors or speakers THE ROYAL INSTITUTION OF NAVAL ARCHITECTS 10 Upper Belgrave Street London SW1X 8BQ Telephone: 020 7235 4622 Fax: 020 7259 5912 ISBN No: 1-905040-22-9
Investigation into the use of Geopolymers for fire resistant marine composites A.C.J Flowerday, P.N.H Wright, R.O. Ledger, A.G. Gibson University of Newcastle upon Tyne
Main Participants This work was conducted as part of the individual research projects of: Arran Flowerday School of Marine Science and Technology Rhiannon Ledger Formerly School of Mechanical and Systems Engineering - Now working for Faber Maunsell
Background Why are composites used? Why is fire protection required? Current options
Why are composites used?
Material properties
Weight
Cosmetics QuickTime and a TIFF (Uncompressed) decompressor are needed to see this picture.
Why is fire protection needed?
The night before Rapid surface spread of flame High heat release High smoke emissions
Current options
Types of protection Active Intumescent coatings Passive Fabric materials Rockwool Sheet materials Firebarrier
Properties defining fire performance Fire Resistance Thermal properties Mechanical properties post v. pre exposure
Properties defining fire performance Fire Reaction Time to ignition Surface spread of flame Heat release Emissions
SOLAS SOLAS Chapter II provides specifications for fire resistant partitions H - Capable of preventing the passage of smoke or flames for 1h against the hydrocarbon curve A - Capable of preventing the passage of smoke or flames for 1h against the standard curve
Emissions
Geopolymer - Meyeb Meyeb is a potassium alumino-silicate Two component resin system Easy to work with No emissions to the workplace
Test Rig
Heat Flux Meter
Analysis The heat flow into a heat sink is given experimentally by Q(t) = m C ( s P S T S T ) 0 a S This can be graphically equated to the theoretical values found using the thermal conductivity, diffusivity and the front face temperature Q(t) = k(t 1 T 0 ) t X X α 1 6 + 2 π 2 n=1 ( 1) n n 2 exp n 2 π 2 αt X 2
6 Glass - Meyeb 4.E+04 3.E+04 3.E+04 2.E+04 2.E+04 1.E+04 5.E+03 Q(t) Measure Q(t) Theoreti 0.E+00 0 200 400 600 800 1000 1200 1400 1600 Time, t (secon
Analysis Verification There is no other source of published thermal properties for this material. The manufacturers were unable to supply any values. How to check the validity of the results?
k Q (Measured) 0 100 200 300 400 500 600 700 Time, t t 0
Valid results? Sample 4 Glass - Meyeb 6 Glass Š Meyeb (rpt) 6 Glass - Meyeb 3 Carbon - Meyeb t 0 (sec) Calculated Graphical 45 45 110 107 145 150 82 80
Results Sample k MEYEB 4 Glass Š Meyeb 6 Glass Š Meyeb 6 Glass Š Meyeb (rpt) 3 Carbon Š Meyeb 0.144 0.147 0.155 0.164 Average k 0.153
Results Average alpha Density of composite 4.75E-08 2269.11 Density of fibre 2580 Density of Meyeb 2150 V f 0.277 V m 0.723 Cp G-M 1416.48 Cp fibre 810 Cpm 1695
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Any Questions?
Advanced Marine Materials & Coatings, London, UK CONTENTS Managing Coatings Through Life Raouf Kattan and Rodney Towers, Safinah Ltd., UK Improved Corrosion Resistance and Durability with Single Component Moisture Cure Urea Morten Sorensen, MC Technology, Belgium A New Approach for Ballast & Cargo Tank Coating: a Solvent-free and Humidity Tolerant Epoxy System with Edge-Retentive Properties Joao Azevedo, Euronavy, Portugal The Effect of a Foul Release Coating on Propeller Noise R. Mutton, M. Atlar, M. Downie, University of Newcastle upon Tyne, UK C.D. Anderson, International Paint, UK Environmentally Friendly Marine Anti-Fouling Additive Guy Seabrook, Magellan Companies Inc., USA Alocit Delta T and Delta db Brian Glover, Alocit Systems Ltd Investigation into the use of Geopolymers for Fire Resistant Marine Composites Arran Flowerday, Rhiannon Ledger, Dr Peter Wright and Prof Gibson, University of Newcastle Upon Tyne, UK Vacuum Consolidation of Commingled Thermoplastic Matrix Composites for Marine Applications M Ijaz, Peter Wright, M Robinson and Geoff Gibson, University of Newcastle, UK Enviropeel Systems: Setting New Standards Tim Davison, Enviropeel Systems Ltd, UK A Non Chromate Conversion Coating Process for Corrosion Protection of Al2024 Aluminium Alloy in a Marine Environment. Wayne C. Tucker and Maria G. Medeiros, Naval Under Sea Warfare Center, USA Richard Brown and Dharma Maddala, University of Rhode Island, USA. Fatigue Crack Growth in Anodised Aluminium Alloys A M.Cree, Britannia Royal Naval College, UK G W.Weidmann, The Open University, UK Composite Overlay for Fatigue Improvement of a Ship Structure Gáspár Guzsvány and Ivan Grabovac, Defence Science and Technology Organisation, Australia Authors Contact Details 2006: The Royal Institution of Naval Architects
Advanced Marine Materials & Coatings, London, UK MANAGING COATINGS THROUGH LIFE M R Kattan and R H Towers, Safinah Ltd. UK SUMMARY This paper provides an overview of the issues related to the coating of vessels and the management of the coating system to prevent corrosion through the life of the vessel. The paper reviews how different factors throughout the ships life influence the potential for corrosion. Decisions made at each stage of the vessels life from design through to in service life and ultimately to its disposal will be considered and their impact discussed. Throughout the paper recommendations are made as to alternative approaches that owners may be consider to control costs. 1. PLANNED MAINTENANCE Planned maintenance has really grown out of the regulatory requirements of the Classification Societies, and as a function of ship management, it has become mandatory that all ships under Class must adopt some form of planned maintenance system. The main elements of any planned maintenance system will cover the main propulsion, navigational machinery and equipment, electrical power generation, and the hull structure. In fact planned maintenance systems have been developed to cover almost every part and function of the ship. The majority of shipowners/managers therefore already operate planned maintenance systems. Some owners have developed their own systems whilst others have contracted for proprietary software, the purpose of which is to provide planned maintenance information to the crew and the manager to ensure the safe running of the ship. Information from these systems will be monitored by Classification Societies as required, and they will provide other information for regulatory authorities such as for Flag or Port State control inspections. Planned maintenance systems are therefore well established in the operation of the vessel. These days there is a rising trend for Classification Societies to be offering hull management services that enable owners to record and retrieve a variety of information about their vessels and fleet, while at the same time allowing the Classification Societies to take a broader view on the performance of differing designs and alternative technologies in ships under their registration. Despite therefore all the progress and development in planned maintenance, and its wide acceptance as a vital function of ship management, there remains one on board system, which is often not subjected to a proper planned maintenance scheme, and that is the coatings system. This observation upon industry practice may be surprising for some, but perhaps not to others. There seem to be two main reasons for this. One is about the perception of the role, which paint plays in the operational life of the ship. The other is to do with the cost of paint in the initial investment package of a new ship. 2. PAINTING OR PRESERVATION? In M&R, it seems that the traditional view of ship painting still generally prevails. The underwater area and the need to antifoul is a prima facie case for taking the ship out of service for drydocking, and has therefore always been treated as an important and specialist function. The direct link between fuel consumption and the performance of the antifouling coating has, of course, long been established, but despite this, many owners still seek to compromise on the quality of the work carried out on the underwater hull during dry-docking. Operators of certain special ship types, have also had the additional need to monitor and maintain particular locations. For chemical tanker operators, it was tank internal coating. Operators of LNG carriers came to recognise the direct relationship between preserving the WB tanks and achieving an extended trading life for such ships. More recently, there has been an entirely new industry focus on cargo hold painting in bulk carriers driven by ship safety issues. However the painting of other locations has often been seen more in terms of a stop the corrosion spots and clean it up activity to deal with unsightly rusting and staining damage, which need covering up, rather than the need to maintain a long term preservation system, which can be important to sustain asset value and ensure the longevity of the vessel. Some owners do run their own systems for managing coatings. This often takes the form of a Partnering Agreement with a leading paint company, and there is trend amongst marine coating manufacturers to offer these types of services for the purpose of differentiating themselves, and as a way of providing added value to clients. 2006: The Royal Institution of Naval Architects
Advanced Marine Materials & Coatings, London, UK 3. PAINT IN THE INITIAL INVESTMENT PACKAGE OF A NEW SHIP With the exception of chemical and products tanker ship types, coatings are generally seen as a low cost item, and in relative terms, this is correct. For example, and to place the paint supply and application in perspective, the following information may be of interest. The current market price (Feb 2006) for a 300K dwt VLCC newbuilding in Korea, as the benchmark, is in the range of $118-125 million dependant upon specification. Steel prices in Korea are currently around $ 700 per ton with some considerable tonnaqe imported from China. For such double hull design, the steel weight will be ± 35,000 tons This leads on to a quite logical question. What is the cost of protecting my asset within such a major capital investment? What therefore is the relationship between the overall cost to construct my asset and the input cost of preserving it? 300K VLCC ± 35,000 tons steel Man hours / Korea Man hours per ton steel Full ship ± 500,000 14 Paint application 35,000 40,000 1 The current cost for the supply of all coating materials, except shop primer, for one 300 K VLCC will be in the region of $ 2 million which currently equates to 1.6 1.7 % of total ship cost For standard ship types therefore, the cost of the paint package, that is the coating materials and the application work, will together represent something of the order of 9-10% of the total ship cost, possibly higher. This is therefore a larger cost item than is perhaps generally understood by the shipowner. The shipyard will only seek the owners approval about the proposed paint supplier, whose supply items only represent between 1.5 2 % of the ship cost. For this reason there will usually be limited scope for the purchaser to influence the shipbuilder on preservation issues during the final negotiation. work, and they will contract this work out in parcels of varying manhour content, often at a lump sum price. For this kind of work, shipyards will probably maintain better records of total cost, including consumables such as blasting abrasive where used, but figures for this are difficult to ascertain. When manhour figures can be obtained, these may be difficult to reconcile between yards. When viewed on their own, manhours may also understate the total cost, and so they should be used cautiously. In the case of chemical tankers and Aframax tankers with fully coated tanks, the paint package is likely to represent 15% of the ship cost or higher, and so the specification detail for a new tanker of this type becomes even more important, with approval and the decision on the buyers side often reaching Director level. It is worth stating that this cost differential will be reflected in the detail of the ship specification; for example, the painting of cargo tanks will be developed from a functional specification; the selection of an antifouling will have to meet a performance requirement, whereas the rest of the hull coatings will be a specification based on generic products. The starting point for painting specifications is therefore not consistent. Both the functional and performance approach, in conjunction with the acceptance of the manufacturers recommendations for maintenance, have shown that it is possible to achieve the functional and performance objectives in service. If therefore a shipowner is going to invest $100+ million in the steel structure of a new ship, it must surely be increasingly logical to ask the question should I be taking a more modern approach to the preservation of my asset through its life? 4. ROLE OF COATINGS Coatings can serve a variety of functions on board a vessel and these include: - Protection from corrosion - Prevention of fouling of the hull - Cosmetic appearance and house colours - Protection from corrosive effects of cargoes - Protection from corrosive effects of having to carry non earning liquids, e.g. ballast, freshwater, grey water etc. This paper will focus on how to improve the prevention element of corrosion. With regard to the man hours for paint application, this is an area, which, in practice, is wide open for variance between shipyards in the same country, and between countries, where best practice painting methods can differ greatly; eg as between Korea and China. These days there is a widespread practice amongst shipyards to subcontract surface preparation and paint application 2006: The Royal Institution of Naval Architects
Advanced Marine Materials & Coatings, London, UK 5. COATING PERFORMANCE Like any system the correct performance is dependent on a number of factors: Coating selection Specification of the coatings to perform the tasks required Correct installation of the system Subsequent maintenance at sea by crew or riding squad Reinstatement of system at major maintenance events (Dry-dock) 6. COATING SELECTION For many fleet owners and operators, there is a well established pattern of treating the new build phase of the vessel as a separate project with finance and budgets set by non technical departments, and within which limits the new building project team must endeavour to deliver the vessel. In practice, this financial approach tends to override the technical requirement, and often results in scant regard being paid to the through life needs. As a consequence, this approach often leads to the selection of coatings, based wholly on cost without any evaluation of through life performance requirements, and cost benefits. Of course coating selection at new building can be influenced by a number of things: the shipyard will purchase the paint and so may have a preferred supplier or a limited makers list. the shipowner may have a fleet paint supply agreement with one or two paint companies, and may therefore wish to limit selection to these companies to sustain consistency across the fleet. the paint supplier may be offering incentives or rebates to particular clients to help secure the business and keep out competition. overall first cost and payment terms can also be issues Two key factors are often missing from this approach. They are How will the coatings selected perform during the new build phase and the overall building schedule of the shipyard. How the coatings selected will match the intended operational pattern of the vessel; one particular aspect of this is the nature of and the elapsed time between final coating acceptance and loading the first cargo. If the needs of these two criteria are not recognised, then the ongoing penalty to the shipowner will emerge in the form of increased costs through life. Once their performance has been compromised, there will result a commitment to increased costs of maintenance through life. 7. SELECTION OF COATINGS The current approach to coating selection therefore may not be the best possible approach. The lack of confidence in coatings not being able to perform satisfactorily through life is reflected in the results of the Joint Tanker and Joint Bulk Carrier studies. Both studies have concluded that the only real way to ensure that ship strength will be maintained through life, is to design the hull structure with additional steel rather than by placing undue reliance on coatings systems being able to perform as planned. Whereas this increase in scantlings is not a substitute for the corrosion protection afforded by good coating systems, it is an indication of the importance given to coatings by Classification societies when thinking about the structural integrity of a vessel. Thus a step change is required in the selection process; a change in which the following factors are taken into account: Where the vessel will be built and the duration of the build as well as the season. How the vessel will be operated and the anticipated operational environment to which the ship will be exposed. The planned maintenance system to be adopted for maintaining the condition of the coating systems, whilst at sea and during scheduled drydocking periods. The employment of suitable methods to assess coating condition, and enable preventative maintenance to be carried out The resources available to carry out the maintenance on board. All these factors will have a considerable impact on the life expectancy of the coating and can only be properly taken into account through the use and development of a functional paint specification. This also has the added approach of very clearly distinguishing the true and objective technical merit of competitive bids from various paint companies as well as ensuring that the shipowner devotes adequate thought to the benefits of different functional requirements. 8. THE MEANING OF FUNCTIONAL SPECIFICATIONS A simple example of a traditional coating specification would be as follows for a deck: Coat in Type of DFT Colour Generic Scheme coating type Coat 1 Anticorrosive 80 microns Grey Epoxy type Coat 2 Finish 50 microns Green Epoxy type 2006: The Royal Institution of Naval Architects
Advanced Marine Materials & Coatings, London, UK All paint companies that respond will meet these technical criteria and therefore limit the choice down to price. If however a functional specification were developed, then the following questions would need to be addressed by the intending paint supplier: Function Anti-corrosion Gloss Abrasion resistance Requirement 3 year life with 1% spot rust acceptable Initial gloss retention and gloss retention after 24 months Taber value If this was a new build deck, then the following shipyard functionality could be added: Function Max time to Overcoat Drying time to walk on at 10 centigrade Requirement 6 months 12 hours Other factors could be considered for the deck but the above serves to illustrate the example. In this way the technical merit of each paint company solution can be quantified against specific functional needs and performance gauged. Additional items can be added to meet specific vessel needs in operation, maintenance and also taking into account HS&E issues. This makes performance measurable against defined and objective technical requirements. 9. CORRECT INSTALLATION OF THE SYSTEM Picking the right system is fine but work with which the authors have become involved during the last 8 years has clearly shown that the majority of paint failures are caused by the paint being asked to perform out-with its defined envelope of capability. Poor selection has been in part responsible for this, but poor surface preparation and application (Installation) of the system has usually contributed. This leads to an analysis of paint failures carried out by Safinah Limited: We can summarise a number of problems found: - Poor design of the vessel had resulted in inadequate access and ventilation for initial application work to be carried out. - The installation work for these activities was found to have been poorly scheduled and planned or integrated into the build or repair processes. It was recognised that such instances had usually been treated as an after thought. - Supervision of the installation was found to have been relatively poor when compared to other systems on the vessel (superintendents tend to have a marine engineering or deck background, with varying knowledge of coatings systems and their installation). - Standards for assessing work tend to be subjective and open to broad interpretation. - Coating system installation often takes a very low priority with owners superintendants, when compared to other systems. - Weather and other environmental factors can adversely affect installation, and it was not possible to overcome these in instances where vessel or yard had to meet the defined delivery schedule or other operational constraints (e.g. tides, charters etc.) 45 Percentage 40 35 30 25 20 15 10 5 0 Design Spec Applic Chem Operation Other Cause Figure1: Cause of failure analysis 2006: The Royal Institution of Naval Architects
Advanced Marine Materials & Coatings, London, UK Not withstanding all of the above, considerable time is still spent inspecting and approving the installation, and yet there is still often recourse in the event of a failure. Poor records of the installation or repair is another problem which complicates the issue. During installation the owner s representative will usually rely heavily on the Paint Supplier s technical supervisor, and it is a common misnomer that this supervision is there to protect the owner s interest, when in truth at new build, the makers s supervision is primarily to protect their own interests, and secondly to protect those of their paymaster, which, for any new construction, is the shipbuilder. When ownership passes from the builder to the owner, and after the 12 month shipbuilders warranty period has also expired, the paint supplier becomes responsible to the owner but this cannot undo what has been done at the shipyard during the construction.. At repair, the attendance of the paint company s technical representative is primarily to protect their own interests, although it must be said that the owners representative will often impose upon the paint supplier to take general responsibility for control of surface pretreatment standards, and the inspection of the various applications by the shipyard workforce. The extent of the owners reliance upon the paint manufacturers representative will depend upon the degree of mutual trust and confidence, which can be established between the two parties at site. The specification is frequently changed or adjusted at the time of the indock inspection, and consequently much paintwork repair activity tends to be at best ad hoc, with few examples of pre-planned work packages linked to any planned maintenance system. By contrast, the offshore industry has been adopting planned maintenance for structural painting for some considerable time, probably driven by difficulties of confinement and safety constraints, when undertaking even basic maintenance painting, whilst platforms or drilling rigs are operational. 10. WARRANTY INCOMPATIBILITY WITH LONGER TERM PRESERVATION OBJECTIVES Every owner will get a 12 months shipbuilders warranty on their new ship. However, because of advances in antifouling technology, it may be anything up to 5 years before a VLCC will drydock for the first time. The consequence of this has been to prompt shipowner s to search for the security of some longer term warranty from the paint supplier in respect of the antifouling system. In the case of coated cargo tanks, the extended warranty concept is now fairly standard but initially this was promoted by paint manufacturers as a means of persuading shipowners to accept and specify advanced technology coatings, which would enable them to carry a much wider and more aggressive range of chemical cargoes with beneficial higher freight income. This practice of split warranty responsibility has become an industry standard but, shipbuilders, in stark contract to car manufacturers, have still not changed their warranty offer to meet that of the clients operational market requirement. At the end of the day, this is all about shipbuilders being prepared to embrace functional specifications within their standard offers, adjusting their working practices to achieve the necessary technical control over application, and to consider ceasing the practice of treating all paint products as commodities. This would open up the concept of shipbuilders entering into longer term arrangements with one or two appropriate paint suppliers, who have both the product assortment and technical capability to fully support the shipbuilder. 11. SUBSEQUENT MAINTENANCE AT SEA BY CREW OR RIDING SQUAD On board maintenance by crew is often poorly planned and poorly executed. A simple example of this would be to consider a small area touch up of a 2 coat deck system. The crew would detect a rust bloom or a coating failure; they would generally surface prepare the area back to bare steel using a mechanical method, and with some inevitability, feather the edges by grinding. Normal practice will probably be to apply the anticorrosive by either brush or roller or both, and then apply a finish coat. However, what is often not so well understood, is that for an original 2 coat system as outlined above, that is say 80 microns + 50 microns, this will require a 5-coat manual application to re-instate. A typical brush and roller application will achieve only 30 microns per coat. From our own observations, it is very rare for the crew to know this or be allowed the time to full re-instate the system in this way. The problem is that if the proper DFT s are not reached, this invites an early repeat of corrosion activity at the same location. Repairs by riding squad tend to be better planned and better executed because they are seen as significant operational costs, and the work will usually have been specified in more detail to assist the contractor price the work. Nonetheless to ensure that the owner gets value for money these also need to be properly supervised and planned. 2006: The Royal Institution of Naval Architects
Advanced Marine Materials & Coatings, London, UK It is felt that the proper planning of coating maintenance should provide the crew with appropriate work packages and timings for their execution to ensure cost effective maintenance of the vessel to a good standard. Such standards exist for ballast tanks, but owners should establish their own standards to meet their own operational needs in particular locations, based on corrosion, cosmetics etc. 12. REINSTATEMENT OF SYSTEMS AT MAJOR MAINTENANCE EVENTS (DRY- DOCK) At major scheduled repairs the quality of the work carried out is often simply dictated by the time available, and the weather conditions, as well as any unforeseen underwater hull work required either for steel or machinery/equipment. The net result is that, in practice, the proposed paint plan/programme is often compromised to meet operational schedules, and hence the practical result is often less than satisfactory. This can apply even to antifoulings. Assuming long term preservation is a continuing objective, the owner must apply the same rigorous approach to the reinstatement of full coating systems as they do to other critical systems. To achieve this, proper work packages need to be developed and a proper schedule of work defined with agreed standards and reporting. Such approach is clearly best suited to computerisation, and the use of existing software solutions can readily assist in accomplishing this. Supervision of coating activities during these major works is often given a very low priority by the owners personnel who often have a primary focus on steel and machinery repairs (perhaps more familiar ground for them). Reliance is again placed on the paint supplier. It is also an unfortunate fact, and very necessary to understand, that the costs of recoating are often disproportionately higher than during newbuild. The authors repeatedly hear about estimates for reinstating coating systems reaching up to $50 per square metre, which only seems to emphasise the importance of getting the initial selection right and the application done well. It is the opinion of the authors that if planned maintenance systems were applied to all the coating locations on board ship, then the payback would come from the reduction in costly steel replacement later in the ships life. However, there is again often a lack of consideration of the importance of planned maintenance to avoid even more and to ensure that the Anti-fouling is well applied to assure cheaper running/fuel costs. 13. OTHER BENEFITS Planned maintenance systems allow data to be collected over time. The benefits of this are that the performance of particular solutions can be evaluated on a continuous basis, and feedback from lessons learnt in similar ships across a fleet are likely to prevent the same mistakes being made again. This in itself is likely to result in some future cost savings. Ship owners need to develop appropriate systems to monitor and plan the coating work, so that over time they can eliminate the most common causes of failure by better selection, and control of the installation. The effect of this will lead to the better overall management of coatings through life. Some of the existing planned maintenance systems allow Internet driven access, and provide remote expertise to deliver solutions working together with the crew and the managers of the vessels. To gain the benefits from such an approach, owners will need to consider how to develop in house expertise or alternatively to outsource the appropriate resources to manage such systems across a fleet. 14. CONCLUSIONS With the exception of antifoulings, and the attention given to paint in respect of some specialist ship types, coatings often appear to fall into a no-mans land in terms of the resource allocation of many ship owners. Standard specifications need to be carefully reviewed, not just for functionality but also to take into account the age of the vessel. Having a standard fleet wide specification might increase costs by using too high a quality of coating or too low a quality of coating on both new ships and older ships. Better to specify a coating that fits the need. Even a simple manual planned maintenance system could generate cost savings for owners whilst, at the same time, increasing the life of the vessel and reducing the incidence of coating failures. More comprehensive computer/internet based solutions are likely to result in additional benefits arising from the better management of paper work, and the automated. generation of reports and work packages. 2006: The Royal Institution of Naval Architects
Advanced Marine Materials & Coatings, London, UK The information generated will provide a real method of monitoring coating performance; will provide a system of early warning for locations likely to need maintenance; and will help to highlight common trends arising across a fleet of ships. Lessons learnt may lead to improvements in the detailed design of future ships, and possible fleet wide savings in operational costs. Improved knowledge in-house will lead to better supervision of painting work both on board and in the repair yard, and it is felt that this can be achieved by the use of modern systems with a minimum of either additional internal or external resources. If therefore planned maintenance systems, which are now being applied to so many shipboard functions, are in fact generating their own cost benefits for operational ship management, then it must make sense to consider extending this principle to embrace coatings systems also. The first steps therefore could be to just trial one or two specific locations. 2006: The Royal Institution of Naval Architects
Advanced Marine Materials & Coatings, London, UK IMPROVED CORROSION RESISTANCE AND DURABILITY WITH SINGLE COMPONENT MOISTURE CURE UREA M Sorensen, MC Technology, Belgium SUMMARY In the 1970 s the offshore industry made a request to the coating industries to develop a coating that could be applied in high humidity conditions. This was due to the numerous pre-mature coatings failures for offshore marine maintenance. We will discuss here one of the most viable new technology developments the moisture cure urethane, more aptly called polyurea and developments over the past 30 years. The most viable result was a single component pure urethane product that goes through a rather complicated production procedure where it is pre-reacted. The final cure is through the exposure to minimal amounts of moisture forming a polyurea. This is quite a different product to the two component polyurethane coatings in many ways. In comparison to two-component urethane, it is a much safer product for the applicator in primarily due to the lack of isocyanate (carcinogenic) free monomer. The polymer technology for this technology is used for production of many common products today including artificial heart valves, tennis shoes, automobile parts and caulking compounds for example. Independent third party testing has proven this to be more effective for corrosion resistance and long term monitoring of projects have demonstrated the MCU s to be more durable and have a longer lifespan, when compared to plural component technology. 1. EARLY MCU DEVELOPMENTS: Initial products produced had inherent problems associated with them; Over application of the then low recommended dft s produced gas entrapment or film blistering, The intercoat adhesion was not very good They were unstable often curing in the can prior to opening Developments in laboratories often do not succeed in the real world. In the real world a coating must have as wide tolerances as possible as it is next to impossible to complete an application exactly as per manufacture s recommendations. Time is limited, the overcoat needs to be as short as possible with subsequent coats applied too soon or beyond the overcoat limitations, the coating application is often too thick, and the climatic conditions are often beyond the manufacturers recommendations, too humid, too cold or beyond the dew point. Several coating manufacturers attempted very lengthy and complicated production methods of MCU s in order to try and stabilize the material often involving nitrogen blankets over the product in the production tanks and in pails after canning. This process was time consuming, not cost effective and in the end offered no guarantee of stability and the other problems still have not been dealt with. All the major coating suppliers became discouraged and simply put this down as another good idea that does not work and could not justify continuing with the developments. Over the initial years several smaller firms maintained a research into developments of these coatings. However the initial three key problems still exist with most commercially available products even today. Despite these inherent problems numerous projects were completed. 2. WASSER, BACKGROUND In 1980 William J. Brinton made significant discoveries and developed his own proprietary resins and formulations. Mr. Brinton s new formulations were the beginnings of a major turn-around for the MCU technology. He was able to solve the three key problems and manufacture a product line with; Better than average intercoat adhesion, No maximum recoat time, Products capable of being applied at 2 3 times their recommended DFT, without gas entrapment. Long-term stability in the can. The new firm, Wasser High-Tech Coatings, was established in the USA, with the sole intent to manufacture and market MCU s. In the early stages Wasser focused on the bridge and Dam business. Within six years Wasser MCU became the single largest supplier of bridge and dam maintenance coatings in the USA [1]. This was quite an achievement for a brand new, previously unknown firm, producing a technology product, which the industry s majority did not believe in. Naturally to gain approvals for these major government projects came only after third party testing required generally by each state and provincial s approved third party testing laboratory. This involved numerous testing and the results were very positive. All testing showed this material to be either the top performer or of the top, depending on the test criteria. 2006: The Royal Institution of Naval Architects
Advanced Marine Materials & Coatings, London, UK The Army Corps of Engineers (ACE), a premier American group, dealing with marine structures, have completed a series of tests for steel structures in harsh corrosion environments. In total Wasser has been tested by ACE for over a 12-year period with various tests. This has included Panama Canal project, 3.5 years testing (Wasser became the exclusive supply for maintenance for 15 years), also testing for over-coating of existing coatings (Wasser rated best), and recent test comparisons of various MCU firms Wasser rated the best. [2] labour time and also the revenue loss for down time, which can be considerable, the owners and superintendents need to keep the vessel in dock a little as possible. Therefore time is of the essence and time is money, usually big money. Many ship owners are adopting riding crew work completed at sea during voyage. This reduces the loss of revenue associated with downtime at key-side or in drydock. However the time factor of completing a job is still a significant cost, with the labour costs, equipment required, mobilization, air travel, etc., are still over 90% of the project cost and the coatings are generally 5% - 10% of the cost. The MCU coatings non-restrictions can save and reduce project time and associated costs by as much as approximately 20% - 30%. 3.1 TYPICAL PROBLEMS ASSOCIATED WITH COATING PROJECTS Figure 1: The Astoria-Megler Bridge The Astoria Bridge was the one of the first major projects Wasser was entirely used for. This structure is on the Pacific Oregon coast and subjected to constant salt fog and condensate. It was also part of a 6-year joint Federal Highways Agency and Oregon Department of Transportation coatings evaluation program [3]. This test report included 10 of the top-performing technologies available including; various zinc systems, various epoxies, waterborn s, Wasser mcu and even rust converters. It is interesting to note that in this test the zinc silicates as a stand-alone coating, out-performed the same primers as compared to being over-coated with epoxy and a polyurethane finish coat. This test concluded that the Wasser system was the only coating that was rated SSPC SP10 (less than 0.01% corrosion) after 6 years exposure to marine salt fog environment. After the last full inspection 14 years after this Wasser coating project was completed, the structure was still rated SSPC SP10. This was previously unheard of for bridge structures in or outside of a marine environment. 3. COATING OF STEEL IN ADVERSE CONDITIONS The ship and platform owners and their contractors are often faced with these adverse environment conditions, potentially and frequently causing delays for the completion of a project, due to the application restrictions of most all coatings. However delays are usually unacceptable and the applications have to be carried out in conditions beyond the manufacturer s recommendations, which can cause potential paint failure down the road. Due to the expense of a dry-docking, the The problems start out simply in three parts, coatings choice, surface preparation and the application. The choice of the correct coating for the job is the first task. The coating generally must be as capable and flexible in its characteristics as possible. When deciding the suitability for the intended use some considerations are; surface tolerance, overcoat & cure time, adhesion, flexibility, moisture tolerance, abrasion and erosion resistance and life span. The life expectancy of the vessel and of the project should be considered in order to determine when this may have to be repaired or recoated again. Surface preparation problems: The tight time frame for vessel repairs, leave little time tolerance for proper surface preparation. It is often inadequate and at times when proper the substrate flash rusts. This should be reblasted to accept most coatings, however time or budgets do not allow. Coating requirements for these situations need to be surface tolerant to flash rust, exhibit good wetting out characteristics as well as having good corrosion protection properties. Coating s intolerance to flexing varies. Flexibility in coatings helps a great deal as vessels are subjected to flex, in their weld seams, corners and along the longtitudinals. The external hull is subject to reverse impact and decks, cargo hatches and coamings are subjected to impact and abrasion. If coatings do not have enough flexibility or become brittle over time, the coatings can crack. In turn these cracks open the film and allow moisture to penetrate under the coatings starting at the crack interphase and in many cases start the premature failing and corrosion process. 2006: The Royal Institution of Naval Architects
Advanced Marine Materials & Coatings, London, UK Remain flexible, inert after full cure and n/c chemically or physically. Better resistance over salt contamination. Better UV stability. Better abrasion resistance. 2 3 times longevity These MCU coatings offer many applications as well as performance advantages. They are all single component and cure with minute traces of moisture. They can be applied in humidities up to 99% and without dew point restriction and in temperatures from -15 C to +50 C. Figure 2: This paint cracking caused by hull flexing (likely a reverse impact) and a coating choice that was too rigid. The top coating adhesion was not good and when the membrane broke the result is intercoat adhesion failure causing the paint to peel. A contributing factor to this could be that the surface was either damp when coated or the surface may have reached the dew point before it had a chance to cure. 4.1 THE BENEFITS OF MICACEOUS IRON OXIDE Figure 3: This coating cracked along an inside corner and as this coating system had no corrosion protection other than the film itself, corrosion started from moisture creeping in through the interphase and undercutting the coating. 4. THE MCU SOLUTION Initially these moisture cure urea coatings were intended to be a solution for cold/hot and damp conditions. However during the past 25-years of the varied applications of these products and numerous third-party [3] testing have shown them to be a superior coating in many ways: They have outperformed most all coatings available on the market in corrosion testing. Passed long-term salt spray 20,000+ hrs. [4] They have excellent adhesion and require less blast profile (20-35µm), primers are surface tolerant to flash rust and magnetite. Better wetting out properties, necessary to penetrate into deep pittings. Excellent adhesion to and often rejuvenating old coatings. Better edge retention. They can be applied without dew point restrictions and in humidities to 99%. Figure 4: This illustration shows the two of the key workings properties of micacious iron oxide (mio). The upper part of the diagram demonstrates the layers of mio flakes shielding the medium form the degrading effects of uv radiation. The lower diagram shows how the interleafing particles also reinforce and strengthen the coating film, by impeding the penetration of moisture and pollutants. This overall structure also avoids accumulation of moisture and gas entrapment by allowing micro permeable dissipation[5]. This phenomena is similar to the workings of gortex material. The key for a MIO pigmented coating is the quality of MIO used and the quantity used by weight in the volume of the coating. MIO is a mined material (later developments of synthetic types do not perform), and some mines may have more impurities than others, therefore it is critical to use a high quality. Two other key attributes of MIO is the resistance to erosion and longevity of the system and the edge retention of the film. The degree of MIO hardness is considerably more than any coating material and as the top layers of coatings erode the MIO becomes exposed and then retards this erosion further. The laminar aspects improve the edge retention, findings by improving the film strength, reduce polymer swelling, and form a tough laminar seal [6]. The pigment characteristics are much improved over glass flake epoxy and aluminium, without the negative aspects of cohesion problems. The MIO actually improves the inter-coat adhesion significantly. 2006: The Royal Institution of Naval Architects
Advanced Marine Materials & Coatings, London, UK The Wasser coatings use MIO in most of their coating products and are used in all of their marine and structural steel coating systems. 5. MCU PRODUCT HIGHLIGHTS The two key primers are both surface tolerant to dampness and also flash rust. They exhibit excellent wetting our properties that allow the coating to penetrate into pittings and into poor weld seams and inside corners. They offer excellent adhesion to steel, iron, aluminium, alloys, stainless steel, galvanized steel, Metalized and corten steel. They will also both adhere to most all, existing coatings. The over-coat time is generally 3 4 hours and with the PURQuik additive a 3-coat system can be applied in as low as 3 hrs. Most coatings in these systems, (including the surface tolerant zinc primer), have no maximum overcoat time and can be over-coated (on a clean surface) in many months later and have ideal intercoat adhesion. These coatings can be subjected to rain, condensate or even immersion within 30 minutes. There will not be any affect as to the cure and will not cause an amine blush. There are 3 key coating systems that can be applied and used on the entire vessel. One of two primers, one of two intermediate coats and one of three finish coats. Two coat systems can also be used. 5.1 MC PREPBOND Surface tolerant penetrating primer/sealer Highly abrasion resistance Designed initially poor surface preparation All metal, GRP and concrete surfaces Will penetrate loose rust, recommend to remove scale & apply mechanically Overcoat within 3 5 days Passes 5,500 hrs. salt spray, NORSOK approved 5.2 MC MIOZINC The industry s 1 st surface tolerant zinc rich primer. Can be applied to both ferrous and non-ferrous substrates. Zinc and Mio filled, excellent edge retention. Compatible with zinc anodes. Recommended for immersion Surface preparation from ST 2 to SA 2.5. Excellent adhesion to existing coatings. Capable of high builds to 300 µm without bubbling or cracking. Infinitely re-coatable. Potable water approved [7] Passes 10,000 hrs. salt spray, NORSOK approved Figure 5: Upper Macro photo of a proper blasted corrosion spot. Small omega pittings are visible. The pittings should be cleaned as much as possible. Lower Good filling properties of the Wasser MC Miozinc into the fine cavities. [8] 5.3 MC BALLASTCOAT / MC CRPW Light coloured for ease of tank inspections Suitable for; ballast, drinking water, grey-water, black-water, drilling mud, cargo and fuel tanks Use as an intermediate coat for white finish Potable water approved [7] High abrasion resistance Applied in a one or two coat over primer 5.4 MC LUSTER True aliphatic pure urea Excellent gloss and colour retention Capable of exposure to condensate, dew, rain fog or immersion within 30 minutes after application. Will not amine blush. High abrasion resistance. 5.5 MC FERROGUARD Environmental friendlier coal-tar epoxy replacement Manufactured with further refined pharmaceutical grade coal tar. Mio pigmented, uv stable, resists cracking Adheres well to existing coal tar without abrading VOC compliant Excellent moisture, chemical, Passed 20,000 hrs salt fog test [4] There are 13 coatings in the full range. All are VOC compliant worldwide. 2006: The Royal Institution of Naval Architects
Advanced Marine Materials & Coatings, London, UK 6. CASE HISTORIES Figure 6: MV Hual Trubador, Ballast Tank, Hoegh Fleet Services AS System: MC Miozinc MC BallastCoat Figure 6: The Stena Discovery is a large aluminium fast ferry catamaran traveling at 40 knots capable of carrying 400 cars or combinations of cars and commercial trucks. Having a design life of 40 years. The much of the internal facing aluminium was not coated. In order to reduce the corrosion of these some of these areas for example ballast tanks, are flushed with sweet water and together with dry voids use a complicated and costly system of air-drying. However the air intake chambers presented a problem area. Completed by riding crew in 2000, water jetting surface preparation. After 3.5 years, the coating is in 100%, with no coating breakdown and no signs of corrosion, even on edges and scuppers. Figure 7: MV Spaarneborg, RoRo vessel deck, Wagonborg Shipping. System: MC Miozinc MC Prepbond RoRo vessels experience pre-mature coating failures often and typically within 6 12 months after application either new or after recoat. Wagenborg conducted a detailed test study on one of their vessels with various coating systems including ceramic filled epoxy, glass flake epoxy, high-build epoxy and Wasser s MCU. After several months and destructive testing by a consulting firm [8], Wasser was chosen as the replacement for their deck coatings. These vessels load containers weighing 60 to 90 tons each. Figure 7: Aluminium in the turbine air intake chambers, developed 4 6 mm omega pittings in the 8 mm plate. Many areas required already to be replaced. These pitting vary from steel as they have extremely sharp edges and can develop inwards at an angle. Initially an epoxy system was applied to a portion of the air intake chamber. After several months it was discovered that this system failed to solve the problems, and the electrolysis in the pittings under the coating were still active. A test panel was prepared by UHP and the MC Prepbond was applied. After approx. 60 days in service an inspection was carried out and the system appeared to be performing well and the problem had been solved. The penetration was evident deep into the pittings and the adhesion value was between 7 9.2 Mpa. In all 14 readings the failure was in the glue attachment of the dolley, not in the coating or the aluminium coating interphase. 2006: The Royal Institution of Naval Architects