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Causes and Prevention of Marine – Coastal Corrosion

The total corrosion loses faced by the Indian industry es-pecially ports, marine installations, harbours and indus-tries located in the coastal belts accounts to a net some

of ̀ 1,50,000 cores These damage costs are irreversible if not attended in due

course of time and hence it’s imperative to take cognisance of the situation and act upon in time to prevent the loses of ma-chinery and equipment by suitable means of (a) preventive means and the (b) in process maintenance by engaging a proper corrosion prevention , eradication program fine-tuned to balance the situation

Contrary to popular belief, the coastal area corrosions are, not merely accounted by salt spray corrosion alone but also by the following endurances

1 Severe attack by microbes like fungi ,algae and mose ,leads to the inevitable organic decay and imminent corrosion which leads to a slow organic inhibited corrosion

1.1 This needs to be address by a preventive maintenance sys-tem to avoid the growth of such micro organisms

1.2 As the growth of these organic masses depends totally on the, anchoring possibilities based on the roughness of the surface. Hence it’s imperative that the surface has to be smooth , repellent to the above , one way or the other

1.3 The problem solution for this area is by addressing with a suitable priming medium after proper scrubbing and appli-cation of a mastic nature primer to repel water inculcation

1.4 The second severe endurance comes from sun’s UV rays

V. Raghunathan Vice President -TechnologiesCera-Chem Pvt Ltd

which tends to break the substrate by two major detoria-tion factors viz.,(a).chalking and (b).fading

1.5 This is tackled by a suitable top coat system which is capa-ble of shielding substrate against chalking and fading

1.6 The 3rd major factor which kills is the saline atmosphere (the main constituent of which is NaCl otherwise called as brine solution ) causes the ultimate corrosion

1.7 Hence a complete painting system capable of highest lev-el of penetration, adhesion and moisture tolerance should be employed to counter the high rate of corrosion for both concrete and metal structures

1.8 The marine corrosion salvation /prevention program totally is a dependent factor on the correct selection of primers ,intermediaries and top coats

1.9 This is very crucial for saving the structures made out of M.S and concrete .

2. There have been many attempts to passivate the adverse effects of impact/abrasion and corrosion to structural members of offshore platforms, drilling rigs, pipelines, risers, pilings, wharfs, or any edifice that is located in the splash or tidal zones of a marine environment. There are several known techniques for applying pre-installation

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protection to metallic structures for protecting them from the ultimate effects of corrosion and erosion that attack the supports of the structure located in the splash zone. By way of example, steel pilings and/or production piping are usually covered with a rust-resistant inorganic zinc silicate primer and organic top coats as a coating system during the fabrication phase of new construction .

3. Once a structure such as a production platform is em-placed offshore and subjected to prolonged exposure of the marine environment during normal operating procedures, previously coated steel surfaces tend to become slowly penetrated and eroded to a point whereby the existing steel substrate is ultimately exposed. The corrosion rate of steel in the splash zone is typically about 100 mils per year. Nor-mally these steel support members, without good repair procedures, will lose their structural integrity after about seven to ten years of exposure. The replacement cost of ris-ers and other steel supports in situ offshore are considered extremely expensive such that replacement is preferred to be avoided.

4. This invention relates to a novel system and method of ap-plication for effecting corrosion protection of marine struc-tures. More specifically, the invention relates to a novel such system and method of applying the protection to afford su-perior corrosion and erosion protection to a support struc-ture to be used or being used in a marine environment. The installation can be either pre-applied during initial fabrica-tion or post-applied on site to existing support structures in

need of repair or restoration. In either situation, the life ex-pectancy of the structure upon which the protection here-of has been installed can typically be increased by at least about five years over the otherwise current life expectancy of such structures

5. Some common type of marine and coastal environment corrosions typically are :

Pitting CorrosionCrevice CorrosionStress Corrosion Cracking

Cera Chem offers an exclusive range of products which shall counter the severe endurances of nature and vagaries to make the structures stand safely to perform for a long run…

System Recommendations for various areas of Marine cor-rosion:

CEAR CHEM Product Nature of coat Areas prone for corrosion Salient Features

System 1

CERA ETCH PRIMER

CERA HIBUILD ZINC PHOS-PHATE PRIMER 118

CERA EPOTEK 280 (Or) CERA COTE PU 100 HB HG

First coat

Intermediary coat Top coat (only in interior)

If the said item is exterior exposed

0 Metal level to elevated areas of girder water feeder ,Gangways, Towers, pipelines and water logged areas

Excellent abrasion resistance and water impermeability

System 2

CERA ZINC OR 262 (Zinc rich primer)

CERA EPOTEK 280 (Or) CERA COTE PU 100 HB HG

Primer coat

Top coat (only in interior)

If the said item is exterior expose

On not cleanable manual cleaned, pre-viously painted area

Trolley towers, storage tanks generator rooms, battery rooms, material storage yard bulk handing equipment chemical containers, packing area motor area. Excellent cathodic protection

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System 3

CERA PROTECTO PRIME 361(Protectomastic self-priming coating)

CERA ZINC RICH PRIMER

CERA EPOTEK 280 (Or) CERA COTE PU 100 HB HG

Primer coat

Intermediary coat

Top coat (only in interior)

If the said item is exterior expose

Super structures (where sand blasting is not possible and rust is available and partial cleaning is only possible), pipelines (where the water dampness is always there. Mainly joint area), lift areas, storeys from 4th stage onwards where rust removal is not effective .structure where the previous paint is not fully removable. Critical pipeline where previous paint is not fully removable. Tolerates rust and dampness

System 4

CERA ETCH PRIMER

CERA HI-BUILD MIO ZN.PHOS.PRIMER

CERA HIBUILD ZINC PHOS-PHATE PRIMER 118

CERA EPOTEK 280 (Or)

CERA COTE PU 100 HB HG

Primer coat

Intermediary/Primer coat

As a second primer coat

Top coat (only in interior)

If the said item is exterior exposed

Railing in interior and MS sheet steel structures in walk aways and wire mesh structure / interior structure which support the asbestos roofings, Crane and jetty areas, piers, stands and concrete adjoining areas where moisture inculcations are prone for

System 5

CERA HIBUILD ZINC PHOS-PHATE PRIMER 118

CERA CHLOR 163 HB

First coat

Top coat (only in interior)

Water logged areas Immersion areas and sand witched areas of metal and concrete with high porosity

Excellent abrasion resistance and enhances water impermeability

Table 1

MARINE STRUCTURES: CORROSION