Feature 1 | PAINTS, SEALANTS & COATINGS No cracking under pressure


As offshore support vessels and platforms venture deeper into areas prone to extreme temperature changes, selecting the right passive fire protection coating for the job becomes a key consideration


industry, largely prompted by the lessons learnt from the 1988 Piper Alpha disaster. While companies engaged in offshore oil and gas exploration are, in the main, aware of the importance of deploying fire-retardant coatings on their fixed and floating assets, selecting an epoxy capable of withstanding the demands of their working environments can be a far more challenging process. Tis is particularly true of units subjected


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to extreme temperatures. With offshore activity thriving in Latin America and West Africa, and the Arctic and Alaskan regions set to witness a surge in oil and gas exploration from 2015 onwards, it is crucial that PFP coatings do not crack when exposed to wild variations in temperature. PPG Protective & Marine Coatings


has studied these scenarios in the course of the development of its PITT-CHAR XP epoxy brand, designed to withstand both high impact blasts and the bending and flexing forces that have become a commonplace result of the modern vessel and platform construction process. Having based the solution on a flexible resin solution, the manufacturer has achieved a set of test results compliant with key industry standards such as IMO SOLAS and NORSOK, and recognised by all of the major classification societies.


Tensile strength Peter Wilson, global PFP project support manager at PPG, tells Offshore Marine Technology: “There are three main classifications of fire type. Te first, A-rated cellulosic fire, applies to those fires that typically occur in homes or offices, which can generate heat up to 950˚C. Hydrocarbon pool fires and hydrocarbon fires under pressure [or ‘jet fires’] are those most likely to occur in the petrochemical industry. If unchecked, hydrocarbon pool fires can


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ydrocarbon passive fire protection (PFP) coatings have become a permanent fixture in the offshore


Hydrocarbon PFP coatings can buy personnel valuable, vital time to escape the vessel or


platform – but they must be able to deal with extreme temperature swings and rough treatment too


generate up to 1,100˚C, while hydrocarbon jet fires can generate 1,350˚C in just two to three minutes.” In part, he says, the severity of the Piper Alpha tragedy can be attributed to the application of protective coatings which proved inadequate in withstanding the ferocity of the conflagration. PITT-CHAR XP has been designed to


exhibit a higher rate of tensile strength than more common, rigid hydrocarbon PFP solutions, having demonstrated a superiority of 20% over one such PFP in tests held in -10˚C to -40˚C conditions. Te group also found that, at -40˚C, PITT-CHAR XP’s recorded tensile strength was almost two times greater than that of the rigid product. Tis grants the PPG solution a commercial


edge when it comes to satisfying demand from the bullish Brazilian, African and (soon to be) Arctic markets. As vessels and platforms operating in areas with extreme temperatures will undergo significant temperature fluctuations across various sections of their steel structures – perhaps plummeting to -50˚C in the coldest areas, whilst other structure sections, warmed by sunlight, maintain a temperature of 0˚C – the PFP must be flexible enough to cope with the stress that such temperature swings will exert upon the unit as a whole.


The tests also demonstrated that


PITT-CHAR XP’s percent elongation values – the extent to which the epoxy can be deformed without breaking – were five times higher than that of the conventional rigid PFP. “An advantage of modern epoxy technology is that we can produce coatings that last for 25 years, maintenance-free, not accounting for mechanical damage,” says Wilson. PITT-CHAR XP also serves as an ‘all in one’ anti-corrosive and flame-retardant solution, removing the need for multiple coating applications. “Most epoxy coating thicknesses are measured in microns, but PITT-CHAR XP layers come in millimetres,” he adds. Construction and conversion jobs can also


cause high levels of stress in steel materials. While it used to be the case that painting was completed aſter units had been fully assembled, it is now more common to find yards assembling vessel / structure modules after the coatings have been applied, the actual paint jobs sometimes being conducted in facilities far from the final fabrication site. Te epoxy must be strong but flexible enough to undergo these processes. Reaction to blast pressures is where


epoxies really prove their worth, however, and PITT-CHAR XP has shown, via shockwave tests, that it can absorb


Offshore Marine Technology 1st Quarter 2013


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