Epoxy on you – the best defence
Published: 01 January, 2008
In early 2007 Leighs Paints finished work on Tapti offshore oil platform in Lamprell Yard, Dubai, destined for deployment by British Gas India off the coast of Mumbai. The new platform, now protected with Leighs Paints Firetex M90 – is part of an expansion project for an oil field currently in operation.
The importance of proper application of epoxy coatings is well known. In a worse case scenario, improper application can necessitate the need for removal and reapplication of thousands of square meters of column, deck and bulk heads, top beam, and bracings. It is a good example of where doing a rush job due to small windows of opportunity can have disastrous consequences – particularly in high humidity conditions that can affect curing times and therefore contribute to system failure.
Why are intumescent coatings so important?
“Steel begins to lose its design strength at temperatures over 4000C and structural elements need to be protected against these elevated temperatures. In hydrocarbon fires, concrete can spall under thermal shock, revealing steel reinforcement which can then be attacked.
Large outbreaks can cause very rapid flame spread due to spillage (pool fire) or pipelines under pressure (jet fire). Even when insulating protection has been applied, damage can be caused by the stripping away of insulation due to the scouring or abrasive effect of high velocity flames. A pool fire can reach 1,100 0C, but a jet fire can go as far as 1,300 oC.
Our Firetex M90 provides protection against both pool and jet fires for up to two hours – it is also solvent-free, has low water uptake, and is corrosion-resisting.”
How do you make sure the paint is applied correctly?
“We sell our paints to specialist applicators, whom we train either in-house or at their premises. The applicators use specialist equipment – for this project two component heated machines were used. The thickness of the paint is critical, because that dictates the time of the protection offered. As part of our final sign-off inspection we either drill through the intumescent to measure the thickness or use a special electronic gauge such as an Elcometer.”
Are there any problematic issues?
“Yes. Quite often people don’t understand the specification because they are not involved with passive fire protection. In this industry, you often have a number of stakeholders, so you could have three different parties passing comment. I would advise people to ensure that the data given by the applicator is correct and verified by independent testing and assessments.
The insurance company behind a project – eg Det Norsk Veritas or Lloyds Insurers – will dictate the specification of the passive protection features. These two verification bodies have slightly different philosophies. Whereas the Under Writers Laboratories (UL) of the USA stipulates a single thickness for the whole structure, Lloyds/DNV will dictate different thicknesses of intumescent dependent upon the member size and load ratio. People should always start off with the design approval document from the insurer.”
How can people ensure they have taken the correct course?
“If you want the comfort factor, I suggest you take the intumescent design specification supplied by either the supplier or the applicator, and send it to the insurance company. Once assessed, they should send you an approval letter to say it will work. This process does not happen very often, but it should. Lloyd’s call it ‘design approval’, and I believe it should be done before a job is started.”
Was Tapti a complex project?
“Tapti was a normal project for us, although satisfying the technicalities is always a challenge. A typical problem is that the design of the structure is not finished when we begin on the specification side, which means that we have to make revisions before we get to final approval. With Tapti we got to revision number three, which meant four revisions – we start at zero. Then we gave a fire design verification and approval documentation.”
What other interesting projects have you worked on recently?
“We recently finished work on the sixth largest mosque in the world – the Sheikh Zayed Al Nahyan mosque in Abu Dhabi. Covering an area of 22,000 m2, it is named after the former ruler of the UAE. The Grand Mosque, as it is usually called, was built by the Royal Family and therefore the architect wanted to use the highest specification materials for extra durability, which is why they chose Firetex M90 to protect the structure.” y
