PPG introduces new intumescent coating
Published by Callum O'Reilly,
Specialist industrial fire resistant coatings, commonly referred to as ‘fireproofing’ or Passive Fire Protection (PFP) are complex products that must perform a difficult task: providing consistent protection and durability in extreme environments, while also delivering in terms of total lifecycle cost.
Coatings end users in the onshore and offshore energy and petrochemical industries have varying requirements but all need products certified to international standards that can provide the required level of safety.
It is a market subject to strong price competition with many apparently similar products available. This makes understanding the stakeholders and their requirements all the more important in supplying the right product.
Understanding the value chain
At the top of the value chain are the owner-operators (the end-users if there is a fire) whose principal desire is a safe solution. They are concerned with price, but this comes in the context of durability and minimising the need for maintenance across an asset’s lifecycle that could be 20 years or more. If operating offshore they are also very interested in a high quality, durable coating with lighter applied weight.
Next is the engineering, procurement and construction (EPC) contractor who has a shorter period of liability – perhaps as little as five years – and is looking to meet client requirements for performance against a stronger competitive incentive. Finally, where the coating meets the steel are the fabricator and the applicator, sub-contractors who are interested in which coating system will be fastest to apply to the specified quality level and target price.
The stakeholders in the supply chain – whether asset owners, engineers, fabricators or contractors – all need to be aware that while some coatings appear designed (and some are certified) to resist all potential fire hazards, they may in fact only be suitable for pool fires rather than jet and pool fires; a critical difference in selecting a coating that is likely to face both scenarios.
Most intumescent coatings developed in recent years still rely on a rigid formulation and as a result, many may not perform as well as expected in practice when the steelwork moves either mechanically or with change in temperature. They can also be prone to delamination and cracking, so offer very limited integrity. The industry standard has moved on to use of an insulation system that slows the rate of heat-up and buys additional time for rescue or evacuation.
Creating better products
For over 35 years, PPG’s PITT-CHAR technology has been trusted to safeguard personnel and equipment in hazardous environments around the world.
In considering the development of the next generation of intumescent coating, PPG set out to develop a coating system that was safer, tougher, thinner, lighter and faster to apply. PPG PITT-CHAR NX draws on the heritage of the original PITT-CHAR product but has an entirely new formulation based on a fresh research and development cycle. The aim of this was to bring increased value to the customer.
As a result, PPG has developed a unique product with the flexibility required by the industry, which also offers the additional properties of thinness and lightness. PPG PITT-CHAR NX works equally well in onshore and offshore environments with no drop in performance after as much as 20 years exposure. Because the coating is thinner in application, less volume is required but it is still resistant to pool fires and jet fires so can be safely used in either situation with little or no additional material thickness.
Changing standards in coatings certification were also a driver to developing PITT-CHAR NX. In particular, PPG wanted a new coating that was compliant with the latest environmental exposure and fire standards including NORSOK M501 Rev 6, UL2431, UL1709 Rev 5 and BS 476 hydrocarbon fires with ISO 22899-1 jet fire – for all types and sizes of structural steel and safety-critical equipment.
PPG PITT-CHAR NX is also tested to the International Maritime Organization’s FTP Code and the latest ISO 20902 standard for hydrocarbon fire-rated divisions such as decks and bulkheads.
Globalisation and lower oil and gas prices have put pressure on project costs leading to a rise in off-site modular or stick-built fabrication techniques. While this is generally more cost-effective, it does add unique challenges for PFP coatings.
Before they are assembled on-site, pre-fabricated coated steel often travels long distances, sometimes across continents, and in vastly varying climatic conditions. Any damage to the PFP coating can impact its ability to perform effectively when the structure is in service or result in expensive repairs and potential delays to start-up.
Extremely tough yet flexible, PPG PITT-CHAR NX is designed to minimise the risk of cracking and delamination during fabrication, transportation and construction. This toughness provides dependable performance against weathering and excellent corrosion protection throughout the asset’s entire lifetime.
Once installed and when exposed to the high temperatures of the fire, PPG PITT-CHAR NX expands to form a robust, insulating char that significantly reduces the speed of at which the protected item heats up.
The insulation maintains steel integrity, and hence buys crucial time for personnel to escape and equipment to function on demand.
By utilising the carbon fibre PPG PITT-CHAR® CF mesh, it was possible to significantly improve the system’s fire resistance performance making it thinner, lighter and faster to apply than alternative systems.
The incorporation of the carbon fiber mesh not only produces substantial savings, but turns the coating system into a composite, greatly enhancing its toughness and improves the crack and damage resistance throughout all phases of the project, making the system even safer and tougher under extreme environmental and accidental load conditions.
Flexible fire protection
Some intumescent coatings are designed and marketed towards onshore fire protection applications and as such, are designed to tackle less aggressive pool fires. A coating designed for more aggressive jet fires will normally require a more robust material and additional thicknesses due to the erosive forces it generates.
PPG PITT-CHAR NX is unique in providing class-leading loadings and the flexibility to tackle jet and pool fires, whether onshore or offshore in oil, gas or petrochemical applications. For PPG customers this means they have the assurance that a single product provides the protection for either situation with little or no additional material, thereby providing a safer solution. Lightness of the coating is an advantage where weight is important, whether in moving steel components or in an offshore application. PITT-CHAR NX can help significantly in reducing both transport and construction costs.
The previous generation of PITT-CHAR had a typical application thickness of 12 mm for 2 hr pool fire protection. Competing coatings are now at 10 mm but PITT-CHAR NX has moved the bar to less than 8 mm for the same scenario.
Faster results recognised
Product lightness also translates into less product to apply, but in addition PITT-CHAR NX has been formulated to cure in a unique way allowing a saving of 60% in application time. A three to four day application process could be reduced to one day and the steel can be moved only a few hours after application. The enhanced environmental performance was also achieved without a topcoat, so further savings on material and application time can be realised.
Written by Peter Scott, PPG Protective and Marine Coatings.
Read the article online at: https://www.hydrocarbonengineering.com/petrochemicals/04092019/ppg-introduces-new-intumescent-coating/
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