Kansas City, MO (PRWEB) July 5, 2010
Fire protection is a necessity for steel construction in the oil, gas and chemical industry where combustion of hydrocarbon fuels such as oil, methane, liquefied natural gas (LNG) and liquefied petroleum gas (LPG) can spell disaster. Typically, these fires, that can reach temperatures of 2,012 degrees F (1,100 degrees C), can cause structural steelwork to lose load bearing strength and eventually buckle and collapse. The fires may also cause “jet fire” from fuel under pressure, and may in turn lead to explosion of storage vessels or pipelines Hydrocarbon fires can be devastating, such as the one that destroyed the Deepwater Horizon rig in the Gulf of Mexico this year.
Since the introduction of intumescent coatings in the U.S. in the mid-1980s, this type of passive fire protection for structural steel has been commonly used in offshore oil and gas platform applications and onshore refining and petrochemical processing facilities. Intumescent coatings for hydrocarbon fires are made from epoxy resins that are filled with active ingredients that react at temperatures of around 392 degrees F (200 degrees C) to form a thermally insulating carbonaceous char or foam that can help structural steel retain its strength in the event of a fire. These coatings can intumesce up to several times their original thickness, thus extending the time it takes for steel to reach its critical failure temperature of 932 degrees F (500 degrees C). This extra time allows a facility’s occupants more time to escape while enhancing the ability of firefighters to bring a fire under control, and save the asset from structural failure.
According to a study prepared by the Civil Engineering Research Foundation for the National Institute of Standards and Technology (NIST), two-component epoxy intumescent coatings offer these advantages:
- Durability – intumescent coatings are typically quite durable and do not readily flake off when struck. Also, they can be fairly easily repaired.
- Application – intumescents are relatively quick to apply. They are good at covering complex structural details and can be applied on-site or off-site.
- Aesthetics – the relatively thin coating compared to other fire protective materials is often aesthetically acceptable and can be left exposed to show the shape of the structure and also can be given a colored finish.
- Maintenance – post installation repairs are relatively easy. Also, intumescent coatings are relatively easy to clean.
At a major gulf coast refinery in Louisiana, FIRETEX M90 epoxy intumescent coating was used as part of an exterior coating system on several steel spheres used to store liquefied petroleum gas (LPG). Resistant to atmospheric and chemical attacks, the intumescent coating offers up to two hours of fire protection on onshore and offshore facilities that are required to have hydrocarbon pool and jet fire protection. Manufactured by Leighs Paints based in the United Kingdom, FIRETEX M90 intumescent coating is distributed in the U.S. and eastern Canada by Tnemec Company, Inc.
“The steel spheres range in size from 9,000 square feet to 23,000 square feet,” according to Andy Hoffman, market support manager, Industrial Market. “The project involves surface preparation consisting of ultra-high pressure water jetting at 30,000 psi to remove existing coatings, followed by priming, fireproofing with FIRETEX M90 and the application of a topcoat.”
Each sphere is primed with a coat of Series 66 Hi-Build Epoxoline epoxy, followed by a coat of FIRETEX M90 spray-applied at 200 to 250 mils dry film thickness (DFT) on the surface of the spheres and up to 500 mils DFT on the legs. “An average sphere requires nearly 25,000 pounds of intumescent coating using plural component equipment,” Hoffman noted. “When the job started, both Tnemec and Leighs Paints had technical service representatives on-site for a full day of contractor training.”
The topcoat consists of Series 740 UVX, an advanced technology polyurethane that combines exceptional color and gloss retention with low volatile organic compounds (VOCs). “When coatings are applied this thick, it is often difficult to achieve an aesthetic finish,” Hoffman acknowledged. “According to the coating contractor, this project has the appearance of a paint finish.”
Intumescent coatings are increasingly preferred over other passive fire protection materials for their aesthetic and durability benefits, according to the outline for the Frost & Sullivan report titled U.S. Intumescent Coatings Markets. “They are applied in relatively lesser thicknesses compared to other fire-protective materials and are used as highly durable materials for protection against both hydrocarbon and cellulosic type fires,” the outline explains. “They are also easy to apply on complex structures, and are easy to repair and easy to clean.”
Intumescent coatings are rigorously tested by independent classification organizations in the U.S. and Europe, including Underwriters Laboratories (UL). “These tests usually call for a lot of time and huge expenses for the intumescent coatings manufacturers,” Frost & Sullivan added.