CoatingsPro Magazine Supplements

STEEL 2019

CoatingsPro offers an in-depth look at coatings based on case studies, successful business operation, new products, industry news, and the safe and profitable use of coatings and equipment.

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One flexible and three rigid PFP coatings were applied to 3.5-millimeter-thick steel T-Bars. ese were then subjected to continuous thermal cycles of eight hours at -20°C (-4°F) and 16 hours at +40°C (104°F). As the chart (Figure 2) indicates, each rigid PFP coating began to crack or peel within 1 to 20 cycles. e flexible PFP coating endured 50 thermal cycles with no evidence of fatigue or failure. COATINGSPRO STEEL SURFACES 2019 17 Passive Fire Protective coatings (PFP) are vital to the protection of structures in chemical, petrochemical, mining and other industries because of their ability to resist pool fires, jet fires, explosions and similar hazards. W hen these products fail, they pose a danger to the people staffing these facilities, and the loss of surface integrity (cracking, peeling or loss of adhesion) can cost asset owners hundreds of millions of dollars in repairs and lost productivity. is article examines a potential preventive solution by applying two commonly accepted testing procedures to new flexible PFP materials. Test Procedure 1: ASTM D638 Tensile Strength (Elongation and Break) ASTM D638 specifies methods for testing the tensile strength of plastics and other resin materials. Seven paired sets of rigid and flexible epoxy PFP materials were cast into a mold and then inserted into a universal tensile-testing machine. Each sample had a test area measuring ½-inch wide and 3½-inches long. e samples were cured at room temperature for one week and then placed in an environmental chamber with a starting temperature of -40°C (-40°F) that increased in incre- ments of 10°C (50°F) until it reached +25°C (77°F). As shown in the elongation vs. temperature chart (Figure 1), the tensile strength of the rigid PFP coatings remained at or barely above zero throughout the temperature cycling, while the flexible PFP coatings retained significant tensile strength. (Figure 1) Elongation vs. Temperature Chart Test Procedure 2: ASTM D638 Tensile Strength (Elongation and Break) e T-BAR test was designed to characterize the thermome- chanical fatigue (TMF) of the rigid and flexible PFP materials in a specific temperature cycle. (Figure 2) T-Bar Low-Temperature Cycle Test -20°/+40°C Conclusion As the tests demonstrate, flexible PFP materials will retain sufficient elongation at lower temperatures to mitigate residual internal stress caused by both the shrinkage of the coating and the expansion and contraction of the steel substrate. It is, therefore, safe to conclude that flexible PFP materi- als can enhance the safety and fire-security of coated steel structures in severe cold weather conditions compared to the same structures coated with rigid epoxy PFP coatings. Passive Fire-Protective Coatings: Tests Show It Pays to be Flexible PPG One PPG Place Pittsburgh, PA 15272 (888) 9PPGPMC Juan Pablo León Arellano, PPG Business Development Manager, Protective & Marine Coatings Company Profile: PPG SPONSORED CONTENT

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