STRUCTURAL FIRE SAFETY OF EXISTING STEEL BUILDINGS, Possible general approach and application to the case of the intumescent coatings

Bilotta, Antonio; Silva, Donatella de; Nigro, Emidio

doi:10.14311/asfe.2015.011

Cited by 6 publications

(3 citation statements)

References 4 publications

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“…These expanding coats are favored in steel structures, especially due to their architectural and aesthetic significance. They are also preferred because they can be applied more quickly and easily on complex surfaces compared to other passive fire protection materials [23,[26][27][28][29][30][31][32][33][34][35][36][37][38].…”

Section: Introductionmentioning

confidence: 99%

Mechanical Properties of S235 Steel Protected with Intumescent Coatings Under High Temperatures: An Experimental Study

Yazici

2024

Buildings

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This study investigates the impact of high temperatures on the mechanical properties of fire-protected versus unprotected S235 cold-formed steel (CFS) specimens with variable thicknesses. Through axial tensile tests, we assessed how intumescent coatings influence the behavior of steel under fire-like conditions. The results reveal that as temperatures increase, the mechanical strength of unprotected steel diminishes significantly, especially at temperatures beyond 400 °C. However, at temperatures between 500 and 900 °C, coated specimens demonstrate considerably enhanced strength compared to their uncoated counterparts. The coating effectively reduces the steel’s temperature exposure by approximately 200 °C, crucially preserving its integrity at critical temperatures. The thickness of the steel also plays a role, with thicker specimens maintaining higher ultimate strength up to a threshold temperature. The study culminates in a predictive analytical model that estimates the ultimate strength of coated and uncoated steel based on temperature and specimen thickness. These insights contribute substantially to the design of safer, more fire-resistant steel structures.

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Section: Introductionmentioning

confidence: 99%

Mechanical Properties of S235 Steel Protected with Intumescent Coatings Under High Temperatures: An Experimental Study

Yazici

2024

Buildings

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“…The char works as a heat transmission barrier, protecting the coated steel structure physically and thermally. In the event of a fire, the coatings can operate as passive fire protection for steel, which loses half of its load bearing capability at 500 °C, minimizing structural damage and extending evacuation time, preventing the loss of life and property. − Organic and inorganic components are bonded together in a polymer matrix to form thermally reactive intumescent coatings. − An acid source (“catalyst”), a carbonaceous chemical (“carbonific”), a blowing agent (“spumific”), binders, and additives are typically used in intumescent coating compositions; their functions have been extensively detailed in the literature, and formulas have been refined over the last decades to produce an effective protective char. The intumescent process of intumescent coatings can be separated into four steps: reaction, swelling, char formation, and char degradation. Reaction (melting step): When an inorganic acid source is exposed to a heat source and reaches a certain temperature, the surface melts and converts into a viscous fluid …”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of the Fire Behavior of Storage Rack Systems Protected by Intumescent Coating

et al. 2022

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Using a finite element strategy, this study investigates the behavior of beam-to-column connections in storage rack systems exposed to high temperatures. The purpose of this research was to develop moment−rotation (M−θ) curves after painting various structural members with varied configurations in order to evaluate the performance of intumescentcoated beams, uprights, and connectors, which are components of storage rack systems. Within the scope of this work, finite element analyses were carried out in two stages. First, thermal analyses were performed using the transient thermal analysis system of ANSYS Workbench software to estimate the ultimate temperatures of the beam, upright, and connector, which were painted with 1 mm thick paint and exposed to standard (ISO-834) fire. The results were then compared to the Eurocode 3 Part 1.2 with a satisfactory agreement. In the second stage of the analysis, a total of 9 possible alternative models were investigated in the static structural analysis system, reflecting the effect of applying fire protection to the different portions of the rack system. Since the most critical stress level is achieved around the connector tabs, it has been observed that protection of the connector in individual or binary conditions provides higher performance while protection of the beam causes divergent joint behavior. Additionally, comparison of fully protected and unprotected conditions presents an increment of more than 7% on the joint's ultimate moment capacity and initial stiffness, which is an explicit contribution of the intumescent coating to fire resistance.

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“…They are applied in three layers: a rust-proof primer layer, an intumescent compound layer, and a decorative layer. Intumescent coatings are especially preferred in steel structures because they are significant in terms of architecture and aesthetics and can be applied faster and easier than other passive protective materials, especially on complex surfaces. − …”

Section: Introductionmentioning

confidence: 99%

Reformative Effects of Intumescent Coating on the Structural Characteristics of Cold-Formed Steel

et al. 2022

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Intumescent fire-resistive coatings are a more recent type of passive fireproofing thin film that swells many times its initial applied thickness, generating an insulating char that functions as a thermal barrier between the fire and structural steel. It keeps the heat of steel members from reaching critical levels and aids in the structural integrity during a fire. They are architects and designers’ favorite choice for passive fire protection of load-bearing steel frame structures because of their aesthetic look, versatility, rapidity of application, and ease of inspection and maintenance. In this study, axial tensile, thermal conductivity, and hardness tests have been performed on S235 cold-formed steel specimens that were exposed to increasing temperature periods. The mechanical behavior of coated and uncoated specimens was investigated over the modulus of elasticity, yield strength/strain, and ultimate strength/strain values for all temperatures. As a result of the research, gradually increasing changes were observed in the mechanical properties of coated and uncoated specimens at increasing temperature levels, compared to each other. However, performance increment on the coated specimens was limited in terms of strength and strain characteristics than expected. Two essential reasons for this conclusion are that the specimens were exposed to heat for a long time after reaching the target temperature and also that the wall thickness of the specimens was thinner with respect to the usual application method of the protective coating. In order to examine the structural properties of the test specimens after elevated temperature effects, thermal conductivity measurement was also performed. Temperature difference between coated and uncoated surfaces provided a benefit in the range of 29–56% due to the coating. Lastly, microstructure imaging techniques demonstrated grain coarsening and no crack development with the increase in temperature.

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STRUCTURAL FIRE SAFETY OF EXISTING STEEL BUILDINGS, Possible general approach and application to the case of the intumescent coatings

Cited by 6 publications

References 4 publications

Mechanical Properties of S235 Steel Protected with Intumescent Coatings Under High Temperatures: An Experimental Study

Mechanical Properties of S235 Steel Protected with Intumescent Coatings Under High Temperatures: An Experimental Study

Numerical Investigation of the Fire Behavior of Storage Rack Systems Protected by Intumescent Coating

Reformative Effects of Intumescent Coating on the Structural Characteristics of Cold-Formed Steel

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