Fire characteristics of steel members coated with nano‐enhanced polymers

Abstract

Polymeric coatings applied to masonry infill walls have been demonstrated to provide protection against blast. Steel frames may be embedded in these walls to improve the structural characteristics of the building. During the process of retrofitting the walls with blast protection polymeric coatings, the steel frame may be fully or partially coated with these materials to provide adequate anchorage of the retrofit system to the frame and to avoid global failure of walls subjected to blast loading. The development of a blast-resistant coating for masonry walls that safeguards all structural elements in a fire would provide buildings with protection against explosions and a fire following the blast, as well as against ordinary building fires. This paper uses a numerical tool based on the particle finite element method to evaluate the melting and dripping of nano-enhanced polymeric coatings applied on steel members embedded within masonry walls. Viscosity measurements were performed to obtain needed parameters for the simulations. Polyurea nanocomposite residues showed a minimum in viscosity with temperature, possibly caused by cross-linking and charring. Model results for the polyurea residue with the lowest value of minimum viscosity showed that the coating remained attached, although there was some flow that caused a chunk of material to break off from an overhang.

Simulation of the burning and dripping cables in fire using the particle finite element method

“…Constant values of density, conductivity, and specific heat have been used in the absence of better information as in previous numerical works. 15,35–43,54 This is supported by the studies based on simulation results by Stanislav et al, 55 where it was concluded that the effect of these parameters is of little importance on the burning behavior of polymers versus other parameters affecting combustion. However, accounting for density, heat capacity, and thermal conductivity dependence with the temperature and decomposition may improve the simulation in the future.…”

“…The analytical definition of the viscosity–temperature curves used is given in Table 6 and plotted in Figure 9. For estimating the viscosity value for those ranges where the curve is not available, the procedure presented in Butler et al 42 is used. While the viscosity in the jacket is a function of temperature, the viscosity of the core is considered as constant and set to a very high value.…”

“…We note that the pyrolysis model used in this work is based on the simple, thermally activated, single-step decomposition. The validation of this approach is presented in Oñate et al 39 Although it is a simple model, the numerical results presented in Oñate et al; 35,39 Kempel et al; 15 Butler et al; 40 Butler; 41 Butler et al; 42 Matzen et al 43 have revealed that the model it is accurate enough to predict the pyrolysis during burning of a polymer object.…”