An educational version of the SMARTFIRE V4.0 (4) software, developed by the Fire Safety Engineering Group at the University of Greenwich, was used to perform the fire simulations in this study, with a special feature developed particularly for this project. This included a simultaneous capture of temperatures data from selected control volumes specially positioned along the structure.

SMARTFIRE is an open architecture CFD environment written in C++; it has four major components: a CFD numerical engine, a graphical user interface, an automated meshing tool and an intelligent control system. It permits to simulate a fire, in a fast and confident way. It uses three-dimensional unstructured meshes, enabling complex irregular geometries to be meshed without the recourse of cruder methods such as the stepped regular meshes or body-fitted meshes. The first step was to introduce the scaled apartment ambient that is materials, fire characteristics, etc. Walls, slabs, apertures, fuels, were all introduced in the model. Some control volumes were introduced, in a way of capture the gas temperatures (along time) facing the samples we took for analysis (Fig. 8). In the following, it was created a CFD mesh with more than 105,000 tetrahedron elements. We started the fire on the TV rack (as proposed by the Fire Dept. Report), propagating to a Christmas tree and, then, to a sofa. Some items were not included (as the living room curtain), for simplicity. The peak heat output inputs were 15.65 MJ for the sofa, 7.84 MJ for the Christmas tree, and 5.37 MJ for the TV rack; detais were presented before by Pannoni et al.(5). Objects burns were triggered, so some trigger volumes were constructed to activate the other fire, and so on. We created two trigger condition to ignite the fire: 573K OR maximum radiation Y negative flux greater than 22000W/m2 (the radiant flux down onto the object from the hot gases, in the ceiling layer - the most common mechanism for remote objects to be ignited). It was assumed the six-flux radiation model, and for turbulence, the K-Epsilon model. Simulation results are represented, synthetically, in Fig. 9 and 10. Maximum temperatures were obtained in the control volume located over the steel sample located at V1, that is, in the top of window. Minimum temperatures were obtained in the control volume close to sample A3, that is, in the lower part of the central column. In a general way, higher temperatures were obtained with times around 25 - 26 minutes from the fire beginning.

Fig. 8 - SMARTFIRE graphical interface, showing volume controls.

Fig. 9 - SMARTFIRE fire scenario after 2 minutes.

Fig. 10 - CFD temperature estimate, using specific control volumes.

Fig. 11 - Compartmentation effect over temperature distribution, 5 min scenario.

It is important to point out that, while the inner doors were all opened, compartmentation was very effective. Fig. 11 shows a plane for a 5 minute scenario; temperatures around 190oC were obtained inside the bedroom (≈ 2 m height). Fig. 12 shows the gas temperatures close the central column and beam (the most heated one).

Fig. 12 - Gases temperature based on the SMARTFIRE.

Fig. 13 - Reduction factors of the steel.

If it was used traditional method, ISO-Fire(6), the section factors would be 147 m-1 and 208 m-1 , respectively, for column and beam, or approximately 600°C and 655°C for 15 min and 780°C and 815°C for 30 min.

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