Steel Buildings in Europe

Part 7: Fire Engineering 7 - 43 a) Self-stable fire wall inserted between two independent steel framework b) Partially fire protected steel beam crossing a fire wall fixed to steel columns Figure 5.20: Views of fire walls after fire disaster in steel single-storey building 5.6.3 Recommendations for steel frames based on lattice beams Fire wall perpendicular to steel frame Figure 5.21 illustrates the situation where the fire wall is perpendicular to the steel frame. For this situation:  Columns that are built into or near a wall must be always fire protected.  Where fire wall is inserted between the flanges, the lattice beams should be fire protected on both side of the wall (see Figure 5.21 (a)).  Were the fire wall is fixed to one flange, only the lattice beams on the wall side have to be protected. Fire protection must be applied to the beams over a minimum length equal to the distance separating the wall with the first vertical member of lattice frame (see Figure 5.21 (b)).  Purlins do not cross the fire wall in this situation and no special considerations are required. The thickness of fire protection material applied to columns may be simply calculated assuming a critical temperature of 500°C and the same fire resistance as required for fire walls. Fire protection should be provided over the full height of the columns. If lattice beams are partially protected, the thickness of fire protection material may be calculated assuming for the section factor: a steel section exposed on four faces for bottom chords, vertical members and diagonals; and on three faces for top chords. A standard fire exposure of one hour and a critical temperature of 500°C may be used.