Effects of Flame-Retardant Treatment on the Fire Behavior of Upholstered Sofas in a Residential Building in Brazil

Residential fires cause substantial fatalities worldwide, yet upholstered furniture in Brazil rarely incorporates flame retardants (FR). This study evaluated the fire performance of a standard FR-free Brazilian sofa and compared it with an FR-treated sofa from the United Kingdom via full-scale compartment tests. The masonry enclosure was instrumented with thermocouples, heat flux gauges, and a residential smoke alarm. For the FR-free sofa, the smoke alarm activated at 1 min 47 s; temperatures measured at a height of 1.5 m exceeded 513 °C within 7 min 12 s, with the total heat flux approaching 22 kW/m2 and the 100 °C tenability threshold reached at 2 min 34 s (leaving only 47 s for post-alarm egress). In contrast, the FR-treated sofa suppressed initial fire spread for over 10 min, delaying alarm activation to 4 min 01 s and the 100 °C threshold to 14 min 42 s, extending safe evacuation time to 10 min 41 s. Peak thermal conditions (373 °C; 12.2 kW/m2) were deferred beyond 24 min. The FR-treated sofa substantially enhanced occupant survivability and increased the probability of fire suppression crews intervening during the incipient phase within standard NFPA 1710 response deployment timelines.