Analysis of the Fire Resistance Properties of Epoxy Resin Ceiling Coatings and their Suitability for Fire Protection in Buildings

Abstract

Epoxy resin coatings are widely used in building applications because of their excellent adhesion, chemical resistance, and durability; however, their inherent flammability limits their effectiveness as passive fire protection materials. This study investigated the synergistic effects of magnesium hydroxide (Mg(OH)₂) and ammonium polyphosphate (APP) on the fire resistance and mechanical performance of epoxy resin ceiling coatings. Three formulations were prepared: unmodified epoxy (Sample A), epoxy reinforced with 25 wt% Mg(OH)₂ (Sample B), and epoxy reinforced with 25 wt% Mg(OH)₂ and 10 wt% APP (Sample C). Fire performance and mechanical properties were evaluated using ASTM-based procedures. All experiments were conducted in triplicate (n = 3), and data were analysed using one-way ANOVA with Tukey's post hoc test (p < 0.05). Sample C exhibited the best performance, reducing the Flame Spread Index from 130 ± 4.0 to 40 ± 1.8 and the Smoke Development Index from 480 ± 10 (Sample A) to 190 ± 6 (Sample B) and 100 ± 4 (Sample C) (p < 0.001). Intumescence increased to 200 ± 6%, thermal stability improved from 180 ± 3°C to 340 ± 4°C, adhesion strength increased from 2.40 ± 0.08 to 3.60 ± 0.06 MPa, and abrasion resistance improved from 1000 ± 35 to 2200 ± 38 cycles. These findings demonstrate the potential of Mg(OH)₂–APP hybrid epoxy coatings as sustainable passive fire protection materials for building applications.