Institute for Color Science and Technology (ICST) Progress in Color, Colorants and Coatings 2008-2134 19 2 2026 05 01 Development of Low-Smoke, Eco-Friendly, Fire Retardant, Intumescent Coatings for GI and Steel Structures 189 205 82136 10.30509/pccc.2025.167584.1413 EN C. Mehta Fire Safety Engineering, CSIR- Central Building Research Institute, P.O. Box: 247667, Roorkee, India A. Kumar Fire Safety Engineering, CSIR- Central Building Research Institute, P.O. Box: 247667, Roorkee, India M. Kumar Tiwari Centre of Excellence-Occupational Health, Safety, Fire and Environment, GD Goenka University, Sohna, P.O. Box: 122103, Gurugram, India R. Kumar Fire Safety Engineering, CSIR- Central Building Research Institute, P.O. Box: 247667, Roorkee, India Journal Article 2025 07 04 This study presents the development of eco-friendly intumescent coatings with reduced smoke emission. Water-based formulations were developed by adjusting the type of binder used (PVAc, PVAc-Epoxy) and incorporating a smoke suppressant filler (Zinc Borate) to enhance performance. Fire tests revealed that these coatings produced carbonaceous char layers over 70 times thicker than the original coating. Char morphology and composition were evaluated via SEM-EDS and TGA. The most effective formulation, comprising a water-based binder with 50 % epoxy and hardener, exhibited superior fire resistance, passing the BS 476 Part 5 ignitability test. It achieved a fire propagation index below 12 (BS 476 Part 6) and attained Class 1 surface flame spread (BS 476 Part 7). Smoke density (ASTM E 662) remained below critical thresholds specified by NFPA 230, with optical densities under 100 and 200 at 1.5 and 4 minutes, respectively. Formulation IC3 nearly satisfied non-combustibility criteria and maintained steel substrate temperatures at approximately 200 °C for 120 minutes in direct flame, demonstrating robust thermal insulation. https://pccc.icrc.ac.ir/article_82136_1256fa8b6a3505ed6b0463a4b7123c9e.pdf