A simple and economical fire test setup for examining the fire retardancy/extinguishing ability of water additive fire-retardant materials on class A fires

A portable lab scale test setup (1 × 1 × 0.72 m³) with apparatus and procedure has been illustrated to test the fire extinguishability of fire retardant materials (FRMs) as water additives on class A fires. The main objective was to use selected commercial, eco-friendly FRM powders such as hydroxides, carbonates, and clays as water additive-based fire extinguishing agents for suppressing solid fires. FRM powders, namely, Mg(OH)₂, Ca(OH)₂, CaCO_3, and MMT-Clay were added to water and were mist sprayed on a wooden fire (class A) to test their fire-suppressing ability. A comparison involving tests with only water (without any additives) was also recorded. The solutions made with FRM additives in water showed promising results in suppressing the fire in comparison to systems with only water as an extinguishing agent. Heat sink materials, such as hydroxides and clays depicted commendable performances in retarding the burning process and almost doubled the capability of fire suppression with low loading. Their heat-absorbing nature resisted the increase in temperature and slowed down the burning process causing an increase in the total burning time of the crib and avoiding reignition. Whereas, carbonates (CaCO₃) showed a faster flame out by the release of CO₂ gas, which diluted the oxygen content in the surroundings. The article concludes with a discussion of the requirements for the ideal water mist additive-based fire extinguishing agent and a recommendation that future work include validation of the laboratory-scale method based on a comparison with full-scale suppression data for the same additives.