The cup burner method is internationally accepted methodology for determination of Minimum Extinguishing Concentration (MEC) of fire extinguishing agents. The present study aims at measuring MEC value of Halon 1301, HFC 227ea and water mist for suppression of diffusion flame in cup burner apparatus. The MEC of Halon 1301 & HFC227ea is measured in standard cup burner apparatus which does not change with increase in air flow rate in laminar region (Re < 2000), For the transitional region (Re 2000 - 4000), there is not appreciable increase in MEC value and increase in MEC is observed in near turbulent region (Re ∼ 4000). The MEC of water mist with average droplet size of 34μm is measured in Modified Cup Burner Apparatus in the turbulent region (Re ∼ 3900–4200). It is observed that MEC increases with increase in the air flow rate. It is also observed that on mass to mass basis water mist is 1.7 times more effective then Halon 1301 and 4.4 times more effective then HFC227ea in suppressing a n- heptane diffusion flame.
