Different Fire Indices || overman examination || Mine Environment
* Important fire Indices For Overman exams * 1. Grahm’s Ratio -: CO produced ——————————- O2 consumed Index value:- Less than 0.5% :- Normal More than 0.5% but less than 1% :- Existence of Fire More than 1% but less than 2%:- Fire in advance stage More than 3%:- Active fire 2.Young’s Ratio:- CO2 Produced —————- O2 consumed Index value:- Less than 25:- Normal 25-50:- superficial heating More than 50:- heating 3.Oxides of Carbon Ratio :- CO —— CO2 Index value:- More than 2:- Normal 2- 13Superficial Heating More than 13:- Blazing Fire 4. Willet Ratio :- CO produced % ——————————- Black Damp + combustible Gas Index value :- Ratio increases with increase in temperature 5. Justin & Kim’s Ratio(Hydro Carbon Ratio) : {1.01(THC)-CH4}1000 ———————————- THC+C { THC= Total Hydro Carbon in ppm,CH4 in ppm,C=0.01ppm} Index Value:- 0-50 :- Normal 50-100:- possible spice of Heating More than 100 :- Hot Zone 6.Jone...