- Author
- Takahashi, S.
- Title
- Minimum Oxygen Concentration to Extinguish Stack Solid Fuel Fires by Means of Air, Diluted by Carbon Dioxide.
- Coporate
- Fire Research Institute, Tokyo, Japan
- Journal
- Bulletin of Japanese Association of Fire Science and Engineering, Vol. 41, No. 1, 21-28, 1992
- Keywords
- solid fuels | oxygen concentration | air | carbon dioxide | extinguishment | crib fires | combustion
- Abstract
- The effects of accumulation of solid fuels on extinguishment by inerted air with CO₂ was investigated in this study. It is commonly known that the extinguishment of stack solid fuel fires used to be very difficult. This difficulty seems to arise not just from geometric reason which prevents reaching extinguishant, but from intense heat stored inside the fuel array. The author have firstly performed extinguishment tests of plastic crib fires and wood crib fires with portable CO₂ extinguisher and obtained the order of relative easiness of extinguishment. Secondly, the minimum oxygen concentration [O₂] which can sustain combustion, in another word, which can extinguish flaming combustion, when plural number of burning-plastic rods and wood sticks were submerged into the inerted air stream, were measured. The measured oxygen concentration clearly decreased as the number of rods were increased. These two experiments were compared, but good correlations did not hold unless [O₂] were very small or large. POM was a unique material and the author never succeeded in extinguishment with portable CO₂ extinguisher. PU, PC and PF were relatively easy materials to do. Some reasons were also considered. For instance, the raw material for POM is CH₂O and (CH₂)₂O and they have wide range of combustion. If the pylolysis gives them or some close materials, then the pylolysis gas must be easy to burn even under lower [O₂]. In case of solid PU, the extinguishment was extremely easy even though [O₂] and OI was not so unique. This material drips waterly melt material violently, thus seems to remove the heat on the surface. This must be making extinguishment very easy.