Safety Technology Exchange Edition: Daily Question (2016.5.20)
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This post was last edited by 68589544 on 2016-5-22 at 10:14. File: bg10.png. Type: Fill-in-the-blank question. Question: [Fire Safety Technology] Does the presence of the three conditions for a fire necessarily mean that a fire will occur? The combustion of combustibles (other than combustible gases) does not involve the substance itself catching fire; it usually occurs when its volatile combustible vapors mix with air and are ignited by a heat source. However, the flammable vapor and air must be in a certain proportional relationship in terms of quantity. For example, burning one kilogram of oil requires 10–12 cubic meters of air ； And burning one kilogram of wood requires only 4 to 5 cubic meters of air. Experiments have shown that when the oxygen content in the air is below 14–18%, combustion does not occur, and any material that is burning will gradually go out. Even with combustible materials and oxidizers, a fire will not occur just by coming into contact with any source of flame. To cause a substance to burn, the ignition source must have a certain temperature and sufficient heat. For example, the sparks emitted from chimneys reach a temperature of about 600°C; if they fall on kindling or wood shavings, they can start a fire, but if they fall on large pieces of wood, they go out. This means that less heat is required to ignite sawdust, while more heat is needed to ignite large pieces of wood. Although the temperature of the sparks from the chimney is high, the heat generated is minimal; therefore, it can only ignite sawdust but not large pieces of wood. Different substances require different ignition energies to burn. It can be seen that for a substance to burn, not only must all three conditions be met simultaneously, but certain amounts must also be achieved in terms of quantity ratios and ignition energy. Otherwise, it wouldn’t catch fire either. Once people realize this, they can take measures to prevent fires and ensure safe production.
Combustible materials, oxidizing agents, ignition sources
Having these three elements is only a necessary condition for ignition, but not necessarily a sufficient one
Even with combustible materials and oxidizers, a fire will not occur just by coming into contact with any source of flame. To cause a substance to burn, the ignition source must have a certain temperature and sufficient heat
The presence of the necessary conditions for combustion does not mean that combustion will necessarily occur. Among these various necessary conditions, there must also be a requirement regarding \"quantity\", which represents the sufficient conditions for combustion to take place.
For a substance to burn, not only must three conditions be met simultaneously, but certain amounts must also be achieved in terms of quantity ratios and ignition energy. Otherwise, it wouldn’t catch fire either. Once people realize this, they can take measures to prevent fires and ensure safe production.
For a substance to burn, not only must three conditions be met simultaneously, but certain amounts must also be achieved in terms of quantity ratios and ignition energy. Otherwise, it wouldn’t catch fire either.
The combustion of combustibles (other than combustible gases) does not involve the substance itself catching fire; it usually occurs when its volatile combustible vapors mix with air and are ignited by a heat source. However, the flammable vapor and air must be in a certain proportional relationship in terms of quantity. For example, burning one kilogram of oil requires 10–12 cubic meters of air ； And burning one kilogram of wood requires only 4 to 5 cubic meters of air. Experiments have shown that when the oxygen content in the air is below 14–18%, combustion does not occur, and any material that is burning will gradually go out. Even with combustible materials and oxidizers, a fire will not occur just by coming into contact with any source of flame. To cause a substance to burn, the ignition source must have a certain temperature and sufficient heat. For example, the sparks emitted from chimneys reach a temperature of about 600°C; if they fall on kindling or wood shavings, they can start a fire, but if they fall on large pieces of wood, they go out. This means that less heat is required to ignite sawdust, while more heat is needed to ignite large pieces of wood. Although the temperature of the sparks from the chimney is high, the heat generated is minimal; therefore, it can only ignite sawdust but not large pieces of wood. Different substances require different ignition energies to burn. It can be seen that for a substance to burn, not only must all three conditions be met simultaneously, but certain amounts must also be achieved in terms of quantity ratios and ignition energy. Otherwise, it wouldn’t catch fire either. Once people realize this, they can take measures to prevent fires and ensure safe production.