Development of Fires

1. As a rule a fire breaks out in one space and for some time it develops imperceptibly. Flaming or smoldering is developing due to oxygen of the air present in the space volume or supplied through the ventilation system.

2. Combustion products fill the space and heat walls, ceilings, furnishings, etc. In the majority of cases investigated fires are detected visually or by small of smoke coming from the space through uptightness in doors, windows, ventilation openings, etc. In a number of cases fires are detected by an automatics fire alarm and fire detection system with heat detectors fitted.

3. Upon fire detection attempts are made to extinguish the flame using portable fire extinguishing appliances or other means of fire outfit. But fresh air is admitted through opened doors (indoors), which result in abrupt intensification of burning of preliminary heated materials and their decomposition products. Flame blow-out from the door (window) is observed. Under such conditions portable fire appliances are not adequate, their use becomes impossible due to smoke production, temperature rise, toxic effect of gasses and oxygen deficiency.

4. People do not always guess to close the doors (windows) until more effective appliances can be brought. The fire gets out of hand, its activity increases. In this case it is dangerous for people to remain in the building, they must be evacuated as soon as possible and fire extinguishing with more effective methods is to be organized.

5. Only when the fire extinguishing equipment is prepared the fire can be localized and prevented from spreading outside the space where it has organized. The main factor in this case is bringing the equipment in a state of readiness before the door to the space where the fire has broken out is opened.

6. The process of burning occurs mainly due to the air contained in the compartment. The combustion of each kilogram of a solid combustible material at least 4-6 cubic meters of air is required. The doors, windows, ventilation systems are to be closed as they promote burning.