Complexity categories and types of fires. Overview.
Complexity categories and types of fires. Overview
There are several parameters by which the degree of complexity of a fire is assessed, from the point of view of the fire fighting process itself. These parameters include: levels of complexity, types of fires. The main dangerous factors of fire occurrence play an important role in determining the above parameters.
Fire complexity categories
Fire complexity, is determined by three main conditions described in the Federal Law «Technical Regulations on Fire Safety Requirements»: 1. by the type of combustible material: used to indicate the area of application of fire extinguishing equipment; 2. by the complexity of their extinguishing: used to determine the composition of the forces and means of fire departments and other services necessary for extinguishing fires; 3. hazardous factors affecting the complexity of the fire: used to justify fire safety measures necessary to protect people and property during a fire. In firefighting practice, it is customary to distinguish levels of call complexity, which are designated by the concept of category of fire complexity. There are six of them, including a false call — this is called «call No. 0». Next comes «call No. 1», during which a message about smoke or fire was received, two teams left for the scene on two main fire engines; the fire was detected and the extinguishing operation began. This category of fire complexityanother – adjacent – “call No. 1 BIS” is allocated: a fire is detected and there is a shortage of forces and means to extinguish it, in connection with which two more units are additionally called (a total of four units are working). In case of “call No. 2” – a fire report is confirmed; there is a large burning area, a shortage of forces and means, and no water sources. Accordingly, two more units are additionally called from neighboring areas (a total of 6 units). In case of “call No. 3”, 10 units work at the fire site after an additional call for forces. “Call No. 4” – 13 units and “call No. 5” – 15 units under similar conditions until the fire stops.
Main Fire Factors
The process of extinguishing a fire can be complicated by some accompanying hazards that arise in the form of Main Fire Factors Fire Factors. These include: 1. flame and sparks; 2. heat flow; 3. increased ambient temperature; 4. increased concentration of toxic combustion products and thermal decomposition; 5. decreased oxygen concentration; 6. decreased visibility in smoke. Associated manifestations of the main fire factors are also distinguished.— these are: 1. fragments, parts of destroyed buildings, structures, buildings, vehicles, process plants, equipment, units, products and other property; 2. radioactive and toxic substances and materials released into the environment from destroyed process plants, equipment, units, products and other property; 3. high voltage transfer to conductive parts of process plants, equipment, units, products and other property; 4. hazardous factors of explosion caused by fire; 5. impact of fire extinguishing agents.
Types of fires
Depending on the type of burning substances and materials, corresponding types of fires are distinguished. They are conventionally designated by letters. Type A1 includes combustion of solids, which is accompanied by smoldering — extinguished with water with wetting agents, freon, powders of the ABCE type; type A2 includes combustion of solids without smoldering — extinguished with any types of fire extinguishing agents. Types of fire categories B1 and B2 are combustion of liquid substances, insoluble and soluble in water, respectively — extinguished with the help of foam fire extinguishing systems, finely atomized water, freons, powders of the ABCE and BCE types. Category C — combustion of gaseous substances, for example, household gas, propane — extinguished by volumetric method and phlegmatization of gas compositions, powders of the ABCE and BCE types, water for cooling equipment. Combustion of metals refers to type fires of category D: D1 – light metals (aluminum, magnesium); D2 – alkali metals (sodium, potassium); D3 – combustion of metal-containing compounds (organometallic compounds, metal hydrates). Class E – combustion of electrical equipment under voltage up to 10,000 volts.