Fire resistance of structures is their ability to limit the spread of fire and maintain the required performance when exposed to high temperatures during a fire. Its main characteristics are the limit of fire resistance and the limit of the spread of fire.
Instructions
Step 1
Organize tests. To simulate a fire, use stoves where you inject kerosene through nozzles, and then ignite the fuel. The temperature in the furnace is controlled by thermocouples, while the flame should be 10 cm away from the test surface.
Step 2
Make a standard calculation. Do it manually or use computer programs. The purpose of the heat engineering calculation is to determine the temperature for the section of the structure under the influence of fire. So the limits of fire resistance of concrete structures and reinforced concrete products are primarily influenced by the type of concrete, binder, aggregate and the class of reinforcement. Much depends on the type of structure, the shape of its cross-section and dimensions, as well as on the heating conditions, concrete moisture and the degree of load. Wood is capable of igniting under the action of an open fire at a temperature of about 230 degrees C, and stable combustion begins at 260 degrees C. And even if there is no open flame, in a maximum of 2 minutes, wood can heat up to 330 degrees C.
Step 3
The fire resistance limit is determined in accordance with the established methodology and is expressed in hours or minutes of exposure to structural elements of a conventional fire, when the structure itself reaches at least one of the limit states. These include the collapse or deflection of the structure, an increase in the temperature of its unheated surface by 160-220 degrees, the formation of through holes or cracks in it as a result of combustion. The limit of fire resistance also occurs when an unloaded structure reaches such a temperature at which it loses its load-bearing capacity even in the presence of fire-resistant coatings.
Step 4
Examine building documents, materials, structures. The characteristics of the fire resistance of materials must be indicated when developing projects for buildings and structures. There are five groups of buildings and structures, where the fire resistance limits range from 0.25 to 2.5 hours, and the range of fire spread is 0-40 cm.
Step 5
Pay attention to whether there is a mark about the use of special technologies in the conclusion of the State Fire Inspection or in the passport of the building. To increase the indicators of fire resistance of the structure, fire retardant technologies are used.
