In the design of buildings and facilities and choice of building materials is very important to take into account such factors as the fire safety of buildings.Existing regulations in the construction industry (SNIP) strictly regulate the use of certain materials, structures and design solutions for buildings, depending on their destination.One of the most important testimony of the development of the construction project is the degree of fire resistance of a building.
What is it?Under fire resistance of structures, of which the building is erected, is meant their ability to contain the spread of a fire in the fire without losing their basic operational properties.These properties include:
a) the load-bearing capacity;
b) enclosing capacity.
loss of the bearing capacity of the construction is its collapse.Loss of the ability to partition is considered to be warming up to the appearance of cracks and holes with penetration of the products of combustion and ignition of materials (especially inflammable) in adjacent compartments and areas or heating to a temperature at which ignition is possible.
fire resistance of structures is the time in hours from the start of the fire to the onset of signs of such a loss.It is installed by experimentation.For this prototype design of original size lay in a special oven, where exposure to high temperatures (fire), while using the design loads (temporary and permanent under its own weight, weight of stationary equipment and machines, the dynamic of the movement mechanisms and so forth.).
Another critical feature in determining the fire resistance of the structure index is the excess of a certain amount of its temperature at discrete points or an average of the surface compared to the original.The smallest have a fire resistance metal structures on top of anything not covered, the greatest - reinforced concrete.The maximum limit of fire resistance of up to 2.5 hours.
Another indicator of the degree of fire resistance of structures - limit the spread of fire, t. E. The size of damage outside of the fire.It is measured in inches and is 0 - 40 cm.
Thus, the degree of fire resistance is proportional to the degree of fire resistance of the building constructions.Those, in turn, are divided into fireproof (stone, brick, metal), nonflammable and flammable.By nonflammable materials are mixed character -goryuchie material protected outside fireproof or fire impregnation.(Example - the felt impregnated with a solution of cement).The third group -materials, which are easily ignited and burn (wood).
actual degree of fire resistance of buildings must comply with the required.Determine its SNIP II-2-80, which contains information on the above characteristics of the building structures.
on this indicator (the degree of fire resistance) of a building divided into 5 groups or classes.The first and second group - a stone building with the main structures of different fire rating.The third group - with fireproof and nonflammable construction.The fourth - with designs made of legkosgoraemyh protected material on top of plaster;fifth - plastered wooden houses.
degree of fire resistance of a building in the design should correspond to the degree of explosion and fire facilities.According ONTP-24, production facilities are five categories of fire risk.
A. Premises where applicable flammable gas or liquid with a flash point below 28 degrees (storage of petrol).
B. premises where there are flammable fibers or dust in suspension (shop kruporushek mills, fuel oil separation plants).
B. premises for the storage and processing of solid combustibles (feed mill, closed coal storage).
G. Facilities for burning fuel (including gas) - boilers, forges, etc. D.
D. Premises for the processing of non-combustible materials in the cold state (greenhouse, plant production product).
