Class of functional fire hazard. Fire-technical classification of buildings, structures

Fire hazard of substances, various kinds of materials - a set of properties that characterize their ability to quickly ignite and further spread the combustion process, which may result in a fire or even an explosion.

Classification of buildings based on a functional fire hazard

Within the framework of the considered aspect, it is necessary to interpret some important concepts. Buildings (their parts, fire compartments, structures) - premises (groups of rooms), which are functionally related to each other by a criterion such as a functional fire hazard.

Depending on the methods of their operation and the degree of threat to be inside them in the situation of people's fire (taking into account their age, the probability of being in a state of sleep, physical condition, etc.) it is customary to allocate the following classes:

• Ф1 - a class of functional fire danger of a building intended for temporary stay, residence of people (pre-school institutions, hotels, single and multi-apartment dormitories, specialized homes for the disabled and the elderly, hospitals, etc.).
• F2 is a class that includes entertainment, cultural and educational establishments of different kinds (cinemas, circuses, libraries, theaters, dance and concert halls, sports facilities with stands, museums, etc.).
• F3 - a class of functional fire danger buildings of enterprises, whose activities are related to the maintenance of the population (trade institutions, catering organizations, polyclinics, banks, railway stations, mail, etc.).
• F4 - a class that includes the building of educational, research institutions, editorial and publishing, information and design organizations, fire stations, buildings of institutions of government.
• F5 is a class of functional fire hazard of premises, such as book storages, warehousing (production) premises (here also include similar buildings from the above classes, as well as laboratories).

Why do we need this classification and where is it indicated?

The fire hazard class is indicated in the special design documentation for the relevant facility. This classification is used to establish requirements for constructive and volumetric planning decisions concerning buildings, and also as a rule for these requirements (regarding the evacuation of people in the process of fire).

Categories of fire and explosion hazard of buildings and premises

The concept of "categorization", from the point of view of the aspect under consideration, is treated as the correlation of buildings (buildings) over fire, explosion and fire hazard to certain categories. It is compulsory, and the following objects are subject to it:

1. All production buildings (buildings, structures), workshops, laboratory and production facilities (class of functional fire hazard F5.1).
2. Any external installations in the form of a set of technical equipment and apparatus that are located outside buildings (structures).
3. Warehouse buildings (buildings, structures), as well as parking lots (excluding repairs and maintenance), book storages, storage facilities and archives (class of functional fire hazard F5.2).

The categorization is carried out exclusively for warehouses, industrial premises. The definition of premises for fire hazard is at the design stage based on fire safety standards or departmental documents developed on their basis.

Based on the fire and explosion hazard, all the premises are divided into five categories: A, B, B1-B4, G, D.

The categories of fire and fire hazard of the premises are determined specifically for the most unfavorably affecting fuel (regarding fire and explosion in apparatuses, rooms), its quantity, nuances of the technological process, fire hazard properties.

Categorization of warehouse, industrial premises for fire, explosion and fire hazard

Categories of premises	The main characteristics of materials and substances present in the room
1. A (explosive)	LPG, flammable gases (flash point above 28 ° C), which in an amount sufficient to form explosive liquid-gaseous mixtures, and which, upon ignition, develop an overpressure pressure of ˃ 5 kPa Substances, materials that are capable of exploding, burn in the process of interaction with oxygen, water or with each other (if the value of the calculated excess pressure of the explosion is ˃ 5 kPa)
2. B (explosive)	Flammable fibers or dusts, flammable liquids (flash point above 28 ° C) in an amount forming explosive dust or vapor-air mixtures, during ignition of which there is an overpressure of explosion ˃ 5 kPa
3. In (fire-hazardous)	Liquids (combustible, hardly combustible), substances (solid combustible, hardly combustible), including fibers and dust, as well as materials and substances that are only capable of burning in the process of interaction with oxygen, water or with each other (if the premises in which they are located, Do not fall under the above categories)
4. D	Non-combustible materials, all sorts of substances (in hot, hot or melted state) that, during processing, produce heat, flames, sparks, flammable liquids and gases, solids intended for utilization as fuel.
5. D	Non-combustible materials, all kinds of substances in the cold state.

Recommendations for establishing a building category

The definition of the fire hazard category of the premises is based on the following non-mandatory instructions:

1. The object belongs to the first category (A), provided that the total area of its building exceeds the total area of all the premises inside it (200 m ² ) by 5%. It is allowed not to assign a building to category A (explosive) if its total area does not exceed the established value (25%), calculated from the total area of all the premises located in it (no more than 1000 m ² ), provided that they are equipped with special automatic fire extinguishing equipment.

2. The category B falls into a building that, first, can not be classified as Category A. And secondly, it has the value of the total area of its premises (A, B) exceeds the value of 5%, calculated from the total area of the entire complex of premises , Located inside it (or 200 m ² ). It is permissible not to assign a building to this category, provided that the total area of its premises (A, B) does not exceed 25%, calculated from the total area of all premises located inside it (not more than 1000 m ² ), if equipped with facilities Special automatic fire extinguishing.

3. The conditions for assigning a building to category B are:

• It does not fall under any of the above categories;
• The value of the total area of premises (AB) exceeds 5% (or 10% in the absence of other categories of premises) of the total area of the premises inside the building.

It is permissible not to assign a building to this category if the total area of its premises (AB) does not exceed 25% of the total area of all premises inside it (no more than 3500 m ² ), provided they are equipped with special automatic fire extinguishing equipment.

4. The conditions for classifying a building as Category D are:

• It does not fall under any of the above categories;
• The value of the total area of premises (AG) exceeds 5% (or 10% in the absence of other categories of premises) of the total area of the premises within the building.

It is permissible not to assign a building to this category if the total area of its premises (AG) does not exceed 25% of the total area of all premises inside it (no more than 5000 m ² ), provided that equipment is installed with special automatic fire extinguishing facilities of A- AT.

5. The building is classified in category D provided that it does not fall under any of the above categories.

The definition of the fire hazard category of buildings is a guideline in determining the probability of occurrence of individual fires (level of fire resistance of buildings) and solid (building density).

How to calculate the category in question?

In order to calculate the fire hazard category, you will need to collect the data for the corresponding room first (its plan is mandatory). Next, make measurements of the walls and height of the ceilings of the sections most dangerous in the fire (this is done directly by fire safety specialists). Then determine the temperature regime of the evaluated object, as well as the material from which the floor covering is made. It is important to establish the availability of special fire extinguishing systems and ventilation outlets.

Calculation of the category of fire hazard - calculations that allow to establish a class of danger of an explosion (fire) on the basis of analysis of stored, used and processed substances, as well as technological process and equipment. It is regulated by Russian legislation in the field of fire safety.

The calculation of the fire hazard category of premises is carried out in order to form the relevant requirements regarding the sphere in question, which are aimed at reducing the likelihood of a fire, as well as adequate provision of professional fire protection for people (valuable property) in the situation of its occurrence.

Classification of structures on the basis of constructive fire hazard

The existing class of constructive fire hazard of the building (building) is determined by the degree of participation of the relevant building structures in the process of fire development and the formation of fire hazard factors.

There are 4 classes in the framework of the aspect under consideration: C0, C1, C2, C3. It is important to note that the class of constructive fire hazard of the structure is directly dependent on the classes of fire hazard of the main carriers, enclosing structures (building): crossbars, walls, ceilings, walls of staircases, columns, fire barriers, farms, partitions, coatings, platforms and marches Stairs. The fire danger with respect to the filling of the openings protecting the building structure is not standardized at that (except for the openings of fire protection barriers).

Class C0 is the best in terms of fire safety. Here all the designs are made exclusively of non-combustible materials (they do not burn, do not produce a thermal effect, are not damaged, do not form a toxic smoke evolution).

Class C1 - the use in buildings of structures made with the use of difficult-combustible materials.

Class C3 - the majority of structures (in addition to walls, fire barriers, structural staircases and partitions) to which fire protection requirements are not required.

Classification of fire hazard constructions

Building structures in this aspect are divided into classes:

• К0 - a class of fire hazard constructions, which includes non-flammable structures;
• K1 - a class of low-fire hazardous constructions;
• K2 - a class of moderately flammable structures:
• K3 - a class of fire-hazardous structures.

The numerical values of the criteria by which the building structures relate to the corresponding class are determined based on the methods established by regulatory documents for fire safety.

The definition of the fire hazard class of structures is prescribed in Annex 6 of the Federal Law (No. 123 of 22.07.08).

Requirements for the location of rooms of different classes of functional fire danger inside a building

They have the following form:

1. Premises that have a functional fire hazard class F2-F4, are allowed to be placed within the same fire compartment (including technical rooms and storage rooms).

2. A mandatory condition is the presence of fire hydrants in an amount not less than three pieces.

3. It is permissible to design evacuation staircases (general purpose) for rooms inside one object (functional fire hazard of premises is different), provided they are equipped with smoke-free fire doors of the second type with filling of doorways. At the same time, there must be an appropriate calculation of the validity of these structures, taking into account the dynamics of the hazards preceding the fire; The required conditions for the evacuation of people must be ensured.

4. Film complexes, the total capacity of cinemas of which is more than 300 seats, should be allocated to detached fire compartments and be provided with separate evacuation outlets or staircases (at least two pieces).

5. Buildings should be equipped with the following elements:

• Installations of professional automatic fire extinguishing, as well as fire alarm of special address type;
• Special smoke protection systems;
• Collective and individual life-saving appliances;
• A fire alarm system, starting from the fourth type;
• External and internal fire water supply;
• Power supply systems of special fire protection, starting from the first category of reliability.

6. Differentiation of premises of different classes of functional fire danger inside one building is carried out through fire barriers of the second and the first types. Also the distinction to the corresponding fire compartments is made with the help of fire walls and overlappings of the first type.

7. In the process of designing multifunctional buildings, calculations are compulsory, which will make it possible to justify the correctness of previously accepted space-planning decisions.

Ensuring adequate fire safety

All buildings (buildings) are objects having a certain degree of fire hazard, most of which have various types of combustible substances. Their number may be sufficient to cause substantial damage. Also, most often there is an oxidant in the form of oxygen and an ignition source (conditions for the onset of a fire).

The main problem of fire safety of the structure is bringing its fire danger into proper condition, in which the probability of a fire is excluded, and in the situation of fire, the protection of people (valuable property) is professionally ensured.

Ensuring adequate fire safety is achieved by the following:

• Fire prevention systems;
• Organizational and technical complex of events;
• Special fire protection systems.

In this regard, the general condition regarding the provision of adequate fire safety of the building is as follows: it will be achieved if the actual amount of measures aimed at ensuring adequate fire safety corresponds to the amount of measures regulated and approved by the relevant rules and regulations.

What causes the wrong classification of the building?

It is considered that a competent and correct definition of a class of functional fire danger is a guarantee of security. The set of rules for fire safety - measures that are mandatory for execution, which must be strictly observed. However, these rules are established by means of certain characteristics, one of which is the assignment of a class of functional fire hazard to a building (building).

In order to prevent a fire, it is important to correctly classify the corresponding building (structure, structure, fire compartment). It is the final decision that will be taken into account in the process of drafting the above-mentioned rules for various organizations.

If it is not set correctly, the current rules will be grossly violated, and as a result, the likelihood of a fire will increase significantly. This identification with respect to the functional purpose is carried out according to three main characteristics, the most important of which is classification based on the functional fire hazard of structures (buildings).

It is worth recalling once again that in accordance with the technical regulations on fire safety requirements, such a concept as a class of functional fire hazard is a special classification characteristic of premises (buildings) that is established based on the purpose and operation characteristics of these facilities (including the features of their technological Processes).