Fire distances between buildings. Fire distances between houses: why observe them? More about fire safety

This time we will talk about what a fire distance (gap) is, what it is intended for, and based on what prerequisites it is selected and standardized.
First of all, let's define what a fire gap (distance) is. So, the fire distance is the standardized distances between objects (buildings, structures and (or) structures), which are established in order to prevent the spread of fire between them.

At the time of publication of this article, fire protection distances are standardized in accordance with SP 4.13130.2013 “Fire protection systems. Limiting the spread of fire at protection facilities. Requirements for space-planning and design solutions.”

The key characteristic when choosing fire breaks between buildings, structures and structures in accordance with the current regulatory framework is their degree of fire resistance and class of structural fire hazard.
For example, for industrial and warehouse buildings, open ground warehouses, various clarifying requirements for fire safety distances are introduced depending on the fire hazard category and the type (volume) of stored materials.

The degree of fire resistance of a building, as is known, characterizes the geometric immutability of the building during a fire, in other words, its indestructibility (stability) during a fire. Therefore, the lower the degree of fire resistance of a building, structure or structure, the sooner the destruction of it or individual structures will occur, which can lead to the spread of fire to neighboring objects.

The structural fire hazard class, as is known, characterizes the fire hazard of the building structures that make up the building. The higher the fire hazard of building structures, the faster the fire develops and the higher the likelihood of it spreading to neighboring buildings, structures and structures.

Thus, as follows from the definition of the term “fire distance” and from the concept of the parameters by which it is selected, the fire distance should exclude the spread of fire from a burning object to neighboring ones. Speaking abstractly from the requirements of the norms fire safety, then the choice of fire gap value is based, of course, on the factors that determine the spread of fire from one object to another. Let's look at them.

Fire spread between buildings.
So, the main factors (mechanisms) determining the spread of fire between buildings, structures and structures are the following:

Burning particles (sparks). During combustion various materials sparks can be formed that are able to travel significant distances, often exceeding fire breaks, without losing their ignition ability. Burning particles in most cases do not pose a great danger as a direct source of ignition. It should be noted that this applies primarily to buildings, structures and structures, therefore, when determining fire distances, for example, between residential and public buildings, or between two residential buildings, the possibility of combustion transfer through sparks is not taken into account.

The appearance of sparks near “cold”, or combustible structures slightly heated above the ambient temperature, as already noted, does not pose a serious danger. At the same time, during a fire there may be cases when the transition of a fire from one structure to another does not occur only due to the heating of combustible structures to temperatures lying in the range between the temperature of ignition and self-ignition. Those. The only thing missing is a combustion initiator (ignition source) - a spark! In other words, sparks pose a fire hazard due to the combined effect of both the sparks themselves and thermal radiation.

Direct exposure to flame. In the case of a close location of a burning and irradiated building, a fire may spread as a result of the direct impact of open fire on the combustible building structures. As a rule, in practice this occurs as a result of non-compliance with fire safety distances. The determining factors in the spread of fire between buildings by this mechanism, in addition to distance, are the power of the fire, wind speed, and the size of the opening through which the flame is released from the burning building.

Convective currents. The spread of a fire by this mechanism is possible only in the case when buildings, structures or structures are located very close to each other and the temperature of convective flows (smoke) is several hundred degrees Celsius. In practice, this possibility is also realized due to non-compliance with the fire break.

Thermal radiation. This mechanism of fire spread between buildings is the main one that determines the value of the fire distance. Ignition by radiation occurs over much greater distances than as a result of ignition by direct flame or convective currents. A heat flux of 35 kW/m2 can lead to spontaneous ignition of wood almost instantly without the presence of any ignition sources. And a heat flux of 12.5 kW/m2 leads to the ignition of wood by an ignition source, such as a spark or a burning brand, for example. This value is widely used in world practice.

A very important caveat must be made. The fact is that thermal radiation is the most dangerous factor in the spread of fire between buildings and structures, while burning particles are not taken into account due to their weak ignition ability (large thermal thickness building structure). However, when it comes to fires in forests or other vegetation, in open warehouses of combustible materials, one cannot ignore the transfer of burning particles over long distances. The scattering of sparks and firebrands during such fires occurs within a radius of up to 300 m, and at storm wind speeds over distances of up to 1 km.

It must be said that the development of a fire in a building and, consequently, the choice of fire breaks is influenced by the presence of automatic fire extinguishing installations, as well as the time of arrival of the first fire departments. In other words, these factors significantly influence the development of a fire and its spread between buildings.
Therefore, in the domestic practice of regulating fire breaks, the time of introduction of fire extinguishing forces and means was initially taken into account.

Well, and finally, I would like to note that at present there are no regulatory requirements in the field of fire safety that would allow calculating the fire distances between buildings, structures and structures.

Important addition to the article dated November 7, 2013! Requirements for fire safety distances.

The correct question was posed in the comments - “the question of the mandatory use of fire-fighting distances remained unclear, since this norm is excluded from 123-FZ. And what to do with fire safety distances today remains an open question.” Well, we will close it as much as possible.

So, at present there are only two (!) ways in which the protected object meets fire safety requirements. These conditions, or methods of ensuring fire safety requirements, are described in Article 6 of the Technical Regulations on fire safety requirements.

The fire safety of the protected object is considered ensured when one of the following conditions is met:
1) the fire safety requirements established are fully met technical regulations adopted in accordance with the Federal Law “On Technical Regulation”, and the fire risk does not exceed the permissible values ​​​​established by this Federal Law;
2) fire safety requirements established by technical regulations adopted in accordance with the Federal Law “On Technical Regulation” and regulatory documents on fire safety are fully met.

Fire code requirements. Let's consider the second condition. On July 12, 2012, Federal Law No. 117 came into force, which amended Federal Law No. 123, essentially removing from it the requirements for fire safety distances between buildings and structures. It is important to note that the requirements for fire safety distances between petroleum products storage facilities and adjacent facilities still remain in the Technical Regulations.

Then, with some delay, the firefighting community learned that SP 4.13130 ​​was already in force, which was approved by order of the Russian Ministry of Emergency Situations No. 288 of April 24, 2013 and came into force on the same day.
Thus, on this moment, as stated earlier, in relation to buildings and structures various classes functional fire hazard (except for petroleum product warehouses, etc., see Federal Law-123 in the new edition), SP 4.13130 ​​is in effect.

At the same time, as follows from the provisions of SP 4.13130, the requirements for fire safety distances between buildings and structures are applied deterministically, i.e. It is impossible to justify fire breaks by calculations.

There are two sides to this situation - negative and positive.

The negative aspect of the impossibility of substantiating fire breaks by calculation is the too narrow application of fire standards and the application of the same requirements to many objects that are diverse in their design and space-planning solution. In other words, fire clearance regulations are not flexible.

The positive aspect of the fact that calculations cannot be used to justify the requirements of SP 4.13130 ​​is that it eliminates the possibility of “hack-working” and adjusting calculations to the required conditions, as happened at one time after the widespread introduction of the practical application of avoiding fire safety requirements by calculating fire risk. After all, there is currently no approved methodology for such calculations.

Fire distance and fire risks. Let's consider the first condition associated with the possibility of deviating from the requirements of regulatory documents on fire safety by calculating the fire risk, at which it will be less than the standard value. Let’s say a building or structure is designed in violation of the requirements of SP 4.13130, but all the mandatory requirements established by technical regulations adopted in accordance with the Federal Law “On Technical Regulation” have been met. In this case, according to the requirements of Federal Law-123, the building has the right to exist provided that the fire risk meets the required values.

To determine fire risk, there are currently two methods approved by orders of the Russian Ministry of Emergency Situations:
— a methodology for determining the calculated values ​​of fire risk in buildings, structures and structures of various classes of functional fire hazard, approved by Order of the Ministry of Emergency Situations of Russia No. 382 of June 30, 2009;
— a methodology for determining the estimated values ​​of fire risk at production facilities, approved by Order of the Ministry of Emergency Situations of Russia No. 404 of July 10, 2009.

Fortunately, changes made by order of the Ministry of Emergency Situations of Russia No. 749 dated December 12, 2011, removed objects of functional fire hazard classes F1.1, F1.3 and F1.4 from the methodology. Therefore, at present, for these objects it is not possible to justify compliance with fire safety requirements by calculating fire risk.

For other public facilities, the method allows one to calculate the fire risk for people in the building. However, there is no calculation algorithm and corresponding mathematical apparatus that allows calculating the fire risk created by the protection object for neighboring objects. There are also no appropriate criteria by which to judge the level of fire danger of public buildings created for neighboring objects, the fire distance to which may be lower than the standard.

The situation is different with production facilities. In addition to the fact that in the event of a fire (explosion) at a production facility, a fire risk is created both for people on the territory of the facility itself and for people in neighboring facilities.

In accordance with paragraph 4 of Article 93 of Federal Law-123, the amount of individual fire risk as a result of exposure to dangerous fire factors at a production facility for people located in a residential area, public business area or recreational area near the facility should not exceed one hundred millionth per year.

Thus, from this point of view, the calculation justification of fire gaps between production facilities and neighboring buildings and structures using fire risk calculation is possible.

Arbitrage practice. In my opinion, an interesting situation may arise when the issue of fire breaks is considered in court, for example, in a claim for recognition of ownership rights to unauthorized construction, or in a claim to invalidate the conclusion of an expert from the State Expertise.

Here is an excerpt from Article 222 of the Civil Code of the Russian Federation:
The right of ownership of an unauthorized structure cannot be recognized for the specified person if the preservation of the structure violates the rights and interests protected by law of other persons or creates a threat to the life and health of citizens.

Despite the fact that the definition of the term “threat to life and health” has never existed in legal acts and regulations on fire safety, the court has the right to decide whether or not the object of protection in question creates a threat to the life and health of people in neighboring buildings and structures .

A court decision on this issue can be based on evidence from the competing parties, including calculations in which the fire distance is justified.
Perhaps similar court decisions are already available in the regions, it would be very interesting to learn about them.

Thank you for your attention, I would appreciate your opinions!

1. Fire distances between residential, public and administrative buildings, buildings, structures and structures of industrial organizations, depending on the degree of fire resistance and the class of their structural fire hazard, should be taken in accordance with Table 11 of the appendix to this Federal law.

2. Fire distances between buildings, structures and structures are defined as the distances between external walls or other structures of buildings, structures and structures. If there are structures protruding more than 1 meter of buildings, structures and structures made of flammable materials, the distances between these structures should be taken.

3. Fire distances between the walls of buildings, structures and structures without window openings it is allowed to reduce by 20 percent provided that the roof is made of non-combustible materials, with the exception of buildings of IV and V degrees of fire resistance and buildings of structural fire hazard classes C2 and C3.

4. It is allowed to reduce the fire distances between buildings, structures and structures of I and II degrees of fire resistance of structural fire hazard class C0 by 50 percent when more than 40 percent of the premises of each building, structure and structure are equipped with automatic fire extinguishing installations.

5. In areas with seismicity of 9 points and above, fire safety distances between residential buildings, as well as between residential and public buildings IV and V degrees of fire resistance should be increased by 20 percent.

6. Fire distances from buildings, structures and structures of any degree of fire resistance to buildings, structures and structures of IV and V degrees of fire resistance in a coastal strip 100 kilometers wide or to the nearest mountain range in climatic subregions IB, IG, IIA and IIB should be increased by 25 percent .

7. Fire distances between residential buildings of IV and V degrees of fire resistance in climatic subregions IA, IB, IG, ID and IIA should be increased by 50 percent.

8. For two-story buildings, structures and structures of frame and panel construction of the V degree of fire resistance, as well as buildings, structures and structures with roofs made of flammable materials, fire distances should be increased by 20 percent.

9. Fire distances between buildings, structures and structures of fire resistance degrees I and II may be reduced to 3.5 meters, provided that the wall is more tall building, structures and structures, located opposite another building, structure and structure, is a fire protection type 1.

10. Fire distances from one-, two-apartment residential buildings and outbuildings(sheds, garages, bathhouses) on a private plot of land to residential buildings and outbuildings on neighboring plots of land land plots should be adopted in accordance with Table 11 of the Appendix to this Federal Law. It is allowed to reduce the fire distances between the specified types of buildings to 6 meters, provided that the walls of the buildings facing each other do not have window openings, are made of non-combustible materials or are subject to fire protection, and the roofing and eaves are made of non-combustible materials.

11. Minimum fire distances from residential, public and administrative buildings(functional fire hazard classes F1, F2, F3, F4) I and II degrees of fire resistance to industrial and warehouse buildings, structures and structures (functional fire hazard class F5) must be at least 9 meters (to buildings of functional fire hazard class F5 and classes structural fire hazard C2, C3 - 15 meters), III degree of fire resistance - 12 meters, IV and V degrees of fire resistance - 15 meters. The distances from residential, public and administrative buildings (functional fire hazard classes F1, F2, F3, F4) of IV and V degrees of fire resistance to industrial and warehouse buildings, structures and structures (functional fire hazard class F5) must be 18 meters. For these buildings of fire resistance class III, the distance between them must be at least 12 meters.

12. The placement of temporary buildings, stalls, kiosks, sheds and other similar structures must be carried out in accordance with the requirements established in Table 11 of the Appendix to this Federal Law.

13. Fire distances between solid end walls with a fire resistance limit of at least REI 150, buildings, structures and structures of fire resistance degrees I - III, with the exception of preschool buildings educational institutions, stationary medical institutions (functional fire hazard classes F1.1, F4.1), and multi-level parking garages with passive movement of cars are not standardized.

14. Areas for storing containers must have fences and be located at a distance of at least 15 meters from buildings, structures and structures.

15. Fire distances from the boundaries of urban settlements to forests must be at least 50 meters, and from the boundaries of urban and rural settlements with one-, two-story individual development to forest areas - at least 15 meters.