What are non-smokeable stairwells. Types of staircases and features of their design; classification: non-smoky, l1, l2 n1, n2, n3. Requirements for fire barriers

A prerequisite in multi-storey buildings is the presence of a smoke-free staircase, which can be the only way to escape in the event of a fire. For such structures there is a special classification. Each type of cell has its own design features, which should be considered in more detail.

Design purpose

The first thing to start with is the question of the functional purpose of smoke-free stairs. This design is a march of certain sizes, which should be located in a suitable area of \u200b\u200bthe building.

Smoke-free staircases are designed to serve as an emergency exit for people in this building. The main focus is on the fire emergency. The consequence of any scale fire is the smoke of the interior space of the house. Many people who died in a fire were negatively affected by smoke and toxic fumes, and by no means flame. That is why one of the main requirements for an emergency exit is isolation from smoke.

In addition, this type of ladder should allow rescuers to reach the interior to extinguish the fire and rescue injured people. In particular, it is possible to carry people on stretchers.
The presence of smoke-free staircases is a prerequisite for high-rise buildings. Depending on the specific type, different requirements are imposed on them.

Smoke-free staircase performs the function of evacuating people in case of fire

Main types

There are several types of smoke-free staircases. They are classified by location, access to them and the principle of operation. Consider the standard types of smoke-free stairs:
H1. This is the base model. For such a design, the characteristic features are the availability of access through an open area. The approach to the emergency exit must also be smoke-free.

H2. For such stairs, air support is provided in the event of a fire.

H3. They are very similar to type H2, but in this case, access to the march is provided through a vestibule lock. Additionally, the same air support is provided, but it can be supplied both in case of fire and on an ongoing basis.

Standard types of smoke-free staircases

In order to better understand the difference between these types of stairs, you should consider the types H1, H2 and H3 in more detail and identify the most characteristic features for them.
Stairs H1

The presence of a smoke-free H1 type staircase is a prerequisite for residential and public buildings of any plan with a height of 30 meters or more. The peculiarity of this design is, first of all, in providing access to it. In order to get to the stairs of type H1, you need to go along the corridor to an open area of the outdoor type. It can be a balcony, a veranda or a fenced area outside the premises.

Passing through the open segment, you will find yourself in that part of the building where the location of marches of this type is provided. Such requirements are due to the need to provide natural isolation of the evacuation exit from the smoky part of the building. Therefore, the best option for their placement is the corner part of the building. A particularly advantageous position is the inner corner with additional piers. It is advisable to provide for the presence of a fenced evacuation exit even in the process of designing the building itself, so that in the future it would not have to be converted to fire safety requirements.
Stairwell type H1 is mandatory for residential and public buildings

Stairs H2 and H3

Another design option is smoke-free staircases marked H2 and H3. They are placed in buildings with a height of more than 50 meters. Mostly in modern buildings, it is models of the H2 type that are used, so you should start with them.
For smoke-free staircases of the H2 type, the characteristic features are the presence of an air backwater. The exit to it remains within the inner part of the building, but the presence of a ventilation duct is mandatory. It is thanks to this design that the requirements for air overpressure in the stairwell are met.

More complex in execution are stairs of the H3 type. They provide for the presence of an additional vestibule located on the way to the emergency exit. It is thanks to this extension that the best protection against fire and smoke is provided. The vestibule provides for the use of non-combustible materials for the removal of walls and partitions, a fire door is also installed, preferably with an automatic porch.

The very design of the staircase remains the same as for the H2 model. The ventilation duct provides air supply and adequate passage pressure. As a result, the ingress and accumulation of smoke and other combustion products in the territory of the emergency exit is prevented.

Stairs type H2 and H3 must be placed in buildings with a height of more than 50 meters

In addition to structural features, it is also important to comply with the requirements of SNiP regarding the dimensions of the passages and the materials used. If violations are detected, the ladder will not be able to fully perform its functions and can be very dangerous in the event of a fire.

Exit to the stairs

In order for the staircase to remain smoke-free even in the case of a close location of the ignition source or in the event of a large-scale fire, it is necessary to ensure the availability of safe approaches. Basically, the emphasis is on the presence of fire partitions and special doors. They must be made of non-combustible and non-toxic materials, all joints are additionally sealed and the degree of resistance to high temperatures and open fire is checked.

The main requirements for exits to this type of evacuation staircase are as follows:

Lighting. To ensure sufficient visibility, the stairs must be equipped with light sources. According to the rules, windows should be provided on the stairwell of the evacuation type. Auxiliary and emergency light sources are also mandatory.

Ventilation. To ensure air supply, it is necessary to build a ventilation shaft associated with marches. A hole is left on the top tier to ensure constant air circulation. In some cases, forced provision of this process with the help of ventilation equipment is required.

Partitions. To prevent the penetration of fire into the territory of the emergency exit, it is necessary to provide additional partitions on the way to the main part of the building. A distance of about 2 meters must be maintained between the elevator shaft and the evacuation passage.

Free access. In order to get to the cage there should be no obstacles on the way. It is forbidden to block the passage and place objects on its area for both permanent and temporary storage. It is strictly forbidden to close the doors leading to the exit or install additional obstacles on the way to it. The passage must remain open around the clock.

Information access. People in the building should be aware of the presence and specific location of the emergency exit. For this, a prerequisite is the presence of special signs and an evacuation plan directly.

Requirements regarding exit to the evacuation stairs

Dimensional requirements

In addition to the above requirements for smoke-free stairs, other conditions are also imposed, they relate to the size of the cage and the marches themselves. In order to systematize these indicators, they can be divided into the following groups:

Height. In order for the average person to move comfortably along the evacuation route, the height of the ceilings in the march area should be at least 190 cm.

Width. The dimensions of the passage should be 120 cm wide in the air zone. The width of the path to this passage must be at least 110 cm. The unhindered movement of two people must be ensured, as well as the transfer of victims on a stretcher.

Number of steps. Within one march, a maximum of 16-18 ordinary steps is allowed.

Step dimensions. The optimal ratios are taken as the basis, which are established for all types of stairs. The step should be wide enough for comfortable placement on its surface of the foot. At the same time, its height is about one and a half times smaller. All elements of the march must be the same in terms of parameters. The slope varies on average from 30 to 40 degrees.

Number of people. In most cases, standard evacuation marches are limited in terms of the simultaneous presence of people on the cage. Often this number is 15 people, but the exact value depends on the dimensions of the building and its purpose, as well as the type of staircase.

Handrails. To minimize the risk of injury and facilitate movement, barriers and handrails made of non-combustible materials are mandatory. It is important to consider that they must have a minimum thermal conductivity to prevent them from heating up in case of fire.

Acceptable materials

A smoke-free staircase is often made from materials that are able to withstand heat as much as possible and, of course, not ignite upon contact with high temperatures and fire. That is why the favorites are:

Metal. It is usually used when it is not possible to build a massive structure. The internal structure of concrete marches is strengthened with metal elements, and fences are also equipped.

Concrete. The leader in use, as it is completely fireproof. In addition, concrete marches are quite comfortable and durable, they meet the standards for dimensions and other requirements of SNiP. Concrete is used for the construction of internal evacuation structures.

Evacuation ladders are most often made of metal or concrete.

Alternative designs

In addition to smoke-free stairs, other types of structures for special purposes can also be used. The main alternative to a non-smokeable staircase of type H is an evacuation model of category L. Such structures are often installed in buildings with a lower number of storeys. In general, they repeat the requirements of the cells described above, but there are some design features of these models.

Fire escapes should also be mentioned separately. They are used to facilitate the process of rescue operations and fire fighting, and can also be used to leave the building, but this is an extreme case. They are smaller in size and are placed outside the building at a certain distance from the walls.

If smoke-free stairs do not meet the requirements of SNiP, they are allowed to be used only in the form of emergency passages. In this case, it is necessary to ensure the presence of serviceable evacuation exits. Without them, it is not allowed to put the building into operation according to the rules.

In multi-storey buildings, this is a guarantee of saving many human lives and ensuring the safety of the property of the people living there.

One of the conditions that must be met when putting multi-storey buildings into operation is the presence of a certain type of stairwells, which, in case of fire, do not smoke.

Smoke-free staircases include special designs that provide quick and safe evacuation from the facility.

This type of construction has its own classification, which distinguishes cells according to their technical parameters and structural design.

Functional purpose

A smoke-free staircase is a special design, which is implemented as a march of certain geometric dimensions, along which people can be quickly and efficiently evacuated in the event of a fire in one of the premises of the facility.

The main requirement that is put forward for this type of structures is the absence of smoke in their space during a fire.

The air zone of a non-smokeable staircase must be clean from smoke masses throughout the entire evacuation.

This will eliminate the death of people and their injuries, which often occur from suffocation with flue gases intensively released during a fire.

Among other things, a smoke-free staircase should provide an opportunity for rescuers to quickly get inside the premises in order to evacuate the people remaining there and start fighting the fire from the inside. The design of this kind of stairwells should provide for the transportation of evacuees using stretchers.

The regulatory documents strictly stipulate when the installation of smoke-free staircases is required.

The objects where these structures must be mandatory include various multi-storey buildings (residential, industrial, general use).

Types of smoke-free stairs

According to the SNiP on fire safety of buildings, the stairs used in them are divided, taking into account fire resistance, the possibility of smoke and the degree of ignition, into the following types:

internal stairs, which are part of the staircase structures of the building;
open internal stairs;
outdoor open stairs.

Simple escape stairs are classified into two categories.

L1 - these are structures that are distinguished by the presence of fully open or glazed openings in the external partitions of each floor. Stairs of this type are used in buildings with a total height of no more than 28 m. On the platforms of these stairs it is forbidden to lay electric cables, pipes for gas and water mains, and also to store any things.
L2 - structures with natural light, which is provided through open or glazed openings in the roofing of the building. This type of construction is used in houses whose maximum height is not more than 9 m, in rare cases - 12 m. Such stairs are used in buildings that belong to I, II and III degrees of fire resistance.

Types of smoke-free stairwells

Depending on the device of the smoke-free staircase, its location, the organization of access to it, the principle of use, they are divided into three categories:

H1 - these are types of stair structures, for which they are distinguished by the presence of free access through open areas. Approaches to such evacuation structures must be smoke-free.
H2 - this type of smoke-free stairwells is distinguished by the presence of air backwaters.
H3 - these openings are in many ways similar to the previous ones, but they differ in that the exits to the marches must be carried out through special vestibules in the form of locks. There is also air support, which can be carried out both in case of fire and constantly.

Stairwells H1

Smoke-free staircase H1 is one of the mandatory elements that must have public and residential buildings, the height of which is 30 meters or more. Features of this type of cells are access to them.

In order to get to the smoke-free H1 type stairwells, one should get through the corridor to an open outdoor area, made in the form of a balcony or a separate fenced area.

These access requirements are established to ensure that the escape route is naturally isolated from smoke-filled areas. The best place for the location of this type of structure is the corner part of the strong.

It is especially advantageous to place them on the inner corner with additional piers. In order for the landing to meet all fire safety requirements, all the nuances of its location should be taken into account even at the design stage of knowledge.

Otherwise, it will be necessary to re-equip the structure in order to fulfill all the established requirements.

Stairwells H2 and H3

Smoke-free staircases H2 and H3 are a slightly different type of evacuation structures that are designed for use in buildings whose height is more than 50 meters. In the construction of most modern facilities, it is H2-type landings that are used.

Smoke-free stairwells of the H2 type are characterized by the presence of an air overpressure provided by means of a ventilation duct. The exits to such stairwells are carried out through the inner part of the building.

H2 and H3 types of smoke-free staircases are structures with air support, but in the second case, the obligatory presence of a vestibule in the form of a gateway is provided, which should be placed on sections of the path leading to emergency exits. The use of outbuildings in the form of vestibules will significantly improve the protection of people from smoke and fire.

When creating a vestibule, only those materials that do not support combustion are used, and the presence of a fire door should also be provided, in which there should be an automatic porch.

As for the design of this staircase, it is similar to that of the H2 type cage.

The presence of a ventilation duct will allow you to supply air flows and create the required backwater passage. This will prevent the ingress of smoke and combustion products to the places of evacuation of people.

Technical requirements for stairs

In addition to the requirements listed above for smoke-free cages, other conditions are also established that relate to the geometric dimensions of their structural elements.

March width

The width of the passage should be 1.2 m when measured in the air zone. The width of the approach to this passage should be at least 1.1 m.

The passageway must be such that two people can easily pass through it or the injured person can be transported using a stretcher. In one march, up to 18 ordinary steps are allowed.

Step Height

The overall dimensions of the steps on the march should be optimal for each type of smoke-free stairwells.

The width of the step should be sufficient so that the human foot can comfortably and stably sit on its surface.

As for the value of the step height, it can be 1.5 times smaller than the width.

Each of the structural elements of the evacuation marches must correspond to each other in terms of their overall dimensions.

Height of escape route passage

In order for a person to move freely by evacuation, the height of his ceilings should not be less than 1.9 m.

Other nuances

For the manufacture of smoke-free stairs, such building materials should be used that can withstand heating and ignition in direct contact with an open flame and heated structural elements of the building.

Basically, concrete is used to build staircases, which has a high level of fire safety. In addition, concrete marches are highly durable and easy to use.

To strengthen the structure of marches, as well as to create fences, metal structural elements are used.

Conclusion

If we summarize the information presented above, we can conclude that smoke-free staircases are important structural elements that provide the building with the required level of fire safety.

In addition to smoke-free stairs, other kinds of special structures can be used at the facilities, which may differ in design, but have the same functional purpose.

It is important that smoke-free stairs and other similar structures fully comply with the norms of SNiP, which determines the fire safety of an object.

If they contradict the normative documentation, then their use will be possible only as emergency moves.

SNiP and GOST for a number of buildings provide for the installation of such equipment as a smoke-free staircase. It ensures the safety of people in the premises during a fire. Thanks to the presence of these structures, residents can be saved from fire and smoke.

Despite the introduction of regulations requiring the use of exclusively non-combustible materials for the construction and decoration of buildings, the situation with fire safety often remains critical. To avoid the death of people and animals from fire and combustion products, structures such as smoke-free stairwells were developed. Architects developing projects for multi-storey buildings are required to take into account fire safety requirements and provide for the presence of these evacuation routes and exits.

A smokeless stairwell is a structure made of non-combustible materials, the space of which is protected from the effects of fire and smoke. This is the main difference between evacuation stairs and those that serve to connect the floors of a building.

H1 - located in the most protected from fire and smoke places in the building. Access to the H1 stairwell is possible through open corridors, which cannot be penetrated by fire and combustion products. In multi-storey residential buildings, such a transition is a balcony that acts as an air zone. Passing through this corridor, a person gets directly to the stairs of type H1, through which he can leave the building.
H2 - is a room (complex of flights of stairs), fenced with walls made of non-combustible materials and equipped with ventilation ducts with air overpressure.
H3 - a room located next to the flights of stairs, access to it is possible through special gateways. They provide for the presence of ventilation ducts that provide air overpressure either in continuous mode or with the onset of ignition. The entrance to the gateway is a fire door with an automatic porch.

All listed types of staircases are assembled from metal and concrete structures.

Doors leading to the exit from the building and the entrance to the area protected from fire and smoke have the status of evacuation doors and must comply with the requirements of SNiP 21.01.97. According to the rules and regulations of fire safety, the width of the emergency exits must be sufficient to enable the unhindered movement of the stretcher. Therefore, the boundaries for the width of evacuation corridors are set: at least 1.2 m.

Requirements for smoke-free staircases

Stairwells of type H1 are designed to ensure the evacuation of people in buildings whose top floor height exceeds 30 m. These include reinforced concrete structures of type A, B and C. Evacuation marches are located in the corners of the building. There should be a window on each floor of these fire and smoke protected rooms. Transitions leading to the emergency exit (balconies or galleries) must provide a constant flow of air.

Staircases of type H2 are designed to provide emergency exits in public and residential buildings from 28 to 50 m high. Tambour locks that serve as a passage to the safe area must be equipped with category E130 doors. The same requirements apply to H3 type stairwells.

Evacuation exits located on the outside of multi-storey buildings are often decorated with openwork gratings made of metal or other non-combustible materials. Therefore, a logical question arises for residents: will these decorative panels and grilles interfere with the free access of air, which is the main safety measure during a fire? But you can be calm about this: the experts took into account all the nuances, so the openwork grilles on the facades of the houses have openings sufficient for unhindered access to fresh air.

There are a number of requirements for passages located on the outside of the building (balconies and galleries) and leading to emergency exits:

on the territory of such transitions it is forbidden to place bulky and other things of residents;
laying of cables and wires is unacceptable;
it is forbidden to lock or otherwise block the door that is the entrance to the safe area.

Video about testing the fire escape platform:

Compliance with these rules and requirements is required to be monitored not only by the fire safety service, but also by employees of communal departments. Administrative liability is provided for violation of the introduced rules. In order to ensure free access to the smoke-free zone, specialists regularly inspect these areas and urge residents of multi-storey buildings to report violations in a timely manner.

Jargon used in fire safety design of buildings.

On the website of VNIIPO EMERCOM of Russia, the opinion of specialists from this institute is given regarding the use of the indicated name in relation to stairwells of the H2 type, the exit to which goes through a tambour lock with air overpressure.

Given that the EMERCOM of Russia periodically "cleans" the question-answer sections on its websites, we consider it necessary to cite this opinion here, with reference to the original source.

Question asked by VNIIPO EMERCOM of Russia:

VNIIPO answer:

The use of the phrase “smoky H2+H3 stairwells” is essentially a typical jargon that has nothing to do with the normatively established classification, and, in a number of ways, contradicts fire safety requirements. In particular, in accordance with the provisions of the Federal Law of July 22, 2008 No.

No. 123-FZ "Technical regulations on fire safety requirements" fire-technical classification provides for only three types of smoke-free staircases: H1, H2 and H3.

Moreover, for stairwells of the H2 type, non-smoking (or preventing the spread of combustion products into their volumes during fires in buildings) is provided by supply smoke ventilation by supplying outside air to these volumes to create excess pressure in them relative to adjacent rooms, corridors, halls on different floors. Floor-by-floor entrances to non-smoky H2-type stairwells are arranged through single or parallel doorways (floor-by-floor entrances are allowed through sequentially located doorways in vestibules provided exclusively for operating technology conditions, but not for additional fire protection). In turn, for stairwells of the H3 type, smoke-freeness is achieved by installing tambour locks at all floor entrances, which are protected by inlet smoke ventilation that provides outdoor air supply to one of these tambour locks (when leaving the floor on which the fire broke out) with the creation of excess pressure in it relative to adjacent rooms, corridors, halls.

note

Thus, each of the considered established types of smoke-free staircases corresponds to a specific design of a single staircase in conjunction with the space-planning elements of the building.

Consequently, the used symbolic addition “H2 + H3” is clearly meaningless: it physically combines various spatial structural elements - two separate stairwells of different designs (at the same time, according to the laws of algebraic addition, a casuistic non-existent type of non-smokeable stairwells is obtained - H5).

In addition to the noted absurdity of physical perception, such an innovation of “smoke-free stairwells of the H2 + H3 type” does not allow to fully implement the existing regulatory framework in all aspects of the use of smoke-free stairwells in buildings for various purposes.

In this regard, even if we exclude from consideration the impossibility of the physical implementation of this "innovation" and analyze only the forced combination of the principles of ensuring smoke-free operation, characteristic of both of these types of staircases, then regardless of the design features of the building part of buildings, it becomes necessary to install on all floor entrances of smoke-free stairwells of type H2 tambour locks, protected by inlet smoke ventilation (a graphical interpretation of such a conclusion is given in Fig. 1 and 2).

At the same time, according to the current requirements of SP 7.13130, such use of vestibule locks on all floors is not required.

For example, when arranging an internal exit from a smoke-free staircase of type H2 to the lobby of the lower floor of the above-ground part of the building (without dividing it into fire compartments), a normative separation of such an exit from the lobby by a vestibule-gateway protected by inlet smoke ventilation is required (Fig. 3).

At the same time, on the upper floors, an additional device of vestibule locks at exits to the stairwell is not required.

In the case of dividing the building part of the building into fire compartments, the arrangement of tambour locks protected by inlet smoke ventilation is necessary at floor-by-floor exits to a non-smoke-proof H2-type stairwell only on the floors of the lower fire compartments while maintaining the usual single doorways on the floors of the upper fire compartment (as it is shown in Fig. 4).

Thus, taking into account the noted features of the design of smoke-free staircases, it is necessary to unconditionally comply with the current regulatory requirements for fire safety in accordance with the established fire-technical classification - without any unreasonable, including jargon "innovations".

Classification of staircases for fire safety

Having visited the houses built according to the projects of various construction companies, you can see that the staircases in them are very similar and have only minor differences. The reason for this is the safety regulations in force, which have been put in place to minimize the risk of casualties in the event of a fire.

The standardization of these elements helps citizens quickly leave the building, and firefighters and rescue teams make it much easier to fight fires, since they know the structure in advance.

So what are the types of staircases?

Depending on the presence or absence of insulation, ordinary (L) and non-smoky structures (N) are distinguished.

Type L1

This type of staircase assumes its integration with the corridor leading to the apartments and the elevator. The lighting of the staircase passages of this design occurs naturally through small glazed windows, or through open openings on the walls facing the street.

Homeowners in such homes must exercise a responsible attitude to safety and not block the path of a possible evacuation. An important requirement is a ban on the placement of power cables in the stairwell, since their malfunction can turn the means of ensuring the safe exit of citizens outside into a trap.

There is a restriction on the use of this design: it can be used in buildings whose height does not exceed 28 meters (the indicator is determined by the floor line of the last floor). In practice, we are talking about houses consisting of no more than 10 floors.

Type L2

This design option, like the previous one, is not isolated from the corridors of the rest of the building. Its main difference from type L1 is lighting, which is carried out in a natural way through glazed or open openings in the coating (overhead lighting).

Stairwell type L2 is approved for use in buildings whose height is not more than 9 meters. This is due to the fact that the only source of light can be blocked as a result of smoke, which can disorient citizens during the evacuation.

Type H1

In buildings with a height of more than 28 meters, the use of smoke-free staircases is mandatory. This requirement is due to the fact that if using the usual design for citizens evacuating from the upper floors, there would be a high risk of carbon monoxide poisoning. Another factor is the limited capacity of fire and rescue equipment.

Type H1 is most often found in high-rise buildings. It involves separating the staircase from the corridors near the apartments and elevators with the help of an open passage, which is a loggia or balcony. In the event of a fire, the smoke exits through the passage without getting on the stairs.

Type H2

The design of the H2 staircase differs from the previous version in that the passage to it is closed.

Isolation from the source of smoke is provided by means of forced ventilation. It starts working after receiving a signal from sensors that detect the presence of smoke and allows you to create an air backwater. In order not to create a dangerous draft of air from the fire source, the exit to the stairs is separated by sealed doors.

The ventilation system itself is located inside the staircase.

The design H3 is distinguished into a separate type of staircase. However, it differs only in the location of the air boost system, which is located inside the transition.

Requirements for smoke-free staircases

Along with the safety standards that determine the design of the staircase, there are also requirements related to its individual elements. And this is necessary, since each of them can affect the overall effectiveness of a building's fire protection.

Fire doors

Regulatory requirements provide for the presence of fire barriers. One of their elements are fire doors that fill the openings. They must have the following properties:

Metal outer part;
Filler of fire-resistant substances;
Coating of metal with non-combustible coloring materials.

The marking of fire doors involves the use of the letters E, I along with a numerical value, where:

E characterizes the loss of the integrity of the door, due to the formation of holes and cracks in it, through which flame or smoke penetrates;
I denotes the loss of the heat-insulating function, in which there is a temperature effect that destroys the surface of the door that is not facing the flame.
The numeric value determines the number of minutes after which the above changes occur.

Dimension of the ladder for evacuation

The current standards determine the dimensions of many elements of the staircase:

The width of the flight of stairs;
The slope of the stairs and the size of the steps;
The height of the fence;
The width of the staircase.

The flight of stairs must have a width not less than the same parameter of the exit (door) to it.

Separate requirements are established for buildings used as kindergartens, hospitals, institutions for the elderly and disabled, as well as in the case of their use to accommodate boarding school students during sleep. The required march width in these cases is 1350 mm. This allows you to speed up the evacuation of these categories of citizens.

If more than 200 hundred people are simultaneously in the building on the floors above the first, the width of the flight of stairs should be 1200 mm. This decision will also speed up the evacuation, minimizing the risk of stampede and panic.

The slope of the stairs must have a ratio of 1/1 and a minimum tread depth of 250 mm. The riser must be no more than 220 mm high.

Stairs must be equipped with a railing (railing), the minimum height of which is 1200 mm.

The landing should have a width equal to the width of the flight of stairs. This is done in order to eliminate the effect of the "bottleneck" and the panic caused by it.

Walls

The main requirement for the inner walls of a smoke-free staircase is the absence of any openings, except for the door.

If walls are used as one of the elements of fire barriers, they, like fire doors, must have fire-resistant properties. In this case, the parameter R is added to the indicators E and I, which characterizes the time of maintaining the load-bearing properties in case of fire.

Illumination standards and light opening

The outer walls of the staircase must have windows with a glazing area of 1.2 sq. m. The distance from the stairway to the window cannot be less than 1.2 m. This is done so that natural light falls on the flights of stairs.

Type H1 cages are equipped with opening windows, while the height of the opening device cannot exceed 1.7 m.

Due to the presence of forced ventilation systems, H2 stairwells are equipped with windows that do not open.

Internal open staircase

Under the internal open staircase understand the transition between floors, located outside the stairwell. If there is no wall on at least one side, then the staircase fits this definition.

Often this design is decorative and has limited evacuation use. Current regulations require a redundant output.

Double ladder

This design is based on the use of two symmetrical flights of stairs, which are directed to a common area. This solution is becoming increasingly common due to its decorative properties.

From the point of view of safety, the structure should have a platform and a subsequent single (if any) march, ensuring the minimization of congestion during the evacuation of citizens.

Smoke-free staircases (H1, H2, H3) and fire evacuation stairs

The current level of development of scientific and technological progress does not in any way affect the existence of the fact that fire has been and remains one of the most dangerous enemies of human habitation for thousands of years.

Despite the widespread introduction of rules requiring the use of exclusively non-combustible materials for interior decoration, the statistics remain relentless: people's homes today are by no means invulnerable.

Often the only thing left in the event of a fire for the residents is to flee, that is, to evacuate. The safest way to escape from multi-storey buildings is fire evacuation stairs.

The danger to people in case of fire is not only fire. The smoke is also dangerous. But the most terrible invisible enemy is carbon monoxide.

A person may not notice its effects (unlike ordinary burning, carbon monoxide has neither smell nor color). Carbon monoxide poisoning is characterized by rapid development.

After a few minutes, the victim may lose consciousness, after which he has practically no chance of salvation.

Therefore, in every house, smoke-free stairwells are necessarily equipped as the most important condition for saving residents during a fire. What are the types of smoke-free stairs and stairwells?

Staircase is an integral element of buildings

The staircase is an integral element of multi-storey buildings. There are ordinary structures that serve to communicate floors, as well as evacuation stairs, that is, non-smokeable.

The presence of the latter is the most important condition under which the evacuation of people in case of fire is ensured. For a number of buildings, it is dictated by SNIP, therefore, architects must necessarily provide for when creating a structure project.

Evacuation ladders: purpose

Evacuation stairs must certainly be present in high-rise buildings. Such structures ensure the safety of residents during a fire or in case of other emergencies.

The arrangement of evacuation stairs in various types of buildings is subject to certain standards regarding their size, configuration and placement.

Regardless of the type of model, the general purpose of these structures is to ensure the safe exit of people from the building if necessary.

Residents of the building, employees and visitors of the institution, using evacuation stairs, can leave the premises without danger to life and health. The evacuation exit is designed to protect them from fire and smoke. It is very important to ensure free access to it for all those in the building.

Evacuation stairs can be used as an alternative exit from the premises. This is true for structures that are not equipped with a separate back door. Fire safety rules prohibit the operation of buildings above three floors that are not equipped with an evacuation staircase.

Location

Separate requirements apply to the location of evacuation stairs. Usually their placement is designed in the back of public buildings or from the end, if an open exit is planned.

With the proposed arrangement of an emergency exit inside the building, a separate room or corridor is allocated for such a staircase. This is necessary in order to ensure the safety of descending people in the event of a fire and prevent blocking the often only possible exit from the house.

Such a room must be equipped with a fire-resistant door capable of containing the flame for at least 1 hour. At the same time, it is important to ensure the sealing of the joints and the rapid removal of smoke.

Each floor must be equipped with an exit to the stairwell. Its width depends on the size of the passage and steps. Semi-closed models provide for the location within the premises of the site, the door from which leads to an external staircase. This is an excellent option for cases where it is not possible to completely isolate the passage from smoke.

For open outdoor types, a special rule applies: the distance from the edge of the stairs to the wall must be at least 100 cm. This reduces the risk of fire entering the emergency exit and prevents the structure from heating up, as well as the protective handrails.

materials

Since this design is intended for use in extreme situations, including fires, the choice of materials used for its construction is determined by certain requirements. The main condition is to ensure the strength and fire resistance of the stairs. Therefore, the most popular materials are concrete and metal.

The use of materials that flammable, crumble or release toxic substances when heated is strictly prohibited.

SNIP and GOST requirements

GOST and SNiP standards regulate the norms by which all types of stairs are installed. They also apply to evacuation models.

The standard slope of the evacuation stairs is such that the ratio of the length and height of the span is 2:1.
For 1 march, 3-18 steps are allowed. For 2 marchers, their number should not exceed 16 pieces.
The width of the tread should serve to ensure the comfort of movement, the optimal size is 24-29 cm.
The step height is usually 20-22 cm.
The width of the stairs is provided by the requirements such that 2 people can pass along it at the same time. The smallest allowable value is - 1 m. It is allowed to reduce the dimensions for external structures to 70 cm.
The area between the marches should correspond in size to the width of the stairs and the exit to it.
To ensure the safety of evacuation from the building in case of fire, it is necessary to provide an exit to the stairs, which leads to an open space or to a separate room, protected from fire and smoke.

Classification

Evacuation ladders are classified according to the type of material, location, and design features. There are three main types of modern evacuation stairs, which differ in such characteristics as purpose, width and configuration:

placed on special smoke-free staircases inside the building;
is located inside the building, and is not enclosed by walls;
located outside and is an emergency exit design.

The latter is used exclusively for evacuation, while the first two types of stairs sometimes replace the main entrance.

About admissible types of constructions

For evacuation, direct marches are also used, equipped with intermediate platforms. In some cases, when there is not enough space for their location, vertical structures like firefighters are installed parallel or with a slight slope to the wall.

Strictly prohibited

Fire safety rules prohibit the construction of stairs:

with winder steps;
with curvilinear and irregular spans;
screw;
with steps of different sizes.

What are smoke-free stairwells?

The presence of such structures in the house is designed to ensure maximum safety of life and health of people in case of fire. They are marches of certain sizes, which should be located in the areas of the structure suitable for them.

One of the main requirements for an emergency exit is its isolation from smoke. Smoke-free stairwells are distinguished by the fact that during a fire, OFP (fumes, smoke, etc.) do not get into them.

The presence of these structures ensures successful evacuation of people in multi-storey buildings in case of fire. Different requirements are placed on them depending on the specific type.

Types

Smoke-free staircases are divided into several types, which can be classified by their specific design features, location, access to them and principles of operation. Types of stairwells:

H1 is considered the base model. Characteristic features of the design is the availability of access using an open area. It is necessary to have a smoke-free approach to the emergency exit.
H2 provides for the presence of air pressure in the event of a fire.
H3 is an analogue of H2, but provides for access to the march through the vestibule-gateway. Additional air support is also provided, which is supplied both in case of fire and on a permanent basis.

Requirements

Fire safety in stairwells is ensured by the rules that provide for the safety of human life:

Emergency lighting is installed in all smoke-free stairs.
The width of the doorway should be from 1.2 m, and the height - from 1.9 m.
The width of the exits from flights of stairs should not be narrower than the width of the span.
When installing a smoke-free cage adjacent to the elevator shaft, a ventilation hole is arranged in the wall to ensure free air access (at the level of the upper floor).
It is forbidden to place personal belongings in the passages to smoke-free stairwells. The landing should be uncluttered, as rubbish can interfere with the evacuation of people and the work of firefighters.
It is forbidden to independently install partitions not provided for by the construction project, as well as cutting passages in existing fire bulkheads.
It is mandatory to equip smoke-free flights of stairs with handrails made of non-combustible and slightly heated materials.

Smoke-free stairs H1

"Building norms and rules" state: in buildings whose height is more than 30 m, smoke-free staircases of type H1 must be arranged.

This view requires the installation of ladders that can be accessed from the landing of the floor, using open air space to move. The location of H1 can be a veranda, a balcony or a fenced landing, taken out of the room.

This is due to the need to provide natural isolation from the smoky part of the building of the emergency exit. The best option for placing this type of staircase is the corner part of the building. The most advantageous position is the inner corner, equipped with additional piers.

Their design feature is the absence of a direct connection with the floors of the building.

The usual placement of H1 cells is in the corners of buildings on the windward side. They are characterized by the presence of transitions of a balcony type, as well as fences with protective screens. The transition is carried out in the form of an open gallery or loggia, the width of the passage must be from 1.2 m. The width between the passages, as well as the gap from the wall to the window, must be at least 2 m.

Smoke-free stairs H2

Staircase H2 is arranged in a building, the top floor of which is located at a height of 28-50 m. Air pressure is created in H2 cells (the principle of stove draft).

It can be permanent or open in the event of a fire alarm.

It is also possible to install an autonomous backwater using electric air pumps that provide air pressure, which must be equipped with uninterruptible power supplies.

When designing ventilation, it is necessary to correctly calculate the traction force (or backwater). The pressure should allow the fire doors to open freely to the stairs. The pressure on the lower floor should be at least 20 pascals, on the upper floor - no more than 150 pascals.

The vestibules or gateways through which the entrance to the H2 stairwells is provided are equipped with fire doors. In smoke-free cages of this category, it is advisable to install vertical partitions with an interval of 7-8 floors.

Smoke-free stairs H3

Smoke-free staircase H3 is also built using air overpressure. Their difference lies in the arrangement of special walk-through rooms with self-closing doors. Their dimensions must be at least 4 square meters. m.

In cells of this type, air is pressurized into the space occupied by the stairs and into special locks. Air draft is carried out on a permanent basis or turns on automatically in case of fire or smoke.

Basic materials

When creating evacuation smoke-free passages, concrete is most often used. It is a fire-safe, durable and easy-to-use material. As an addition to the concrete base, steel structures are used, for example, in the manufacture of fences or doors. Metal spans are also justified in light construction structures.

Wooden elements are used in a small volume: wooden handrails or door handles, which must be treated with fire-fighting compounds.

When erecting stairs in multi-level premises, builders must take into account the fact that in the event of a fire, it is the stepped structure that can become the only way to get out into the air and save people. Depending on how adapted the system is to the evacuation of people in the building, staircases are usually divided into types H1, H2, L1 and L2. The main design features of these spans, as well as the requirements for them, will be discussed in this article, illustrated with a large number of photos and videos.

Before proceeding with the design of a multi-level building, the architect must pay special attention to the development of sketches of staircases.

What is a staircase

Before the construction of the stairs begins, a special vertical opening is designed for it in the building - the stairwell.

A staircase is a combination of all elements of a stepped structure, as well as walls, ceiling, floor, window and door openings

stepped marches;
sites;
fences;
walls with door and window openings;
ceilings and floors.

Types of stepped platforms are classified depending on their fire safety and the degree of smoke in the event of a fire

The main criterion by which stairwells are divided into types is fire safety and unhindered evacuation of people in the event of a fire and smoke.

In case of fire, it is the stairs that may be the only way to evacuate people from the building

Classification of stairwells

Depending on the level of smoke in the event of a fire, staircases can be:

ordinary - this species is divided into types L1 and L2;
smoke-free - types H1, H2 and H3.

Cages of stepped constructions can be normal and non-smokeable

Ordinary staircases

Structures that may be subject to smoke in case of fire belong to ordinary landings, which in turn are divided into two main types - L1 and L2. Next, consider them in more detail in the photo.

This drawing schematically shows two types of conventional ladder systems - L1 and L2