Types of smoke-free stairs. Smoke-free stairwells: H1 and H2 design features

When constructing stairs in multi-level rooms, builders must take into account the fact that in the event of a fire, it is the stepped structure that may become the only way to access the air and save people. Depending on how adapted the system is to the evacuation of persons in the building, staircases It is customary to subdivide 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 starting to design a multi-level building, the architect must give Special attention development of staircase sketches

What is a staircase

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

A staircase is a collection of all elements of a stepped structure, as well as walls, ceiling, floor, windows and doorways

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

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

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

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

Classification of staircases

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

• ordinary – this type divided into types L1 and L2;
• smoke-free – types H1, H2 and H3.

Cages of stepped structures can be ordinary and smoke-free

Regular staircases

Structures that may be susceptible to smoke in the event of a fire belong to ordinary staircase landings, which in turn are divided into two main types - L1 and L2. Next, let's look at them in more detail in the photo.

This drawing schematically demonstrates two types of conventional staircase systems - L1 and L2

Type L1

The stepped platform L1 is characterized by the presence on each floor of glazed windows located in load-bearing wall buildings through which natural light enters the room. In some cases, these wall openings may not be glazed.

At each level of the staircase belonging to type L1, there must be glazed window openings

Type L2

The landing of type L2 has natural lighting, which enters the flight through glazed open spaces made in the covering. The photo below clearly demonstrates this type of conventional staircase.

Type L2 is characterized by the presence of natural light entering the cell through glazed or open wall openings

Smoke-free stairwells

The main requirements for this type systems are:

• the presence of special airlocks for air flows from a smoke-free area to enter the stepped cage;
• the presence of evacuation passages allowing people to leave the dangerous premises at the time of fire.

Smoke-free structures also have their own division - these are types H1, H2 and H3. Let's look at them in more detail.

In many multi-storey buildings, smoke-free staircases are used, which are safer for use in extreme conditions

Type H1

This type of staircase has an entrance from the floors of the building through the street part of the building along an open passage free of smoke. This type of design is often used in administrative, public and educational institutions, whose height exceeds 30 meters. It is considered the most suitable for evacuating people from a building engulfed in smoke.

Distinctive feature stepped cage type H1 is the presence of an exit from the stairs directly to the street

Type H2

Site H2 is distinguished by the presence of a special ventilation head, through which in the event of a fire the supply will be carried out. clean air onto the stairs, which will allow people to get oxygen. Applicable this option in rooms whose height is 28 meters. A photo of the structure is presented below.

Type H2 is equipped with a special support for supplying clean air flow in case of fire

Type H3

A smoke-free stepped cage of type H3 is equipped with an entrance from the floor through a vestibule, as well as an oxygen supply with the ability to repeatedly supply air to people in the event of a fire in the room.

If we are talking about low buildings, then they are more often used here ordinary stairs types L1 and L2, in high-rise buildings it is necessary to build systems belonging to types H1, H2 and H3

We reviewed the main types of staircases, according to SNiP standards. However, the above classification does not apply to household step structures installed in country houses for the transition between two or three levels.

This photo shows a staircase system illuminated in a natural way through windows in the wall located throughout the entire structure

Requirements for stairs and stairwells

Since staircase systems serve evacuation purposes in the event of a fire, they must be built taking into account the standards prescribed by SNiP 21-01-97.

All standards and regulations of SNiP 21-01-97 for stair cages must be taken into account at the very beginning of construction

According to this normative act, the following requirements apply to staircases located inside multi-level buildings:

• 1 m 35 cm – for buildings of class F 1.1;
• 1 m 20 cm - for houses with more than 200 people on each floor;
• 0.7 meters - for stairs designed for a single workplace;
• about 90 cm - in all other cases.

This photo schematically demonstrates three types of smoke-free staircases, according to the requirements for them

2. The permitted slope of the structure for carrying out evacuation measures is 1:1.

3. Tread depth – at least 25 cm.

4. Step height – no more than 22 cm.

5. Slope for open systems - 2:1.

According to the standards, the slope for open staircases is permissible in a ratio of 2:1

6. Designs open view must be made from non-combustible materials and install near blank walls, class no less than K1 with the highest fire resistance limit. The landings of such stairs must have a fence with a height of at least 1 m 20 cm.

7. The width of the platform must correspond to the width of the march.

The width of the flight must be sufficient to evacuate people from the building in case of fire or smoke, this is especially true for children's and school institutions

8. When opening the doors to the cage, they should not block the march and the platform.

9. It is not allowed to clutter the staircases with cabinets and other equipment.

SNiP standards allow the staircase to be equipped with special luminous railings

10. The use of luminous railings is allowed.

11. Landings of type H1 must have an exit to the outside.

12. Cells of types L1, H1 and H2 should be illuminated with natural light through specialized holes in façade walls on every floor.

13. Type H2 sites are equipped with blind (non-opening) windows.

When constructing a staircase, it is necessary to take into account all fire safety standards applicable to it

Video on the topic

In the video below you will find supporting information on the topic discussed.

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

Purpose of the design

The first place to start is the question of the functional purpose of smoke-free stairs. This design is a march of certain dimensions, which must be located in a suitable area of ​​the building.

Smoke-free staircases are designed to serve as an emergency exit for people in the building. The main emphasis is on emergency associated with a fire. The consequence of a fire of any size is smoke in the interior of the house. Many people who died in the fire were exposed to negative influence namely smoke and toxic fumes, and not flame. That is why one of the main requirements for an emergency exit is insulation from smoke.

In addition, this type of ladder must allow rescuers to reach interior spaces to extinguish the fire and rescue the injured people. In particular, the possibility of carrying people on stretchers is provided.

The presence of smoke-free staircases is prerequisite for high-rise buildings. Depending on the specific type They have different requirements.

A smoke-free stairwell serves as a fire escape for people

Main types

There are several types of smoke-free staircases. They are classified according to their location, access to them and principle of operation. Let's consider the standard types of smoke-free stairs:

• H1. This basic model. For such a design characteristic features is 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. Very similar to type H2, but in this case access to the march is provided through the airlock. Additionally, the same air supply is provided, but it can be supplied both during a 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 types H1, H2 and H3 in more detail and identify the most characteristic features for them.

Stairs H1

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

After passing through the open section, you will find yourself in that part of the building where the location of marches of this type is provided. Such requirements are determined by the need to ensure natural isolation of the emergency exit from the smoke-filled part of the building. That's why the best option for their placement is the corner part of the building. A particularly advantageous position is the inner corner with additional walls. It is advisable to provide for the presence of a fenced emergency exit during the design process of the building itself, so that in the future it does not have to be converted to meet fire safety requirements.

Staircase type H1 is required 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 over 50 meters high. Mainly in modern buildings It is the H2 type models that are used, so you should start with them.

For smoke-free stairwells type H2 characteristic features is the presence of air support. The exit to it remains within the internal part of the building, but the presence of ventilation duct. It is thanks to this design that the requirements regarding air pressure into the staircase are met.

H3 type stairs are more complex in design. They provide for the presence of an additional airlock located on the way to the emergency exit. It is thanks to this extension that it is ensured best protection from fire and smoke. In the vestibule, it is planned to use non-combustible materials to remove walls and partitions; a fire door is also installed, preferably with an automatic shutter.

The design of the staircase itself remains the same as for the H2 model. The ventilation duct provides air supply and appropriate passage pressure. As a result, the entry and accumulation of smoke and other combustion products into the emergency exit area is prevented.

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

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

Exit to the stairs

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

The basic requirements for exits to this type of emergency staircase are as follows:

• Lighting. To ensure sufficient visibility, the stairs must be equipped with light sources. According to the rules, windows must be provided in the stairwell of an evacuation type. Auxiliary and emergency light sources are also required.
• Ventilation. To ensure air supply, it is necessary to build a ventilation shaft connected to the flights. A hole is left on the top tier to ensure constant air circulation. In some cases, it is necessary to force this process using ventilation equipment.
• Partitions. To prevent fire from penetrating into the emergency exit area, it is necessary to ensure the presence of 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 prohibited to block the passage and place objects in its area, both for permanent and temporary storage. It is strictly forbidden to close the doors leading to the exit or install additional barriers on the way to it. The passage must remain open 24 hours a day.
• Access to information. People in the building must be aware of the presence and specific location of an emergency exit. For this, a prerequisite is the presence of special signs and an evacuation plan itself.

Requirements for exiting the emergency staircase

Requirements regarding dimensions

In addition to the requirements described above, other conditions are imposed on smoke-free stairs; they relate to the size of the cage and the flights 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 ceiling height in the march area must be at least 190 cm.
• Width. The passage dimensions should be 120 cm in width 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 stretchers.
• Number of steps. Within one march, a maximum of 16-18 ordinary steps are allowed.
• Dimensions of steps. They take as a basis optimal ratios, which are installed for all types of stairs. The step should be wide enough to comfortably fit on the surface of the foot. Its height is approximately one and a half times smaller. All march elements must be identical in parameters. The slope varies on average from 30 to 40 degrees.
• Number of people. In most cases, standard evacuation marches are limited to the number of people on the cage at the same time. Often this number is 15 people, but exact value depends on the dimensions of the building and its purpose, as well as the type of staircase structure.
• Handrails. To minimize the risk of injury and facilitate movement, guardrails and handrails made of non-combustible materials are required. It is important to take into account that they must have minimal thermal conductivity to prevent them from heating up in a fire.

Acceptable materials

Smoke-free stairs are often made from materials that can resist heat as much as possible and, naturally, will not ignite upon contact with high temperatures and fire. That's why the favorites are:

• Metal. It is usually used when it is not possible to build a massive structure. Metal elements The internal structure of the concrete marches is being strengthened, and fences are being installed.
• Concrete. The leader in use, as it is completely fireproof. In addition, concrete marches are quite comfortable and durable, and comply with dimensional standards and other SNiP requirements. Concrete is used for the construction of internal evacuation structures.

Evacuation stairs are most often made of metal or concrete

Alternative designs

In addition to smoke-free stairs, other types of special-purpose structures can also be used. The main alternative to a smoke-free staircase of type N is an evacuation model of category L. Such structures are often installed in buildings with fewer floors. They generally 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 carrying out rescue operations and extinguishing fire, 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 comply with the requirements of SNiP, they are allowed for use only as emergency passages. In this case, it is necessary to ensure the availability of serviceable emergency exits. Without them, the building is not allowed to be put into operation according to the rules.

Fire has always been considered the most terrible element. Much water has passed under the bridge since Prometheus taught people how to use its benefits. But until today there is an acute question about fire safety. Fire is especially dangerous in multi-story buildings that simultaneously accommodate big number of people.

Types of smoke-free staircases

Most people who become victims of fire die from smoke inhalation and carbon monoxide, which is why smoke-free evacuation routes are so important in this regard when a possible fire is suspected. The main evacuation routes from multi-storey buildings were and remain flights of stairs. Construction codes and regulations (SNiP) provide for the construction of smoke-free stairwells of three types: H1, H2 and H3.

Building codes and regulations divide smoke-free stairs into the following categories:

• H1 – stairs, the entrance to which is through an open space outside the building;
• H2 – staircases with additional air supply;
• H3 - staircases, the entrance to which is through specially created zones with air pressure.

General requirements for smoke-free stairs

According to fire safety rules, all smoke-free staircases must be equipped with emergency lighting. The width of the doorway must be at least 1.2 meters, and its height must exceed 1.9 meters. Exits from flights of stairs should not be arranged as wide as the flight. If a smoke-free cage is installed through a wall with an elevator shaft, then a vent at the level of the upper floor for free access of air.
Personal belongings must not be placed in passages to smoke-free staircases or on landings. It is forbidden to independently install those not provided for. construction project partitions. Also, passages must not be cut into existing fire bulkheads.

Smoke-free flights of stairs must be equipped with handrails made of non-flammable and low-heating materials.

Construction of smoke-free stairs of the first type (H1)

In buildings higher than thirty meters according to " Building codes and rules”, staircases must be constructed according to smoke-free class H1. This type requires the construction of stairs that can be accessed from the floor landings through a space with open air. Design feature of such structures is that they are not directly connected to the floors of the building.
Typically, H1 cells are located in the corners of buildings and structures on the windward side and have balcony-type transitions, fenced protective screens.
The transition can be made in the form of a loggia or open galleries; the passage width must be at least 1.2 meters. The width of the partition between the aisles, as well as the distance to the nearest window, cannot be less than two meters.
The width of the passage must ensure the transportation of fire victims on stretchers!

Construction of smoke-free stairs of the second type (H2)

Stairs arranged according to type H2 are recommended in buildings whose upper floor is located at a height of twenty-eight to fifty meters. The air supply in the H2 cells is arranged according to the principle of stove draft and can be constant or open during a fire alarm. It is also possible to install autonomous backup from electric air pumps.

The principle of operation of a smoke-free staircase (PD - pull-up) ventilation system)

Electric pumps that provide air pressure must be equipped with an uninterruptible power supply.
The draft force (or support) must be carefully calculated when designing ventilation. The pressure must be such that the fire doors to the stairs can be opened by anyone. On the lower floor, the pressure on the doors should be at least twenty pascals, on the upper floor - no more than one hundred and fifty pascals.

The entrance to the H2 staircases is arranged through vestibules or airlocks equipped with fire doors of the appropriate category.

It is advisable to arrange in smoke-free cages of the second category vertical partitions every seven or eight floors. The air supply is installed in the upper zones of the resulting compartments.

Construction of smoke-free stairs of the third type (H3)

The third type of smoke-free stairwells also uses air pressure. The difference from cells constructed according to the H2 type is the construction of special rooms for the passage of people with self-closing doors with closers. The dimensions of the premises must be at least four square meters. Air supply in cages of this class is carried out both in the space occupied by the stairs and in the airlocks arranged in this way. Air draft can be carried out on a constant basis or turned on automatically during a fire or smoke.

Materials for manufacturing

The main material used in the construction of smoke-free evacuation passages is concrete. Concrete is fire-safe, durable and easy to use. Application steel structures, such as fences or doors, is in addition to concrete base. Also, the use of metal spans can be justified in lightweight building structures.
Application wooden elements perhaps in a small volume, for example wooden handles doors or handrails, subject to their processing fire-fighting compounds.
Other types building materials When constructing smoke-free staircases, they are practically not used.

Other types of evacuation structures

As an alternative to smoke-free stairs, other structures can be used. For example, staircases of categories L1 and L2 with natural light through window openings.
Various outdoor installations are also being carried out on residential and public buildings. In the event of a fire, evacuation is carried out along such stairs and fire-fighting equipment is delivered.

This article described in detail the design of smoke-free staircases. Why are they needed, what types are there? In addition, considered general principles fire safety in relation to staircases. Our site is dedicated to stairs and everything connected with them, so ask questions, make suggestions interesting topics for articles – our authors will fulfill any wishes of site visitors.

IN multi-storey buildings is the key to preserving many human lives and ensuring the safety of property and 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 staircases that do not become smoke-filled in the event of a fire.

Smoke-free stairwells include special structures that ensure quick and safe evacuation from the site.

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

Functional purpose

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

The main requirement for this type of structure is the absence of smoke in the event of a fire.

The air zone of the smoke-free staircase must be clear of smoke masses throughout the entire evacuation.

This will eliminate the loss of life and injuries that often occur from suffocation from smoke gases intensely released during a fire.

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

IN regulatory documents strictly stipulated when the installation of smoke-free staircases is required.

Objects where these structures must be present include various multi-storey buildings (residential, industrial, general use).

Types of smoke-free stairs

According to 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 fire, into the following types:

1. internal stairs, which are part staircase structures building;
2. open internal stairs;
3. external open stairs.

Simple escape stairs are classified into two categories.

• L1 are structures that are distinguished by the presence of completely 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. It is prohibited to lay electrical cables, gas and water main pipes, as well as storing any things.
• L2 - structures with natural lighting, which is provided through open or glazed openings in the building's coverings. This type of construction is used in houses whose maximum height is no more than 9 m, in rare cases - 12 m. Such stairs are used in buildings that belong to the I, II and III degrees of fire resistance.

Types of smoke-free staircase openings

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

1. H1 are types of staircase structures that are distinguished by the presence of free access through open areas. Approaches to this kind of evacuation structures must be smoke-free.
2. H2 - this type of smoke-free stairwells differs in the presence of air supports.
3. H3 - these openings are in many ways similar to the previous ones, but have the difference that exits to the flights must be made through special vestibules in the form of gateways. There is also an air supply, which can be carried out either during a fire or constantly.

Staircases H1

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

To get to the smoke-free staircases of type H1, you should go through the corridor to an open outdoor area, made in the form of a balcony or a separate fenced area.

Such access requirements are established to ensure reliable natural isolation of the escape route from smoke-filled areas. The best place for the location of this type of structure is the corner part of strongium.

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

Otherwise, the structure will have to be re-equipped to meet all the established requirements.

Staircases H2 and H3

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

Smoke-free staircases of type H2 are characterized by the presence of air support provided by a ventilation duct. Exits to such staircases are provided through inner part buildings.

H2 and H3 types of smoke-free staircases are structures with air support, but in the second case the mandatory presence of a vestibule in the form of an airlock is provided, which must be located on sections of the path leading to emergency exits. The use of extensions 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 must be provided, which must have an automatic shutter.

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 the supply of air flows and create the required backpressure of the passage. This will prevent smoke and combustion products from reaching evacuation sites.

Technical requirements for stairs

In addition to the requirements listed above for smoke-free cages, other conditions are 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 must be at least 1.1 m.

The passage must be such that two people can easily pass through it or the injured person can be transported using a stretcher. Up to 18 row steps are allowed in one flight.

Step height

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

The width of the step must be sufficient so that the human foot can rest comfortably and steadily on its surface.

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

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

Escape route passage height

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

Other nuances

For the manufacture of smoke-free stairs, building materials must be used that can resist heating and ignition in direct contact with open flame and warmed up structural elements building.

Concrete is mainly used to build staircases, which differs high level fire safety. Besides, concrete marches differ high strength and ease of use.

To strengthen the structure of the marches, as well as to create fences, structural elements made of metal 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 staircases, other special structures can be used at facilities, which may differ in structural design, but functional purpose have the same.

It is important that smoke-free stairs and other similar structures fully comply with the SNiP standards that determine fire safety object.

If they contradict regulatory documentation, then their use will only be possible as backup moves.

The staircase is integral element buildings with several floors. In private homes, many craftsmen equip staircases with their own hands, since the price for the services of professional companies is overpriced. However, along with conventional designs, serving to communicate floors, there are also evacuation ones, which are called smoke-free.

The presence of smoke-free staircases is dictated by SNIP for a number of buildings, so many architects, when designing a particular structure, are required to provide for them. In this article we will look at the features and types of smoke-free staircases that exist today.

Modern stairs, based on the characteristics of their location in the structure, are divided into 3 types:

• 1st, in which the staircase is located in a stairwell located inside the building.
• 2nd, the staircase is open, but located inside the building.
• 3rd – open structure located outside the building.

We are talking about structures intended for evacuation purposes..

In turn, they come in two types:

1. Regular:

• • L 1 - when the structure has open or glazed openings in the external walls. They should be located on each floor.

• • L 2 has open or glazed openings in the covering.

1. Smoke-free.

Types of smoke-free staircase openings

First, let's look at what a smoke-free staircase is. Its difference lies in the fact that in the event of a fire, non-permeable substances (smoke, fumes, etc.) do not penetrate into it.

Types of smoke-free staircases:

• Smoke-free staircase type H1. This design allows direct access to the building only through the balcony, which in this case is a smoke-free zone. In other words, it will be impossible to enter the building through it. Thus, having entered on any floor, a person will have to go through the balcony, which is an air zone, and only then will he enter the corridor, hall, etc.

• Smoke-free staircase H2. We are talking about a room with fire walls, where a continuous supply of fresh air is provided through ventilation ducts into the H2 type structure.

• The H3 type design assumes that a staircase is located in a stairwell, which can only be accessed through a vestibule-gateway with fire walls. Air is pressurized into this room, which occurs through ventilation ducts. Doors in such systems, as a rule, are made fireproof, equipped with an automatic shutter.

Evacuation from smoke-free cages

The doors leading from such staircases are evacuation doors, and therefore they must comply with all the requirements of SNIP for smoke-free staircases, in particular, SNIP 01/21/97*, which state: the emergency passage must be more than 1.2 meters wide, its height must be more than 1.9 meters. Such parameters refer to premises A 1.1, that is, when we are talking about the evacuation of more than 15 people at the same time.

Advice!
It is necessary to provide an opening width that would be sufficient for convenient transportation of a stretcher with an adult.

If the exits leading from smokeless cells do not meet the requirements of SNIP, then such structures should be considered as spare ones that can be used in the event of evacuation.

Advice!
Those exits that do not comply with SNIP and are considered spare are not considered as evacuation exits during the initial design, that is, in addition to them, the architect must provide full-fledged exits that comply with the standards.

Such outputs include:

1. Exits to the balcony, which is open on all sides or on one side.
2. To the passage that leads to the adjacent section of the building, which has a class F 1.3.
3. On the veranda/balcony, which are equipped with outdoor.

In turn, exits that lead to:

• From the premises located on the ground floor of the building to the street. In this case, the exit should be:
  • Through the foyer or lobby.
  • Through the corridor.
  • Through the lobby.
  • Through the corridor and lobby.
• From premises located on any floor, with the exception of the first:
  • To the stairs that lead to the street.
  • Into a corridor that ends with a type 3 staircase or a smoke-free cage.
  • In the foyer or hall, which has access to a staircase or staircase belonging to the 3rd level.
• To the adjacent room, which is located on the same floor and has exits to the street.

The following output options are allowed:

1. Evacuation basement and basement exits should be provided to the lobby.
2. From the foyer, dressing rooms, sanitary and smoking units, which are located on the ground or basement floors, exit should be provided to separate stairs belonging to the second type, or the lobby of the first floor.
3. Evacuation exits from premises for various purposes, should be provided for type 2 stairs.
4. The exit to the outside from the basement or basement floor can be equipped with a vestibule, including a double one.

Requirements for the width of marches

The width of the flight of stairs, which is intended for the evacuation of people from the building, must be at least:

1. 1.35 m, if we are talking about buildings of class F 1.1.
2. 1.2 m if there are more than 200 people in the building.
3. 0.7 meters for stairs that lead to single workstations.
4. For all other cases the width flight of stairs should reach 0.9 meters.

The width of the tread must be at least 25 cm with a step height of less than 22 cm. Otherwise, during a panic, the risk of injury to evacuees increases. In no case should the steps be too large or too small.

Some nuances

The instructions for arranging smoke-free stairs are based on the features of each of these structures.

Let's look at them in more detail:

1. H1. If we are talking about buildings exceeding 30 meters in height, then in this case all staircases of category H1, according to the regulations, must be smokeless. Each unit must be provided with natural lighting from the windows, in addition to which the span should be equipped with emergency source staircase lighting.

Type H1 is excellent for high-rise residential and public buildings. Such a flight of stairs can be accessed from the lobby or corridor through the open external air zone of the loggia, through an external passage, balcony or gallery. The width of the air zone is at least 1.2 meters, and the width of the approach to this zone should be less than 1.1 meters.

Advice!
Such structures are best located in internal corners buildings.
Remember that the distance from the stairwell exits to the adjacent window must be more than 2 meters, which will ensure effective smoke-free airspace.

1. Based on the requirements of SNIP 31.1, sites of types N2 and N3 are allowed to be designed in major cities for buildings with a height of 28 to 50 meters.

Advice!
These types of cells are also applicable for lower buildings that are residential or public.

Access to cell H" can be carried out through a corridor or vestibule; it is also possible to pass through the elevator hall, but only if the elevator is equipped fire doors class E130.

Smoke-free cages of type H2 are distinguished by a device for supporting the air flow, which is supplied to the staircase area in the event of a fire. It is advisable to delimit such cells vertically, creating compartments every 8 floors to reduce air volumes, as a result of which air pressure is created.

• Obstruction of the passage with personal belongings of residents (boxes, sports equipment, strollers, etc.).
• De-energize a fire shield equipped with a smoke protection system in a new home after acceptance by the fire department.
• Hang cables and wires other than those required by fire safety regulations.
• Cutting doors in blind partitions (fireproof).
• Force them with furniture, lock them with a key, or block emergency exits and balcony hatches.

Requirements for fire barriers

SNIP 21-01-97* specifies the following requirements for fire barriers:

1. Such barriers are intended to prevent the spread of fire and combustion products from the room with the source of fire to other rooms of the building.
2. Fire barriers include walls, ceilings and partitions.
3. Such barriers must be characterized by fire resistance and fire safety.

Fire resistance in this case is determined by the fire safety of the following structural elements:

• Structures that are responsible for the stability of the barrier.
• Structures that support a fire barrier.
• Mounting points.
• The enclosing part.

• The ceilings and partitions of airlock vestibules should also be made fireproof.

Conclusion

Evacuation stairs are an integral part of any multi-storey building. In case of fire they must provide safe exit people in the building to the street, so their proper arrangement is very important. You can get everything useful information on this topic in the video in this article.