Smoke removal system: design and installation of smoke ventilation

Crowded places must be equipped with fire alarms.But since carbon monoxide is invisible and spreads at high speed, in addition to the alarm system, a smoke removal system (SDS) is required - a set of air ducts and equipment for forced removal of smoke from the room.

Let's figure out what elements are included in the SDS, what are the features of designing a system for private houses and public premises. In addition, we will outline the standards for calculation, installation and maintenance rules for the smoke removal complex.

Types of smoke removal systems

A system for removing smoke from a room is installed if there is a high risk of fire when a confined space is filled with toxic volatile emissions.

Its installation is rational if it is impossible to remove combustion products by simple ventilation or even if the window is open, the movement of the contaminated air mass towards the windows will be too slow.

Based on the method of removing smoke-laden air from premises, systems can be divided into two types:

1. Static.
2. Dynamic.

Their functionality is based on fundamentally different processes.

Static SDS at the moment a fire is detected, it turns off ventilation and oxygen supply from outside and blocks smoke in one room, preventing its spread.

If there is a possibility that the room will fill with toxic gases during a fire, you should not skimp on installing a smoke removal system (+)

At the same time, the temperature in the room heats up to critical levels of 1000°C. If people from the building are being evacuated through this room, it is dangerous and can lead to poisoning, burns and difficulty in evacuation.

Dynamic SDS work differently.Air circulation is increased due to the operation of powerful fans and carbon monoxide is removed, which prevents the accumulation of smoke.

The smoke level decreases, but the concentration of carbon monoxide still occurs. The air temperature also continues to rise. The main purpose of a dynamic control system is to gain time for evacuation. She excels at this goal.

If we talk about the price criterion, then static SDUs are cheaper than dynamic ones. This is one of those cases when it is better not to skimp on security. When using dynamic systems, there is a higher chance of avoiding poisoning from volatile toxins. It is worth noting that fire safety regulations allow the installation of both types of systems.

Even the simplest ventilation significantly increases the chances of survival in a fire. It is precisely because of the lack of SDS in old high-rise buildings that there is a need for their modernization. The same applies to old buildings adapted for storage and production needs.

Basic and additional components of SDS

The main elements of a dynamic system are powerful fans that pump air. They remove not only carbon monoxide from the premises, but also fine suspended matter such as ash, soot, and soot.

This equipment is able to work with air whose temperature does not exceed 600°C. This safety margin is sufficient to ensure the safe removal of people from the building.

Fans pump air masses through smoke shafts. This is an extensive network of channels, which is installed according to the project. Different sections of the SDS have different throughput - it depends on the complexity of the system.

Pipes intended for air removal in small rooms have a smaller perimeter and are not connected to the general flow of the smoke shaft

These elements are made of non-combustible materials. The most popular smoke shafts are made of cold-rolled black steel.

Another component of the SDS is fire-retarding valves. Their task is to keep flames out of the ventilation and prevent it from spreading throughout the building. Models with electric or electromagnetic drive are mainly used.

Fresh air comes through air ducts. They are pipes to which fans are connected to pressurize air masses. The channels are connected to places where people are evacuated, including elevator shafts.

The main component of any SDS is the control unit. The panel is connected to a fire alarm, or less often - directly to sensors.

As soon as a fire signal is given, the control unit turns on the control system, which begins to remove smoke from the building. At the same time, the automation opens all hatches and regulates the operation of fans

Another element of the system is automation, which opens windows and doors in the event of a fire. These elements are not included in the mandatory composition of the systems. They are used in places where there is a large glass area, and this makes it impossible to install smoke shafts.

Use of SDS in private homes

According to the standards, the installation of SDS is not required in residential buildings. It is believed that open windows are enough to get rid of combustion products. The only exceptions are buildings that belong to private individuals and are used for commercial purposes. For example: hotel, boarding house, private clinic or school.

Since the number of residents in a country house is usually small, the operation of a standard system for removing smoke from the premises during a fire allows people to leave the house in almost safe conditions.

To notify of a fire, it is enough to install a fire alarm. This is quite enough for a private home.

If you want to protect your stay in a private home, you can use another type of ventilation device that removes smoke. This is a complex of electronics that controls the opening of doors and windows when receiving signals from sensors (+)

You need to pay attention to the sensitivity of the installed sensors. If they have a low response threshold, then the efficiency of the entire system will sharply decrease.

Fire safety standards for installation

For crowded places, the requirements are different. In multi-storey buildings, people's lives depend on this system. When masses leave their apartments, residents will be forced to move slowly, since the capacity of the elevators is limited, and going down the stairs takes time.

It is mandatory to install SDS in the following premises:

• residential multi-storey buildings;
• shopping, business, sports and cultural centers;
• production premises;
• infrastructure facilities and schools.

These requirements also apply to gambling and entertainment business facilities. In addition, there are other objects to which these requirements apply.

Design of SDU in a building

Before calculating and designing the SDS, you need to study the factors that need to be taken into account:

1. Building characteristics — number of floors, area and a clear evacuation plan in case of fire.
2. Glazing features - number, location and area of ​​windows.
3. Characteristics of smoke permeability of materials from which the building, thermal insulation and facade are made.

The development of a building SDS project can only be carried out by companies that have received a license from the Ministry of Emergency Situations of the Russian Federation. The drawn up project must also be agreed upon with the Ministry of Emergency Situations before installation.

Main locations of the SDU

In buildings with a height of more than 28 m for various purposes, from administrative to household, a system for removing smoke and combustion products is required. The height of the building is determined without taking into account the basement and attic technical rooms.

The SDU must pass through corridors more than 15 m long, where there are no natural sources of fresh air, there are no window openings, balconies and loggias.

In ground floor rooms and corridors, if they are used not only for servicing the building's communications, but also as underground parking lots, warehouses and industrial premises. Evacuation routes from the basement also require SDS

In addition to common corridors, there must be a way to remove combustion products from each workshop, production or administrative premises in which people stay for a long time.

If rooms or corridors have a system for automatically opening windows when a fire alarm is triggered, then it is not necessary to install control systems in them.

Where can you avoid installing a smoke removal system?

In rooms that are equipped with autonomous fire extinguishing systems of powder, foam or water type. This refers to systems that detect the source of a fire and extinguish it automatically. It is worth noting that parking lots are an exception.

If a control system is installed in each room, then the common corridor may not be equipped with a combustion product removal system. This rule only applies if each room has an area of ​​less than 50 square meters. m.Otherwise, installation of smoke ventilation in the corridor will be mandatory.

How to calculate the required volume of ventilation

There are clear design recommendations given by the Russian Ministry of Emergency Situations. The document provides formulas for calculating the required ventilation parameters. Also in the text of the recommendations are tables on the properties of the materials used in the construction of the building.

Here are examples of formulas and tabular data for design and calculations.

When determining the air permeability of a building facade, one formula is used. However, it is worth making adjustments for wind direction and ambient temperature fluctuations (+)

An important characteristic of the system is its resistance to hot smoke temperatures. In addition, throughput and pressure resistance are taken into account (+)

The power of the SDU must be sufficient to service the premises. Index air circulation speed should not exceed 1 m/s. This limitation is dictated by safety considerations - the flow of air increases the source of fire.

The parameter can be adjusted by decreasing or increasing the valve cross-section. Valves are installed based on one per 600-800 sq. m.

For each point requiring the installation of an SDS, there must be at least one supply opening through which fresh air enters. The parameters of the openings for air flow are determined by the area of ​​the premises

Air movement is carried out by external fans. Since these systems use forced air circulation, during design it is allowed to make more than two turns of the air duct pipes.

SDU installation technology

In addition to the threat of poisoning, smoke causes loss of orientation and panic during evacuation. There are specially designated places where the smoke removal system should be installed.

First of all, these include:

• staircases and landings;
• foyer;
• corridors, passages and galleries;
• entrances.

In addition to its evacuation purpose, the SDS allows firefighters to quickly enter the building. This allows them to find the source of the fire, localize it and eliminate it. This is primarily beneficial for the building owner, as it allows minimizing possible damage from fire.

Installation work begins with laying chimney pipes and ventilation. This stage consists of attaching individual modules. First, special clamps are installed in the ceiling, to which each module is attached.

The modules are connected in series. When they are connected, sealing is performed. These pipes must be installed in strict accordance with the design

Branches are installed as necessary. As a rule, these are elements that have one or two channels. Such a branch must be installed in each zone where, according to regulations, air mass circulation must take place.

The channel openings are closed with a special grille. Chimneys transport combustion products to larger smoke shafts.

Each smoke shaft leads to an exhaust fan, which is installed directly on the roof of the building. Fans are mounted directly at the exit of smoke shafts. They are installed in strict compliance with the manufacturer's recommendations.

Above the fan there is a small section of shaft that leads to a hatch on the roof. Hatches must be installed in accordance with the manufacturer's recommendations.

There are models of fans that are located vertically on the roof of a building. These models do not require protective hatches. They use less automation, but they do not look aesthetically pleasing

Air supply pipes are installed parallel to the chimneys.They can be installed next to chimneys. It is necessary to pay attention to the fact that the air vents should not be located next to each other. If this rule is not followed, the efficiency of the system will sharply decrease.

Wiring runs over the chimney. It must be three phase power cable with a voltage of 380 V and non-flammable braiding. The electronics necessary for automatically opening the hatches and valves of the system are connected to it.

The cable should not come into contact with or be in close proximity to heating parts of the chimney. Most often, the cable is attached above a parallel air supply branch.

This protects against short circuits that occur when the wire melts. Incorrect wiring installation leads to failure of the entire smoke removal system.

The final stage of installation work is connecting an alarm or sensor system. In buildings with large areas, zoning is done. Separate control units are responsible for each section. There are systems where ventilation and smoke removal must be started manually.

Ventilation system maintenance

After ventilation system installation and smoke exhaust shafts are checked for serviceability. This is done before and during the submission of work to regulatory authorities. Verification consists of sequential testing of each element of the system for operability.

After the building is put into operation, supervisory authorities will check its working condition during scheduled inspections. If the system fails, the owner will be given an order to correct the problem. It is recommended to carry out preventive work, which will be carried out by the organization that installs the equipment.

If a faulty control system leads to mass deaths during evacuation, the owner of the building will be held criminally liable for violating fire safety standards.

Conclusions and useful video on the topic

Installation standards and rules for checking ventilation:

It is important to monitor the performance of the VSD, since if used incorrectly, debris and foreign objects can get into the ventilation pipes. This may be a consequence of poor-quality installation, when some of the construction debris remains in the ventilation.

If debris accumulates, the air supply may be partially or completely blocked. Preventive inspections must be carried out regularly - this will protect against loss of life if a fire occurs.

Do you have anything to add or have questions about smoke removal systems? Please leave comments on the publication - the feedback form is in the lower block.