Ventilation and smoke exhaust systems. Smoke exhaust system and installation. Providing a comfortable microclimate for the work of fire departments.
Smoke exhaust systems interact with automatic fire extinguishing systems, a fire alarm system and form a single protective building complex. Static smoke protection systems in case of fire turn off the fans in the building, dynamic smoke removal systems that provide localization and non-proliferation of smoke and fire are more effective.
According to engineer Ernesto Lopez, the bells need to be cleaned, which are washed by the same kitchen staff. Each type of restaurant has a diverse cleaning system when preparing different types of food. For example, in establishments that use a lot of fat, frequent cleaning is required.
Channels also need to be cleaned for at least four to six months, but if necessary, they need to be cleaned every month or two months if there are no filters. If they have them, there is no need to perform this type of service, although the filters must be changed at a specific time.
In case of fire and smoke increase, the fans in the building continue their work and create various sections in the building with air pressure.
Ventilation systems can both remove smoke from the room and supply fresh air and provide air intake. But using the same ducts is somewhat difficult, so it’s better to smoke removal systems installation separate fire protection system. You can also make a separate ventilation system for smoke removal and backwater on the escape routes.
Components of the Bell system: where does the extraction of contaminated vapors begin. Fans: machines that make air move, creating pressure. Driving: where air circulates from one room to another. Extractors: evacuation of polluted air, creates pressure inside the pipeline. Filters: to stop fats. Elements of diffusion: mesh or mouth of the air inlet and outlet. Accessories: gates, controls and regulators.
Based on information from Sanchez engineer, two types of ventilation are recommended: localized and environmental. In the case of the restaurant’s kitchen, it is better to resort to localized extraction in order to avoid the expansion of gases and odors throughout the room. For rooms or dining rooms, environmental ventilation can be applied, ”says Sanchez, an engineer.
But the use of the same ventilation systems for the influx of fresh air and the creation of increased pressure in the areas above and below the fire and low pressure in the areas where the fire occurred.
Each floor should have its own smoke exhaust systems. If smoke removal is provided through the elevator shaft, fire-retardant valves must be installed on each floor, which open in case of fire and direct smoke through the elevator to the roof.
During installation, there are bad methods that have negative consequences for productivity and business growth. In addition, in order to influence employees, they influence nearby homes. Poor air quality Poor productivity at work Lack of customers Short duration of meals Main incidents Damage to the environment Disruption to people's health Unhappy with the surroundings of the restaurant, that is, the neighbors, when they suffer from smoke, cochamber, smell and noise due to exhaust gases. Unhealthy ventilation One of the important points, according to Sanchez's engineer, is that a poor ventilation system can come from people's health because they are responsible for extracting or introducing new air into the room to avoid the formation of toxic atmospheres resulting from excessive concentrations of pollutants .
During large fires or when local ignition sources occur, deaths are caused by neither open fire nor even high combustion temperatures, namely the presence of caustic, dense smoke. Many of us have more than once learned from the media or heard about sad events from neighbors or acquaintances that in a fire people are suffocating, unable to navigate, lose consciousness and are poisoned by toxic products of combustion.
Engineer Sanchez, faced with such a panorama, warns that "a person can manifest itself from simple symptoms, such as sinusitis and cough, even serious lung diseases." In addition, engineer Ernesto Lopez notes that in Europe, studies are being conducted on the likelihood that smoke leakage causes affects that lead to cancer. However, this is still a problem that is simply hypothetical.
In addition to the above, engineer José Lopez mentions some short-term problems caused by a lack of airflow. Pain Syndrome Insufficient moisture control leading to the formation of biological agents. A person at rest absorbs 25 liters of oxygen per hour, which is equivalent to 400 liters of air, the consumption of which increases through activity.
In order to prevent such dangers and reduce the likelihood of death, it is necessary to foresee the design of the smoke removal system and install high-quality equipment.
What is a smoke exhaust system?
This is one of the elements of the general fire protection system, the installation of which must be approached with all responsibility. A high-quality smoke removal system ensures the safety of people in the building from the first minutes of fire or even smoldering.
Today, a person needs to find solutions that allow him to cover his needs without causing environmental problems. In the case of extraction and ventilation systems in restaurants, in addition to seeking efficiency and saving energy, you should also see how not to damage the ecosystem.
In this regard, engineer Ernesto Lopez notes that "mechanical and ultraviolet filters can interfere with the release of fats and smoke into the atmosphere, which allows the system to be environmentally friendly." National perspective In Mexico, there is a delay in the methods used in restaurants because, compared with European and North American countries, the Republic of Mexico has little time to professionalize the extraction mechanism, says engineer Ernesto Lopez.
The smoke exhaust system includes a ventilation complex, which in the event of a fire draws combustion products, a smoke screen, particles of ash and dust, and also helps to pump fresh air.
The system works according to the law of physics: hot, polluted air rises up, and the cool air that arrives remains at the lower level. This creates favorable conditions for the successful evacuation of people, reduces the risk of the rescue team and firefighters. Timely removal of smoke prevents its spread to neighboring rooms, corridors, to interfloor stairs. Such a ventilation system works automatically, at the same time as a fire alarm.
That is why more and more companies or restaurants are interested in obtaining and using such systems. On the other hand, engineer Jose Lopez believes that the country is installing the right ventilation systems in this type of institution and that there is only a greater emphasis on energy saving with the introduction of energy recuperators.
He concludes that installing a good air conditioning system is the responsibility of architects, civil engineers, and mechanical engineers who need to see how to save energy without compromising air quality. The climate of the future is a challenge to the present, he says.
In accordance with safety standards, all public spaces with a large concentration of people (shopping and business centers, medical and children's institutions, industrial, sports facilities, multi-story residential buildings, etc.) must be equipped with a high-quality fire ventilation system.
The main functional tasks of smoke exhaust systems:
While engineer Ernesto Lopez believes that "specialization should be adopted in Mexico and Latin America more quickly in order to benefit both investors and those who receive this service." It is important to establish a good extraction and ventilation system in restaurants with professional hands, as this can not only affect the success of the business, but it is also important for a comfortable and healthy stay, both for workers in the Kitchen and for guests in the dining room.
Industry Committee Passive Protection Products. Exhaust ducts, such as exhaust ducts in evacuation zones or internal exhaust, in addition to ventilation duct problems, have an aggravating effect that, in the event of a fire, must withstand the vapor flow from the outside without transferring smoke and heat to the immediate sector. Therefore, it is imperative that resistance to fire and smoke is always guaranteed. In practice, the duct should be able to work in case of fire, even as the corresponding thermal evacuators and the same combustion gases, without losing water resistance.
- the ability to quickly notify everyone in the building about a fire;
- reduction of smoke arising from fires in evacuation passages, corridors, stairs and elevators;
- containment of the spread of the source of fire in neighboring rooms;
- reduction in smoke concentration and improved visibility during the evacuation of people, as well as during fire fighting;
- providing the ability to open windows, doors and special hatches for additional ventilation of the premises;
- a significant decrease in air temperature, which in the early stages of a fire minimizes people getting burns, and in case of strong fires, it allows ensuring the safety of ceilings, thereby preventing large damage;
- maintaining the necessary oxygen level in the air, which allows for the most effective evacuation, reducing the harmful effects of smoke on the human body.
Based on these tasks, it is easy to understand how important it is not only competent ventilation design, but also the professional installation of the smoke removal system, and its regular and timely maintenance.
Passive protection in the canals is fundamental, we know that 80% of deaths are caused by many toxic fumes. Increasingly, smoke and gases are responsible for the largest number of fire victims in buildings. Lack of visibility, disorientation. Therefore, it is very important that the systems provided by the regulations work properly in the event of a fire in order to minimize the consequences.
This type of chimney should be checked. There are two types of chimneys. Smoke control panel. Graduation channels. Designed to provide a degree of fire resistance, so it can be used in multi-chamber systems. Background document Safety in case of fire.
What are they like?
The modern and most common types of smoke exhaust systems for convenience are divided by the way they function.
Static
The principle of its work is to immediately turn off the ventilation system, which helps to prevent the spread of smoke in other rooms. But it is possible to call this smoke removal only with a big stretch, because the removal of combustion products does not take place, just the smoke is blocked and remains in the room where the ignition site is located.
Item 8: Smoke Control. Cases of installing a smoke control system. Ventilation and removal of smoke and flue gases in industrial buildings. The removal of fumes and gases from burning, and with them the heat, from the premises occupied by the fire sectors of industrial enterprises should be carried out in accordance with the typology of the building with respect to the characteristics that determine the movement of smoking.
For use on the site, it is necessary to comply with the relevant field of application “Classification”. Applies only to vertical ducts. Duct measures: can be increased to the values \u200b\u200bof table 6. Pressure difference: can be increased to the difference in the table.
The advantage of such a system is that its installation is inexpensive, but the disadvantages include low efficiency and the inability to ensure the relative safety of all people in the building.
Extrapolation to 1, 2 or 3-way channels is not allowed. Single-sector and multi-sector cables are classified. You must check at least one sample. Be made of non-combustible materials. At room temperature. Leak rate. Reduced cross section.
A staircase can be naturally lit when a space is placed in an urban space in front of or behind a building, and no local border can affect vertical circulation. This pipeline will carry out the mission of evacuating the vapors and gases generated during combustion in order to provide a predetermined time for evacuation when the stairwell meets the safety and visibility requirements for the circulation of the building residents. These times of vapor and gas removal will depend on the ability of the products that manipulate their production activities, the occupation of the building and the evacuation requirements that use this use. With the above data, we can approach the calculation of the surface of the exhaust channel for vapors and gases, which will be obtained by dividing the flow rate by the exhaust channel by the speed of drawing in the channel. The extraction manifold section should be four times the size of the chimney flue. The air injection section should be the same as the exhaust duct for smoke and gases. The upper edge of the smoke and gas exhaust mesh should be located no more than at the level of the ceiling or stove. The maximum distance between the "air intake channel" and the "flue gas extraction channel" should be two meters in plan. The smoke and gas line will enter the “exhaust manifold”, one level higher than the one it is extracting. This system can be supplemented with mechanical elements that cooperate in air injection or extraction of vapors and gases, but in no case can they reduce the dimensions that arise from the proposed calculation method. The smoke and gas system can only be installed in the access door to the blocks or the protected space in front of the staircase entrance, in no case is it allowed to establish direct commissioning in the fire fighting sector. They are exempted from the inclusion of a vapor and gas evacuation system as a suitable mechanism for maintaining circulation on the stairs, of all those activities that are developed at different levels, connected with each other by voids, allowing us to consider all uses as a single fire sector. For activities that meet these characteristics, management will establish criteria and develop an appropriate system for the removal of vapors and gases. In the descriptive report, which is part of the documentation inserted in the fire condition cards, it is necessary to include the calculation of the smoke and gas evacuation system. Done, submitted to the legal department. This system is designed to solve a long topic with a delay, since the purely formal solution used today is the chimney and gases, despite the fact that it has been subjected to serious criticism throughout its normative life, until it found a simple proposal and technical support. who can replace it. The smoke and gas evacuation system can be basically defined as a combined air injection mechanism, which will ensure extraction of the extraction column and will help to capture the most common vapors and gases in the combustion process, located in the room height section. This system is aimed at preserving staircases from the dangerous presence of vapors and gases to ensure a sufficient duration of the evacuation of the building population. The goal indicated above obliges this system to accompany each staircase, and its location can be suggested in a switchboard or in a protected space in front of the entrance to the drawer or in the hallway on the staircase when the building requires it. To achieve a clearer understanding of the system, it is proposed to develop an example, which will indicate not only the calculation procedures, but also the elements that make up it. The first parameter, given that the system has natural gravity, will be related to the prevailing wind speed, and its value will be common to all cases; in the second aspect, the minimum time will be set for the evacuation of the volume of fumes and gases, which will be calculated and will mainly depend on the ability of products that manipulate activities to degenerate them so that their value depends on use. Fume and gas removal times Events Removal times Multi-family housing Administrative activities 10 minutes Education Commercial activities Exhibitions 7 minutes Education-1 Deposits and industries-1 Deposits and industries-2 Health 5 minutes Laboratories Note: smoke and gas elimination times may be required, except for those that are expected when, at the discretion of the Office, the characteristics of the activity in question are required. Education 1: when there are laboratories, classrooms, workshops, halls of events associated with the staircase where the system is installed. Deposits and industries 1: risks 4 or less. Note: all channels will be resolved with a square section. The exhaust manifold section should be four times the area of \u200b\u200bthe exhaust duct for vapors and gases. At the floor level of the plant on which it is located. The objectives of the temperature and smoke control system will depend on the building for which it is intended.
Dynamic
This system works on the principle of removing smoke and combustion products from the room while ensuring an influx of fresh air. Typically, for the device of such a system, two fans are used that operate autonomously from each other. But now you can meet a dynamic system with one fan, during operation of which the air supply directions alternate - either the removal of smoke from the premises, or the supply of air from the street. In some cases, depending on the installation location of the system, it is more convenient to use a combination of two axial fans.
The popularity of the dynamic type is due to high efficiency, maximum fire safety and reliability in operation, which, undoubtedly, justifies the cost of equipment.
Depending on the control, smoke extraction systems are automatic and semi-automatic. In industrial buildings and buildings with a large number of communications and equipment, it is recommended to equip with an automatic fire ventilation system that will help prevent the possibility of fire, signaling even minor problems.
Installation of the main parts and the principle of the system
The installation of smoke removal elements is most often carried out in the ventilation shafts of buildings, but arrangement of individual air ducts is considered a safer and more efficient installation method.
The main parts of the system:
- Smoke detectors.
- Chimney fan
- Air pressure fan.
- Fire damper.
- Smoke exhaust hatch.
- Ventilation ducts.
Fire detectors are perhaps an element that is familiar to most of us. They, when a fire occurs, give an alarm signal that activates the entire fire safety system, including ventilation.
The operating conditions of the chimney fan require high heat resistance, increased wear resistance and strength. The power of such fans reaches 20 thousand cubic meters of air per hour at very high temperatures. According to most projects, such fans are often installed on the roofs of buildings.
The supply of fresh air from the street ensures the creation of some pressure in the evacuation passages, thereby reducing the risk of smoke.
An important working element in the smoke removal complex is the fire damper, which regulates the air supply from one room to another.
In case of fire:
- fire retardant valves prevent the spread of fire;
- smoke - send combustion products to smoke mines;
- fan valves - provide the removal of smoke, gases and toxic fumes that occur during a fire;
Hatches through which smoke comes out are mounted on the roof of buildings and open automatically when a security system is triggered.
Special ventilation pipes for exhausting hot, smoky air are made of black steel with a thickness of at least 1.2 mm, which ensures strength and resistance to high temperatures.
Responsibility of the owner of the premises, the professionalism of the designer of the fire system and the quality installation of the smoke exhaust system can save human lives. But at the same time, it is equally important to carry out repair and maintenance work in a timely manner and monitor the system’s performance.
Activation of the smoke exhaust system takes place in several stages. When a fire is detected, the sensors are triggered, and the signal goes to the control room. Then the fire-retardant valves are closed and ventilation is automatically turned on. In the ignition zone, the smoke valve opens, smoke begins to flow into the pipes and the smoke exhaust fan turns on. At the same time, the fresh air supply system starts.
It should be remembered that the smoke removal system will only remove smoke from the ignition zone, so the evacuation of people should be organized as soon as possible!
Inspection and maintenance of smoke exhaust systems
When installing and commissioning the fire ventilation system, a schedule for scheduled maintenance is necessarily developed, indicating the timing and frequency of inspections.
Most often, these responsibilities are assumed by the same company that was involved in the installation of the system and the supply of components. The availability of these services must be preliminarily specified in the installation contract. The advantages of further service by the system installer not only increase his responsibility during installation, but also guarantee the possibility of timely replacement of individual parts, assemblies or quick troubleshooting.
According to safety standards, scheduled maintenance of fire ventilation should be carried out once a month and quarterly.
Monthly checks
Monthly checks suggest:
- monitoring the actual health of the system;
- checking the technical condition by inspecting sensors, valves and fixtures, as well as conducting their technical diagnosis;
- troubleshooting and replacing defective parts.
The work is carried out by specialists of the service company within the time agreed on the schedule. In case of failure to fulfill these obligations, the responsibility for the malfunction of fire ventilation systems lies with this service company.
Quarterly service
In addition to the activities carried out during the monthly inspections, once every three months is carried out:
- cleaning and debugging devices;
- verification of the operation of the ventilation system from backup power sources, in case of a power outage;
- verification and diagnostics of hidden cable lines of the system;
- elimination of defects and subsequent adjustment of the smoke removal system.
Information about each check, detected system malfunctions, as well as the work performed must be documented. The established form is pre-certified by the organization that monitors the state of fire safety.
Sad statistics confirm that neglect of the smoke exhaust system often leads to human casualties. Therefore, it is extremely important to observe all safety measures and always maintain fire ventilation in good condition!
