Industrial ventilation. Features of ventilation design at industrial facilities Design of ventilation systems for industrial buildings
Specialists of the Nimal Group of Companies will design industrial ventilation at sites for various purposes, including manufacturing enterprises, office and administrative buildings, logistics complexes, commercial centers, etc. Our design engineers have extensive practical experience in this area. Among the projects we have implemented is the creation of ventilation systems for a number of large industrial facilities in Moscow.
Development technical solutions for the installation of ventilation systems for commercial facilities is carried out on the basis of regulatory documents, which regulate the value of climatic parameters and air exchange for a particular room, taking into account its footage and functional purpose.
What problems does the design of industrial ventilation systems solve?
Industrial ventilation is much more powerful than domestic ventilation, but this is far from the only difference between this system. First of all, we are talking about a broader list of tasks, the solution of which is necessary to create favorable conditions for the flow of technological processes in production.
In particular, from technological system ventilation may require more than just a reduction in concentration hazardous substances, but also dust removal from the air, removal of dangerous fumes outside working area.
To summarize, the main tasks that the design of industrial ventilation systems is designed to solve are as follows:
- Removal of exhaust air with an increased concentration of harmful compounds outside the working area;
- Removal of excess heat;
- The flow of air into the room, the characteristics of which correspond to existing sanitary standards, create favorable conditions for personnel work and technological operations.
It is best to plan the development of an industrial ventilation project at the stage of preparation for the construction of a facility. In some cases, this event is part of reconstruction or overhaul buildings, structures engineering systems which needs modernization.
Event stages
Designing industrial ventilation systems is a multi-stage undertaking. First of all, the development of an appropriate terms of reference, which can be provided by the client himself. This document contains requirements for the ventilation system, taking into account the location of the building and its layout, its intended purpose and operating mode.
When developing a project, an engineer performs an extensive list of calculations. It is necessary to determine what cross-section and placement of air ducts is suitable for a given facility in accordance with current regulations.
The quality of system operation largely depends on proper calculation of the air exchange rate. This parameter can vary significantly for objects different types. It is necessary to take into account how many people and fuel-generating equipment will be located on the territory of the facility, and you also need to focus on the relevant SNiP.
Another important criterion- method of supply and distribution air masses, their removal outside the premises. To do this, it is necessary to perform calculations and create a suitable configuration of the air distribution network, select the correct type ventilation system and equipment for its arrangement.
In the process of work, the design engineer takes into account not only specifications buildings, but also economic feasibility from the use of one or another technical solution.
Production premises- enough difficult task. The creation of schemes is carried out taking into account the specifics of the enterprise’s activities. Let us next consider what it is ventilation production premises. Its types and requirements for it will also be described in the article.
Classification
The main task of production facilities is to promptly “catch” all impurities and remove them. Certain settings are selected depending on specific operating conditions. The air in the units can move mechanically or naturally. There is also a classification based on the principle of operation. Ventilation can be supply, exhaust or mixed. Each group has its own subgroups of equipment. So, forced ventilation may be local. It is presented in the form of an air shower, curtain or oasis. General ventilation production premises provides dispersed or directed inflow.
Natural filtration
Supply and exhaust ventilation in production premises functions due to the difference in pressure and temperature outside and in the workshop. The driving force in this case will be thermal or wind pressure. Due to the pressure difference, the expanded masses are forced out of the workshop. In their place, in turn, cold, clean ones are drawn in. A high pressure area forms in the windward area. It increases the flow of outside air. The pressure is always reduced. This promotes the outflow of waste materials. Ventilation systems and equipment, the functioning of which is based on physical laws, are used, as a rule, in enterprises with intense heat generation. However, powerful exchange does not always ensure the formation of proper working conditions for employees. The greater the temperature difference between the ceiling and floor, the higher the workshop itself, the more efficiently the natural ventilation of industrial premises. If there are cracks in windows and walls, or if doors or gates are opened frequently, drafts may appear. This helps reduce the temperature in the workshop. In the summer, in areas far from windows and doors, ventilation standards are significantly violated.
Aeration
It is used for flexible duct. Aeration is carried out according to the principle natural traction. In some cases, during the construction of a building, the installations are not installed. In such cases, channels and shafts operating from thermal pressure can be placed in the workshop. Flexible duct covered with a deflector. The wind blows on it, due to which an area of rarefaction is formed. Found these wide application on agricultural and livestock farms, in small bakeries, in forges. They are installed on the high area roofs. Aeration is considered one of the most effective methods natural ventilation. It is often used in enterprises where large amounts of heat, poisons and gases are generated.
Device
Natural involves the arrangement of three levels of openings with vents that have a specific design. The first 2 rows are located from the floor at a height of 1-4 m. Light-aeration lanterns equipped with adjustable vents are installed in the roof. In summer, clean flows pass through the lower transoms, and dirty flows are directed upward. When calculating the system, the area of openings and vents is determined. The worst operating conditions for the installation are windless weather. It is taken as a starting point. This works effectively in windy conditions. However, with a certain strength and direction of wind, it may appear reverse thrust. As a result, air mixed with gases and dust is directed into rooms where people are located. To prevent the spread harmful substances Lanterns with wind protection are installed. In summer, the influent masses are cooled by spraying into them cold water. It comes from nozzles that are located near the vents. With this cooling, the humidity rises slightly.
SNiP: ventilation and air conditioning
The Regulations set out a number of requirements for buildings that use a natural filtration scheme. In particular, it is necessary that the perimeter of the structure be open to air access. The Rules also state that workshops with a height of no more than 1 floor or located on top floors building. In multi-bay rooms, installation of natural ventilation is significantly difficult. If the width of the workshop is more than 100 m, practically no clean flows reach its center. In such cases, special Baturin lamps (non-blown) are installed. They have separate channels for supply and exhaust. However, in winter time such an installation can provoke an undesirable decrease in temperature in the workshop. To prevent such consequences, a forced ( artificial) ventilation of industrial premises.
Advantages and disadvantages of aeration
The ventilation elements are controlled mechanically. One of the main advantages of the aeration scheme is the low cost of components. At the same time, the installation can provide sufficiently powerful air exchange. Meanwhile, it also has several disadvantages. First of all, the functioning of the system depends on weather conditions. In addition, as mentioned above, it does not ensure the delivery of clean flows to remote areas of the workshop. Another disadvantage is the complexity of control. Aeration is not used in enterprises that use technologies that involve the distribution of harmful substances.
Forced
It allows you to bring the flow rates supplied to the workshop up to standard values. The required parameters are defined in SNiP. Ventilation and air conditioning forced method have the following advantages:
Most popular installations
Exhaust ventilation is now widely used. The installation limits the spread of contaminated streams and removes them directly from the source. The quality of ventilation depends on the correct selection of equipment, the degree of rarefaction of the atmosphere, and the shape of the receivers. The key elements of the installations are:
- Suction.
- Fan.
- Retraction.
- Filters.
- Exhaust duct.
The entire volume of dirty flows must be captured by the receiver and transmitted further through other elements.
Specifics of suction
Air intakes come in closed and open type. The latter include:
- Protective cover.
- Exhaust hood.
The protective casing eliminates the flow of dust that is formed, for example, in a carpentry shop during polishing, sanding, etc. It is equipped with a visor and is installed across the movement of particles. reduces the area of distribution of hot air containing harmful impurities and rising according to the principle of convection, and removes it. It should be of such a size as to completely cover the source. The umbrella can be equipped with overhangs. They are made of thick fabric or rigid sheets. It is more convenient to use open umbrellas. In them, overhangs do not interfere with the access of enterprise employees. In hazardous industries, the flow speed entering the umbrella ranges from 0.5 m/s, if it is without impurities, then 0.15-0.25 m/s.
Side/articulated-telescopic suction units
They are installed directly at the workplace in galvanic or pickling baths. The air moves over them and draws in harmful vapors of acids and alkalis before they begin to spread throughout the workshop. If the width of the bath is small (up to 70 cm), single-sided suction units are installed; if this parameter is greater than the specified value, double-sided elements are installed. In addition, the latter are equipped with structures that ensure the blowing of vapors from the surface of the liquid. The volume of flow passed through these installations will depend on the level of toxicity of the steam and temperature. The size of the liquid surface is also important. Since vapors quickly destroy metal, suction units are made of PVC and other sustainable materials. Articulated-telescopic receivers are quite common. this type is equipped retractable elements
. They can be brought directly closer to the source of pollution. In shops with soldering irons and welding machines, suction units are installed directly into the tools.
Closed type receivers
- These include:
- Cabins.
- Fume hoods.
- Cameras.
Shelter boxes. The latter are used in enterprises with particularly toxic and radioactive substances, where workers carry out all manipulations wearing gloves or using mechanical devices . The cabinets are installed in workshops with intense emissions of harmful gases. Ventilation pipes for hood
with complete isolation of the source of pollution are considered the most effective.
Forced-type ventilation systems for industrial premises are equipped with special units. They are electric fans. As a rule, axial or radial models are installed. The latter are also called “snails” due to the shape of the body. A wheel with blades is built into it. During the movement, the flows enter the housing, change direction and are supplied to the outlet under pressure. The sucked masses are often saturated with aggressive and dangerous compounds, and sometimes explosive substances. Depending on the impurities, fans are installed at enterprises:
- Standard. They are designed to capture flows with a low dust content, the temperature of which is up to 80 degrees.
- Anti-corrosion type. Such installations are used to capture vapors of acids and alkalis.
- Having protection against sparks. They are used for explosive mixtures.
- Dusty. These installations are designed to filter streams containing particles in quantities greater than 100 mg/m 3 .
Axial fans include inclined blades mounted in a cylindrical housing. During operation, the flows move parallel to the axis. These units are installed, as a rule, in mines, emergency channels, etc. The advantage of such devices is that they can supply air in opposite directions.
Dust collectors
The current norms and standards determine. Installations must operate so that the content of harmful impurities is within the limits permissible value. Accordingly, one of the key parameters is cleaning efficiency. In some cases, one dust collector is enough to filter the air. In this situation, cleaning is called single-stage. If air pollution is significant, multi-stage filtration is organized. Type treatment plant will depend on the form, chemical composition and volume of impurities. The simplest design of a dust collector is a dust-sediment chamber. It significantly reduces the intensity of flow movement, due to which harmful impurities settle. However, this installation can only be used for primary filtration. Dust settling chambers can be labyrinthine, simple, or with a bumper.
Cyclones
They are inertial dust collectors and are used to filter air containing particles greater than 10 microns. The cyclone is designed as a cylindrical metal container, tapering downwards. Air is supplied from above. Under the influence of centrifugal force, dust particles hit the walls and fall. Purified air comes out through the pipe. To increase the volume of retained dust, water is sprayed inside the housing. These installations are called cyclone-washers. IN Lately The most popular are rotoclones and rotary dust collectors.
Filters
They are also used to purify the air. Filters can be powered by electricity. In this case, positively charged particles are attracted to the negative electrodes. Passes through the filter high voltage. To subsequently clean the electrodes from dust, periodic automatic shaking is carried out. The collected dust is sent to storage tanks. In practice, coke and gravel filters are also used. Fine and medium cleaning devices are made from special material. It can be synthetics, felt, porous fabrics, mesh. They capture not only dust, but also fine particles oils However, such materials quickly become clogged and require regular cleaning or replacement. If it is necessary to filter the air from explosive compounds or gases, as well as aggressive substances, ejection systems are used. They have 4 chambers: diffuser, neck, confuser and for discharge. Streams enter them under high pressure. The direction is set by a compressor or fan. Dynamic pressure in the diffuser is converted into static pressure. After this, the flow is directed outward.
Alternative option
Before directing the air into the room, it must be processed: warmed or cooled, filtered. In some cases, it also requires moisturizing. For these purposes, forced ventilation is used. It consists of:
- Fence.
- Taps.
- Filters
- Heaters.
- Fans.
- Distributors.
Installation of installations is carried out according to certain rules. For fan, filter and heater it is provided supply chamber. Receivers should be located at a height of 2 meters from the ground, in places remote from sources of pollution. In some cases, installation above the roof of the structure is allowed. When choosing an installation location, consider the wind direction. On the outside, the air intakes are covered with umbrellas, blinds or grilles. Filters in installations can be various types. Typically, devices from nonwoven materials. In winter, the air is heated using air heaters or heaters. The coolant is electricity or water. For humidification, special irrigation chambers are installed. A fine air fraction is sprayed into them. Cooling is carried out in a similar way.
Local installations
These include air souls. They represent clean flows directed to work areas. The purpose of such a shower is to enhance heat transfer from the employee’s body to prevent overheating. Installations can be mobile or stationary. Hot shops, as well as rooms with infrared radiation greater than 350 W/m2, are equipped with showers. The standards depend on temperature, severity of work, and radiation intensity. Average temperature in the shower is +18...+24 degrees. The flow moves at a speed of 0.5-3.5 m/sec. Its indicator is directly proportional to the radiation intensity and air temperature.
Oases and veils
These devices are often used in large enterprises. Oases serve a section of the workshop, fenced off from the rest of the area using light screens. Within its limits, air moves at a certain speed and has a given temperature. Curtains are used to prevent hypothermia of workers and cooling of the workshop through openings or open doors. They can be without heating or with it.
Preventive supervision
Such sanitary control of industrial premises ventilation systems performed when:
- Reconstruction, planning, construction or changing the technology/profile of an enterprise, site, workshop.
- Launch of installed or repaired treatment plants.
- Introduction of new technological units, processes or chemical substances, which can have a harmful effect on environment or a person.
Reconstructed or newly built ventilation systems are launched by the commission in the prescribed manner. It includes a representative of the sanitary and epidemiological service. Assessment and inspection of the ventilation system can be carried out after completion of all construction and installation activities. In this case, before the inspection it is necessary to adjust everything technological processes according to the regulations. During the examination production plants must function with the planned load, ventilation devices must reach the specified performance. Preventive supervision is carried out in the form of:
- Drawing up conclusions on design materials on the correctness of selection ventilation circuit. Working and technical drawings serve as documents for verification.
- Observations on the installation process
- Participation in the reception and execution of conclusions on the compliance of units with current sanitary and hygienic requirements.
Current examination
It is performed in the form of sampling control:
- Conditions of the environment in areas where intake devices are located. The inspection can also be carried out directly at the workplace.
- Work, condition, operation of ventilation systems.
The frequency and scope of the sample examination is established by the sanitary doctor. This takes into account the degree of probable negative impact production environment at a specific enterprise for personnel.
Ventilation design industrial buildings should only be performed by a specialized organization. The calculation of the ventilation system of an industrial building differs significantly from the design of ordinary residential premises. By doing design work of this type of structure, it is necessary to take into account many factors and conditions that affect comfortable working conditions for thousands of employees and maintaining the necessary microclimate for the operation of high-precision equipment, such as: the huge size of the premises, the number of staff, heat generation from technological equipment and harmful emissions.
Main stages of design work for ventilation of industrial buildings
Below are the main stages of design work on ventilation systems for an industrial building. These include:
- selection of a fundamental solution for the air ventilation system, which must meet the requirements of creating and maintaining a comfortable microclimate in the room;
- determining the method of air distribution: mixing ventilation, displacement ventilation, air distribution from under the floor;
- based on the technical specifications, the location of the building, as well as functional characteristics premises, the calculated values of air are determined, the parameters of heat and moisture entering the room are taken into account, the flow rate is calculated supply air and minimal required consumption outside air, the sound pressure level is determined;
- aerodynamic calculation of air ducts;
- hydraulic calculation of pipelines;
- selection of equipment on which the ventilation system will be implemented.
- selection of an automatic control system to maintain the specified parameters.
Scheme of a ventilation project for an industrial building
Selection of equipment for ventilation of industrial buildings
IN modern world a large number of companies supply ventilation equipment, but not all products provide required parameters, therefore, when choosing an equipment supplier, give preference famous brands, which has proven itself well on the Russian market. When designing a ventilation system, in particular selecting air handling units, our company gives preference to the brands DANTEX (made in Poland) and WESPER (made in France). Air ducts from Galvent and network equipment from the brands Systemair and Solar Polar have also enjoyed well-deserved popularity for many years.
Only a competent selection of sensors, controllers and elements of automation systems will ensure easy control. In industrial buildings, recently it is increasingly necessary to create a point central control- all management and maintenance of everything ventilation equipment occurs from one central console. When selecting an automation system, it is also better to trust proven brands, such as: SIEMENS, Schneider Electric, Johnson Controls, CAREL.
Composition of the detailed design for ventilation of industrial buildings
The detailed design for ventilation systems for industrial buildings includes:
- explanatory note;
- initial data adopted when calculating the system;
- system characteristics;
- plans and sections of systems and installations;
- axonometric diagrams;
- specification of equipment and materials.
