A person about half of his life is at work, where he can be affected by harmful factors: dust, polluted air, elevated or lower temperature indicators of the surrounding air environment. In addition to human exposure, there are some factors that adversely affect the room itself or the technological processes that take place in it - this is the fire hazard of some substances that are in the air in a high concentration.

To ensure the safety of construction and create a comfortable microclimate in the production room for personnel, an industrial ventilation system is used.

The main requirements for these systems

When designing industrial ventilation, specialists should take into account several basic requirements to it:

• Sanitary and hygienic.
• Acoustic.
• To fire safety.
• Operational.
• Energy-saving.
• Ecological.

An important factor in the design of industrial ventilation systems is their cost, i.e. cost of equipment and commissioning.

Types of industrial ventilation systems

There are several types of industrial ventilation systems:

1. General exchange systems are used for the whole room.
2. Local ventilation systems are used for a certain area.
3. Local systems are used to remove contaminants and harmful substances, vapors and gases, in the areas of their allocation.

In addition, there are still such types of ventilation as: emergency, which accompanies certain technological operations.

All types of industrial ventilation are divided into two types: natural and mechanical.

For natural ventilation   The motivator of the movement of air masses is wind or gravity, and for mechanical, various devices are used: fans, etc. With natural ventilation of the production room, air flows are used that spontaneously penetrate through various openings, leaks in windows and doors. Extraction of them occurs through exhaust ducts. The performance of this type is highly dependent on the difference in room temperature and outdoor air, pressure drop, wind speed and direction. As auxiliaries for natural ventilation, deflectors are sometimes used, and for best air exchange and mixing of air streams, the aeration effect is often used in production shops.

When mechanical system   ventilation, air exchange is carried out through ducts or channels,. Depending on the direction of the air flow, mechanical ventilation can be supply and exhaust. Industrial exhaust ventilation is arranged in the upper part of the room, and the supply air is at a height of 1.5-1.8 m from the floor.

In some cases, a mixed type of ventilation is used, due to the large volume of air being removed through natural exhaust openings, there is a need to use a forced industrial air supply ventilation.

In addition to natural and mechanical ventilation, some enterprises began to use the third type - a combined system. This happens in the event that none of the types of ventilation individually can not create an effective air exchange. For example: in the paint shop, along with, introduce a local one, which is installed in the places of harmful substances release, and prevents the mixing of air flows, thereby increasing the efficiency of ventilation with minimal airflow.

The role of air purification in industrial ventilation systems

In modern ventilation systems, an important role is played by the purification of polluted air. It can be of several types:

• Gravitational. As a rule, these are dust-collecting chambers, which are used in industries with strong dust formation. They are used to precipitate the largest particles in the air.
• Inertial, dry type. They can be cyclonic and louver. They differ in design and compactness, but serve to purify air from non-sticking dust.
• Inertial, wet type. Effectively remove dust from the air by the method of its moistening.
• Fabric filters. They purify the air, accumulating it in a special fabric.
• Porous air filters have the property of accumulating a large amount of contaminants from the air stream, in numerous pores of the filter element.
• Electrofilters clean air of mechanical impurities by means of their electric charge, after which, the contamination settles on one of the filter electrodes.

There are sorption-catalytic, acoustic, plasma-catalytic filters, which are used to purify air in industrial ventilation systems.

The basic stages of design of industrial ventilation

In the design of industrial ventilation, the decisive factors that influence the choice of equipment and its installation are:

1. Calculation of air circulation in each production room.
2. The main task that the ventilation system must solve.
3. Localization of the released harmful substances and its maximum permissible values.
4. Selection of air purification systems.
5. Feasibility study of the proposed supply and exhaust equipment.

The design consists of the following main stages:

• Preparation of technical specifications. The customer independently or with the help of specialists is engaged in its development. The technical design takes into account a number of factors, such as: the layout of the production premises, the material of which the construction is made, the thickness of the walls, the number and schedule of personnel, and some features of the technological process.
• Calculations made by the engineer-designer of industrial ventilation systems, guided by regulatory documents and existing standards. The calculations include such values ​​as:
  • Air exchange - this is how often, the air in the room will be completely replaced with a new one. The main indicator of this value will be.
  • Climatic parameters for a particular building. Calculations are made separately for the cold season, for the transition period and for the warm season. The customer of the project himself determines in those. task, what microclimatic indicators he would like to receive.
  • Air ducts. Due to the calculation of the air ducts, the optimum material is selected from which they must be made, their cross-sections and shapes.
• The next stage of design is the choice of equipment. Here, the economic justification for the appropriateness of the application of a particular type of equipment, the earlier calculations, the layout of the room and the technological process are taken into account.
• The final stage of the design of industrial facility ventilation is the drawing up of drawings, diagrams, graphs and explanatory notes. Based on this, the engineer of the project prepares a feasibility study for the entire project.

Important!
  Correct design of an industrial ventilation system for a particular production is an extremely important and responsible step on which the creation of a comfortable microclimate for personnel depends on, the economical consumption of electricity, etc. In order to avoid ineffective operation of ventilation and unnecessary financial costs, we strongly recommend that you only apply to specialists for all calculations and project creation.

Lecture 7. Ventilation

1.Ventilation of industrial premises

2. Assignment and classification of ventilation systems

3. Natural ventilation

4. Artificial ventilation

2.4. Ventilation of industrial premises

2.4.1. Purpose and classification of ventilation systems

To maintain the required parameters of air purity and microclimate parameters of the production room, various types of ventilation are used. Ventilation is an organized air exchange, consisting in the removal of polluted air from the workplace and the supply of fresh outside air instead. Depending on the method of air movement, ventilation can be natural or mechanical.

2.4.2. Natural ventilation

Natural ventilation is carried out due to the difference in air temperature in the room and outside air (thermal head) or the effect of wind (wind pressure). Natural ventilation can be unorganized and organized. With unorganized ventilation, the volume of air that enters and leaves the room is unknown. Air exchange depends on the direction and strength of the wind, the temperature of the external and internal air. Organized natural ventilation is called aeration. For aeration in the walls of the building, openings for external air are made, and special devices (lanterns) are installed at the top of the building to remove the exhaust air. As a result, it is necessary to calculate the areas of inlet and exhaust aeration holes that provide the necessary air exchange.

2.4.3. Artificial ventilation

Artificial (mechanical) ventilation, unlike the natural one, provides an opportunity to purify the air before it is released into the atmosphere, to catch harmful substances directly near the places of their formation, to treat the fresh air (clean, warm up, humidify) more purposefully to supply air to the working area.

General ventilation artificial ventilation ensures the creation of the necessary microclimate and the purity of the air environment throughout the entire working area of ​​the room. It is used to remove excess heat in the absence of significant toxic emissions, as well as in cases where the nature of the process and the features of the production equipment exclude the possibility of using local exhaust ventilation. There are four main schemes for organizing air exchange with general ventilation: top to bottom, top to top, bottom to top, bottom to bottom.

Fig. 2.4.1. Scheme of air exchange in general ventilation

Schemes from top to bottom and from top to top are advisable to apply in the case if the supply air during the cold period has a temperature below the temperature of the air in the room. The supply air is heated by the room air before reaching the working area. The other two circuits are recommended to be used when the supply air is heated during the cold period and its temperature is higher than the temperature of the indoor air.

If gases with a density exceeding the density of air are emitted in the production premises, general ventilation must ensure that 60% of the air is removed from the lower zone of the room and 40% from the upper one. If the density of gases is less than the density of air, the removal of polluted air is carried out in the upper zone.

The general exchange supply and exhaust ventilation consists of two units: for supplying clean air and removing polluted air. The ratio of these two streams is called the ventilation air balance. This balance can be balanced (if the inflow is equal to drawing), positive (if the inflow prevails) and negative (if the extract is dominant).

Local ventilation also happens supplyin the form of air smothering (when fresh air is fed into the breathing zone of the worker) or exhaust   (when the polluted air is removed from the source of harmful substances by means of exhaust umbrellas, panels, slots, etc.).

Forced ventilation . The scheme of the forced mechanical ventilation (Fig. 2.4.2) includes the air intake device 1; filter for air purification 2; air heater (air heater) 3; fan 5, duct network 4 and supply nozzles with nozzles 6. If there is no need to preheat the supply air, then it is passed directly to the production facilities along the bypass channel 7.

Air intake devices must be located in places where air is not contaminated by dust and gases. They should be at least 2 m above the ground level, and from the exhaust ventilation shafts: vertically - below 6 m and horizontally - no closer than 2.5 m.

The supply air is sent to the room, as a rule, by a diffused flow for which special nozzles are used.

Fig. 2.4.2. The scheme of forced ventilation

Exhaust ventilation and combined extract and input ventilation. Exhaust ventilation (Figure 2.4.3.) Consists of a cleaning device 1, a fan 2, a central 3 and suction ducts 4.

Fig. 2.4.3. The scheme of exhaust ventilation

Air after cleaning should be thrown out at a height of not less than 1 m above the ridge of the roof. It is forbidden to make ejection holes directly in the windows.

In conditions of industrial production, the most common supply and exhaust ventilation system with a general inflow into the working area and local extraction of harmful substances directly from the places of their formation.

In industrial premises where a significant amount of harmful gases, vapors and dusts are released, the exhaust should be 10% greater than the inflow, so that harmful substances are not displaced into adjacent rooms with less toxicity.

In the system of supply and exhaust ventilation, it is possible to use not only the outside air, but also the air of the premises themselves after cleaning. This reuse of indoor air is called recirculation and is carried out during the cold period of the year to conserve the heat required to heat the supply air. However, the possibility of recycling is stipulated by a number of sanitary and hygienic and fire safety requirements.

Local ventilation

Local ventilation can be supply and exhaust.

Local fresh air ventilation, at which the concentrated supply of fresh air to the set parameters (temperature, humidity, speed of movement) is carried out in the form of air showers, air and air-heat curtains.

Air showers are used to prevent overheating of workers in hot shops, as well as for the formation of so-called air oases (sections of the production zone that differ sharply from their physical and chemical characteristics from the rest of the premises).

Air and air-heat curtains are designed to prevent the penetration of significant amounts of cold outside air into the premises when frequent door or door opening is required. The air curtain is created by a stream of air, which is guided from a narrow long slit, at an angle to the flow of cold air. A channel with a slit is placed on the side or at the bottom of the gate or doors (Figure 2.4.4).

Fig. 2.4.4 Air-heat curtains:

a - with a lower air supply, b - with a lateral two-way supply of air; в - with side unilateral delivery of air

Local exhaust ventilation   is carried out with the help of local exhaust hoods, suction panels, exhaust hoods, on-board suction pumps (Figure 2.4.5) and other devices.

The design of the local suction should ensure the maximum collection of harmful emissions with the minimum amount of air removed. In addition, it should not be cumbersome and interfere with maintenance personnel to work and monitor the technological process. The main factors when choosing the type of local exhaust are the characteristics of harmful emissions (temperature, vapor density, toxicity), the position of the worker in performing the work, the features of the technological process and equipment.

Fig. 2. 4.5. - Examples of local exhaust ventilation

a - exhaust hood, b - suction panel in - fume hood with combined extraction d - side suction with blower

By the degree of isolation of the area of ​​local exhaust ventilation from the surrounding space, open-type suction pumps and suction pumps from hollow shelters are distinguished (Fig. 2.4.6.).

The main work performed by the ventilation of production facilities is the removal of used air and the injection of fresh air. With its help in the workshops the enterprises create a comfortable air environment that meets the regulatory requirements. Only in such conditions it is possible to achieve an increase in labor productivity.

All existing ventilation systems are grouped according to 4 characteristics:

1. Depending on how the air is moved, ventilation is called natural, mechanical or artificial, combined, when both options are present simultaneously.
2. If we proceed from the direction of the air flow, the ventilation systems can be divided into inflow, exhaust or supply-exhaust.
3. On this basis, as a place of action, ventilation systems are grouped into 3 groups: general exchange, local, combined.
4. Based on the designation, the working and emergency systems are singled out.

The basis for the design of ventilation for workplaces in production are the norms prescribed in SNIP 41-01-2003. Natural and mechanical air exchange work according to different schemes.

While the processes occurring during natural ventilation depend on the heat and wind pressure and are practically uncontrollable for a person, forced air exchange is possible only with its active participation.

When talking about ventilation in production, they mean not only equipment, but also its maintenance, and a whole range of activities related to the creation of a healthy microclimate

The scheme of the action of natural air exchange

Ventilation of premises, carried out in the first way, is nothing more than a simple airing. It occurs without human intervention and is possible, when the fences are not tight enough, and let air into the room from outside as well as from inside.

The direction is influenced by pressure. If its indicators have a higher value from the outside, then the way is opened for penetration into the room of clean air from the street, otherwise warm air from the room finds out the way out. Often these processes occur in parallel.

A big plus of natural ventilation is that its device does not require significant costs for either equipment or power supply. Of all the existing schemes, this is the simplest

Active natural ventilation occurs unorganized due to accidental circumstances. It is observed in conditions where the temperature of the air outside and inside the building is very different.

This process is also facilitated by the appearance of separate sections with high and low pressure indices from the side of the hull, intensively blown by the wind and from its more protected side, respectively. In this situation, infiltration is observed - air enters the room from the windward side, but exits outward from the leeward side.

The air exchange coefficient characterizing the intensity of the process, with the natural ventilation method, does not exceed 0.5. Comfortable conditions for people in the workplace and working equipment, an unorganized view of this type of ventilation can not provide. Specially designed systems must be present here.

Natural ventilation of the organized species is realized by aeration or by means of deflectors. Both the supply and the removal of air from the room occurs either through openings in the enclosing structures, or through the air outlets. In the duct ventilation there is necessarily a deflector.

Air exchange using aeration

In shops where the technology provides for the generation of heat in large quantities, aeration involves air exchange, carried out through light lanterns and window openings under the influence of temperature and wind pressure. In cold shops, air assimilation takes place only under wind pressure.

When aeration is necessary, compulsory accounting of the wind rose, otherwise harmful emissions from the pipes of neighboring enterprises may enter the production room. Nothing should interfere with the exit of vapors, harmful gases through light lanterns.

The best conditions for ventilation creates an arrangement of the structure from the windward side in relation to harmful production. Opening and closing the transoms must be automated so that they can be controlled from the bottom.

Their different arrangement allows you to regulate the supply of fresh air. Aeration - more suitable option   for shops of large volume, in which there is no possibility to apply mechanical ventilation because of its high cost.

With the help of aeration in individual cases, it turns out to be organized, based on natural draft, efficient air exchange. To this end, install light-aeration lanterns

The recommended height of the supply of air to the room with this type of ventilation is a minimum of 0.3 and a maximum of 1.8 m in the warm period and a minimum of 4 m in the cold one. The best option   - Special designed window panes on 3 levels. When warm, fresh air passes through transoms, located below, and dirty - leaves through the top.

The middle row of ventilations provides a flow of air at a negative temperature. During the time when the air mass reaches the floor level, it has time to warm up.

When it is necessary to remove a large volume of air, a deflector of a considerable size or a few smaller ones equal to a larger capacity

In production buildings of small volumes, ducts or pipes intended for drawing are installed deflectors. With their help remove the exhaust air from the shops, where there is a general exchange hood. And also they are used to remove hot gases from furnaces, presses, and horns. When installing them proceed from the trajectory of the mainstream air flow.

Artificial or mechanical ventilation

Being more perfect, than natural, this type of ventilation, assumes significant financial and operational investments. In such a system there can be devices not only cleansing, but also ionizing, moisturizing, warming air.

The mechanical ventilation circuit includes a cyclone (1), air ducts (2), an exhaust fan (3), a heater (4), an air intake shaft (5), air ducts of an exhaust ventilation unit (6)

Mechanical ventilation can be either supply air, exhaust or combined ventilation, i.e. supply and exhaust. Its advantages are obvious:

1. It provides a clean air intake, its processing - heating, drying, humidification.
2. Moves air masses over considerable distances.
3. It gives the opportunity to bring the delivery of clean air directly to the workplace.
4. Allows you to remove dirty air from any place and clean it.
5. Her work is not affected by the surrounding conditions.

In general, the exhaust and supply system work together, but sometimes it is recommended to use only one of these two types. The task of forced ventilation is to ensure the supply of the working space with air that has a beneficial effect on people's health.

Apply it mainly where production processes are accompanied by large heat releases, containing a small amount of harmful substances. Clean air coming through the air ducts is distributed to workplaces through the use of distribution nozzles.

Systems that remove air from the room containing various contaminants are called exhaust. This type of air exchange is used in production rooms where there are no harmful emissions and the minimum value of such parameter as the air exchange rate is not ruled out. It can be warehouse, auxiliary, household premises. The inflow of air is provided by infiltration.

In the case of the need for active and reliable air exchange, the intake and exhaust ventilation is used. In order to somehow protect low-contaminated rooms from adjoining rooms with a high concentration of harmful substances, where pollutants are released in small quantities, a small pressure is created in the system.

The air exchange scheme at the enterprise is mounted on the basis of calculations. Their accuracy is the guarantee of competent and effective functioning of the system

At the stage of design work on the creation of a forced-air ventilation system, the air flow is calculated, for which the formula is used: Lots = 3600FWo. Here F denotes the total area of ​​the openings in m², W0 is the average value of the rate at which air is drawn in. This parameter depends on the toxicity of the emissions and the type of operations performed.

The exhaust hoods can be at different heights. The main thing is that the contaminated air currents do not change their natural trajectory. Emissions having a greater specific gravity than air are always in the lower zone, therefore devices for their collection must also be located there.

In the autumn-winter period, the air supplied to the room must be heated. To reduce costs, use recycling, which involves heating part of the cleaned air and returning it to the room. In this case, two rules must be observed:

1. Outside, no less than 10% of fresh air comes in, and in reverse air, the content of hazards does not exceed 30% relative to the maximum allowable capacity.
2. It is prohibited to use recirculation in the workplace, where explosive dust is present in the air mass, microorganisms capable of causing various diseases, emissions related to the 1-3 classes of danger.

The choice of the type of ventilation in the place of action depends on the weight of the emissions, their concentration, temperature. Generalized ventilation allows you to remove the entire amount of dirty air, regardless of the points from which it is emitted.

Mechanical ventilation can be both general exchange and local. The first of these can be channel and non-channel

The channel version was the most widespread. Here, to move the air through special air ducts, there is an ejector installation or a fan - centrifugal or axial.

If there are no air ducts, then the system is called channelless. The ventilation equipment in this case is mounted directly in the wall or in the ceiling. The main condition - the presence of natural ventilation.

The possibility of emission in the room with a high degree of explosion hazard, does not allow the installation of non-explosive ventilation equipment on ducts, therefore ejectors are used in these cases. The supply ventilation system is often connected with central heating. Outside the structure, air receivers are arranged for the intake of fresh air.

The shafts are located above the roof and above the ground. The main thing is that there should not be any production with harmful emissions near the receivers. The air intake openings themselves should be at least 2 m from the ground, and if production is located in the green zone, the minimum permissible distance from the ground level to the lowest point of the opening should be 1 m.

The principle of the general exchange ventilation is simple: the fan sucks air masses through the heater, here there is heating. Further, the air is moistened, and sometimes dried and enters the building by special air ducts. The volume of incoming air is coordinated, designed for this purpose, by valves or flaps.

Concentrated vapors, gases that could not remove exhaust ventilation general and local, dilute the supply system. Also, it assimilates excess moisture and heat

The general exchange artificial ventilation of the supply and exhaust type is open and closed. In the first case, there are 2 independent systems, one of which pumps air, and the second - in parallel, removes previously deactivated spent. These systems are suitable for shops where substances of the 1-2 hazard classes are allocated, and production itself belongs to categories A, B, and B.

Emergency artificial ventilation

In addition to working ventilation in potentially hazardous production facilities, there must be an emergency version. Do it mostly exhaust. For rooms belonging to categories A, B, E, the system is supplied with a mechanical drive.

All elements of the system must comply with the requirements of the PUE. In the shops of categories B, D, D, the presence of a natural impulse for ventilation is permissible, provided that the productivity is provided under the most unfavorable weather conditions. Lattices and branches of the emergency ventilation system are located in the places of the highest concentration of hazardous substances.

On pipes and mines of emergency ventilation do not need to install umbrellas. It is inadmissible to place openings in areas where people are constantly standing. This will worsen the local microclimate.

The role of emergency ventilation is to reduce the saturation of emissions of harmful substances during the evacuation of workers from the shop. The more people work in production, the longer the evacuation process takes

The forced emergency ventilation is installed in the shops, where in the event of an emergency, there will be a release of vapors or gases that are lighter than air. Switching to emergency ventilation should occur automatically, as soon as the normal system goes out of operation.

Local ventilation of premises

Local exhaust removes exhaust air in places where it is contaminated. The exhaust hood includes exhaust fans, pipelines, ventilation grilles. Local ventilation designed to remove substances belonging to the 1st and 2nd hazard classes from the equipment is arranged so that when the ventilation system is switched off, equipment start-up becomes impossible.

In some cases, reserve fans are provided and local automation pumps are provided. Divide such ventilation into 2 types - supply and exhaust. The inlet type of ventilation is performed in the form of heat curtains, air showers.

Air curtains from the air

Openings that remain open for a long time (more than 40 m per shift) or open quite often (more than 5 times), contribute to the supercooling of people in the room. The negative consequences are also caused by the operation of drying plants that emit pollution.

In these cases, air curtains are arranged. They act as a barrier to cold or very hot air. Air and air-thermal screens are designed so that in cold weather when opening openings the temperature in the shops does not fall below the mark:

• 14⁰ - during the execution of work that does not require much physical effort;
• 12⁰ - when the work is classified as of medium gravity;
• 8⁰ - when doing hard work.

If workplaces are located near the gate and technological openings, install screens or partitions. The air curtain near the doors facing outwards should consist of air with a maximum temperature of 50⁰, and at the gate - no more than 70⁰.

Local exhaust using special suction pumps

The local exhaust system with special suction first captures, and then removes harmful for health impurities in the form of gases, smoke and dust. This is a kind of air shower, the task of which is to inject fresh air at a fixed location and lower the temperature in the inflow zone.

It is used in production, where workers are exposed to high temperatures and radiant energy intensity of more than 300 kcal / m² per hour, radiated by heating and melting furnaces. There are such installations as stationary, and mobile. They should provide a blowing speed from 1 to 3.5 m / s.

The use of an air shower is one way of establishing a heat balance between a person and the environment in which he is forced to be

There is also such a thing as an air oasis, which is the same device included in the local ventilation system. It creates a microclimate with specified parameters in a certain part of the production room. Purified air supplied to a given alienated zone is usually subjected to a special heat and moisture treatment.

The air oasis creates improved conditions in the workplace and neutralizes the impact of harmful substances. Often these are separate cabins, but when their installation is not possible, a jet of air

If the local suction device is approached directly to the point of release of pollutants, it will be possible to remove air containing a higher percentage of them than with ventilation of the general exchange type. Local ventilation can significantly reduce air exchange.

Calculation of air exchange in two parameters

If harmful substances are not released as a result of production activity, the amount of air required for ventilation is calculated by the formula: L = N x LN. N is the number of people usually in the room, Ln is the volume of air required for 1 person, measured in mᶾ / h. Normally it is from 20 to 60 mᶾ / h.

With the use of such a parameter as the air exchange rate, the calculation is carried out according to the formula: L = n × S × H, where n is the air exchange rate in the room. For a production room, n = 2. S is the area of ​​a room in m², and H is its height in m.

Video on the topic of industrial ventilation

Here all about the intricacies of all possible ventilation systems:

  Details about the installation of the system:

  Whichever ventilation system is chosen, it must have two main properties: competent design and functionality. Only if these conditions are met in the production premises is the microclimate that is always optimal for health.

  Creating a truly comfortable and cozy atmosphere at the workplace not only increases the productivity and efficiency of the labor process, but is also an indispensable condition that the sanitary authorities put forward. Therefore, ventilation systems are as important in production as the elements of the system central heating   or utility services. The installation of such systems is a rather complicated and time-consuming work, therefore it is usually not done by oneself, but trusted by professionals with solid experience. In any case, to know about the principles of functioning, design and development will not hurt anyone.

Air conditioning and various areas of the premises in production is carried out using sophisticated systems, including in addition to the air duct, also various air heaters, filters, coolers, recuperators, fans and other elements. The ventilation system, regardless of the variety of the production process, the area and size of the workshops and the contamination of the airspace, should perform such functions:

• Providing fresh clean air to the workers of the enterprise.
• Removal of unpleasant and foreign odors, as well as dust from the room.
• An important function of the ventilation system is filtration from various harmful impurities that arise as a result of certain technological influences and conditions.

Inset: Important: Ventilation of mechanical and natural type is used in industrial and production shops for normal air exchange. When designing works, it is necessary to take into account various regulatory documents regulating the condition of factory and factory shops.

During the manufacturing process associated with the manufacture of pharmaceuticals or products from processed oil, toxic elements that represent a certain danger to human health are released, so the ventilation system must ensure their efficient and immediate neutralization.

To develop or in a production room, it is necessary to admit only highly qualified specialists, certified engineers and professionals. At the same time, it is necessary to take into account climatic and weather conditions, the number of workers, the size of the room, the features of production and many other nuances and features.

1. Elements of any ventilation system are air ducts, exhaust and supply devices, as well as equipment that helps create a comfortable and cozy indoor microclimate (including humidity stabilizers, as well as air-conditioning units and air conditioners).
2. For normal ventilation of various objects in production conditions, it is necessary to use such equipment that is able to remove from the air particles of dust, aerosol and gas that appear as a result of the operation of complex equipment.
3. In some industries (such as pharmaceutical or high-precision electronics), specific working conditions are required, therefore, various additional elements, such as special filters and high-power air conditioners, are added to the powerful ventilation system.
4. According to the operating instructions for certain types of equipment, those workshops and areas where evaporation that is hazardous to human health may be present should be additionally equipped with trap-extractors, which are separated from the general workshop network.
5. Devices that carry out hygienic-sanitary control of ventilation systems are part of air exchange systems, and depending on their indications, special equipment that removes various toxic impurities and purifies air can be connected.
6. During the design of ventilation systems, it is necessary to take into account such a parameter as the cost of operation. It is best if the hot air that leaves the room is used in special exchangers, and cold air is used to cool the machines and other equipment.

Table: Heat consumption of the ventilation system

Ventilation, which is used in industry, is divided into the following varieties:

1. Ventilation of the general exchange type is responsible for the normal replacement of air masses in the room. The most typical example is an ordinary fan of an axial sample, which is inserted into a wall or window channel. Based on such parameters as the length of the duct and the cross section, the corresponding capacity of the equipment is selected.
2.   (or individual type) - allows you to purify the air of various toxic impurities, smoke, heavy dust and other substances that can harm human health, directly in the workplace.
3. Emergency air purification from gas, smoke or all kinds of toxic impurities is resorted exclusively to force majeure cases, therefore the standards here are different from those generally accepted in the industry and will not be considered in this context.

Ventilation is also mechanical and natural. The natural scheme removes and influxes the air masses through a thrust that arises because of the difference in temperature and pressure inside and outside the production room. The effective functioning of such a ventilation system is influenced by:

• The difference in the temperature of the ambient air inside the production hall and on the street.
• The difference in atmospheric pressure near the exhaust outlet of the extractor and near the floor in the room.
• The speed of movement of air masses in the street.

Types of ventilation system

The natural system of ventilation and airing is distinguished by its noiselessness, ecological compatibility and economy. However, changing weather conditions can negatively affect its effectiveness. Such a drawback is devoid of mechanical ventilation, which is able to move the air flow through the duct of any configuration and cross-section to any distance. In such cases, often installing additional equipment that heats the air, and also moisturizes, dries or filters it if necessary. To date, the most popular combined ventilation systems, which use elements of both mechanical and natural systems.

To realize normal natural ventilation, there is no need to spend significant funds, conduct electricity, or buy additional equipment. Turning to professionals who make exact calculations and plans for optimal ventilation in a particular industrial or industrial room, you can solve the problem of ventilation and compensate for such a disadvantage as the dependence on speed and wind speed changes, pressure and temperature.

To carry out mechanical ventilation of industrial and industrial premises requires a fair amount electric power, so this method is not always economically viable. The advantage of this method of ventilation is the independence of airflow and temperature from environmental conditions. Air in such systems is often heated, and also cleaned or cooled if necessary. To date, the most popular is the combined ventilation system, which combines elements of mechanical and natural ways of airing the room.

To the standards of ventilation include certain provisions, according to which the ventilation system must be absolutely in all production halls and premises. And regardless of the functional characteristics of the occupied area and the number of employees on it. Capacities ventilation equipment   should be enough for the fastest possible cleaning of the air in the room in case of emission of harmful substances or smoke. Develop a project, which will further realize the operation of the ventilation system, should professionals who are able to do this in full compliance with applicable laws, documents and normative acts. During design, you should take into account such parameters:

•   inside the workshop or production room.
• Conditions of fire safety.
• Indicators of air humidity.
• The presence and number of toxic and toxic substances that pollute the environment.
• Climatic features.
• Area of ​​the room and functionality.

It is worth noting that the provision of air for each employee is the norm, which is monitored by various agencies and services. The norm is equal to thirty cubic meters per hour on an area less than or equal to forty square meters. For large production complexes, such norms are calculated in a separate order. When calculating technical specifications   The ventilation system should take into account such nuances:

• The ventilation system should not be a source of noise, which is very prominent even during the operation of process equipment and machines. The noise level should be at an average or low level, otherwise a long stay in the shop will become problematic.
• In the event that the ventilation system has been installed for a long time and has not been thoroughly cleaned for a long period of time, it is most likely that it itself is the cause of increased pollution of the surrounding airspace. To ensure that the ventilation system is not a source of pollution, it is recommended to clean it at least several times a year.

The tasks of the ventilation system of the supply air type include compliance with sanitary and hygienic standards due to the assimilation of excessive moisture, dilution of toxic emissions that can damage the human body and reduce the concentration of harmful impurities. All this allows the employee to be on his own site in a comfortable environment that meets all established norms and rules. In the event that there is a low temperature in the room, the ventilation system of the supply air type can solve this problem by heating the supply air masses.

The simplest device, which is installed in various workshops and production facilities, is a fan that has an air vent. Due to the fact that the number of various harmful and toxic impurities in enterprises is usually higher than normal, the use of only one ventilation system is not always effective. To maximize the safety of employees, modern enterprises use both a natural and a mechanical system.

In the modern market, a huge number of different systems, ventilation, which allow you to create within the workplace the most safe and comfortable working conditions. The widest choice of devices that differ from each other both in functionality and price, will satisfy the demands of even the most demanding customer. During the construction of a complex industrial ventilation system, it is necessary to install both a supply equipment that is a guarantee of supplying clean air to the shop and plant premises and special extraction systems. With their help, you can remove air from the workplace, saturated with pathogenic bacteria, toxic substances, dust, smoke and other harmful elements. It is selected proceeding from features of manufacture.

Choose one or another variation of the equipment individually, with due consideration for the differences and features that are inherent in a particular industrial or construction large object.

The ventilation system must have the following parameters:

• Economical.
• Efficiency.
• Reliability.
• Quick payback.

Thanks to clean and cool air, you can achieve not only good mood, health and efficiency of employees, but also low wear of technological equipment and various tools. It is economically expedient to add a device in the design of the project, which is connected to the ventilation system and provides a comfortable indoor microclimate.

To date, the most optimal way to control the parameters of the ventilation system is the use of automatic computerized systems that make changes to certain characteristics, based on data obtained from outdoor sensors. Thus, it turns out to achieve maximum economy and efficiency in work.

Thanks to the use of supply air or extraction circuits   , you can easily bring to normal moisture levels in the enterprise, and also neutralize, heat, cool, filter or moisten the air. The huge advantage of forced ventilation is that its operation is not affected by external conditions and weather factors. Removal and air supply can be made from the required point. You can make exact calculations of supply or exhaust ventilation and make a schedule of costs.

The work of ventilation systems is influenced not only by competent selection of equipment and installation, but also by atmospheric discharges, the shape of air receivers, the correct installation of filters, fans, air ducts and other elements. At the enterprises it is most expedient to install axial or radial blowers operating from electricity. Thanks to such a solution it is possible to easily provide employees with clean airspace at the workplace, free of harmful impurities and toxic elements. For the best filtration, electrofilters and other components are often used today, which can safely protect even the environment saturated with aggressive chemical compounds and components.

Air conditioning in enterprises and industries allows to achieve a normal microclimate, which is especially important for the optical industry, instrumentation, the vacuum industry and other areas where maintaining a certain humidity in the room is very important. To configure and install the ventilation system, it is best to refer to professionals with experience and knowledge in their field.

Ready-made ventilation systems need periodic cleaning, since if the channels are clogged, located in the production hall or room becomes unsafe because of the high concentration of particles of dust and harmful elements. For maximum efficiency, different filters are used today, made of felt, fabric, porcelain rings and all kinds of porous materials that perfectly absorb dust and toxic substances that can damage human health.

Features of equipment mounting

During the installation of ventilation systems in factories and industrial facilities, it is necessary to take into account a huge number of features and nuances that directly affect the durability of the design and efficiency directly during operation. That is why it is necessary to attract highly qualified specialists for installation of separate elements of the air exchange network, which have the relevant knowledge and experience. It is also important to choose the right place for installing equipment, such as filtration systems, fan units, heat exchangers and other units.

In industrial and production rooms are usually attached directly to the ceiling. If desired, they can be hidden using hanging decorative panels. In those rooms that are used for commercial purposes, it makes sense to use channels made of plastic or copper, which are reliable and durable and have an attractive appearance.

Currently in the construction of such types of air channels:

• Tough. For their production, materials such as fiberglass, multi-layer aluminum, galvanizing and others are used. Of these elements, the installation of virtually the entire ventilation system is carried out. The only exception is the special parts of the shaped sample, which are used for the device of branching, contours and turns. To transport air, which contains various harmful impurities, it is worthwhile to use air ducts with walls of increased thickness.
• Flexible. Their main purpose is the communication of various sections and openings with the ducts of the main line. For the design of a local ventilation system, the purpose of which is air cleaning in the immediate vicinity of the workplace, aluminum hoses are often used.

Installation of ventilation ducts in industrial and industrial areas is carried out in the following order:

1. To begin with, the wall thickness and air channel cross-sections are calculated, and then the mass of each of the elements of the ventilation system is calculated based on the obtained data. Sometimes the installation of channels with a square cross section is impossible because of insufficient space. Therefore, faced with a similar situation, it is worth using rectangular air ducts to solve the problem.
2. Then, at the junction points, the fixing points of the air ducts should be indicated. Thanks to this, you can easily calculate the required number of fasteners, brackets and other accessories. It should be remembered that for mounting brackets it is undesirable to allow the occurrence of oscillations of long network segments directly during the passage of air through them. It is most preferable to equip the structure with an excessive number of fasteners, since in this case they will withstand even an increased load without problems.
3. When the installation of the trunk channels is carried out, it is possible to start installing separate suction and spray devices. For such cases it is recommended to use special hoses that have the flexibility and the required cross-section.

conclusions

Installation and design of industrial ventilation systems is a responsible and complex process. The finished project must comply with strict building codes and current regulations. This directly affects the health of employees and the efficiency of the whole team.