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Ventilation of industrial premises is very important in the process of human work, as it is in them for quite a long time. Any enterprise needs sufficient air exchange — this is one of the postulates of creating a normal microclimate for the work of personnel and equipment. One or another type of ventilation system is calculated during the design based on the type of room and its purpose. It can be of three types:
- Natural. This is when air exchange is carried out due to the pressure drop and takes place naturally.
- Forced. This type of ventilation system is carried out using various mechanisms that force the air flow to move in a given direction.
- Mixed type. Natural ventilation is complemented by the operation of a forced system, which significantly increases the efficiency of air exchange.
Natural air exchange of industrial premises
Industrial ventilation systems are equipped with supply and air intake openings, which are located at a height of 1.8m and 4m, to control air exchange under various weather conditions. Colder air masses, entering through the upper openings, descend, thereby mixing with warmer air currents.
Natural air exchange allows you to control the temperature in the production areas. In the cold season, the access of cooled air masses through the lower ventilation openings is blocked, thereby regulating the temperature in the workshops.
Forced air exchange of industrial premises
Depending on the specifics of the production premises, as well as their area, special supply and exhaust equipment can be used to increase air exchange. Industrial premises in which there are conditions for the presence in the air of substances hazardous to human health in high concentrations, high humidity or elevated air temperatures — supply and exhaust ventilation is a must.
When it is used, the air exchange rate increases significantly, thereby reducing the concentration of polluted air and its negative impact on the health of personnel.
Paint shop ventilation systems
The main task of ventilation of industrial buildings in which paint shops are located is the removal of toxic vapors of solvents and paint and varnish suspension from the air masses. The concentration of these substances in the air of a working workshop is so high that it can become a threat of explosion or fire, and also causes considerable harm to human health.
Its efficiency is determined by air circulation, but for a paint shop, the air flow must be tens or even hundreds of times more than in other production shops, so they use powerful supply and exhaust ventilation. When designing ventilation systems for rooms in which painting work is planned, the intended method of painting products is also taken into account.
When painting products by dipping them into a bath, i.e. without using a spray gun, the concentration of paint and varnish suspension in the air will be relatively small, and for this it is enough that ventilation provides an air change rate of 5-6 times per hour. But in those workshops where a spray gun is used to paint parts, the concentration of hazardous substances in the air reaches critical values and requires ventilation from 20 to 200 times the change of air in the paint shop.
A ventilation system of such power often becomes very energy-consuming, which is economically unprofitable for the enterprise, therefore, they began to design systems that would reduce the content of explosive volatile substances to a concentration, eliminate the threat of an explosion or fire at the enterprise. Employees of such a workshop are issued personal protective equipment, such as balloon respirators and special protective clothing.
Depending on which pairs emit paintwork products used in a particular production, the location of the supply and exhaust air ducts is designed. The fact is that some poisonous gases are heavier than air, so it is advisable to remove them through the air intake grilles, which are located in the lower part of the room, and the inflow is carried out through air ducts located in the upper part of the workshop. If the vapors emitted by the paint are lighter than air, then the exhaust ducts are located in the upper part of the room, and the supply ducts are located in the lower part.
Mixed air exchange system
The paint shop uses both natural ventilation and forced ventilation, but with different air ducts and air shafts. The local ventilation system is designed in such a way as to effectively carry out air exchange, depending on the volatility of substances, in the following proportions: 2/3 of the air from the top of the room, and 1/3 from the bottom, or vice versa.
Air intake grilles should be located near spray tables, bathtubs, dryers, sprayers, booths, etc.
Hot shop ventilation
In hot catering shops, special attention is paid to the removal of air masses with high temperature indicators, as well as the effective removal of odors and air with a high content of fatty suspension. In addition, in the air streams that rise from the hot surfaces of the stoves, there are a large number of: carbon monoxide, soot, water vapor. These substances, mixing with the air of the room, create a real problem for people who stay in it for a long time.
To combat these phenomena, a forced ventilation system is used, the first barrier in which is the exhaust kitchen «umbrellas» of the 1st level. They are located above the stoves and «intercept» polluted air flows that pass through various filtration systems and are discharged outside the premises through air ducts.
Forced exhaust in hot shops
Forced ventilation in hot shops is also carried out through a system of «umbrellas», but 2 levels through which the extract of cleaner air flows passes. But the most important indicator in the design of ventilation systems for hot shops is its performance, which directly depends on the heat load of the shop. As an example, we will give one of several possible calculation methods that are most often used in the design of ventilation systems for hot shops:
The calculation method is the sum of the capacities of all heating devices divided by the area of the hot shop.
Important!
According to MGSN 4.14-98, the heat density of the room should not exceed 210 W / m2 of area.
Air exchange in hot shops
There is a small air exchange table that recommends:
- for small kitchens, with a ceiling height of 3m to 6m. use the air exchange rate: inflow 20; hood 30;
- for large rooms, with ceiling heights from 4m to 6m. the air exchange rate should be: inflow 15; extractor 20.
Important!
This air exchange calculation is quite approximate, and is suitable for quickly determining the air exchange at the beginning of the design of a hot shop ventilation system.
Ventilation of storage rooms
The main task in the design of ventilation of premises intended for the storage of products is the creation of a microclimate that contributes to the proper preservation of various products, raw materials or food products. The difficulty in designing effective ventilation for such buildings is considered to be the high density of stored products, racks and handling equipment, which is located in warehouses almost along the entire perimeter. Therefore, the ventilation systems of these buildings are subject to the same requirements as the ventilation of industrial enterprises with large equipment.
The ventilation system for these rooms should provide:
- Uniform distribution of air flows of a given temperature throughout the volume of the building.
- Maintaining the humidity level within the specified limits.
- Air exchange required for warehouses.
The main criterion for the effectiveness of ventilation in these buildings is air exchange. If they are used to store non-frozen or bulk food products, they are equipped with both supply and natural ventilation systems. Thus, the supply air enters through the air ducts to the direct location of the goods, and the exhaust removes the exhaust air flow through the air ducts located in the ceiling space. The air exchange rate in warehouses is 1, but this figure can be changed if it is planned to store products with special requirements.
Important!
Today, modern ventilation systems are an integral part of the overall climate solution, which includes: ventilation, air conditioning and heating.
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