In any office space there are people and almost constantly turned on computer equipment. Each room should be equipped with an elementary ventilation system to ensure optimal air exchange and microclimate. This point is very important for any company that wants to run its business successfully, and not pay for sick leave.

Arrangement effective system ventilation in the office key moment required for its efficient operation.

In a poorly ventilated room, the risk of the spread of infection increases, not to mention oxygen starvation, which is very bad for brain activity. That is why the established "project" must be serviced in accordance with the rules.

Designation of air exchange demand

Office ventilation is not as simple a task as it seems at first glance. The air exchange rate for each room is indicated separately, taking into account:

• room area;
• number of persons;
• humidity level;
• presence in the air harmful substances.

The formula for the frequency of air exchange, if the nature and amount of harmful impurities cannot be determined: L \u003d Vom. * Kp (m3/h).

Designations: V – office area, K – minimum air exchange rate. Quantity required air depending on the number of people, is determined by the following formula L=L1*Nl, where L1 is the volume of air needed by one person; Nl is the number of people in the room.

The amount of air required is measured in cubic meters. Its minimum is directly related to the degree physical activity employees and is registered in the norms of SNIP:

• 20–25 cubic meters - with minimal physical exertion;
• 45 - required for light physical work;
• 60 - with intensive physical work.

Formulas are used to determine the amount of air with excessive humidity, with excess heat, when harmful impurities. From these multiplicities we derive average and based on this data, they make an office ventilation project.

How to design an air exchange system?

Office ventilation is thought out in advance. The design of ventilation is directly related to the characteristics of the rooms. Ventilation office space may be of several types:

• supply and exhaust;
• forced ventilation in the office.

The ventilation system in the office can be centralized and decentralized. In the first case, the system supplies air to the entire building, in the second, a separate system is installed for each room. To ensure normal air exchange in office premises, it is impossible to connect the ventilation systems of bathrooms with general exchange ones.

A decentralized system is equipped mainly in rooms where there are no large crowds of people. For each separate group of rooms, small supply or supply and exhaust structures are used.

They are installed for the most part warehouses, corridors. Electricity is used to increase the air temperature in the premises, because the supply thermal pipeline from the boiler room significantly increases the cost of installation.

Requirements for ventilation systems

Ventilation standards must be observed. Hygiene requirements to the microclimate are described in SNIP. The ventilation of offices at different times of the year will be different: in summer, the air temperature should be 19-21 degrees, and in winter 23-25. Humidity in the room warm time year should not exceed 60%, and in winter period– 65%. Speed air flow in winter and summer 0.2–0.3 m/s.

The specified air exchange rates are presented for rooms of 2-3 categories. Rationing of the microclimate can be carried out naturally or by a forced central ventilation system.

Security optimal microclimate and maintaining sanitary and hygienic standards involves maintaining the required temperature regime during the hot period at 28 degrees or below. Otherwise, ventilation and air conditioning must be planned.

The requirements of SNIP are based on the design of the premises, their purpose. The multiplicity of heat transfer is calculated according to special formulas and tables. The power of the air supply will depend on the occupancy of the room with people and household appliances. The most commonly used centralized ventilation system.

The design of an office air conditioning system takes into account the subsequent repair of ventilation. An autonomous hood is equipped in bathrooms, smoking rooms, in rooms with a large accumulation of equipment. According to SNIP, individual exhaust filters can be located in conference rooms.

Maintaining an optimal microclimate is achieved due to the fact that the air flow passes into each separate room. Part of the air is supplied to corridors and rooms equipped with an exhaust system only.

Removal carbon dioxide from the premises occurs due to its displacement by air into a room equipped with an exhaust hood. According to the requirements of SNIP, in rooms with an area of ​​35 square meters and above, it is supposed to install both supply and exhaust pipelines.

Simultaneous installation of supply and exhaust air ducts is required in office premises with an area of ​​more than 35 square meters

How to install the equipment?

When installing ventilation systems in offices, it is necessary to rely primarily on the requirements of SNIP for sanitary standards. First, calculate the area of ​​​​the room. Then they move on to drafting. After determining the effectiveness of projects in ensuring the maintenance of the microclimate, they proceed to the choice of materials and the installation of fans.

According to SanPiN, a supply and exhaust ventilation system is installed in office premises.

The main unit is mounted to the ceiling of the hall, together with exhaust fan and air duct. A distribution pipeline is carried out to the offices.

Adjustment of air exchange and maintenance of the microclimate is carried out due to the penetration of fresh air from the street through openings covered with grilles. Inside the supply system, filtration, heating or cooling takes place as needed, and after distribution along the main line to the premises.

At the same time, carbon dioxide from the offices enters the hood and goes out into the street. If before installation everything was planned in accordance with the rules of SanPiN, then the room after installation does not even have to be ventilated using window openings. So it will be possible to maintain silence inside the office and avoid air polluted by machines from entering the room.

The most common ventilation devices will be discussed below in more detail.

1. Mechanized supply and exhaust structure - can be localized on the roof or in the basement. The system involves the installation of shafts through which clean air from the street enters a separate floor. When the ventilation equipment is installed on the roof, it must be additionally strengthened, and when installed in the basement, there is no possibility to use it for any other purposes.
2. Mini supply and exhaust systems– provide maintenance of a microclimate and air circulation. They are installed on every floor. There are practically no downsides to this system.
3. The multi split air conditioning unit with fresh air can be operated as a natural or exhaust ventilation. The outflow of air masses will be carried out at the expense of the highway, and the inflow will be organized by a split system. Such systems are installed only in rooms with a small area.

For big office centers or, if the building contains numerous offices that are not equipped with a powerful air exchange system, the installation of multi-zone split equipment is recommended.

How to heat or cool the air in a room with a ventilation system?

IN cold weather the room cools down very quickly, so there is a need to heat supply air. The most popular heating method is a heater built into the ventilation system.

The heater, built into the ventilation system, is the most effective method supply air heating

The air temperature regulation system significantly reduces the cost of heating in buildings, but only in the case of a room of 150 square meters. If the room has more dimensions, you will have to use a heater with more power, which is quite expensive.

Heat recovery ventilation can greatly reduce heating costs. The heat exchanger has proven itself well in supply and exhaust types of ventilation. The supply air is heated by the extracted hydrocarbon. With such a normalization of the temperature regime, up to 80% of the heat is transferred from the output air masses.

If it is necessary to heat the air for an office space with large area using a water heater. The main disadvantage of this type of ventilation is the complexity of installation and repair in the event of a breakdown.

Instrument maintenance

Maintenance of the ventilation system includes scheduled inspections, as well as scheduled preventive maintenance. repair work during which disassembly, inspection and replacement, if necessary, of worn parts are carried out.

In order for the ventilation of the room to be of high quality, all kinds of planned work is carried out to prevent breakdowns, which are divided into several types:

• current repair;
• repair work medium difficulty;
• overhaul.

When a breakdown involves partial replacement and dismantling, we are talking about works of medium complexity. Depending on the nature of the breakdown, work can be carried out on site or a decision is made to send the device to the factory.

If, during the inspection of the devices, multiple damage to components and systems is found, defects in the operation of the air conditioner that affect the quality of ventilation, a major overhaul is required. Working with ventilation after installation is a complex process, consisting of a set of measures that allow you to extend the life of the device.

Setting and regulation of devices

Device regulation - important point. Office ventilation systems are controlled by automation. Such a system implies the presence of an electrical panel, with a built-in control panel for the ventilation system.

An elementary option is a lever that regulates the on / off of the device.

The most popular option, which greatly simplifies the control and regulation of serviceability is industrial automation. Such a regulation system allows you to set the level of contamination of fans, filters, if necessary, turns off the system, etc. To implement this complex process built-in thermostats, pressure sensors, hydrostats are used.

One of such devices that control the state of the ventilation system is a microprocessor controller. This device has a screen with a simple interface. All signals about fluctuations in pressure and temperature are given temperature sensors and pressure regulators.

Microprocessor controller - a device that allows you to control the state of the ventilation system

Temperature sensors are divided into devices for rooms and channel. Some are used to control the temperature regime in the line, and the latter determine the temperature of the air flows in the rooms themselves. The work is carried out as follows: the device sends a signal to the control panel, where the received data are compared with the programmed ones and a change occurs in the operation of the ventilation system.

Pressure regulation sensors allow you to monitor the speed of air flow along the highway. Carries out adjustment of work of a heater, protecting from false start and allows to define pollution of filters, cuperators in time.

Conclusion

Installation of ventilation in the office important process. In any such room, ventilation must be designed in advance. Even if you ventilate the room very often, it does not give the same effect as a good supply and exhaust system.

Normally in a room where there are people and Appliances, should be supported temperature regime below 28 degrees in summer relative humidity no more than 65%. During the design of the system, they are guided by those prescribed in SNIP sanitary standards.

The speed and volume of air supplied will directly depend on the area of ​​​​the room, the number of people, equipment, the level of physical activity of persons in the room, the level of the permissible amount of impurities in the air.

Adjustment of ventilation systems is carried out using automation, which allows, through the use of temperature and pressure regulation sensors, to detect changes in time and correct the operation of the system.

Brief summary of SNiP on ventilation (sanitary norms and rules).

In what cases do SNiP provide for the installation of forced ventilation.

• if it does not allow achieving the required microclimate parameters in terms of cleanliness, humidity and content of pollutants;
• if the building or structure has zones and premises in which there is no natural air replacement;

SNiP ventilation on temperature standards.

When designing jointly, SNiP regulates the use of standby (duplicated) fans or the use of at least two heating appliances. This is done in case of failure of one of the fans, and in this case, ventilation SNiP allow a temporary decrease in air temperature, but not less than twelve degrees Celsius.

SNiP ventilation about backup fans.

• if, during an emergency shutdown, the operation of devices, units and equipment automatically stops, technological processes which provide for the release of polluting vapors, gases and dust-air mixtures into the air;
• if the installed in the building includes emergency ventilation capable of providing a performance of at least fifty percent of the capacity of the main system;

SNiP ventilation on fire safety.

In pursuit of comfortable conditions inside offices and residential premises, one cannot do without properly organized air exchange. In other words, inside them there should be a well-calculated, adjustable system ventilation. For premises for various purposes are guided by the relevant regulatory literature, but first we will consider what constitutes air exchange.

The concept of air exchange

Air exchange is a quantitative parameter that characterizes the operation of the ventilation system in enclosed spaces. In other words, air is exchanged to remove excess heat, moisture, harmful and other substances in order to ensure an acceptable microclimate and air quality in the serviced room or work area. Proper organization air exchange is one of the main goals when developing a ventilation project. The intensity of air exchange is measured by the multiplicity - the ratio of the volume of supplied or removed air in 1 hour to the volume of the room. The ratio of supply or exhaust air is determined by the regulatory literature. Now let's talk a little about SNiPs, SPs and GOSTs, which dictate the necessary parameters for us to maintain comfortable conditions in offices and residential areas.

Air exchange rates

Currently, a lot of literature has been published, let's consider only a small part:

Modern buildings have high thermal performance, airtight plastic windows to save costs for space heating, which inevitably leads to the tightness of the space itself and the lack of natural ventilation. And this, in turn, leads to stagnation of air and the reproduction of pathogenic microbes, which is not allowed by sanitary and hygienic standards, and to maintain good health in stuffy room unlikely to succeed. Therefore, in modern residential buildings necessarily provided supply valves in outdoor fences with a natural impulse, and in office premises one cannot do without a supply and exhaust device mechanical ventilation. All this is necessary to create comfortable conditions for people to stay in these premises.

Living spaces

The ventilation system of residential premises can be: with natural inflow and removal of air; with mechanical stimulation of the inflow and removal of air, including combined with air heating; combined with natural air supply and removal with partial use of mechanical stimulation. IN living rooms ah air flow is provided through adjustable window sashes, transoms, vents, valves or other devices, including autonomous wall air valves with adjustable opening. Air removal is provided from kitchens, latrines and bathrooms. The amount of air exchange in living rooms, according to, depends on the number of people living, 3 m³ / h per 1 m² of living space, if one person has less than 20 m² of the total area of ​​​​the apartment and at least 30 m³ / h per person, if one person has over 20 m².

Kitchen

The minimum air exchange rate in a kitchen equipped with electric stove, according to 60 m³/h, in case gas stove, it will be 100 m³ / hour. In the kitchen, air flow is ensured, as well as in living rooms. Since steam is generated during cooking, as well as volatile particles of oil or other fats, the air from the kitchen room must be removed directly to the outside and not enter other rooms, including through ventilation duct. In order for the natural draft to be sufficiently stable, the channel must be relatively high (at least 5 meters). Often in kitchen area installed above the stove exhaust hood, which helps to more efficiently remove excess heat from the room. In order to prevent air from flowing into the higher-lying apartments, an air shutter is made (a vertical section of the air duct that changes the direction of air movement), as a rule, in a building design.

Bathroom and laundry

The air in the bathroom and laundry rooms contains unpleasant odors, humidity and hazards emitted from household chemicals, therefore, like the air from the kitchen, it must be removed outside without the possibility of getting into other rooms. An air lock is also made in the exhaust ducts of these rooms. From the bathroom, according to, the amount of air exchange will be 25 m³ / h, and the laundry room 90 m³ / h. Supply air enters these rooms by overflow from living rooms through open door or through cracks in the doorway.

Office rooms

The amount of air exchange for offices, administrative buildings much higher than for residential buildings. This is due to the fact that the ventilation system must more effectively cope with the large amount of heat generated by numerous employees and office equipment. And a sufficient amount of fresh air has a positive effect both on people's health and on the work process as a whole.

For ordinary office premises, 40 m³/h per employee is accepted, if it is possible to periodically ventilate the room through window sashes, transoms, vents, or 60 m³/h per employee, if this is not possible.

Modern office buildings cannot be imagined without organized system ventilation, which must meet the following requirements:

• The ability to provide required quantity fresh air.
• Filtration, heating or cooling, as well as, if necessary, humidification of the supply air to comfortable conditions before supplying it to the room.
• The device of both supply and exhaust ventilation from the premises of offices.
• Installations must be low-noise and comply with the requirements in.
• The location is convenient for maintenance of ventilation units.
• Automatic control and weather-dependent regulation.
• Economical consumption of heat and electricity.
• The need to have a compact size and, if possible, fit into a business interior.

Properly calculated air exchange rate is vital inside enclosed spaces, because it allows you to remove exhaust air polluted by various technical fumes, particles of carbon dioxide emitted by humans, odors of consumer and vital activity products, heat from equipment and products, as well as many other sources. Considering all these parameters, thanks to the work supply and exhaust ventilation can support optimal performance indoor air, creating a comfortable microclimate.

Ventilation is the removal of air from the premises and its replacement with outdoor clean air. Ventilation is provided by the state air environment indoors in accordance with sanitary and hygienic requirements. in residential and public buildings the life of people, everyday processes (cooking, washing clothes, etc.) are accompanied by a decrease in the oxygen content in the air, accumulation, heat and moisture release, as well as indoor air pollution with foul-smelling substances and necessitate constant or periodic replacement with fresh. The intensity of such a replacement is usually determined by the ratio of the hourly volume of replaced air to the volume of the room, i.e., the frequency of exchange per hour. In accordance with sanitary and hygienic requirements, the norms of the frequency of exchange for residential, children's, school and hospital premises(table).

Ventilation of industrial premises is the most important means of combating emissions of harmful gases, vapors, dust, excess heat and moisture. The sources of these emissions are technological processes, production equipment and people. However, such a fight should begin with measures that prevent or reduce these emissions (localization of the source of unfavorable emissions by shelters with air exhausts - local suctions). Non-localized secretions are removed by ventilation. The required air exchange is determined by the formula:
where g is the hourly amount of harmful substances released into the premises in mg / hour; efficiency - maximum permissible concentration of a harmful substance () and Kp. - concentration of this substance in the injected air in mg/m 3 .

Ventilation air exchange in residential and some public premises

Air exchange in the premises is carried out different ways: 1) natural ventilation - through windows, doors, pores in the walls, due to the difference between the air pressures outside and inside; 2) artificial ventilation- using mechanical devices.

The efficiency of natural ventilation depends on the area of ​​the vents, transoms (which should be at least 1/40 of the floor area), the temperature difference between the indoor and outdoor air, and the degree of porosity of the walls.

Artificial ventilation provides constant air exchange in the room. It can be exhaust, supply and supply and exhaust and is carried out using axial and centrifugal fans (Fig. 1 and 2).

Rice. 1. Axial fan: 1 - wheel with blades; 2 - casing.
Rice. 2. Centrifugal fan: 1 - casing; 2 - bed; 3 - outlet; 4 - suction hole.

Rice. 3. Installation for air conditioning: 1 - opening for incoming outside air; 2 - mixing chamber; 3 - irrigation chamber; 4 - chamber with separators for retaining water drops; 5 - centrifugal fan; 6 - pump for water supply; 7 - heater; 8 - intermediate chamber.

The exhaust system consists of a fan with an electric motor and air ducts. The air of industrial premises, polluted with dust, harmful gases or vapors, must be cleaned before being released to the outside. Supply air to create a favorable microclimate (see) in the room is pre-treated. Therefore, the supply system, in addition to fans, electric motors and channels, includes heaters (heaters), filters or dust chambers, humidifiers or washing chambers, refrigeration and dehumidifiers. When it becomes necessary to maintain conditions of constant temperature and relative temperature in the room, devices for the so-called air conditioning are used (Fig. 3).

Sanitary standards in the USSR related to ventilation devices are concentrated in the following documents: Sanitary design standards industrial enterprises SN-245-63 (section 4B); building codes and rules of SNiP II-G. 7-62 "Heating, ventilation and air conditioning"; Design standards SNiP II-M. 3-68 "Auxiliary buildings and premises of industrial enterprises".

The task (preventive and current), carried out mainly by employees (SES), includes checking compliance with the main provisions of these documents.

When checking the operation of ventilation, one should pay attention to the correctness of its use, namely: that not only exhaust units work, but also supply ones; so that the supplied supply air does not create an unpleasant blast; so that the microclimate conditions correspond to the permissible ones, and the air samples taken do not contain harmful substances above the MPC. When controlling, flags and artificial haze should be used. To control air pollution, chemical laboratories of SES or enterprises should be involved.

§ 4. Sanitary standards for the design of ventilation and methods for determining air exchange

In accordance with sanitary standards, all production and auxiliary premises must be ventilated. IN industrial premises with an air volume per worker of less than 20 m 3, ventilation should be provided to ensure the supply of outdoor air in an amount of at least 30 m 3 / h for each worker, and in rooms with a volume per worker of more than 20 m 3 - at least 20 m 3 /h for each worker.

In industrial premises without lamps and without windows, the supply of outdoor air per worker must be at least 60 m 3 / h. At the same time, the norms of meteorological conditions must be observed, and the content of harmful vapors, gases and dust in the air working area should not exceed the limit values ​​​​according to sanitary standards.

In rooms where the air environment is polluted with dust, harmful vapors or gases or significant heat emissions are observed, the amount of air necessary to provide the required parameters of the air environment in the working area is determined by calculation, based on the condition of diluting harmful emissions to acceptable concentrations or removing excess heat.

When installing supply and exhaust ventilation in interconnected premises, it is necessary to ensure a certain ratio between the amount of supplied and exhausted air in order to exclude the flow of air from rooms with high emissions of harmful substances or with the presence of explosive gases, vapors and dust into rooms with lower emissions or into premises without these allocations.

When installing local exhaust ventilation, the amount of air removed is taken depending on the design of the local suction, the nature of harmful emissions, the speed and direction of their movement. In this case, they are most often guided by a certain value of the air suction rate in the openings of the local suction, choosing it such that the most complete capture of harmful emissions is possible.

For local suctions, performed in the form of umbrellas, shelters, cabinets and chambers, the air intake velocity in open holes (openings) is taken at a rate of 0.5–0.7 m/s to remove gases and vapors with low toxicity (alcohol vapors , ammonia, etc.), and at a rate of 1.2-1.7 m/s to remove gases and vapors of high toxicity and volatility (aromatic hydrocarbons, cyanide compounds, lead fumes, etc.). The volume of air removed L with the help of local exhaust ventilation can be calculated by the formula L = Fv * 3600 m 3 / h,

where F is the area of ​​the lower (open) section of an umbrella or an open opening, shelter, cabinet, chamber in m;

v is the speed of movement of the intake air in this opening in m/s.

The amount of exhaust air ventilation devices from abrasive and polishing machines is calculated by the formula L = AD m 3 / h,

where D is the circle diameter in mm;

A is a coefficient equal to. 1.6 for abrasive machines, 2 for polishers and 2.4 for oscillating emery wheels.

The air removed by local suctions, containing dust, toxic gases and harmful vapors, must be cleaned before being released into the atmosphere. The degree of purification of emissions containing dust, harmful odorous substances is established depending on their maximum permissible concentration in the air of the working area of ​​industrial premises and in such a way that atmospheric air within the enterprise could be used in supply ventilation without prior processing (cleaning).