The principle of installing office ventilation. Office ventilation: sanitary standards for the supply and exhaust system, room standards Standards for supply and exhaust ventilation

The air exchange rate according to SNiP is sanitary indicator indoor air conditions. The comfort and safety of people staying in a particular room depends on its value. The permissible value of this parameter is regulated by state building codes and the rules that determine different requirements for all erected buildings.

General information

Before defining optimal indicator the air exchange rate according to SNiP in premises (residential or industrial), it is necessary to study in detail not only the parameter itself, but also the methods of its calculation. This information will help you choose the most accurate value that is suitable for each specific room.

Air exchange is one of the quantitative parameters characterizing the operation of the ventilation system in enclosed spaces. In addition, it is considered the process of replacing air in the internal spaces of a building. This indicator is considered one of the most important in the design and creation of ventilation systems.

There are two types of air exchange:

1. 1. Natural. It occurs due to the difference in air pressure inside and outside the room.
2. 2. Artificial. This is done through ventilation (opening windows, transoms, vents). In addition, it includes the entry of air masses from the street through cracks in walls and doors, as well as through the use of various systems air conditioning and ventilation.

The air exchange rate is a parameter showing how many times (within 60 minutes) the air in the room was completely replaced with new one.

Its value is determined not only by SNiP, but also by GOST ( state standard). The set of measures that need to be taken to maintain optimal conditions V residential apartments and office premises.

Ventilation in the apartment. What is natural ventilation in an apartment?

Calculation rules

Most newly constructed buildings are equipped with sealed windows and insulated walls. This helps reduce heating costs in cold period years, but leads to a complete cessation of natural ventilation. Because of this, the air in the room stagnates, which causes the rapid proliferation of harmful microorganisms and a violation of sanitary and hygienic standards. Therefore, in new buildings it is important to provide for the possibility of artificial air ventilation, taking into account the expansion rate.

Air exchange standards in premises (residential or industrial) depend on several factors:

• purpose of the building;
• number of installed electrical appliances;
• thermal output of all operating devices;
• the number of people who are constantly in the room;
• level and intensity of natural ventilation;
• humidity and .

The air exchange rate can be determined using the standard formula. It involves division required quantity clean air, entering the building in 1 hour per room volume.

Thanks to natural aeration, this figure can reach 3 or 4 times per hour. If significantly more frequent air exchange is required, then mechanical ventilation is used.

Values ​​for different buildings

In order for people in a particular room to feel as comfortable as possible, it is necessary to comply with the air exchange rates stipulated by building codes and regulations. They differ significantly for various buildings, so you should approach their choice with maximum responsibility. Only in this case can you achieve the desired result and create a ideal conditions to find people.

All residential buildings require provision of not only artificial, but also natural air flow. If one of them is not enough, then it is allowed to use combined option. At the same time, it is also necessary to ensure the removal of stagnant oxygen. This can be done by arranging ventilation ducts from the following premises:

• bathroom;
• restroom;
• kitchen.

Besides this, everything modern buildings are equipped with special autonomous air valves. They can be opened and closed by apartment owners, and also perform the function of removing stagnant air.

The frequency of air exchange in a residential area is indicated in SNiP 2.08.01−89. According to these standards, the indicator should be like this:

• Separate room in the apartment (bedroom, children's room, playroom) - 3.
• Bathroom and individual restroom - 25 (if combined, the value should be 2 times greater).
• Dressing room and washroom in the dormitory - 1.5.
• Kitchen with electric stove - 60.
• Kitchen with gas equipment - 80.
• Corridor or lobby in an apartment building - 3.
• Ironing, drying, laundry in the dormitory - 7.
• Pantry for storing sports equipment, personal and household items - 0.5.
• Elevator machine room - 1.
• Staircase - 3.

Calculation of air exchange in the boiler room ( detailed analysis)

In office centers

The size of the air exchange rate for administrative buildings and offices are much larger than for residential premises. This is due to the fact that the ventilation and air conditioning system must efficiently cope with heat emissions emanating not only from workers, but also from various office equipment. If you properly equip the ventilation system, you can improve the health and increase the productivity of employees.

Basic requirements for the system:

• filtration, humidification, heating or cooling of air before supplying it to the room;
• ensuring a constant supply of sufficient fresh oxygen;
• arrangement of exhaust and supply ventilation systems;
• the use of equipment that will not create much noise during air exchange;
• the most convenient location of installations for the convenience of carrying out repair and preventative measures;
• the ability to adjust the parameters of the ventilation system and adapt its operation to changing weather conditions;
• ability to provide high-quality air exchange with minimum costs electricity;
• the need to have small dimensions.

All these requirements will help you quickly remove from indoors exhaled carbon dioxide and fumes coming from operating equipment.

For correct settings air conditioning and ventilation systems, it is necessary to accurately calculate the multiplicity and compare it with the standards of SNiP 31−05−2003, which provide such meaning:

Production workshops

It is especially important to ensure good air exchange in industrial premises, where people work in the most harmful conditions. To reduce negative influence For their health, it is necessary to properly equip the ventilation system and calculate the air exchange rate.

To total values influenced by several main factors:

Define optimal value air exchange rate for production premises according to table SNiP 2.04.05−91. It indicates the value of this parameter for each specific room.

• Shops where work is performed that does not require much physical effort - 25.





The main ones are:



The air exchange rate, standardized according to SNiP, is one of the most important indicators of the air condition in a particular room. If it is calculated correctly and all recommendations provided by standard standards are followed, you can significantly increase the quality of aeration, as well as make people’s stay in the room more comfortable and safe.

Sanitary standards for ventilation of premises - SNiP standards

During construction, weight must be taken into account various factors, carry out calculations. But no matter what room you build, Special attention attention should be paid to ventilation.

Air exchange or ventilation rules are clearly stated in the Code of Rules SP 60.13330.2012 “SNiP 41-01-2003. Heating, ventilation and air conditioning.” It is this set of rules that must be followed when creating a project for any building and its construction.

A proper air circulation system will eliminate dampness and stuffiness. In addition, air exchange is directly related to the environment and energy supply.

That is why it is better to choose the type of air exchange at the design stage.

There are three main types of air exchange

1. Natural ventilation of buildings. With this type, air masses move in an organized and unorganized manner. Forced or unorganized ventilation occurs through the natural openings of the structure: various cracks, windows and vents. An organized or exhaust ventilation system represents special exhaust valves installed in buildings.
2. Forced ventilation. This type of air exchange is used in rooms with good sealing. This type is characterized by the use of specialized mechanisms - fans, heat exchangers.
3. Combined air exchange system. This type of ventilation involves a combination of two types. The presence of natural and forced intake of air masses into the building.

For various types of structures, our legislation has established sanitary standards ventilation of premises.

Ventilation standards for residential premises

To ensure that air in a residential building is of high quality and in sufficient volume, need to follow the rules established by law. After all, human health directly depends on air quality. For each specific residential structure, a specific value is established.

When calculating air exchange in residential buildings method applied specific standards circulation of air masses. It consists of taking into account sanitary and human loads. The balance of incoming air masses with the outgoing air masses is also taken into account. Air flows should move from the room with the best air circulation to buildings where the air quality is lower.

In order to produce correctly necessary calculations two quantities need to be taken into account - the total area of ​​the residential structure and air exchange rates for each person, which is located in this building. To begin with, the first value is set. To do this, the air circulation rate per hour is multiplied by the total volume of the room.

The first value is fixed and equal to 0.35. Then the ventilation norm of the residents is calculated. When making calculations for rooms with a total area less than 20 sq.m. per person it is necessary to multiply the living area by a factor equal to 3.

And for residential buildings with a total area of ​​more than 20 sq.m. per person, you need to multiply the number of residents by the standard air exchange value per person, which is 60. After the calculations, you need to produce exhaust air in additional premises, taking into account their type (kitchen, bathroom, toilet, dressing room). Each type has its own standard. After this, the maximum result is taken into account.

The ventilation system must provide high-quality air environment. In residential buildings, air circulation between apartments is unacceptable, between the kitchen or toilet and living rooms. Autonomous ventilation is required. Mines exhaust ventilation must protrude above the ridge of the roof or flat roof to a height of at least 1 m. concentration harmful substances in the air should not exceed the norm.

Ventilation standards in office premises

By by and large, an office is a production building with a large number of people in it. The presence of 30-40 cubic meters quality air per person. Fixed for a certain type of office parts different size. For work room and the office it is 60 cubic meters per person, for the reception and meeting rooms - 40 cubic meters, for meeting rooms - 30, the ventilation norm for corridors and halls is 11 cubic meters, for toilets - 75, and in smoking rooms this norm is 100.

Sanitary rules for offices, the percentage of air humidity is set, depending on temperature. At a temperature of 25 degrees, humidity cannot be more than 70 percent, at 26 degrees - 65, and at 27 no more than 60 percent.

Ventilation standards in industrial premises

Production premises are specialized premises. SNiP determines air circulation standards for industrial buildings based on the amount of toxic elements. The air quality in such structures is influenced by many factors - large amounts of dust, excess humidity, special temperature indicators, chemical exposure.

To establish ventilation standards in industrial buildings necessary First, calculate the air exchange rate for a specific room. This is a tabular value. So, the multiplicity rate must be multiplied by the total area and height of the above-mentioned building.

Thus, to establish proper ventilation production buildings need to take into account the characteristics of this very production. Namely, the amount of heat generated, liquids or condensate, harmful substances, emissions from equipment, communications and fittings.

For production facilities, according to sanitary standards, one working person should receive not less than 30 cubic meters per hour, if the building area is less than 20 cubic meters. With a total area of ​​more than 20 cubic meters per person, there should be no 20 cubic meters per hour. And in buildings without natural ventilation, at least 60 cubic meters per person.

Ventilation standards in warehouses

Warehouses are buildings designed to store certain goods and cargo. And the shelf life of the warehouse contents largely depends from its microclimate - temperature, air mobility and humidity. Depending on the characteristics of the warehouse contents, combined and coercive systems ventilation. Ventilation in a warehouse should completely replace the air in an hour - this is a multiple of one.

For warehouses in which gasoline, kerosene, oils and volatile substances are stored, and personnel are located there temporarily, the multiplicity is 1.5-2, if constant - 2.5-5. Warehouses with cylinders liquefied gases and nitro varnishes - 0.5, when people are temporarily in it. In warehouses for storing flammable liquids, the multiplicity for temporary occupancy of people is 4-5, temporary – 9-10. In storage rooms toxic substances hourly multiplicity – 5, during temporary stay.

About approval of the Rules fire safety V Russian Federation

(PPB 01-03)

Excerpt:

75. Smoke pipes boiler installations operating on solid fuel must be equipped with spark arresters and cleaned of soot in accordance with clause 67. Boiler rooms built into the buildings of commercial establishments are not allowed to be converted from solid fuel to liquid.

76. Fire-retarding devices (dampers, dampers, valves, etc.) in air ducts, devices for blocking ventilation systems with automatic installations fire alarm or fire extinguishing, automatic ventilation shut-off devices in case of fire must be checked within the established time limits and maintained in good condition.

77. When operating ventilation and air conditioning systems, it is prohibited:
leave the doors ventilation chambers open;
close exhaust ducts, openings and grilles;
connect gas heating appliances to the air ducts;
burn off accumulated in air ducts body fat, dust and other flammable substances.

78. Ventilation chambers, cyclones, filters, air ducts must be cleaned of flammable production waste within the time limits specified by the organization order.
For explosive and fire hazardous premises, a procedure for cleaning ventilation systems using safe methods must be established.

Sanitary and epidemiological requirements for organizations engaged in medical activities

Sanitary and epidemiological rules and regulations SanPiN 2.1.3.2630 – 10

Excerpt:

6.36 Air ducts, air distribution and air intake grilles, ventilation chambers, ventilation units and other devices must be kept clean and free of mechanical damage, traces of corrosion, leakage. The use of ventilation chambers for purposes other than their intended purpose is prohibited. Cleaning of ventilation chambers should be carried out at least once a month, and air intake shafts at least once every six months. Maintenance, cleaning and disinfection of ventilation systems is provided at least once a year. Elimination of current malfunctions and defects is carried out immediately.

Excerpt:

Fire regulations in the Russian Federation PPR RF clause 50

Cleaning ventilation systems provides:
– safety of ventilation equipment, maintenance efficient work and proper condition of individual parts of air ducts;
– reduces the likelihood of ignition of flammable deposits;
– maintaining design parameters of the ventilation system;
– sanitary and epidemiological safety and protection from numerous viral and respiratory diseases.

Cleaning of ventilation systems includes:
– Cleaning inner surface air ducts, natural ventilation and chimneys from dust and grease deposits, is carried out to ensure fire safety of buildings, maintain hygienic cleanliness ventilation;
– Fire retardant valves must be cleaned regularly to maintain the functionality of the valve actuators during emergency situation;
– Cleaning of heaters and fans is also carried out to ensure normal operation ventilation system.

Cleaning Frequency
Cleaning must be carried out regularly, depending on the purpose of the room:
For administrative, trading, office premises- 1 time per year.
For industrial applications at least 2 times a year.
For organizations Catering– 1 time per quarter.
For healthcare organizations – once a quarter.
For Preschool Educational Institutions– 2 times a year (clause 5.7.8 SanPiN 2.4.1.1249-03)
Cleaning heaters from contamination - 2 times a year;
Clean filters – once a month and replace them when dirty;
Monitoring the cleanliness of air intakes and ducts – once a year

Disinfectants
On the territory of the Russian Federation, the use of disinfectants is allowed only if there is a certificate of state registration (registration certificate) issued in in the prescribed manner Ministry of Health of Russia, guidelines for their use approved by the Ministry of Health of Russia, certificate of conformity.
To achieve a reliable effect of killing microorganisms, it is necessary to comply with the basic requirements set out in methodological guidelines on the disinfectant used - consumption rates, concentrations, exposure time (contact), method of application, frequency of treatment, formulation disinfectant.
When choosing a disinfectant, you should take into account the characteristics of the object being treated, biological properties circulating microorganisms, features of disinfectants.

Risks if there is no maintenance and periodic cleaning:
– accumulation of dust and grease deposits occurs, which makes it difficult to maintain the specified air parameters;
– contaminated air ducts create the possibility of fires;
– spread of fire throughout the building along with the movement of air inside the air ducts;
– the fan may fail due to overheating, which will lead to expensive repairs;
– If the ventilation system, in addition to transporting air, is designed to heat, cool and humidify it, then accumulated dust deposits create favorable soil for the growth of mites, bacteria, fungi and other microorganisms dangerous to humans. Over time, microorganisms can break off from the surface of the air ducts and be carried by the air flow into the premises served. Diseases such as allergies, influenza, and SARS can be transmitted through ventilation, from an infected person to a healthy person;
–imposition of an administrative penalty on entity according to the Code of Administrative Offenses of the Russian Federation, Article 20.4, from 150,000 to 200,000 rubles.

Fire regulations in the Russian Federation

Resolution dated April 25, 2012 No. 390 On the fire safety regime

In accordance with Article 16 Federal Law“On fire safety” the Government of the Russian Federation decides:

1. Approve the attached Fire Regulations in the Russian Federation.

2. This resolution comes into force 7 days after the day of its official publication, with the exception of paragraphs 6, 7, 9, 14, 16, 89, 130, 131 and 372 of the Rules approved by this resolution, which come into force on September 1 2012

Excerpt:

49. In accordance with the manufacturer’s instructions, the head of the organization ensures inspection of fire-retarding devices (dampers, dampers, valves, etc.) in air ducts, blocking devices for ventilation systems with automatic fire alarm or fire extinguishing installations, automatic devices turning off ventilation in case of fire.

50. The head of the organization determines the procedure and timing of work to clean ventilation chambers, cyclones, filters and air ducts from combustible waste with the drawing up of a corresponding act, and such work is carried out at least once a year.

Cleaning ventilation systems Explosion-hazardous and fire-hazardous premises must be carried out using fire and explosion-proof methods.

51. It is prohibited to operate with faulty and disconnected hydrofilters, dry filters, dust collection and other devices of ventilation (aspiration) systems. technological equipment in fire and explosion hazardous areas (installations).

Excerpt:

Decree of the Government of the Russian Federation of December 30, 2011 N 1225 “On licensing of installation activities, maintenance and repair of fire safety equipment for buildings and structures” does not provide for licensing of air duct cleaning work.

March 16th, 2017 y.geny

You can order a range of works for the calculation, selection and installation of a ventilation and air conditioning system for your premises, building, office from our company: .

Work ability office worker directly depends on the indoor microclimate. According to the data medical research, the air temperature in the office should not exceed 26 degrees, whereas in practice in buildings with panoramic windows and with the abundance of technology it can go off scale beyond 30 degrees. In the heat, the reaction of employees is dulled, and fatigue increases. Cold also has a bad effect on work ability, causing drowsiness and lethargy. Lack of oxygen and high humidity create unbearable conditions for employees, reducing labor productivity, and hence the profitability of the enterprise.

To maintain optimal temperature and humidity conditions, an office ventilation system is installed.

Office ventilation requirements

Ventilation in an office building must meet the following requirements:

• ensuring a flow of fresh, clean air;
• removal or filtration of exhaust air;
• minimum noise level;
• accessibility in management;
• low power consumption;
• small size, the ability to fit harmoniously into the interior.

The load on office climate systems is significantly higher compared to household ones. It is required to efficiently remove excess heat and carbon dioxide generated by equipment and employees, and supply clean and filtered air at a given temperature.

Previously used natural systems office ventilation today is not able to provide conditions regulated by sanitary standards. The operation of natural ventilation cannot be controlled; its effectiveness is highly dependent on the air parameters outside. In winter, this method threatens to cool the room, and in summer it causes drafts.

Widely used in the construction of office buildings, modern hermetically sealed windows and doors and continuous panoramic glazing prevent the passage of air from outside, causing it to stagnate and deteriorate people’s well-being.

All requirements for ventilation of office premises are specified in SanPiN (Sanitary rules and regulations) 2.2.4.

According to the document, the humidity in the premises should be:

• at a temperature of 25 degrees – 70%;
• at a temperature of 26 degrees – 65%;
• at a temperature of 27 degrees – 60%.

Office building ventilation diagram

The following ventilation standards in offices have been developed, taking into account the purpose of the room, in cubic meters per hour per person:

• manager's office - from 50;
• conference room – from 30;
• reception - on average 40;
• meeting room – 40;
• employee offices – 60;
• corridors and lobbies - at least 11;
• toilets – from 75;
• smoking rooms – from 100.

SanPiN for ventilation of office premises also regulates the speed of air movement of 0.1 m/s, regardless of the time of year.

As a rule, ventilation of small office premises is carried out using several air handling units. If during the hot season the office supply ventilation is not able to lower the air temperature below 28 degrees, additional air conditioning is required.

Separate air handling units are needed in conference rooms. Additional exhaust devices– in toilets, smoking rooms, corridors and lobbies, copy rooms. Mechanical exhaust from office rooms is necessary if the area of ​​each office is more than 35 square meters. meters.

If the total area is not more than 100 sq. meters and there are 1-2 toilets, natural supply ventilation is allowed in the office through the vents. Supply and exhaust ventilation is installed in medium and large sized offices.

Office ventilation system project

The ventilation system of an office building has a number of functions. Therefore, when designing, many factors are taken into account, regulated by SNiP rules for ventilation of office premises No. 2.09.04.87 and 2.04.05.91. The system is assembled from units of varying cost, functionality and design. The task of designers is to choose them correctly.

The following points are agreed upon with the customer:

• location of the ventilation unit;
• location of ventilation ducts;
• power of the electrical system, possibility of water supply;
• the need and ways of the drainage system;
• access to equipment after installation;
• possibility of design changes.

Design of ventilation systems for offices includes:

• calculations of heat inflows for each separate room depending on the architectural features, appointments taking into account terms of reference to the project;
• calculation of air exchange;
• axonometric diagram of communications;
• aerodynamic calculation, which makes it possible to determine the cross-sectional area of ​​air ducts and pressure losses along the network;
• selection of all necessary equipment to complete the ventilation system in the office;
• calculation of heater power in the air handling unit;
• preparation of a package of project documents.

Technical equipment is selected simultaneously with the preparation of the project and takes into account all the customer’s requirements. A properly designed ventilation system for any office increases employee productivity by 20% or more.

Components of office ventilation systems

Air ducts

Air is delivered to the room and removed through an air duct system. The air duct network directly contains pipes, adapters, splitters, turns and adapters, as well as diffusers and distribution grilles. The diameter of the air ducts, the resistance of the entire network, the noise from the ventilation operation and the power of the installation are closely interrelated. Therefore for optimal performance ventilation during the design process, it is necessary to balance all indicators. This hard work, which can only be performed correctly by professionals.

Air pressure is calculated taking into account total length air channels, network branching and pipe cross-sectional area. Fan power increases when large quantities transitions and branches. The air speed in office ventilation systems should be about 4 m/s.

Air ducts are assembled from flexible corrugated pipes or rigid metal or plastic. Flexible pipes are easier to install. But they resist air movement more strongly and hum. That's why flexible pipes used in small offices. Sometimes the main channels are made of rigid pipes, and the branches to the cabinets are made of flexible ones. But large systems are assembled from rigid pipes.

Air intake grilles

They are installed at the point where air enters the ventilation duct from the street. The gratings protect against the penetration of insects, rodents, and precipitation into the pipe. Made from plastic or metal.

Air valves

Prevents wind from blowing when the ventilation system is turned off. Often an electric drive controlled by automation is connected to the valve. To save money, they use manual drives. Then a check spring valve or “butterfly” is attached to the valve in order to block the outlets of the ventilation ducts for the whole winter.

Air filter

Cleans the supply air from dust. As a rule, coarse filters are used that retain up to 90% of particles with a size of 10 microns. In some cases, it is supplemented with a fine or extra fine filter.

Periodically filtering surface ( metal grid or man-made fibers) must be cleaned. The degree of filter contamination is determined by pressure sensors.

Heater

Used to heat street air in winter, they can be electric or water.

Electric heaters have some advantages compared to water heaters:

• simple automatic control;
• easier to install;
• does not freeze;
• easy to maintain.

Main disadvantage – high price electricity.

Water heaters operate on water at a temperature of 70 – 95 degrees. Flaws:

• complex automatic system management;
• bulky and complex mixing circuit;
• behind the mixing circuit is required special care and supervision;
• may freeze.

But with proper operation it provides significant cost savings compared to an electric heater.

Fans

One of the most important components of the entire ventilation system. The main parameters when choosing: performance, pressure, noise level. There are radial and axial types of fans. For powerful and extensive networks it is preferable radial fans. Axial ones are more productive, but produce weak pressure.

Silencer

Installed after the fan to suppress noise. The main source of noise in an office ventilation system is the fan blades. The muffler filler is usually mineral wool or fiberglass.

Distribution grilles or diffusers

Installed at the outlets of air ducts into rooms. They are in plain sight, so they must fit into the interior and ensure distribution air flow in all directions.

Automatic control system

Monitors the operation of ventilation equipment. Usually installed in the electrical panel. Starts fans, protects against freezing, notifies about the need to clean filters, turns fans and heaters on and off.

Climate control equipment for offices

Supply ventilation unit for office. Brings fresh air from the street directly into the office space. The outflow of air occurs by displacing it into corridors and lobbies. With an area of ​​more than 40 sq. meters the air is evacuated directly from it. Air supply units for office ventilation they are used for areas up to 100 square meters. meters;

• Supply and exhaust office ventilation systems . This is the most widely used type of equipment that provides air outflow, purification and delivery. The kit may include cooling or heating devices, humidifiers. The equipment is very diverse, but supply and exhaust ventilation office should be calculated and installed by professionals. Automatic control over functionality reduces energy consumption and increases efficiency;
• Duct ventilation system in the office. Duct air conditioners with outside air are installed in small and medium-sized offices. Combined with supply and exhaust equipment that brings the outside air temperature to the required level. After which it is served to the rooms;
• Central air conditioning and ventilation in a large office. In large office buildings, the climate is controlled by chiller-fan coil systems and multi-zone VRF systems. The latter consist of many indoor units that provide different temperatures and humidity in the rooms. Central air conditioners are supply and exhaust ventilation in offices with cooling and heating units. This type of climate system is suitable for large offices that are not divided into separate rooms.

Office supply and exhaust ventilation

Duct ventilation of the supply-exhaust system is used for rooms up to 600 sq. m. meters, since the office supply and exhaust ventilation capacity is up to 8 thousand cubic meters per hour.

According to SanPiN standards for ventilation of office premises, 60 cubic meters of air per hour must be supplied per person.

SNiP ventilation of office premises requires air exchange:

• inflow 3.5 times per hour;
• outflow 2.8 times per hour.

The equipment is usually hidden behind suspended ceiling utility room. Air is distributed throughout the offices by a system of ventilation ducts, the outlets of which are hidden behind diffusers or grilles.

Air flow from the street at supply ventilation office is carried out at a height of two meters above the soil surface. The air is passed through a cleaning system, and if necessary, its temperature is lowered or increased (by an electric or water heater).

The exhaust air is discharged into a ventilation shaft or through a pipe, the end of which is located 150 cm above the roof.

To reduce energy consumption, the supply air is heated by a recuperator. It is a heat exchanger in which heat from exhaust air is transferred to fresh air. Recuperators for office ventilation Rotary and plate types are used. The former have an efficiency of more than 75% and operate in bitter frosts. But during operation, about 5% of the exhaust air enters the room.

Plate recuperators are inexpensive, their efficiency is no more than 65%. But they become icy, and we have to provide heating.

All necessary equipment for air treatment in the supply and exhaust system is located in one relatively small housing. Duct ventilation of office premises is a combination of several modules.

To ensure the required air temperature in the office space, supply and exhaust ventilation is supplemented with air conditioners. Depending on the characteristics of the building, these can be several split systems or multisplits.

Office ventilation

Ventilation of a small office building can be provided by a ducted air conditioner. In addition to cooling and heating the air, duct systems supply some fresh air from the street into the halls. To implement this function, the duct air conditioner is equipped with additional equipment mixing air. That is, the equipment both air-conditions and ventilates the office in accordance with the standards.

This scheme works like this:

Outside air is supplied to the mixing chamber located in front of the air conditioner, here it is mixed with exhaust air. The mixture is fed into the conditioner, cleaned, and brought to required temperature and is sent through ventilation ducts to the offices. The air from here moves into the mixing chamber and further in a circular cycle.

The air conditioner housing is hidden above a false ceiling or in a utility room.

The advantage of a duct ventilation scheme for office premises is its invisibility. But it eliminates the possibility of varying the air temperature in different rooms.

Air handling units in combination with VRF systems for the office

On large areas, installation of channel equipment is difficult, so maintenance large buildings carried out by supply and exhaust ventilation units for offices in combination with chiller fan coils and VRF systems.

The power of such equipment can reach 60 thousand cubic meters per hour. Ventilation and climatic equipment installed on the roof of a building or in separate rooms.

The installation consists of many modules, which are assembled depending on the needs of the enterprise and taking into account office ventilation standards. The kit may include:

• fan chamber;
• recuperator;
• sound absorber;
• mixing chamber;
• block with filters.

Air movement is carried out through an extensive system of air ducts. The air temperature in the building is maintained by chiller fan coils or VRF systems.

VRF is a multi-zone climate system, capable of maintaining the microclimate of an entire building. It is possible to differentiate the temperature in different rooms. An internal module is installed in each room to keep the temperature within the specified limits. There are no temperature changes typical for household air conditioners. Internal modules can be of any type (floor-standing, cassette, ceiling).

The chiller warms or cools the refrigerant - ethylene glycol. Which is supplied to the heat exchanger - fan coil with forced air movement. Fan coil units are located directly in office rooms. In order for the coolant to move at a given speed, the system is supplemented with a pumping station. Many offices and halls can be connected to one ventilation and air conditioning scheme. And not all at once, but as the need arises.

Central air conditioners for office ventilation

Central air conditioners belong to industrial climate control equipment. They are installed in accordance with SNiP and provide ventilation and air conditioning for office premises. In the air conditioner module, the air is brought to the required temperature and humidity parameters. Air is recirculated (mixing exhaust and fresh), including partial air recirculation. After treatment, the air is supplied to the premises through an air duct system.

Advantage central systems in the absence of internal modules. At the same time, the air conditioner itself is a rather bulky structure that requires a separate room. The air ducts are also quite voluminous. In this case, the temperature throughout the building will be maintained at the same level.

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

In what cases do SNiPs provide for the installation of forced ventilation?

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

SNiP ventilation on temperature standards.

When jointly designing, SNiP regulates the use of backup (duplicate) fans or the use of at least two heating devices. This is done in case one of the fans fails, and in this case, SNiP ventilation allows a temporary decrease in air temperature, but not less than twelve degrees Celsius.

Ventilation SNiP on backup fans.

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

SNiP ventilation on fire safety.