Sanpin exhaust ventilation. Ventilation standards in various rooms

Ventilation is a technical means that completes the system of measures to improve the air environment of working premises ( the most important prerequisite preventing air pollution in industrial premises is rational organization production processes: sealing and process continuity with remote control and control, automation and mechanization).

Ventilation, heating and air conditioning of production premises and structures (including crane operator cabins, control panel rooms, and other similar isolated rooms) are arranged to ensure that at permanent workplaces and in the work area during basic and repair and auxiliary work necessary in accordance with hygienic requirements meteorological conditions, air purity at work (temperature, relative humidity and air speed, maximum permissible concentrations of harmful substances and dust). Industrial ventilation ensures the fight against excess heat and moisture by creating a general air exchange, as well as removing harmful gases, vapors, dust entering the air of working premises through the use of local, localized ventilation units (see also “SSBT. Gas-cleaning dust collection equipment.” GOST 4.125 -84; “SSBT.Blowout prevention equipment”.

During the sanitary examination of ventilation projects, the expert conclusion reflects the following main issues:

1) characteristics of the system and the correctness of its choice; 2) assessment of the supply system: a) place and method of intake of supply air and devices for its cleaning, heating and humidification, b) location and arrangement of supply openings in the premises, temperature and supply speed supply air, c) assessment of the sufficiency of air exchange by inflow (test calculation), d) cubic capacity of the room per person, air cube and exchange rate, e) recirculation, its admissibility and scale; 3) assessment of local air supply units: direction of air shower inflow, supply air temperature, air supply speed; 4) assessment of the exhaust ventilation system: a) design and location of general exhaust ventilation openings, b) arrangement of localizing shelters, c) initial speed of air movement in the openings, d) device for cleaning the air removed from the room, e) assessment of the location of the exhaust air release, f) air exchange through the hood (test calculation);

5) characteristics and assessment of the ventilation system as a whole: the ratio of the places of intake of supply air and the places of exhaust air, the ratio of the location of supply and exhaust openings in the room, the air balance of the room (i.e. the ratio total number supply and exhaust air). For a detailed description of the requirements, see “Sanitary standards for the design of industrial enterprises” (SN 245-71) and the section “Heating, ventilation and air conditioning” (SNiP 11-33-75), industry design guidelines (issued by individual departments with mandatory approval from Main Sanitary and Epidemiological Directorate of the USSR Ministry of Health).

In the absence of industrial emissions, air exchange must be organized in rooms with a cubic capacity of less than 40 m3 per worker.

The amount of air required to ensure the required air parameters in the working area is determined engineering calculation. At the same time, the uneven distribution of harmful substances, heat and moisture along the height of the room and in the working area is taken into account, namely for rooms with heat emissions - according to excess sensible heat; for rooms with heat and moisture releases - based on excess sensible heat, moisture and latent heat, checking to prevent moisture condensation on the surfaces of building structures and equipment. In those rooms where there are gas emissions, the amount of air that needs to be supplied to the room should ensure the dilution of chemicals to the maximum permissible concentration. The amount of harmful emissions is taken either according to the technological part of the project or technological design standards, or according to data from natural surveys of similar enterprises, or by calculations. If there are simultaneously several harmful substances, heat, and moisture in the room, the amount of supply air when designing ventilation is taken to be the largest, obtained from calculations for each type of industrial emissions.

Emissions cleaning. Technological emissions and emissions of air removed by local suction, containing dust, poisonous gases and vapors, and unpleasant-smelling substances, must be arranged in such a way as to ensure the dispersion of these substances and so that their concentration does not exceed:

a) in atmospheric air settlements- maximum permissible maximum one-time values; b) in the air entering buildings through openings of ventilation and air conditioning systems and through openings for natural supply ventilation,- 30% of the maximum permissible concentration of harmful substances in the working area of ​​production premises.

Ventilation air removed by general ventilation and containing the above-mentioned impurities must be purified before being released into the atmosphere, taking into account that in places of air intake by ventilation and air conditioning systems, the content of harmful substances in the outside air does not exceed 30% of the maximum permissible concentration for working area production premises. If ventilation emissions contain low concentrations of harmful substances, then cleaning may not be carried out, but the dispersion of harmful substances in the atmospheric air under the most unfavorable conditions weather conditions must meet the above requirements.

Forced ventilation. Recycle. In production premises with a volume per worker of less than 20 m3, a supply of outside air in an amount of at least 30 m3/h per worker must be organized, and in premises with a volume per worker of more than 20 m3 - at least 20 m3/h per worker. every worker. If there is more than 40 m3 of room volume per worker in the presence of windows and lanterns and in the absence of the release of harmful and unpleasantly smelling substances, it is allowed to provide periodic natural ventilation - opening the casements of windows and lanterns. When designing buildings, premises and their separate zones(areas) without natural ventilation (airing) with the supply of mechanical ventilation only from outside air; the volume of outside air should be at least 60 m3/h per 1 worker, but not less than one air exchange per hour throughout the entire volume of the room (for air conditioning with recirculation - with a calculated air exchange rate of 10 times or more). With a lower design air exchange rate and when recirculation is used, the volume of outside air supply should be at least 60 m3/h per 1 worker, but not less than 20% of the total air exchange (the volume of outside air supply is up to 10% if the air exchange rate is less than 10 and recirculation - if more 120 m3/h of outside air per 1 worker.

When designing general supply and exhaust ventilation of premises without natural ventilation, at least two supply and two exhaust units must be provided, each with a capacity of at least 50% of the required air exchange (with one installation - backup fans).

When designing ventilation and air heating, recirculation can be allowed during the cold and transition periods of the year (for air conditioning systems - at all times of the year). For recirculation, you can use room air where there are no harmful emissions or if the released substances belong to hazard class IV and their concentration in the room air does not exceed 30.% of the maximum permissible concentration. Application of air recirculation for ventilation, air heating and air conditioning is prohibited in rooms in which:

a) the air contains microorganisms;

b) there are pronounced unpleasant odors; c) substances of hazard classes I, II and III are released in the air.

Air and air-heat curtains must be installed at gates that open at least 5 times per shift or at least 40 minutes per shift. These curtains are also installed at technological openings of heated buildings and structures in areas with a design outside air temperature for heating design of 15 °C or lower in the absence of airlock vestibules. When opening gates, doors and technological openings, the air temperature at permanent workplaces when operating curtains should not be lower than: 14 °C for light physical work, 12 °C for moderately heavy work, 8 °C for heavy work (in the absence of permanent workplaces near gates and openings - up to 5 °C).

The temperature of the air mixture passing through the gate or openings must meet the specified standards.

Exhaust ventilation. The combination of dust and easily condensable vapors, as well as substances that, when mixed, produce harmful mixtures or chemical compounds, into a common exhaust system is prohibited. Local exhaust systems for removing harmful substances of hazard classes 1 and 11 must be interlocked with process equipment so that it cannot operate when local exhaust ventilation is inactive (with the exception of installing backup fans for local exhaust units with automatic switching). When installing local exhaust ventilation, it is necessary to observe the following requirements: 1) sources of harmful emissions must be covered as much as possible; 2) the design of the suction air intake and its location - take into account the natural movement of emissions (convection air flows, the direction of the dust jet, the direction of gas movement, etc.); 3) the breathing zone of workers - to be outside the shelter; 4) the flow of the technological process and the ease of servicing the equipment - not to be disturbed; 5) in the shelter, by suctioning air, a vacuum must be created to prevent the entry of harmful emissions into the air of the room.

General ventilation. To dilute to the maximum permissible concentration that part of the production emissions that cannot be removed using local exhaust ventilation, general mechanical ventilation is installed. The location of the air exhaust zone depends on the nature of the harmful emissions. In the presence of heat or light gases and vapors, joint release of heat and chemicals exhaust air removed from the upper zone of the room; Air is removed (usually partially) from the lower zone in the event of the release of gases and vapors that are heavy in specific gravity. Air is removed from the upper and lower zones when it is simultaneously contaminated with a mixture of gases and vapors, one of which is lighter and the other is heavier than air. You draft receivers should be located in areas of the highest temperatures and the greatest air pollution.

Supply air is usually supplied to the work area in the following cases: a) during the release of heat and the joint release of heat and gases; b) when installing exhaust from an area with the highest dust concentrations above the working area (welding shops, etc.). Supply air is released into the upper zone of the premises in the absence of significant excess heat and dust and gases are sucked out by local exhaust ventilation, with lower exhaust in rooms with the release of vapors of volatile solvents or dust, in rooms with excess heat when cold air is supplied. In the presence of moisture release, supply air is supplied to two zones - the upper (heated) and the lower.

Local inflow is arranged to create limited zones with a favorable microclimate and low concentrations of harmful air impurities (air showers, air oases).

In industries where large quantities of harmful substances (except dust) may suddenly enter the air of the working area, emergency (usually exhaust) ventilation should be provided in accordance with the requirements of SNiP and departmental standards. If departmental standards do not contain instructions on the air exchange of emergency ventilation, then together with the existing ventilation it must provide an air exchange of at least 8 exchanges per 1 hour in the internal volume of the room. It is recommended to provide for blocking emergency ventilation with gas analyzers that determine permissible concentrations of harmful substances. To start emergency ventilation, remote devices must be installed in accessible places and outside the room.

Ventilation, air conditioning and heating installations should not create noise above permissible values ​​(see noise standards).

Heating. For heating buildings and structures, systems, devices and coolants must be used that do not create additional industrial hazards. The use of radiant heating with infrared gas emitters is permitted provided that combustion products are removed to the outside. In heating systems, the average temperature of the heating surface should not be higher than:

a) on the heated floor surface 26 °C (in lobbies and rooms with temporary occupancy of people 30 °C); b) on the heating surface of the ceiling at a height of 2.5-2.8 m 28 ° C; at a height of 2.9-3 m 30 ° C; at a height of 3.1-3.4 m 33 ° C;

c) on the heating surface of partitions and walls at a height of up to 1 m from the floor 35 °C, from 1 to 3.5 m 45 °C. Heating devices in rooms with significant dust emissions must have smooth surface, which makes them easier to clean.

Supply heating and ventilation equipment and air conditioners that serve the premises without recirculation are placed in isolated rooms.

Each enterprise must have a designated person responsible for the operation and condition of ventilation, heating, and air conditioning. All ventilation units, both newly equipped and put into operation after reconstruction or overhaul, are subjected to instrumental acceptance tests to determine effectiveness.

Each enterprise must establish a procedure for operating ventilation and heating in accordance with specially developed instructions and passports (for ventilation units). The instructions contain instructions on how to regulate the operation of each unit (system) in relation to the operating mode of the workshop (department) and technological equipment (during the working day, during the seasons of the year and in different time days depending on meteorological conditions); timing of cleaning air ducts, fans, dust and gas cleaning devices; timing of scheduled preventive maintenance, etc. For all ventilation units, a passport is drawn up in a certain form, in which all changes in the installation, the results of tests carried out at the request of the sanitary-epidemiological station are entered. An operation log must be kept for each ventilation system (kept by the workshop manager). In rooms where chemicals, dust and other harmful substances may be released into the air, it is necessary to systematically test the air for the content of harmful substances within the time frame determined by local sanitary inspection authorities.

Control of ventilation units. The effectiveness of ventilation is determined only on a working ventilation unit. The air supply unit must have air heaters in working order, valves and openings for air intake must be open. Check the water temperature and the addition of steam entering the heaters, the purity of the supplied air; determine the temperature and speed of air flowing out of the supply pipes into the working room.

When checking exhaust devices, special attention is paid to the tightness of the air ducts and, first of all, in the places where the pipes are connected to shelters and main air ducts. It is important to check the tightness of the connections in the flanges of the air ducts; dust and dirt are not allowed to accumulate in them; the suction openings must be open, and the devices for cleaning the air removed from the room must be in good working order. To assess the effectiveness of ventilation, the content of dust and chemicals in the air of working areas during work is determined production equipment at full capacity. Along with this, performance is checked (volume of supplied or removed air per 1 hour) ventilation units and its compliance with design data using either anemometers or pneumometric tubes with a draft gauge. In this case, the speed of air movement in the duct is multiplied by the area vent(in m2) and by 3600 (number of seconds); get installation performance in cubic meters air in 1 hour.

If there are grilles in the air duct opening, then to obtain the volume of air passing through the exhaust openings, the result obtained is multiplied by a factor of 0.8. To determine the volume of air passing through the supply openings with grilles, instead of the area of ​​the air duct opening, take half the sum of the overall area of ​​the opening and the free cross-sectional area of ​​the grille. It is impossible to measure the speed of air movement in the air duct with an anemometer, since this changes the nature air flow(pneumometric tubes with a draft gauge are used). These studies are carried out by specially trained personnel of ventilation laboratories or SES groups or special laboratories of departments and enterprises.

March 16th, 2017 y.geny

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The ability of an office worker to work directly depends on the microclimate in the room. According to medical research, the air temperature in the office should not exceed 26 degrees, while in practice in buildings with panoramic windows and an abundance of equipment it can go 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 office ventilation systems today are 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, 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 ventilation requirements office premises indicated 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- exhaust ventilation installed in medium and large sized offices.

Office ventilation system project

The ventilation system of an office building is responsible for whole line 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 individual room depending on architectural features, assignments taking into account the technical specifications for 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 grids. 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 ventilation performance, it is necessary to balance all indicators during the design process. This is a difficult job that only professionals can do correctly.

Air pressure is calculated taking into account the total length of the air channels, the branching of the network and the cross-sectional area of ​​the pipe. The fan power increases with a large number of 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 main channels are made of rigid pipes, and branches to 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, atmospheric precipitation. 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. In order to save money, they use manual drives. Then the return valve is adjacent to spring valve or “butterfly” to block the exits of 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 special filter fine cleaning.

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

Heater

Used for heating 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;
  • the mixing circuit requires 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 nodes 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, radial fans are preferable. 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 the distribution of air flows in all directions.

Automatic control system

Provides control over work 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 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 represent 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 inflow-outflow systems are 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.

The influx of air from the street during office supply ventilation 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 (using 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 supply and exhaust system located in one relatively small building. 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 the halls with a certain amount of fresh air from the street. To implement this function duct air conditioner equipped with additional equipment for 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 air conditioner, cleaned, brought to the required temperature and 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 ducted equipment is difficult, so large buildings are serviced 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 various rooms. An internal module is installed in each room to keep the temperature within the specified limits. Temperature changes typical for household air conditioners, are missing. 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.

Basic sanitary and hygienic requirements for ventilation of industrial premises have been determined sanitary standards, as well as building codes and regulations (SNiP) “Heating, ventilation and air conditioning”.

For effective operation of ventilation, it is important that a number of sanitary, hygienic and technical requirements are met even at the design stage. The volume of required air must be sufficient. The amount of air required to ventilate production premises and ensure the required air parameters in the work area is established by calculation. The calculation is carried out accordingly according to the excess of sensible heat or moisture or the amount of harmful substances released (dust, gases, vapors). With the simultaneous release of heat, moisture and harmful substances (or their various combinations) in the room, the necessary air exchange should be established according to the prevailing harmfulness.

In accordance with sanitary standards, the amount of outside air supplied to the room per worker must be at least 30 m 3 / h when working in a room less than 20 m 3 per person and at least 20 m 3 / h when the room volume is more than 20 m 3 per person. In rooms with a volume of more than 40 m 3 for each worker, in the presence of windows or windows and lanterns and in the absence of the release of harmful or unpleasantly smelling substances, it is allowed to arrange periodic ventilation. In rooms without natural ventilation, the air supply per person should be at least 60 m 3 /h.

The balance of supply and exhaust air must correspond to the purpose of ventilation and the specific conditions of its use. In classic cases, the amount of supply air must correspond to the amount of air removed, the difference between them should be minimal. However, sometimes a special organization of air exchange is necessary with a predominance of one or another amount of air in the overall balance. For example, when designing ventilation in two adjacent rooms, in one of which there is the release of harmful substances, it is necessary to create a negative balance in it (a slight predominance of the exhaust over the inflow), thereby preventing the possibility of polluted air entering the room without its own sources of harmfulness.

In some cases, such air exchange organization schemes are required when excess pressure is maintained in the entire room relative to atmospheric pressure, i.e., the volume of supply air must be greater than the volume of exhaust air. This, for example, is necessary in electric vacuum production workshops, so-called clean rooms, to prevent outside air from penetrating through leaks in enclosures. A positive air balance is necessary when organizing ventilation with excessive dispersed moisture release to prevent the formation of fog and condensation due to the penetration of cold air from outside.

The volume of air removed from the premises by exhaust ventilation units must be compensated by an organized influx of clean air. An unorganized influx of outside air to compensate for exhaust during the cold period of the year is allowed in an amount of no more than once per hour, if there is no hypothermia of the air and no fog formation.

Supply and exhaust systems must be correctly placed. The influx should ensure maximum purity and optimal microclimatic parameters of the air in the working area. The hood should remove harmful emissions as much as possible. The ventilation system should not cause overheating or hypothermia of workers. The noise of ventilation units should not increase production noise above the level permitted by sanitary standards. The ventilation system must be effective at all times of the year under all climatic and weather conditions. The ventilation system should not be a source of environmental pollution. The ventilation system must be simple in design, reliable in operation and meet the requirements of electrical, fire and explosion hazards.

Methods for reducing noise and vibration of ventilation units. The operation of ventilation units is usually accompanied by more or less noise. In industrial enterprises with low noise levels from production equipment, noise generated by ventilation units can be one of the main unfavorable factors in the production environment.

The noise of ventilation units can be mechanical and aerodynamic. Mechanical noise is created mainly by fans and electric motors as a result of poor damping, poor balancing of rotating parts, poor condition of bearings, etc. Mechanical noise spreads through the air of the room, ventilation ducts and often through the foundations of the ventilation unit to the building envelope, the so-called structural noise . Aerodynamic noise occurs as a result of vortex formation during rotation of the fan wheel, air movement in ventilation networks at high speed, when air exits through supply openings, etc.

Reducing the mechanical noise of ventilation units is achieved by special technical solutions: to eliminate vibration of the fan, it is recommended to mount it on vibration-isolating bases in a separate ventilation chamber. Careful dynamic balancing of the rotating fan mechanisms and covering the fan casing with sound-insulating materials is necessary; To prevent the spread of mechanical noise through the air ducts, flexible non-metallic (tarpaulin, etc.) inserts are made between the latter and the fan.

Reduction of aerodynamic noise is ensured by such measures as the correct selection of a fan (it must create the necessary pressure at a minimum number of revolutions of the impeller), the correct choice of air speeds in the air ducts; The cross-sectional area of ​​the air ducts and nozzles must correspond to their purpose, not create unnecessary turbulent movements of air flows, and if necessary, noise silencers are installed.

Ventilation in rooms with excessive heat generation. Many production processes associated with heating, smelting, casting metal, production of building materials (cement, bricks, ceramics), chemical raw materials at thermal power plants are accompanied by the release of a significant amount of heat into the production premises.

If heat release into the room is greater than heat loss, then their difference is called excess heat. According to sanitary standards, industrial premises with excess sensible heat with a heat intensity of more than 20 kcal/m3 per 1 hour are classified as premises with significant heat release or so-called hot shops.

Calculation of the heat balance, i.e. the heat entering the workroom and leaving it, is one of the main and quite complex tasks when designing ventilation to combat excess heat.

Sources of heat generation include: heating furnaces for smelting, heating metal or other materials; cooling materials; heated surfaces of apparatus, pipelines; working machines and mechanisms; solar radiation; lighting sources; People.

The heat is used to heat the building, which is cooled through external enclosures; heating in cold weather transport and materials entering the workshop; carried away by heated air through leaks in the building enclosures or removed by local suction, etc. Appropriate methods and calculation formulas have been developed to determine the required air exchange. They are set out in special manuals and reference books. The general principles of organizing air exchange in workshops with large excesses of sensible heat provide for aeration in combination with mechanical ventilation.

Ventilation in workshops with excess moisture. For removing excess moisture, the release of which cannot be prevented by technological means, first of all, local exhaust ventilation units should be provided. Recommended air intakes include fume hoods; at temperatures of evaporating water above 80 °C can be used exhaust hoods; display cases are suitable; baths are equipped with side suction.

In a number of industries, with diffuse intense release of moisture, where it is technically not possible to completely cover the sources and remove all moisture using local exhaust devices, they additionally use general exchange supply and exhaust ventilation, designed to remove humidified air and assimilate excess moisture with supply air. The following ventilation scheme is recommended: most of(approximately 2/3) of overheated and overdried supply air is supplied to the upper zone of the room, exhaust steamy air is also produced from the upper zone. If the room height is at least 5 m, it is allowed to overheat the supply air to 35 °C, and if the height is higher. 6 m to 50 - 70°C.

The inflow must prevail over the exhaust in order to avoid unorganized entry of cold outside air into the premises and the formation of fog.

At the same time, a number of architectural and construction conditions are imposed on rooms with significant moisture releases: their height must be at least 5 m to avoid overheating of the air in the workplace with hot supply air; To eliminate the possibility of condensation forming on the inner surface of building enclosures (ceilings, walls, ceilings), they must be made of low thermal conductivity materials.

Ventilation in workshops with the release of toxic gases and vapors. Preventing the entry of toxic substances into the air of working premises should first of all be solved by the rational organization of technological processes, reliable sealing of equipment, etc.

Among the means of ventilation, preference should be given to aspiration. If it is impossible to equip it to localize and remove harmful substances directly from the place of their formation and release, the most rational is local exhaust ventilation with shelters such as fume hoods, side exhausts, umbrellas, etc. For effective ventilation, it is necessary to ensure such air suction rates into open openings and create such vacuum inside ventilation shelters that would maximize the removal of gases and vapors from the room. Local suctions designed to remove technological equipment hazardous substances of hazard classes 1 and 2, should be interlocked with this equipment in such a way that it cannot operate when local exhaust ventilation is inactive.

In a number of cases, when for technological, design and other reasons it is not possible to use local exhaust ventilation, general exchange ventilation is used, designed to dilute toxic substances to maximum permissible concentrations.

In accordance with the standards of technological design and the requirements of departmental regulatory documents in certain cases provided emergency ventilation. There should also be provision for blocking emergency ventilation with gas analyzers set to permissible concentrations of harmful substances.

Calculating the required air exchange poses a certain difficulty. Experience shows that sharp fluctuations in the concentrations of gases and vapors are often observed in individual points of the room, and sometimes their concentrations, even when ventilation is operating at full design capacity, can reach potentially dangerous levels. In this regard, when calculating air exchange, it is recommended to introduce a safety factor. This applies to toxic substances with maximum permissible concentrations greater than 1 mg/m3.

When toxic substances are released, the maximum permissible concentration for which is set below 1 mg/m 3, the use of general ventilation is unacceptable.

Dust control ventilation. Among the measures aimed at preventing dust pollution in the air environment of industrial premises, the leading role should also belong to measures of an architectural, planning and technological nature.

When choosing methods to combat dust through ventilation, it should be borne in mind that local dust extraction ventilation installations are of decisive importance. The use of general ventilation, operating on the principle of dust dilution, is an irrational, uneconomical and insufficiently effective method, since increased air mobility prevents the settling of the fine dust fraction, which is indefinite long time may be suspended. Only in exceptional cases is it permissible to resort to general ventilation to reduce dust levels in the air by diluting the aerosol. For example, during arc welding at non-fixed workplaces in mechanical assembly and other shops, when it is not possible to equip local suction. Active ventilation aimed at removing dust is resorted to in the blind faces of mine workings. In this case, the supply air is supplied at strictly calculated relatively low speeds (0.4 - 0.7 m/sec).

Rice. 29. Installation of ventilation suction, a - incorrect; b - correct.

The optimal method of dust removal using local exhaust ventilation units is aspiration - complete covering of equipment combined with an exhaust hood. To prevent dust from being knocked out through leaks in the suction shelters, it is necessary to ensure sufficient air vacuum. The suction units should be correctly positioned (Fig. 29).

When choosing the design of the suction (dust collector) and the exhaust unit a number of conditions must be met:

    ensure that the source of dust generation is completely covered, while at the same time not interfering with the free performance of labor operations;

    bring the suction hole as close as possible to the source of dust emission;

    provide for a tight connection of the air duct to the dust receptacle, preventing dust from being knocked out;

    ensure that the location of the dust collector is such that the dusty air being sucked out does not pass through the breathing zone of the worker;

    air ducts must be equipped with holes for periodic cleaning of settled dust;

    dust extraction ventilation systems should be as decentralized as possible, i.e., consist of several independent installations. This makes it possible to avoid laying long air ducts and clogging them with dust;

    It is not allowed to combine dust suction units with units for removing excess moisture into one system.

Local exhaust ventilation designed to combat dust must be equipped with dust cleaning devices that guarantee a degree of air purification in accordance with the requirements of sanitary legislation.

Sanitary supervision of ventilation. The design specifications must address the principles and patterns of ventilation. When considering a project, it is necessary to carefully familiarize yourself with its technological part, check the basic calculations, heat-air balance, etc.; assess the compliance of the designed local suction with the nature of the equipment that is the source of the release of harmful factors. It should be borne in mind that in a number of cases, when considering projects, there are complex technical calculations and tasks that require special training to solve them. In these cases, the sanitary officer involves ventilation engineers.

Whenever controversial issues or if the project is particularly complex, it may be sent for sanitary or technical examination to research institutes.

Current sanitary supervision of existing ventilation systems industrial enterprises is based on periodic monitoring of the state of the air in the work area at permanent workplaces, as well as at the locations of air intake devices. If the air in the work area does not comply with existing regulatory requirements, the question arises about the efficiency of industrial ventilation.

Monitoring the operation of ventilation involves technical and sanitary-hygienic tests of ventilation systems and installations.

Technical tests of the ventilation unit are carried out before putting it into operation during new construction or reconstruction in order to check the overall compliance with the design and the quality of its installation; existing ventilation - in order to check the technical condition of the installation.

During technical tests, the speed of the fan and electric motor, the network pressure (static, dynamic, total) are determined; the overall performance of the installation and the distribution of air among its individual elements; the presence of leaks leading to air leaks or leaks; temperature and relative humidity of supply and exhaust air; heater performance.

The correct distribution of supply air throughout the ventilated room and its removal, taking into account the volumes and required speeds, is also determined.

After eliminating the identified defects, ventilation is adjusted. The operating efficiency of the ventilation unit or the entire ventilation system is assessed based on sanitary and hygienic tests.

They provide for assessing the state of the air environment in work areas based on instrumental measurements and carrying out the necessary chemical studies: a) compliance of the air in the work area with the requirements of standards (maximum concentration limits) for the content of harmful vapors, gases and dust; b) microclimate conditions indoors and in workplaces; c) the degree of purity of the supply air, as well as its temperature and humidity; d) the efficiency of purification of air removed from the premises into the surrounding atmosphere.

Each ventilation unit must have a passport, which, along with its description, contains technical test data.

When designing ventilation systems, developers are required to pay attention to the instructions, recommendations and requirements of regulatory authorities. The standards that need to be followed are SanPin, GOST, ABOK data, and so on. They are quite detailed, numerous and complex, as they take into account a large number of parameters:

  • purpose of the object - for example, if ventilation is calculated technical premises, the standards will differ significantly from those applicable to residential spaces;
  • the size of the room - the amount of supplied/removed air, the model and power of ventilation units, the type of system used, and so on depend on this;
  • the number of people present at the site at the same time;
  • season, temperature regime, humidity - this is especially true for residential spaces, but for a warehouse it is also important in what conditions the products are stored;
  • fire safety requirements, other specific conditions.

Basic calculation methods taken into account when standardizing ventilation

Experts rely on generalized tables. They take into account the necessary parameters and, after calculation using all possible methods, the largest value is selected - it is taken as the basis for design (this approach is not used when organizing similar systems in swimming pools). Regardless of what exactly they describe - air exchange in a kindergarten or ventilation storage facilities, the standards are based on several key indicators:

  • volume and air flow per person;
  • level of aerodynamic resistance in the system;
  • permissible percentage of harmful emissions;
  • approximately possible power of air heaters and ventilation equipment;
  • number of windows, humidity, temperature and so on.

In residential, public and industrial premises where people spend a lot of time, calculations are made using the following methods:

  • by area, without taking into account the number of people - standards stipulate orientation on the volume of supply air for objects for various purposes(for example, for residential it is 3 cubic meters per hour per 1 sq. m);
  • according to sanitary and hygienic standards (for one person) - living spaces require 30 cubic meters. m/hour, for production facilities larger than 20 sq. m - at least 20, if ventilation of office premises is organized, the standards provide for 40 cubic meters. m;
  • according to exhaust standards (multiplicity) - it takes into account how many times the composition of the aeromass in the room is updated within an hour (the summary tables show the standard multiplicities).

Features of standards for residential and office premises

High demands are placed on living spaces - when designing ventilation, the safety of people must be ensured. In such construction, a classic aeration scheme is usually used - natural exhaust, with channels. Contaminated masses are removed, first of all, from the sanitary area - kitchens, bathrooms - and the space is considered by default to be uniform in pressure level and leaky, so trimming is taken into account when calculating door leaves and window settings.

Air exchange rates are divided according to the purpose of the premises:

  • For living rooms‒ constant multiplicity parameter of at least 30 cubic meters/hour or 0.35 1/hour, but with total area apartments less than 20 sq. m - 3 cubic meters m per 1 cubic meter of room;
  • for kitchens with an electric stove 60 cubic meters per hour, with a gas stove - 90, minimum - 30 and 45, respectively;
  • for the bathroom and toilet rooms - 25 cubic meters per hour when the bathroom is divided, 50 when the bathroom is combined;
  • for laundry rooms, dressing rooms, utility rooms - a frequency of at least 1 per hour.

This short description, since residential design is a large, complex industry, and it takes into account an impressively large number of standard indicators. The same, in principle, applies to office spaces - people spend a lot of time there, sometimes uniting in large groups. According to design standards for such objects, it is necessary to take into account that:

  • the air temperature was maintained at 19-21 degrees Celsius during the cold period and 23-25 ​​during the warm period;
  • In rooms without windows, a mechanical ventilation system was installed, and in bathrooms, smoking rooms, and offices of more than 35 square meters. m - independent exhaust systems;
  • air mobility was maintained at 0.2-0.5 m/sec;
  • the multiplicity was: for standard offices (managerial, accounting, workers, etc.) - 1.5 per supply, for copying and bookbinding services - 3-5, for exhaust for dressing rooms - 2, restrooms - 50, storerooms - 1- 1.5.

Standardization of technical, production and warehouse facilities

Ventilation standards in industrial premises and warehouse areas are formed in a slightly different way. Here, in addition to the needs of people, it is necessary to take into account the features and technical requirements for the equipment and goods and substances contained in the premises. If we talk about the sanitary component, then in a windowless room it is necessary to organize the supply of external aeromass - 60 cubic meters per person. m/hour. Also standardized (for individual items):

  • dust content;
  • presence and level of harmful vapors, gases, fumes;
  • room temperature (including excess heat), humidity.

As a rule, a system that is organized indoors combines natural and mechanical sources of ventilation and is based on the supply and exhaust principle. The main parameter is the multiplicity. For production and warehouse premises it can vary from one to 10. In general, calculations based on multiplicity alone are not sufficient and the following must be taken into account:

  • suction speed air masses- for low-toxic gases 0.5-0.7 m/sec, for highly toxic gases 1.2-1.7;
  • required emergency ventilation flow rate - with a coefficient of at least 8;
  • compliance with the specifics of stored valuables (for a fuel and lubricants warehouse, for example, the air exchange rate should be at least 2.5, and when storing acetone - 9-10).

In medical institutions (except for infectious diseases departments), in accordance with the requirements of SanPiN, certified forced supply and exhaust ventilation is provided. In all zones, in addition to rooms with cleanliness class A, independent air supply from outside is planned (clause 6.11). Once a year, equipment used to improve the air environment is inspected, maintenance measures are carried out, including disinfection, and repaired if necessary (clause 6.5).

Rules for air exchange in places where infectious patients lie, in accordance with the Norms and Rules:

  • In boxes and sections of wards, individual ventilation with natural supply and installation of a deflector is installed
  • They organize a forced influx with the transportation of air masses into the corridor.

Air conditioning systems are planned for areas of medical institutions with special microclimate requirements. These are the chambers:

  • Operating and postoperative, rehabilitation, intensive care rooms
  • Rodzaly
  • For newborns, premature babies, infants
  • For patients with burns.

The air passes through specialized filters before entering the wards. At the initial stage, the use of an oil filter is prohibited. The speed of movement of air masses and relative humidity are also regulated. It is permissible to design one ventilation system for several rooms if they have a uniform regime and there are no infectious patients in them.

Tasks that ventilation and air conditioning equipment must solve:

  • Prevent the spread of pathogenic microbes. To do this, it is necessary to organize the supply of clean air and the removal of dirty air, to prevent the flow of air from less clean to cleaner areas (clause 6.9)
  • Ensure standard air characteristics - temperature, humidity level, movement speed, amount of impurities that adversely affect human health
  • Prevent congestion static electricity, which can provoke an explosion of narcotic gases used for anesthesia and other technological operations
  • Ensure the necessary sanitary and biological characteristics of the air mass in the premises - percentage oxygen, level of radioactivity, bacteriological purity, absence of harmful chemical components and odors.

When designing, only air conditioners and other equipment are selected that comply with the noise and vibration background requirements of SanPiN (clause 6.7), and also do not emit harmful substances into the space. Supply and exhaust equipment are installed in rooms separate from each other. You should also consider:

  • Qualitative characteristics of air received by supply systems
  • Thermal level in rooms with big amount technological equipment
  • The presence of toxic gases and chemicals used for disinfection, anesthesia and others medical actions, presence of strong odors
  • Foci of infection located inside a medical facility, probable ways of their expansion.

Rules for organizing air supply and exhaust

General requirements:

  • The circulation of air masses within the building (without the passage of air masses through appropriate filters) is prohibited
  • When designing, ensure explosion-proof conditions
  • Air supplied from outside by supply ventilation systems is processed in filters that are located in central supply systems or air conditioners.

Rules for designing the supply and removal of air flows in accordance with the functionality of the room:

  • For operating rooms used for minor operations, the installation of individual air supply units is permitted. An adjacent room is used for the supply cabinet
  • Air intake from outside is carried out from a clean area located at a height of at least 2 m above ground level. The air is cleaned with filters of varying degrees of purification (clause 6.22). The exhaust air masses are released after cleaning using appropriate filters to a height of 0.7 m above the roof level (clause 6.23)
  • In rooms for treatment with light, heat and electric current, the supply and removal of air flow is organized from the upper zone. The temperature of the air masses entering this room must ensure thermal balance. As a result of air exchange, the concentration of harmful impurities is reduced
  • In X-ray diagnostic rooms (with equipment closed type) and X-ray therapy, operating rooms, postoperative, anesthesia, labor air flows are planned both from above (600 mm from the ceiling) and from below (500 mm from the floor) (clause 6.13). X-ray therapy rooms are characterized by more intense air exchange
  • From areas in which liquid nitrogen is used, heavy gases, aerosols, and air are removed from the lower space. When storing biomaterials in liquid nitrogen, it is required individual system exhaust ventilation, as well as emergency ventilation, which is activated when a signal from a sensor monitoring gas levels is triggered (clause 6.14)
  • In “clean” zones, the inflow exceeds the exhaust volume, in infectious zones – vice versa (clause 6.15)
  • Patients with diseases that provoke emergency sanitary and epidemiological situations are allowed to be placed only in boxes with forced ventilation system (6.20)
  • In wards equipped with separate sanitary rooms, the hood is installed in the bathroom (clause 6.27)
  • Workplaces intended for activities involving hazardous chemicals, equipped by local exhaust devices
  • Pharmacies provide individual methods for removing air masses for reception and prescription, washing, sterilization and others.

Design of filters that provide multi-stage purification of incoming air masses:

  • First stage – coarse filter
  • Second stage – fine filter
  • The third stage is microfilters or absolutely fine filters.

Microclimate standards

The presence of efficient heating is one of the most important conditions for creating optimal microclimate for patients, data are given for the winter period:

  • For most patients – 20-22°C
  • With severe burns – 25-27°C
  • With lobar pneumonia – 15-16°C.

When determining the optimal microclimate, the season, period of day, age of the patients, nature and stage of the disease are taken into account.

Standard parameters:

  • Temperature differences vertically – no more than 3°C, horizontally – 2°C
  • Temperature changes during the day – 3°C
  • Relative humidity air in medical premises in accordance with SanPiN - 30-65%
  • The speed of movement of air masses is 0.25 m/s.

Organization of heat supply medical center can be carried out in one of two ways - from an individual boiler room or from centralized utility networks settlement.

Features of the design and installation of heating systems in medical institutions

At the facilities medical purposes V heating devices Only water is allowed to be used as a coolant; other compounds are prohibited. Coolant temperature in heating system+70…+85°C (clause 6.3). Heating can be wall, floor, combined. Automatic temperature control devices are installed in certain rooms.

Requirements for heating radiators used in medical institutions:

  • Smooth surface allowing frequent wet processing using disinfectant compounds and eliminating the accumulation of dust and microorganisms (clause 6.2)
  • Location near external walls under window openings
  • Lack of ribs (tubular, mounted in the wall, or panel) - in wards, diagnostic, preventive and treatment rooms. In other types of premises, convectors or finned radiators can be used.


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