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ventilation hygiene. Ventilation of office premises: air exchange norms, SanPins

3.4. Heating hygiene

The hygienic task of heating is that it must provide a normal microclimate, a stable thermal regime, which excludes hypothermia and overheating of the body, and also contributes to the observance of technological processes. Hygiene requirements for heating enterprises are as follows:

heating devices must provide the temperature established by the standards, regardless of the outdoor temperature and the number of people in the room;

The air temperature in the room must be uniform both horizontally and vertically.

daily temperature fluctuations should not exceed 2-3 °C with central heating and 3 °C with stove.

the difference in air temperature horizontally (from windows to opposite walls) should not exceed 2 ° C, vertically - 2-2.5 ° C for each meter of room height;

temperature internal surfaces fences (walls, ceilings, floors) should approach the air temperature of the premises, the temperature difference should not exceed 4-5 ° C;

space heating should be continuous during the heating season and provide for qualitative and quantitative regulation of heat transfer;

the heating system should not pollute the air;

the average temperature of heating devices should not exceed 80 °C (more heat leads to excessive heat radiation, burning and sublimation of dust);

the surface of the instruments must be accessible for cleaning.

There are local and central heating systems. Local (furnace) heating is characterized by low hygienic indicators, because due to the low heat capacity of furnaces, there are significant daily fluctuations in air temperature, and the premises are polluted with ash, fuel, flue gases, and dust. Central e heating is more hygienic. It, as a rule, provides uniform heating of air during the day. The location of heating devices under the windows prevents the formation of cold air currents near the floor. Central heating is provided by boiler houses or combined heat and power plants. According to the type of heat carriers, heating systems are subdivided for water, steam, air, combined and panel-radiant. Most hygienically acceptable in enterprises low pressure central water heating system. It allows you to provide uniform air temperature in the premises, regulate the flow of heat by changing the water temperature, eliminates the possibility of contamination of the premises with dust, since the surface of the radiators usually heats up to a temperature of no more than 80 ° C. Less hygienic steam heating. The disadvantage of steam as a coolant is the high surface temperature of the devices - not lower than 100 ° C, which contributes to air overheating and dust sublimation. In addition, this system is difficult to operate. air heating usually performed with partial recirculation. Air recirculation is not allowed in rooms containing industrial dust, CO 2 , SO 2 , substances with a pungent odor, etc. Design heating appliances with water and steam heating and their placement are of great hygienic importance, both for the heat exchange of the human body and for the general sanitary condition of the premises. Heating appliances are located at the outer fences, primarily under the windows. It is recommended to use smooth heating devices. The installation of ribbed radiators is undesirable, since the presence of fins complicates their cleaning. In rooms with a significant emission of dust (flour warehouses, a sugar mill, etc.), smooth pipes are used as heating devices. Radiant panel heating- has a number of advantages over others heating systems: it provides uniform distribution of heat in the room, due to the presence of large heating surfaces, reduces heat transfer by radiation, does not occupy the usable area of the premises. With this system, heating elements are laid in the walls, ceiling, floor in the form of pipes or plates with circulating in them hot water or steam, as well as hot air ducts or electric coils. With panel radiant heating, dust sublimation is practically absent, since convection currents in the air are extremely weak. This heating creates more comfortable conditions at an air temperature of 17-18 °C than conventional radiator systems at an air temperature of 19-20 °C. The physiological justification for this effect lies in the fact that under conditions of panel radiant heating, the human body perceives mainly radiant heat, i.e. heat from heated surfaces, which has a stronger biological effect than convection heat (the heat of heated air). The hygienic disadvantages of panel radiant heating include the slow heating of the room to the desired temperature and the inability to quickly adjust the settings. In catering establishments all production, auxiliary premises and premises for visitors must be provided with heating in accordance with sanitary regulations. Preference is given to a water heating system. In newly built and reconstructed enterprises, it is not allowed to install stoves that run on coal, wood, solid fuel, etc. Heating devices should not be located near refrigeration equipment. They should be regularly cleaned of dust and dirt.

3.5. Hygiene ventilation

Ventilation - air exchange through various systems and fixtures. At food enterprises, the sources of air pollution with excess heat, moisture, gaseous and mechanical impurities are production equipment, the technological process of processing raw materials and manufacturing products, etc. In case of insufficient ventilation, indoor air can be dangerous in an epidemiological sense - the possibility of the spread of aerogenic infections increases, as well as pollution food pathogens of foodborne infections and food poisoning. The main purpose of ventilation is to supply a sufficient amount of clean air, remove harmful impurities, ensure appropriate microclimate indicators (temperature, humidity, etc.) and create an air-thermal balance (together with heating). With properly calculated and rationally carried out air exchange, comfortable conditions for people to stay in the premises are created. There are the following ventilation systems: natural, artificial And combined. The general hygienic requirements for the ventilation of enterprises are as follows:

ventilation devices must be provided to all rooms that need them;

ventilation must ensure all sanitary parameters of the air;

all premises of enterprises should be provided with devices that enhance natural air exchange;

when choosing and device artificial ventilation the capacity of the enterprise and the purpose of individual premises should be taken into account;

ventilation systems individual groups the premises must be separate;

when placing an enterprise in a building for other purposes, the entire ventilation system of the enterprise must be isolated from the ventilation of the main building;

places of air intake should ensure maximum compliance with its hygienic standards, and places of discharge of removed air - the absence of reverse flows of polluted air into the room.

natural ventilation due to the difference in temperature and air pressure inside and outside the room. The air exchange created as a result of infiltration through the pores of materials, the cracks of windows and doors, is unorganized and of little value in hygienic terms. The main hygienic value at natural ventilation has ventilation through open window And doors. The effect of ventilation through windows is not constant and depends on the difference in air temperatures inside and outside the room, as well as the direction and strength of the wind. Air exchange is enhanced with through ventilation and can reach 80-1000 volumes per hour. To create a natural organized ventilation (aeration) arrange window vents or transoms. The most preferred transoms. Transoms are located in the upper part of the window and open at an angle of 45 0 upwards to the ceiling. At the same time, the outside cold air is directed upwards to the ceiling, where it mixes with warm air and enters the working area. This avoids drafts and colds. To enhance the intensity exhaust ventilation apply deflectors, whose work is based on the use of wind pressure. artificial ventilation . In rooms with intense air pollution by industrial hazards, only natural air exchange is not enough. Therefore, they are equipped with mechanical ventilation with forced injection of outside air and removal of polluted air. The artificial ventilation system is divided into: supply, exhaust, supply and exhaust, local and system air conditioning. Supply ventilation is used to supply fresh air to the premises, exhaust - to remove contaminated air. The most acceptable is supply and exhaust ventilation(general exchange), which pumps fresh purified air into the room and simultaneously removes polluted air. Such ventilation ensures purity and uniform distribution of air, and, if necessary, allows it to be heated or cooled. The supply and exhaust ventilation system consists of air inlets, dust cleaning facilities, devices for heating or cooling air, fans with motors, air ducts with openings in the premises, and devices for cleaning the exhaust air. local ventilation . Along with general ventilation, for the most efficient removal of excess heat, moisture, smoke, gases, etc., local ventilation is widely used in food enterprises. Ventilation devices are screens, umbrellas, curtains, ring ducts etc. They remove from the room 60-75% of the heat generated by the equipment. Air conditioning. A much more advanced form of artificial ventilation is air conditioning. Air conditioning systems make it possible to artificially create indoor optimal parameters temperature, movement, humidity, air purity and automatic maintenance of them at a given level. Air conditioning cleans the air winter time heats up, in summer it cools and humidifies. In addition, air conditioners can carry out air deodorization, ozonation, ionization and perfumery. The choice of ventilation system depends on the production profile and capacity of the food enterprise. In the production and amenity premises of enterprises, mechanical supply and exhaust ventilation is usually equipped, and in administrative premises - ventilation or air conditioning. At small food objects, the organization of mechanical exhaust ventilation without an organized inflow is allowed. For administrative, household, warehouse and most industrial premises, standard norms for the multiplicity (value) of air exchange are established. For individual production and some other premises, the amount of ventilation air exchange is determined by calculation, taking into account the amount of heat and moisture entering the given room. The more independent ventilation systems at the enterprise, the shorter the length of the air ducts of each of them and the higher their reliability. It is important for the cleanliness of the air in the enterprise to have the correct equipment of the mines for the intake of clean air and the exhaust of the exhaust. Exhaust ventilation shafts should protrude above the roof ridge or flat roof surface by at least 1 m. Sanitary requirements for ventilation of catering establishments. When using air conditioning systems, the microclimate parameters of industrial premises of catering establishments must comply with optimal values sanitary norms, and in the presence of mechanical or natural ventilation - admissible norms. Supply and exhaust ventilation is equipped in industrial, auxiliary and sanitary facilities. All work related to the formation and entry into the air of harmful substances should be carried out only when the supply and exhaust or local ventilation. Ventilation openings should be located in such a way as to ensure maximum removal of industrial hazards, and the supply of fresh air should not cause discomfort to personnel. The place of supply of supply air is determined by the nature of the room and the features of the production process. So, in the hot and confectionery shops, supply air is supplied to the working area, because. the main task is to reduce heat radiation from heating surfaces. In other rooms, supply air is supplied to the upper zone. Of hygienic importance is the correct calculation of the air exchange rate per hour, as well as the ratio of supply and extract air depending on the purpose of the space. In enclosed spaces, an average of 40-80 m 3 of air per hour should be exchanged. exhaust ventilation is planned separately for each group of premises, depending on the hazards emitted from them and the required air exchange rate. So, separate exhaust ventilation should be in the waste chambers (the air exchange rate for the hood is 10 volumes per hour), in industrial premises, refrigerated chambers for storing fruits and herbs (4 volumes per hour). In production shops, the hood should prevail over the inflow (4 volumes per hour to 3, in washing rooms - 6 to 4), and in the trading floor - the inflow should exceed the hood. Under this condition, odors, excess heat and moisture will be removed from the hot shop, and fresh air will enter the hall in the right amount. Amenity premises (toilets, pre-showers, women's hygiene rooms) are equipped autonomous systems exhaust ventilation, mainly with a natural impulse. In mechanical systems inlet ventilation, it is recommended to provide for the cleaning of the supplied outdoor air and its heating during the cold season. Air intake for supply ventilation carried out at a height of at least 2 m from the ground. Supply air supply should be in the cleanest rooms. The temperature of the supply air must be at least 12 ° C, and the temperature difference between the supply air and the room air must not exceed 5 ° C (in winter, this is achieved by heating the air in heaters); the speed of air movement is 0.2-1 m/s, depending on thermal radiation. In cream finishing rooms supply the ventilation system must have an anti-dust and bactericidal filter. Local artificial ventilation systems. Hot and confectionery shops have significant heat emissions (250-300 kcal / m 3 / hour), therefore, in addition to general ventilation, they need a local ventilation system above the heating equipment. The most widespread as local ventilation devices are circular ducts And exhaust hoods. The area of the ventilation device must exceed the area of the slab by 0.5 m around the perimeter. A serious disadvantage of annular air exchange is its location under the ceiling at a considerable distance from the stove, as a result of which part of the emitted harmful substances is not captured by suction and spreads throughout the room. To improve the microclimate of hot shops are used hanging type suction. They are installed above the thermal electrical sectional modulated equipment. These suction devices have not only an exhaust, but also a supply device (compartment), which ensures effective removal of harmful substances from working area And showering workplaces with supply air jets. Air showers are provided with thermal radiation of 300 kcal / m 3 / hour or more. For work of medium severity, the air temperature during air showering in warm periods of the year should be 21-23 ° C at a speed of 1-2 m / s, in cold periods of the year - 17-19 ° C at a speed of 0.5-1 m /With. Air showering must be used to prevent the adverse effects of infrared radiation on the body of cooks and confectioners at workplaces near ovens, stoves, ovens and other heating equipment. In the cold period of the year, it is recommended to equip the premises of the loading, expedition, vestibules thermal curtains. Equipment and washing baths that serve as sources of increased release of moisture, heat, gases, as well as operations associated with sifting flour, powdered sugar and other bulk products should be provided local exhaust systems with preferential extraction in the zone of maximum pollution. Air ducts of ventilation systems are carried out with a minimum number of revolutions to reduce aerodynamic resistance. Openings of ventilation systems are closed with a fine-meshed polymer mesh. Ventilation systems of the enterprise should not worsen the living conditions and stay of people in residential buildings and buildings for other purposes. The exhaust ventilation system should be separate from the ventilation system of these buildings.

Chapter 4

and construction of food facilities

The expansion of the network of food enterprises and the growth of food production are inextricably linked with the construction of new and reconstruction of existing facilities, bringing their technical equipment to the modern level. In such cases, the sanitary service bodies are obliged to ensure strict observance of the current sanitary-hygienic and sanitary-anti-epidemic rules and norms when allocating a land plot, in the process of designing, building and reconstructing, as well as putting food enterprises into operation. It's necessary:

to create impeccable sanitary and epidemiological conditions for the production, storage and sale of food products;

warnings negative influence on employees of the enterprise of harmful factors production environment(microclimate, noise, vibration, infrared radiation, flour dust, etc.);

prevention of harmful effects of the facility on environment and public health (gas, smoke, soot, noise, smell, etc.);

exclusion of contamination of the food object by production waste.

In accordance with the functions performed, food enterprises are divided into three groups. Food industry enterprises - dairy factories, meat-packing plants, sausage, confectionery, breweries, canning factories, bakeries, etc., manufacturing food products, which are further sold through trade and warehouse networks and public catering enterprises. Catering establishments - canteens, restaurants, cafes, bars, fast food establishments, etc., providing the population with ready-made food and culinary products, most of which are eaten directly on the territory of this facility. Trading and warehouse network enterprises - shops, markets, warehouses, bases, etc., providing storage and sale of food and non-food products. Depending on the functional purpose of the food enterprise, five groups of premises are distinguished:

commercial premises designed to serve the public. At public catering establishments, these include a lobby, a cloakroom, toilets and washrooms for visitors, a trading floor, a buffet, a bar, a room for selling semi-finished products, ready-made meals at home, etc .;

industrial premises- providing technological process ( hot shop, distribution, procurement premises for meat, fish and vegetables, confectionery shop, washing for kitchen and tableware, etc.);

warehouses- are intended for separate storage under certain temperature and humidity conditions of raw materials, semi-finished products and finished products(refrigerated chambers, pantries for vegetables and dry products, etc.), inventory, linen, etc.;

administrative premises - intended for the service personnel of the enterprise (director's office, accounting, sales and marketing department, dressing rooms, showers, toilets, a woman's personal hygiene room, a rest room, a health center, etc.);

technical or auxiliary premises- ventilation chamber, switchboard, heat point, boiler room, boiler room, etc.

Each of the listed groups of enterprises has its own peculiarities in organization and mode of operation and requires a special approach to design and construction. However, along with specific hygienic requirements, there are also general ones, without which a high sanitary culture of the work of any food enterprise cannot be ensured, no matter what group it belongs to. General requirements relate to the improvement of the territory, buildings, premises, production and sanitary equipment, inventory, etc.

4.1. Hygienic requirements for the territory and the master plan

During the sanitary and hygienic assessment of the site allocated for construction, attention is drawn to the size of the sanitary protection zone, the size of the site, the nature of the relief of the construction site, hydrogeological indicators, the nature of the soil, the depth of occurrence ground water, directions of prevailing winds, etc. Sanitary protection zones are established in accordance with SanPiN 2.2.1 / 2.1.1.567-96 "Sanitary protection zones and sanitary classification of enterprises, structures and other objects." To reduce the adverse effects on the environment and the human body of enterprises associated with the processing of food products and flavoring substances, the following sanitary protection zones have been established:

1st class enterprises- 2000 m (cattle farms);

enterprises of the 2nd class- 1000 m (slaughterhouses for large and small livestock, meat processing plants, meat-smoking and fish-smoking enterprises, etc.);

3rd class enterprises- 500 m (slaughterhouses of small animals and birds, oil mills and distilleries, tobacco factories, confectionery enterprises, etc.);

enterprises of the 4th class- 300 m (elevators, dairy plants, food alcohol production, fish processing plants, fish canning and coffee roasting enterprises, margarine production, sugar refineries, starch production, etc.);

enterprises of the 5th class- 100 m (canning factories, bakeries, pasta, confectionery and sausage factories, production of fruit, vegetable juices and soft drinks, enterprises for processing vegetables - drying, pickling and fermentation, food procurement factories, refrigerators with a capacity of more than 600 tons, etc.).

For mini-productions enterprises of the food industry, public catering, etc. the minimum sanitary protection zone is assumed to be 50 m. 60%. It is not allowed to place sites for the construction of food enterprises on the site of former landfills, animal burial grounds, etc., if less than twenty years have passed since the termination of their operation. terrain must be level, providing free flow of storm water. Ground height water should not exceed 0.5 m from the base of the foundation or 1 m from the basement floor. The basement soil should not be peaty, swampy and polluted. By the nature of the structure, coarse-grained soil is most acceptable, which is well drained, drained and ventilated. The construction site must be located with lee side in relation to residential, health-improving and cultural buildings and with windward- to sanitary facilities and industrial enterprises. Attention is drawn to the possibility of summing up convenient access roads and parking for vehicles. Plot dimensions must comply with established design standards. The most rational is the shape of the site with the ratio of its sides 1:2.1:1.1:1.5. Land should ensure the placement of the facility itself and the necessary auxiliary buildings for various household needs: fuel storage, transport, vegetable storage, refrigerator compartment etc. The territory of the site must be appropriately landscaped (landscaping, asphalting, etc.). The placement of buildings and structures on the territory of the enterprise should provide the most hygienic working conditions in terms of natural lighting, ventilation, as well as the fight against excessive or insufficient insolation. Production processes accompanied by excessive heat, moisture and gas release should be designed in one-story buildings or on the upper floors. Industrial buildings, auxiliary workshops (sites), warehouses are recommended to be placed in respective zones. All auxiliary buildings and structures included in the economic zone should be located on the leeward side in relation to the buildings of the production and forwarding zone at a distance of at least 50 m from the production facilities, the expedition, storage areas for food raw materials and finished products. In cases where it is possible to separate these zones with a strip of green spaces in two rows, it is allowed to reduce the specified distance to 25 m. The distance from the place of loading of finished products to fuel depots must be at least 30 m, and to ash sites - at least 50 m Garbage bins must be placed at a distance of 25-50 m from windows and doors of production buildings. In the process of sanitary assessment of the allotted area, a decision should be made on the location source of water supply, as well as approved exact locations wastewater discharge. The optimal solution is to connect the enterprise to a centralized network. In the absence of such an opportunity, it is necessary to install a local water supply and sewerage network with separate treatment facilities.

The working capacity of an office worker 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 technology, it can go over 30 degrees. In the heat, the reaction of employees is dulled, fatigue increases. Cold also has a bad effect on working capacity, causing drowsiness and lethargy. The lack of oxygen and high humidity create unbearable conditions for employees, reducing labor productivity, and hence the profitability of the enterprise.

To maintain the optimal temperature and humidity conditions, an office ventilation system is being equipped.

office ventilation requirements

The ventilation of an office building must meet the following requirements:

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

The load on office climate systems is much higher compared to domestic ones. It is required to qualitatively remove excess heat and carbon dioxide emitted by equipment and employees, to supply clean and filtered air of a given temperature.

Previously used natural systems ventilation of offices today is not able to provide the conditions regulated by sanitary standards. The operation of natural ventilation cannot be controlled, its effectiveness is very dependent on the parameters of the air 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, continuous panoramic glazing prevent the passage of air from the outside, causing it to stagnate and worsen people's well-being.

All ventilation requirements office space listed in SanPiN ( Sanitary regulations and norms) 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%.

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

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

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

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

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

If total area no more than 100 sq. meters and there are 1-2 toilets in it, natural supply ventilation is allowed in the office through the windows. Supply and exhaust ventilation is installed in offices of medium and large sizes.

Office ventilation project

A number of functions are assigned to the ventilation system of an office building. Therefore, the design takes into account many factors regulated by the rules of SNiP ventilation of office premises No. 2.09.04.87 and 2.04.05.91. The system is assembled from nodes of different cost, functionality and design. The task of designers is to choose them correctly.

The following points are agreed with the customer:

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

Designing ventilation systems for offices includes:

calculations of heat inflows for each individual room, depending on the architectural features, purpose, taking into account the terms of reference for the project;
calculation of air exchange;
axonometric diagram of communications;
aerodynamic calculation, which allows to determine the cross-sectional area of air ducts and pressure loss through the network;
selection of all necessary equipment for completing the ventilation system in the office;
calculation of the heater power in the supply 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 requirements of the customer. A properly designed ventilation system in any office increases employee productivity by 20% or more.

Components for office ventilation systems

Air is supplied to the room and removed through a system of air ducts. The duct network contains directly pipes, adapters, splitters, bends 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 related. Therefore, for optimal ventilation performance in the design process, it is necessary to balance all indicators. This hard work which only professionals can do correctly.

The 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 \u200b\u200bthe pipe. Fan power increases with in large numbers transitions and branches. The air velocity 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 the movement of air more strongly and buzz. Therefore, flexible pipes are used in small offices. Sometimes the main channels are made of rigid pipes, and the outlets to the cabinets are made of flexible ones. But large systems are assembled from rigid pipes.

Air intake grilles

They are installed in the place where air from the street enters the ventilation duct. Lattices protect from penetration into a pipe of insects, rodents, an atmospheric precipitation. Made from plastic or metal.

Air valves

Prevent wind blowing when the ventilation system is off. Often, an electric actuator controlled by automation is supplied to the valve. In order to save money, manual drives are used. Then a non-return spring valve or “butterfly” is adjacent 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, which retain up to 90% of particles from 10 microns in size. In some cases, it is supplemented with a fine or extra fine filter.

Periodically, the filter surface (metal mesh or artificial fibers) must be cleaned. The degree of contamination of the filters is determined by pressure sensors.

Heater

It is used to heat outdoor air in winter, they are electric or water.

Electric heaters have some advantages over water heaters:

simple automatic control;
easier to install;
does not freeze;
easily serviced.

Main disadvantage– high price of electricity.

Water heaters work on water with a temperature of 70 - 95 degrees. Flaws:

complex automatic control system;
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 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 branched networks, radial fans are preferable. Axial ones are more productive, but they give out low pressure.

Silencer

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

Distribution grilles or diffusers

Are established on exits of air ducts to rooms. They are visible, so they must fit into the interior and ensure the spread of air flows in all directions.

Automatic control system

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

Climate equipment for offices

Supply and exhaust ventilation of the office

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

According to SanPiN norms 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 false ceiling utility room. Air is distributed through the offices by a system of ventilation ducts, the outlets of which are hidden behind diffusers or grilles.

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

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

To reduce the power consumption, the supply air is heated by a heat exchanger. It is a heat exchanger in which heat from the exhaust air is transferred to fresh air. Recuperators for office ventilation rotary and lamellar are used. The first ones have an efficiency of more than 75%, they work in harsh frosts. But during operation, about 5% of the exhaust air gets back into the room.

Plate recuperators are inexpensive, their efficiency is not more than 65%. But they get icy, you have to provide them with heating.

All necessary equipment for air treatment in the supply and exhaust system is 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, it can be several split systems or multi-splits.

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 a certain amount of fresh air from the street to the halls. To implement this function, the duct air conditioner is equipped with additional equipment that mixes air. That is, the equipment both airs and ventilates the office in accordance with the norms.

This scheme works like this:

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

The air conditioner case is hidden above the false ceiling or in the utility room.

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

Air handling units combined with VRF systems for the office

On large areas, the 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 coil units and VRF systems.

The capacity of such equipment can reach 60 thousand cubic meters per hour. Ventilation and climate control equipment is installed on the roof of the building or in separate rooms.

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

fan chamber;
recuperator;
noise absorber;
mixing chamber;
filter block.

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 premises. In each room, an internal module is installed that keeps the temperature within the specified limits. There are no temperature fluctuations typical for household air conditioners. Internal modules can be of any type (floor, cassette, ceiling).

The chiller warms or cools the refrigerant - ethylene glycol. Which is fed to the heat exchanger - fan coil unit with forced air movement. Fancoils are located directly in the office halls. In order for the coolant to move at a given speed, the system is supplemented with a pumping system. Many offices and halls can be attached 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 are industrial climate technology. They are installed in accordance with SNiP and provide ventilation and air conditioning for office space. In the air conditioning module, the air is brought to the required temperature and humidity parameters. Air recirculation is carried out (mixing of used and fresh air), including partial with admixture. After processing, the air is supplied to the premises through a duct system.

As a result of human activity in the air of residential and public buildings, the content of carbon dioxide, water vapor, the air temperature rises. The decomposition of sweat on the surface of the body, organic dust contained on clothing, entails the appearance of unpleasant odors. Together with dust, various microorganisms, including pathogens, enter the air. This so-called room smell reduces efficiency, worsens overall well-being. A hygienic indicator of air pollution in residential premises is the content of carbon dioxide in it, which should be no more than 0.07-0.1% in the air.

Ventilation is the replacement of polluted indoor air with completely or partially clean outside air.

The amount of ventilation air that must be supplied to the room per unit of time depends on a number of factors - the cubic capacity of the room, the number of people, the nature of the work performed, the amount of harmful substances contained in the room air. 30-35 m 3 of air per hour should be introduced into living quarters per person, children under 10 years old need 12-20 m 3, over 10 years old - 20-30 m 3 (ventilation volume).

For premises where heavy physical work is performed (enterprises, sports halls), for hospital wards, etc., the amount of ventilation air per hour per person should be increased, since in these premises, as a result of intensive breathing, sweating, etc., changes in the state air environment are more significant. So, in sports and gyms, 90 m 3 of ventilation air per person per hour are required, in industrial premises - 70 m 3 or more, depending on the nature of the production.

The air exchange rate is a number showing how many times the air in the room is completely exchanged within an hour. Determining the required rate of air exchange in residential premises can be done by dividing the volume of ventilation by the air cube (cubic capacity of the room per person). So, for example, with a room area of 9 m 2 per person and a room height of 3 m, the air cube will be equal to 27 m 3 (9X3). In this case, the air exchange rate will be 35:27= 1.3; with a smaller air cube, the required air exchange rate increases accordingly.

Due to air filtration through pores in building materials, cracks in windows, etc., only one air exchange is provided in the room practically per hour.

There are natural and artificial ventilation. Natural ventilation refers to the exchange room air to the outside through vents, transoms, ventilation ducts, window sill air inlets, furnace openings, pores building materials. Natural ventilation is carried out under the influence of the temperature difference between the outdoor and indoor air, as well as due to the pressure difference.

The amount of infiltration (leakage) of air through the pores in the walls is very small and is practically neglected.

It is most expedient to arrange transoms. The transoms open at an angle of 45° to the window surface, which contributes to the preheating of cold air. This allows even in winter to keep transoms open for a long time in the presence of people. To ensure satisfactory ventilation, the total area of the vents and transoms must be at least 1/50 of the floor area.

A more reliable effect is provided by through ventilation, in which a complete change of air in the room can be provided in 3-5 minutes.

In rooms where there is a large crowd of people or the air is significantly polluted, natural ventilation cannot provide the necessary air exchange. In such cases resort to artificial, mechanical ventilation. Artificial ventilation can be local (for a certain room) and central (for the entire building).

Mechanical ventilation does not depend on fluctuations in temperature and pressure of the outside air, it acts constantly and evenly.

The central ventilation is more perfect and works silently. It can be supply, exhaust and combined (supply and exhaust). With supply ventilation, the room is supplied with atmospheric air, and the contaminated is removed through the windows or transoms. Exhaust ventilation mechanically removes air from the room, and the flow of clean air is carried out through windows, cracks, pores of the walls. With supply and exhaust ventilation, both the inflow and exhaust of air are carried out mechanically (Fig. 20).

Rice. 20. General scheme of mechanical supply and exhaust ventilation

IN Lately air conditioning became widespread. It is the most advanced type of artificial ventilation. With the help of indoor air conditioners, the necessary microclimatic conditions(temperature, humidity, air movement, certain smells, etc.). This eliminates the need for heating devices.

Air conditioning is widely used in medical institutions, enterprises, theaters, clubs and other premises where a stable microclimate is required.

Ventilation - the exchange of air, carried out with the help of various systems and devices.

At food enterprises, the sources of air pollution with excess heat, moisture, gaseous and mechanical impurities are production equipment, the technological process of processing raw materials and manufacturing products, etc.

With insufficient ventilation, indoor air can pose an epidemiological hazard - the possibility of the spread of aerogenic infections increases, as well as contamination of food products with pathogens of food infections and food poisoning.

The main purpose of ventilation is to supply a sufficient amount of clean air, remove harmful impurities, ensure appropriate microclimate indicators (temperature, humidity, etc.) and create an air-thermal balance (together with heating).

With properly calculated and rationally carried out air exchange, comfortable conditions for people to stay in the premises are created. There are the following ventilation systems: natural, artificial and combined.

The general hygienic requirements for the ventilation of enterprises are as follows:

Ventilation devices must be provided to all rooms that need them;

Ventilation should provide all sanitary parameters of the air;

All premises of enterprises should be provided with devices that enhance natural air exchange;

When choosing and installing artificial ventilation, the capacity of the enterprise and the purpose of individual rooms should be taken into account;

Ventilation systems of separate groups of rooms should be separate;

When placing an enterprise in a building for other purposes, the entire ventilation system of the enterprise must be isolated from the ventilation of the main building;

Air intake points should ensure maximum compliance with its hygienic standards, and exhaust air outlet points should ensure the absence of polluted air backflows into the room.

Natural ventilation is carried out due to the difference in temperature and air pressure inside the room and outside. The air exchange created as a result of infiltration through the pores of materials, the cracks of windows and doors, is unorganized and of little value in hygienic terms.

The main hygienic value in natural ventilation is ventilation through open windows and doors. The effect of ventilation through windows is not constant and depends on the difference in air temperatures inside and outside the room, as well as the direction and strength of the wind. Air exchange is enhanced with through ventilation and can reach 80-1000 volumes per hour.

To create natural organized ventilation (aeration), vents or transoms are arranged. The most preferred transoms. Transoms are located in the upper part of the window and open at an angle of 450 upwards to the ceiling. At the same time, the outside cold air is directed upwards to the ceiling, where it mixes with warm air and enters the working area. This avoids drafts and colds.

To enhance the intensity of exhaust ventilation, deflectors are used, the operation of which is based on the use of wind pressure.

Artificial ventilation. In rooms with intense air pollution by industrial hazards, only natural air exchange is not enough. Therefore, they are equipped with mechanical ventilation with forced injection of outside air and removal of polluted air.

The artificial ventilation system is divided into supply, exhaust, supply and exhaust, local and air conditioning systems. Supply ventilation is used to supply fresh air to the premises, exhaust - to remove contaminated air. The most acceptable is supply and exhaust ventilation (general exchange), which pumps fresh purified air into the room and simultaneously removes polluted air. Such ventilation ensures purity and uniform distribution of air, and, if necessary, allows it to be heated or cooled.

The supply and exhaust ventilation system consists of air inlets, dust cleaning facilities, devices for heating or cooling air, fans with motors, air ducts with openings in the premises, and devices for cleaning the exhaust air.

local ventilation. Along with general ventilation, for the most efficient removal of excess heat, moisture, smoke, gases, etc., local ventilation is widely used in food enterprises. Ventilation devices are screens, umbrellas, curtains, annular air ducts, etc. They remove 60-75% of the heat generated by the equipment from the room.

Air conditioning. A much more advanced form of artificial ventilation is air conditioning. Air conditioning systems allow you to artificially create in the room the optimal parameters of temperature, movement, humidity, air purity and automatically maintain them at a given level. In the process of air conditioning, the air is purified, heated in winter, cooled and humidified in summer. In addition, air conditioners can carry out air deodorization, ozonation, ionization and perfumery.

The choice of ventilation system depends on the production profile and capacity of the food enterprise. In the production and amenity premises of enterprises, mechanical supply and exhaust ventilation is usually equipped, and in administrative premises - ventilation or air conditioning. At small food objects, the organization of mechanical exhaust ventilation without an organized inflow is allowed.

For administrative, household, warehouse and most industrial premises, standard norms for the multiplicity (value) of air exchange are established. For individual production and some other premises, the amount of ventilation air exchange is determined by calculation, taking into account the amount of heat and moisture entering the given room.

The more independent ventilation systems at the enterprise, the shorter the length of the air ducts of each of them and the higher their reliability.

It is important for the cleanliness of the air in the enterprise to have the correct equipment of the mines for the intake of clean air and the exhaust of the exhaust. Exhaust ventilation shafts should protrude above the roof ridge or flat roof surface by at least 1 m.

Sanitary requirements for ventilation of catering establishments. When using air conditioning systems, the microclimate parameters of industrial premises of catering establishments must comply with optimal values sanitary standards, and in the presence of mechanical or natural ventilation - to acceptable standards.

Supply and exhaust ventilation is equipped in production, auxiliary and sanitary facilities. All work related to the formation and entry into the air of harmful substances should be carried out only with the supply and exhaust or local ventilation switched on.

Ventilation openings should be located in such a way as to ensure maximum removal of industrial hazards, and the supply of fresh air should not cause discomfort to personnel. The place of supply of supply air is determined by the nature of the room and the features of the production process. So, in the hot and confectionery shops, supply air is supplied to the working area, because. the main task is to reduce heat radiation from heating surfaces. In other rooms, supply air is supplied to the upper zone.

Of hygienic importance is the correct calculation of the air exchange rate per hour, as well as the ratio of supply and exhaust air, depending on the purpose of the room. In enclosed spaces, an average of 40-80 m3 of air per hour should be exchanged.

Exhaust ventilation is planned separately for each group of premises, depending on the production hazards emitted in them and the required air exchange rate. So, separate exhaust ventilation should be in the waste chambers (the air exchange rate for the hood is 10 volumes per hour), in industrial premises, cooled chambers for storing fruits and herbs (4 volumes per hour). In production shops, the hood should prevail over the inflow (4 volumes per hour to 3, in washing rooms - 6 to 4), and in the trading floor - the inflow should exceed the hood. Under this condition, odors, excess heat and moisture will be removed from the hot shop, and fresh air will enter the hall in the right amount.

Amenity premises (toilets, pre-showers, women's hygiene rooms) are equipped with autonomous exhaust ventilation systems, mainly with natural motivation.

In mechanical supply ventilation systems, it is recommended to provide for the purification of the supplied outside air and its heating during the cold season. Air intake for forced ventilation is carried out at a height of at least 2 m from the ground. Supply air supply should be in the cleanest rooms.

The supply air temperature must not be lower than 12 °C, and the temperature difference between the supply air and indoor air must not exceed 5 °C (in winter, this is achieved by heating the air in heaters); the speed of air movement is 0.2-1 m/s, depending on thermal radiation.

In the premises for finishing cream products, the supply ventilation system must have an anti-dust and bactericidal filter.

Local systems of artificial ventilation. Hot and confectionery shops have significant heat emissions (250-300 kcal / m3 / h), therefore, in addition to general ventilation, they need a local ventilation system above the heating equipment.

The most widely used local ventilation devices are circular ducts and exhaust hoods. The area of the ventilation device must exceed the area of the slab by 0.5 m around the perimeter. A serious disadvantage of annular air exchange is its location under the ceiling at a considerable distance from the stove, as a result of which part of the emitted harmful substances is not captured by suction and spreads throughout the room.

To improve the microclimate of hot shops, hanging-type suctions are used. They are installed above the thermal electric sectional modulated equipment. These suction devices have not only an exhaust, but also a supply device (compartment), which ensures the effective removal of harmful substances from the working area and the dusting of workplaces with fresh air jets.

Air showers are provided with thermal radiation of 300 kcal/m3/hour or more. For works of moderate severity, the air temperature during air showering in warm periods of the year should be 21-23 ° C at a speed of 1-2 m / s, in cold periods of the year - 17-19 ° C at a speed of 0.5-1 m / s With.

Air showering must be used to prevent the adverse effects of infrared radiation on the body of cooks and confectioners at workplaces near ovens, stoves, ovens and other heating equipment.

In the cold period of the year, it is recommended to equip the premises of the loading room, expedition, vestibules with thermal curtains.

Equipment and washing baths that serve as sources of increased release of moisture, heat, gases, as well as operations associated with sifting flour, powdered sugar and other bulk products should be provided by local exhaust systems with preferential extraction in the zone of maximum pollution.

Air ducts of ventilation systems are carried out with a minimum number of revolutions to reduce aerodynamic resistance. Openings of ventilation systems are closed with a fine-meshed polymer mesh.

Ventilation systems of the enterprise should not worsen the living conditions and stay of people in residential buildings and buildings for other purposes. The exhaust ventilation system should be separate from the ventilation system of these buildings.

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