Ventilation and air conditioning of medical institutions. Choice of natural ventilation systems. Sanitary norms for artificial ventilation for healthcare facilities

1. In the premises of medical institutions are equipped with:

supply- exhaust ventilation with a mechanical drive

· natural ventilation(transoms, vents, exhaust ventilation ducts).

2. The optimal amount of supply air to the ward is 80 m 3 /h per bed, min 40-50.

3. There are groups of premises where the use of transoms, vents and ventilation ducts is prohibited: operating rooms, delivery rooms, resuscitation rooms, aseptic blocks.

4. Autonomous systems supply and exhaust ventilation and air conditioning are equipped with: operating rooms, resuscitation rooms, wards for burn patients, wards for newborns, wards for children under one year old, x-ray and radiological departments, pharmacies, rooms for mud and hydrotherapy, rooms for bacteriological laboratories, rooms for sanitary checkpoints , sanitary facilities. In the wards, which are fully equipped with incubators, air conditioning is not provided.

5. Redundant emergency ventilation systems are equipped for operating rooms, resuscitation rooms, delivery rooms, aseptic units.

6. Outside air must be taken from a clean area at a height of at least 1 m from the ground. The air intake window must be barred.

7. outside air must be filtered.

8. The air supplied to operating rooms, anesthesia, resuscitation, postoperative wards, intensive care wards, maternity wards, wards for patients with skin burns should be cleaned with bactericidal filters.

9. Premises in which harmful substances may be released into the air must be equipped with local exhaust ventilation (exhausters or fume hoods).

Air exchange rate: in operating rooms: +6 for inflow, -5 for exhaust, when installing air conditioners: for inflow + 10, for exhaust - 8.

Organization of air exchange in infectious departments. Determination of the effectiveness of natural and artificial ventilation.

Ventilation performance indicators

The effectiveness of ventilation is judged by:

1. ventilation air volume (ventilation volume);

2. air exchange rates;

3. ventilation coefficient.

Volume of ventilation- this is the amount of air that enters the room (removed) within 1 hour.

Air exchange rate- a number that shows how many times within 1 hour the room air will be replaced by outside air.

Ventilation coefficient- the ratio of the glazed area of ​​the transom (window) to the floor area. Normal = 1:50.

Sanitary standards artificial ventilation for healthcare facilities:

1. Ventilation volume:

· Minimum volume - 40 - 50 m 3 / h per 1 bed.

· Optimum volume - 80 m 3 / h per 1 bed.

2. Air exchange rate:

· In the wards: for inflow + 2, for exhaust - 2.5.

In operating rooms, generic: for inflow + 6, for exhaust - 5,

when installing air conditioners: for inflow + 10, for exhaust - 8.

Features of ventilation in infectious diseases departments

1. Equipped with supply and exhaust ventilation with mechanical stimulation and air supply to the corridor.

2. Air is removed through individual channels for each box.

3. 75 % infectious diseases transmitted by air, so proper ventilation very important for hospitals.

4. HAI often occurs due to poor ventilation, namely due to a poor ratio between the inflow and outflow of air or due to a violation of the integrity of the ventilation system.

General sanitary and hygienic requirements for the organization of UZ lighting. Hygiene requirements to the natural lighting of the premises.

Sources and lamps of artificial light, acceptable for use in ultrasound. Hygienic requirements for the organization of artificial lighting in the wards.

88. Features of the layout of the premises of the ultrasound and the design of light openings that affect natural light. Insolation mode of premises.

To maintain sanitary and hygienic conditions in the room, favorable for human body, it is required to regularly (permanently) replace the exhaust air with fresh air from the outside or cleaned with filters. Ventilation is an important recovery process environment for the productive activity of the staff, the well-being of the body. In particular, ventilation medical institutions- the key to successful recovery of patients and high-quality work of doctors.

A bit of history

Since ancient times, man has felt a decrease in the favorable climate in enclosed spaces. Therefore, due to natural ventilation in the form of holes under the ceiling, primitive ventilation conditions were created up to the 19th century. During that period, the theory of free movement of air in open pipes and channels was proved. When using thermal ventilation, shortcomings in huge energy costs were revealed almost immediately. As a result, it was shown that mechanical regulation of air flows is the best option.

In the middle of the century, centrifugal fans appeared, and by the end of the 19th century, a similar process of airing rooms was widely used. In the last century, ventilation undergoes another improvement - electrical stimulation to mechanical actions. Further changes occur in design, trim levels, sizes and so on.

The main opponents of fresh air

Basically, with the help of ventilation devices, the following problems are solved:

• getting rid of unnecessary heat that causes discomfort to the body;
• equalization of the level of relative humidity of the room;
• release from air pollution, from harmful fumes, etc.;
• dust for humans is also an irritant;
• regulation of the speed of air flows.

Classification of ventilation systems

A system that includes various kinds of devices for performing specified air replacement programs is called a ventilation system. As already mentioned, according to the method of implementing a comfortable climate, systems are divided into natural and artificial (due to external attraction of energy: thermal, mechanical, electrical). According to the function performed, they are classified into supply systems (supplying air into the room) and exhaust systems (removing unnecessary exhaust air).

According to the principles of air exchange, ventilation is distinguished: general exchange, which serve the entire volume of the room; local value type kitchen hoods; emergency are installed in places of increased danger of harmful emissions for their speedy removal; smoke-proof ventilation is installed in fire-prone buildings for obvious reasons. According to the design, ventilation systems are ducted and non-ducted.

Equipment

Among the main components of the system are directly fans with various options for air exchange: axial, centrifugal and diametrical. The same units and installations are designed to serve more spacious rooms. To improve the quality characteristics of the device, secondary installations are designed in the form of noise dampers, air filters, air flow heaters (water or electric), devices for regulating the rate of intake of the purified atmosphere or its distribution in space, smoke dampers, etc.

Each type of ventilation system and additional devices is suitable for a specific serviced object, for example, for medical and preventive buildings.

Medical institutions

The ventilation of such institutions, in addition to the basic documentation for the operation of houses, is subject to the Orders of the Ministry of Health of Russia. The main features of ventilation in medical institutions are:

1. Vertical collectors are not applicable for any type of system due to poor cleaning of the central part of the room, where the medical staff is located.
2. From such important departments of a medical facility as an operating room, X-ray room, maternity, anesthesia, resuscitation, exhaust air flows are necessarily eliminated at the top and bottom of the room.
3. Certain temperature and humidity indicators are always maintained in operating departments to enable round-the-clock assistance to people.
4. In hospital rooms relative humidity 35 - 50% is regulated only in the cold seasons, since in the summer period natural ventilation methods prevail there.
5. Recirculation of air masses is not applicable to all premises of medical centers, since the incoming air does not meet hygiene and sanitation standards.
6. For each room in the medical and diagnostic buildings, a certain design air temperature is set, which is maintained by the ventilation system;
7. Noise plugs are mandatory due to the permissible sound level of 35 dBA.

Choice of natural ventilation systems

Mostly ventilation in medical institutions is selected with a mechanical principle of movement. At the same time, it is strictly forbidden to pump air from polluted areas to cleaner rooms. Natural extracts are applicable for separately spaced low (up to three floors) buildings, hospital wards, emergency rooms, in hydrotherapy rooms and infectious cases. Supply ventilation is allowed only as artificial, the air mass flows from the outside into the corridors.

Natural exhaust ventilation without a centralized air supply is also documented in detached, maximum three-story buildings. It is also permissible in outpatient clinics and feldsher and obstetric points, ambulances and pharmacies of certain categories, utility and residential buildings of dispensaries, etc.

Ventilation with mechanical stimulation

In warm climatic zones, it is planned to install ceiling devices to change the speed and direction of air flows in the summer in rooms of category “H” in the absence of an air conditioner. For operating rooms, X-ray and laboratory departments, forced-air and exhaust devices with a mechanical mode of operation are required.

Mechanical hoods without an organized supply of fresh air are acceptable in latrines, showers, sanitary and washing rooms. Depending on the same or different required climate in buildings, centralized and decentralized ventilation systems are distinguished, respectively.

Organization of air exchange in medical institutions

When local fans fail to cope, and the accumulation of harmful emissions, moisture and heat occurs everywhere in the building, then general ventilation systems are used that keep the necessary environmental indicators normal. Depending on the required degree of dilution of harmful substances, heat and moisture, the power of the installations is calculated.

If emissions in air affect the body differently, then the highest dilution is taken into account. If the substances have a total effect on a person, then appropriate measures are taken.

Supply type ventilation

This type contains an intake device - an air inlet, also an air duct, various cleaning filters, calorimetric heaters, fans directly, flow distributors, a water irrigation device. Together in the chamber there are filters, irrigation installations, a fan and a heater.

Air is taken in through special intake shafts and channels, which are supposed to be installed in a clean place at a height of more than 2 meters above the ground. It is also possible to place these devices above the roof, but they must be covered by protective devices. Equipment supply ventilation, which is intended for class A and B rooms, cannot be placed in the same place with hoods. Also, such a combination of residential complexes with medical buildings is not allowed.

Exhaust type ventilation

Local hoods emit exhaust air higher than 2 meters from the roof of the building. Also, it is not allowed to jointly arrange the supply and exhaust systems with high air pollution. By frequency, the exhaust fans operate once per hour, and the supply fans operate twice.

To prevent the harmful effects of prolonged stay of patients in the same building, both for themselves and for the surrounding staff and visitors, it is necessary to eliminate the main causes in a timely manner. In addition to improved technologies that minimize emissions, it is important to correctly install the ventilation system.

Ventilation in the office is one of the essential components in the organization of a favorable working atmosphere. The device of high-quality and balanced ventilation in the office is a step towards the success of your enterprise or company.

The ventilation system is not furniture or computers for the office. You can’t just choose an online store and order it with delivery. When choosing and installing an office ventilation solution, it is important to find an installer company that will choose the right technical solution, calculate, design the system and correctly mount and configure it all. A professional engineer during the initial communication he will find out the working conditions and the main wishes and orient how much the solution of the task will cost. In order to clarify what the engineer comes from, we suggest that you familiarize yourself with the basic principles for choosing office ventilation solutions, features various systems and their possible market value.

Any, even a preliminary assessment of the cost of equipment and work on its installation requires a detailed study of the conditions of the object, the architectural plan, the availability of energy sources, space and premises for engineering equipment and communications. Initially, it is necessary to determine the amount of air supplied and removed from the premises. When calculating ventilation systems for offices according to the "Building Norms and Rules" (SNiP), the amount of air supplied is taken equal to 30-40 m3 / h per person or three times the air exchange in the premises. Of the two results obtained, the larger one is usually chosen.

In winter, the supply air must be heated. Electric or water heaters are used to prepare cold air. It is important to understand and determine at the stage of calculations what type of equipment will be used. When making such a decision, it is necessary to clearly understand whether your facility has enough capacity to implement one or another heating method. At the same time, it should be taken into account that air exchange can be organized using supply and exhaust systems with heat recovery. Such systems increase the total cost of the ventilation unit, but allow saving from 30% to 80% of the operating costs for heating the inflow due to heat transfer from extract air to the inlet. A significant part of the cost of the office ventilation system is the system of air ducts, distribution grilles and diffusers. The configuration of the air duct system and their parameters depend on the location of the ventilated premises at the facility. It is not difficult to guess that the more small rooms, the more complicated circuit air ducts and, therefore, more expensive to implement. To determine the approximate cost of the entire system, time-tested values ​​can be used. Based on experience, the following figures can be given: ventilation of an office with an area of ​​​​up to 250 sq.m will cost 60-90USD / sq.m, from 250 to 1000sq.m it will cost 40-80 USD / sq.m, with areas over 1000 sq.m the system ventilation costs 25-50 USD/sq.m.

Initial data

office space with total area 350 sq.m, ceiling height 2.7 m (space behind false ceiling 0.3 m). The office employs 65 people on a permanent basis. In addition, a plan of premises is attached, which recommends a place for placing a ventilation unit. In the office, you need to install a full-fledged supply and exhaust ventilation. Assumed equipment REMAK (Czech Republic).

Even before the start of calculations, it is necessary to determine whether it is possible, in principle, to mount ventilation in these rooms. Namely, it is necessary to agree on the main design points:

• location of the ventilation unit;
• a place for placing a network of air ducts;
• Availability required capacity on electricity and occasion (if a water heater is used);
• the possibility of installing a drainage system (if necessary);
• the possibility of servicing the system after installation;
• the ability to dismantle components if necessary

Air exchange calculation

After clarifying all the points on placement and the possibility of carrying out installation work, you can proceed to the calculations. The first thing to determine is the air performance of the future system. To do this, it is necessary to calculate the air exchange according to multiplicities: L=n*S*h, where S is the area, sq.m, h is the height of the ceilings, m, n is the air exchange rate, for an office usually take values ​​from 2 to 3.

For this office, we get L=2 x 350 x 2.7=1890 m3/h

For this office, we get L= N x Ln = 65 x 30 = 1950 m3/h

A larger value is selected and rounded up, it is by this value that a fan or a supply unit is selected, based on the characteristics of the equipment existing on the market, in this case we will talk about a fan with an air exchange of 2000 cubic meters / h.

Calculation of heater power

The second step is usually to calculate how much energy is needed to heat the supply air in cold weather. To determine the power (P, W), it is necessary to know the required temperature at the outlet of the heater, the minimum outdoor temperature and the air exchange of the entire system. The first two parameters are determined by SNiP. The temperature in residential premises should not be lower than +18°C, the minimum outdoor temperature depends on the climatic zone, for Moscow -26°C (it is defined as average temperature the five coldest days in the coldest month at 13:00). From the above figures it can be seen that for Moscow the heater must heat the supply air when it is turned on at full power by 44°С, ^T=+18°С - (-26°С) = 44°С.

According to the initial data, we get P \u003d (L x ^T) / 2.98 \u003d (2000 x 44) / 2.98 \u003d 29,530 W, i.e. in this case, about 30 kW of power will be needed for heating.

It should be noted here that there are two ways to heat the supply air (electricity or water), but for their implementation, one should remember the mandatory conditions that simply need to be met.

First way. Electric heater. When heating with electricity, it must be understood that with powers of more than 5 kW, 3-phase heaters are usually used (less current, there is no problem with phase imbalance).

Electric heaters have several advantages over water heaters:

• automation for control and adjustment is simpler than that of water heaters;
• does not require a complex system of piping and fittings to control water;
• there is no danger of freezing the system;
• easy to install and maintain.

But not everything is so great in electric heaters, their most serious drawback is the high cost of electricity.

The second way. Water heater. If you plan to use water as a heat carrier, then you need to make sure that there are enough resources for this. The water temperature should be between 70°C and 95°C.

Water heaters have a number of features that are in contrast to the savings during operation:

• complex automation;
• complex mixing unit, consists of a large number of elements and connections;
• requires maintenance and regular monitoring of the state of the node;
• danger of freezing of the heater, in case of emergency shutdown of the ventilation system;

But with proper installation and regular monitoring, these shortcomings cannot be compared with the savings during the operation of water systems.

It should not be forgotten that, regardless of the type of heater, there are other consumers in the ventilation system, usually it is necessary to allocate from 1 kW to 6 kW for them.

After calculating the heater, the problem of a lack of power reserve may arise, what to do in such a situation, do not throw the idea of ​​\u200b\u200bventilation into winter time. And in such a situation, there is a way out, this is the implementation of the principle of heat recovery - in such ventilation systems, heat is transferred from the exhaust air to the supply air.

Recovery systems

The heat exchanger is a separate device that is built into the ventilation system, while the air ducts of the supply line must converge with the air ducts of the exhaust line. There are several types of recuperators - lamellar, rotary and intermediate coolant (for example, glycol).

The latter type is used less often in offices, this is due to the low efficiency of such devices and some difficulty in installing the pipe system. The advantage of this method of heat recovery is the ability to separate the exhaust and supply systems in space and the ability to integrate the heat exchanger into an existing ventilation system at minimal cost, regardless of its geography on the object.

But the first two types are often used in office space. Rotary heat exchangers have the highest efficiency (up to 80%), in which heat is transferred by a rotor that rotates between two flows. This type of regenerative heat exchanger allows you to regulate its operation by changing the speed. The disadvantage of such a system is that when the rotor rotates, part of the exhaust air enters the supply air. The amount of return air can be up to 5% of general air exchange. But such a heat exchanger can withstand severe frosts.

And the last type is plate or flat recuperators. They have no moving parts, and their use does not require additional electricity - this is the most cheap option due to the simplicity of its implementation. But at the same time they have a good efficiency from 55% to 65%. True, this type of recuperators is subject to freezing, to combat this, a line bypass or additional heating is used (sometimes due to a short-term shutdown of the inflow).

Summarizing the above, we can say that, despite some complexity during installation, the need for additional space and some increase in the cost of the entire ventilation system, it makes sense to use a system with heat recovery. With further operation, the difference in the final cost of the system is easily compensated for by savings.

Air distribution network

It is clear that in addition to the ventilation unit itself, for the organization of air exchange, it is necessary to create a network of distribution ducts, which consists of air ducts, fittings (transitions, turns, splitters, adapters) and distribution devices (grilles, diffusers). First of all, when calculating the network, they execute the duct passage scheme. Further, according to this scheme, the calculation is made. The calculation is carried out according to the main parameters: the resistance created by the duct network, the air flow rate and the noise level. All these parameters are interrelated and when calculating them, you have to balance their values ​​in order to achieve the optimal result.

The pressure is calculated depending on the length, cross-sectional area and branching of the duct network. The more turns, branches, transitions from one section to another, the more pressure must be created by the fan of the ventilation unit. The speed in the air ducts depends on their cross section and the pressure supplied by the fan; for the office, they try to limit the speed to 4-5 m / s. In addition, the speed of the air flow is inextricably linked with the level of noise, and pressure losses increase greatly with increasing speed. But it is often impossible to use large sections due to the lack of free space. Therefore, basically the calculation of the duct network is a search for a compromise between these parameters. Therefore, it is better to trust this work to professionals, the performance and comfort of the designed ventilation largely depend on it.

Air ducts themselves can be flexible and rigid. Flexible ducts are cheaper and easier to install, but noisier and have more aerodynamic resistance than rigid ducts. Usually, only for small offices, you can completely build a network on flexible ducts, but in other cases, as a rule, rigid ones are used. Often hard ducts act as a highway from which air is supplied and removed directly from the premises by flexible outlets. The estimated cost of rigid air ducts with installation is $30-45 per sq.m, for flexible ones it is $12-25 per sq.m.

Composition of ventilation systems

Any ventilation is assembled from the same components, they may differ in parameters, shape, efficiency, quality, but they all perform a set of basic functions. Often several components are combined in one housing, so the installations are more compact and can be almost finished ventilation unit. To understand what and why is used in such systems, the main components are listed below and they are given a brief description:

Air intake grille- The first in the ventilation system, it is through it that street air enters the ventilation system. In addition to the decorative function, it performs a protective function, prevents rain and large debris from entering the system.

Air valve- The main task of this device is to prevent the ingress of outside air into the premises when the ventilation is turned off, this is especially true in winter. Often the valve is made with an electric drive, in which case all control is automatic. But here you can save money by installing a manually operated valve, however, in this case it is advisable to install it in tandem with a spring check valve (in common people - a butterfly), which, under the action of a spring, will block access to street air when the ventilation is turned off. In such a tandem, a manual valve is needed to shut off the system for a long period.

Filter - Important element ventilation systems, protects both the system itself and the serviced premises themselves from pollution and dust. Typically, a coarse filter is used, according to the European standard EU1-EU4, such filters do not let dust particles larger than 10 microns pass, while retaining 60-90% of the mass of large dust particles. If there are increased requirements for air purity, in addition to the coarse filter, a fine filter (EU5-EU9) is added, which traps dust particles up to 1 micron and 60-95% of the mass of fine particles of impurities. In special cases, extra fine filters (EU10-EU14) are used, such filters are capable of retaining particles up to 0.1 microns and 97-99.999% of the mass of extra fine particles of impurities.

In coarse filters, a fabric made of synthetic fibers or a metal mesh is used as a filter material. The filter elements of ventilation systems must be periodically serviced and cleaned. If necessary, the level of contamination of the filters can be monitored using a differential pressure sensor.

Heater- In winter, the supply air must be heated, for this a heater is used. Heaters are of two types water and electric. When installing less cost and effort, electric heaters are required. Water heaters are cheaper to operate, but difficult to install and maintain, require attention and periodic monitoring of the state of the water piping and the system as a whole (there is a risk of freezing).

Fan- This is the main element of the artificial ventilation system. When selecting a fan, the main criteria are performance (the amount of air pumped per unit of time), total pressure, and noise characteristics. Among other things, there are fans in a noise-insulated housing, explosion-proof, for working with aggressive environments and at high temperatures, their use is due to the characteristics of the serviced premises.

Silencer- Since the previous component is the source of noise, a silencer is usually installed after it, thereby preventing the noise from propagating further along the ducts. Most of the noise is created by air turbulence on the fan blades. As a sound-absorbing material, glass fiber or mineral wool is used.

air ducts- Serve for distribution of air. There are flexible and rigid. The main characteristic for air ducts is the cross-sectional area. This parameter is selected in such a way that the noise from moving air does not exceed the permissible values. Flexible air ducts are easy to transport and install, but have much more resistance due to their uneven inner surface, for this reason they are used only for a short distance.

Air distributors- Through them, air enters the premises and is taken from them. Typically, distributors are designed as grilles and diffusers. In addition to the aesthetic load, the distributors provide uniform air distribution and can also be used in the final, individual adjustment of air flows in individual rooms.

Automation system- Serves to turn on and control the entire ventilation system. Usually, all automation is mounted in an electrical panel and allows not only to control the on and off of the system, but also controls the operation of the fan, heater, monitors filter contamination, protects the system from freezing. The final cost of the ventilation system during largely depends on the composition and functions of the selected automation system.

From the totals it can be seen that the most expensive are systems with heat recovery. In general, systems where electric heaters are used are more expensive. Systems with water heaters are not only cheaper in terms of equipment, but also require less funds for operation, but they require competent and regular maintenance. Maintenance and control.

So armed with initial knowledge, choose what suits you and call our company. Employees of the engineering department will be happy to answer all your questions and offer the best scheme for solving your problem of office ventilation.