The microclimate of hospital premises. Sanitation of the air environment

Air-thermal regime of hospitals. The compensatory capabilities of the sick organism are limited, sensitivity to adverse environmental factors is increased. Consequently, the range of fluctuations of meteorological factors in the hospital should be less than in any room for healthy people.

The thermal comfort state is a combination of four physical factors- air temperature, humidity, air velocity, temperature of the internal surfaces of the room. Normal microclimate parameters take into account: the age of the patient, the characteristics of heat transfer in various diseases, the purpose of the room and climatic conditions.

Air temperature the most important factor microclimate, which determines the thermal state of the body. It is generally accepted that optimum temperature air in the wards of medical institutions should be slightly higher than 20 ° C than in residential premises 18 ° C (Table 6.7).

1. The age characteristics of children determine the highest temperature standards in the wards of premature babies, newborns and infants - 25 ° C.

2. Features of heat transfer in patients with impaired thyroid function cause high temperature in the wards for patients with hypothyroidism (24 ° C). On the contrary, the temperature in the wards for patients with thyrotoxicosis should be 15 ° C. Increased heat generation in such patients is the specificity of thyrotoxicosis: the “sheet” syndrome, such patients are always hot.

3. The temperature in the halls of physiotherapy exercises is 18 o C. For comparison: the halls of physical education at school are 15-17 o C. Physical activity is accompanied by increased heat generation.

4. Other functional purpose of the premises: in operating rooms, PITs, the temperature should be higher than in the wards - 22 o.

An integral element of the indoor microclimate is humidity air with a range of 30 to 70%, and for medical institutions - 40-60%.

Moving air for the body is a light tactile stimulus that stimulates the centers of thermoregulation. Optimal air mobility in the premises of health care facilities is 0.1-0.3 m/s.

Hygienic requirements for the chemical and bacteriological composition of air in hospitals

When people stay indoors for a long time, waste products of the body accumulate in the air (the concentration of carbon dioxide, the amount of dust and microorganisms increase, the amount of oxygen decreases, etc.). At the same time, people feel worse, mental and physical performance decreases, coordination of movements and reaction speed deteriorate. Therefore, the definition of microclimatic conditions and calculations of the necessary ventilation in a given room are of great importance.

The main criterion for assessing the degree of indoor air pollution and calculating ventilation is the concentration of carbon dioxide in the air. The amount of carbon dioxide (CO 2 ) in indoor air increases as a result of people's breathing, during the processes of combustion, fermentation, and decay. The content of CO 2 in the atmospheric air is within 0.04% (0.03-0.05%). The maximum permissible concentration of CO 2 in residential and public buildings is not higher than 0.1%.

The hospital air contains chemical substances that are accumulated during the work of medical personnel. There are hygienic standards for the content of these substances in the air of hospital premises - the maximum allowable concentrations (table 6.2).

The administration of the medical institution organizes control over the microclimate and chemical pollution of the air in all rooms periodically: 1st group - high-risk rooms - 1 time in 3 months. 2nd group - high-risk premises - 1 time in 6 months. 3rd group - all other premises and, first of all, wards - once a year.

Purpose of the lesson:

1. To study the influence of microclimate factors on the human body (atmospheric pressure, temperature, relative humidity, air velocity) and master the methods for their determination.

2. Analyze the results obtained and give a hygienic conclusion about the microclimate of the training room.

Location of the lesson: educational profile laboratory of atmospheric air hygiene.

Modern man due to objective and subjective reasons, most of the time (up to 70%) of the day is spent indoors (industrial premises, housing, medical institutions, etc.). Internal environment rooms has a direct impact on the health of people.

Microclimate - the state of the environment in a limited space (room), determined by a complex of physical factors (temperature, humidity, atmospheric pressure, air velocity, radiant heat) and affecting the heat exchange of a person.

The influence of the microclimate on the body is determined by the nature of heat transfer to the environment. The release of heat from humans comfortable conditions occurs due to heat radiation (up to 45%), heat conduction - convection, conduction (30%), evaporation of sweat from the skin surface (25%). Most often, the adverse effect of the microclimate is due to an increase or decrease in temperature, humidity or air velocity.

High air temperature, combined with high humidity and low air speed, makes it difficult to transfer heat by convection and evaporation, resulting in overheating of the body. At low temperature, high humidity and air speed, the opposite picture is observed - hypothermia. At high or low temperatures of surrounding objects, walls, heat transfer by radiation decreases or increases. The increase in humidity, i.e. saturation of the room air with water vapor, leads to a decrease in heat transfer by evaporation.

Characteristics of individual categories of work

¨ category Ia - work with an intensity of energy consumption up to 120 kcal / h (up to 139 W), performed while sitting and accompanied by slight physical stress (a number of professions in precision instrumentation and engineering enterprises, in watchmaking, clothing production, in management, etc. .)

¨ category Ib - work with an energy intensity of 121-150 kcal / h (140-174 W), performed while sitting, standing or walking and accompanied by some physical stress (a number of professions in the printing industry, in communications enterprises, controllers, masters in various types of production, etc.)

¨ category IIa - work with an intensity of energy consumption of 151-200 kcal / h (175-232 W), associated with constant walking, moving small (up to 1 kg) products or objects in a standing or sitting position and requiring a certain physical exertion (a number of professions in machine-assembly shops of machine-building enterprises, in spinning and weaving production, etc.).

¨ category IIb - work with an energy intensity of 201-250 kcal / h (233-290 W), associated with walking, moving and carrying loads up to 10 kg and accompanied by moderate physical stress (a number of professions in mechanized foundry, rolling, forging, thermal, welding shops of machine-building and metallurgical enterprises, etc.).

¨ category III - work with an energy intensity of more than 250 kcal / h (more than 290 W), associated with constant movement, moving and carrying significant (over 10 kg) weights and requiring great physical effort (a number of professions in blacksmith shops with hand forging, foundry workshops with manual stuffing and filling of molding boxes of machine-building and metallurgical enterprises, etc.).

The doctor should be able to assess the microclimate of the room, predict possible changes in the thermal state and well-being of persons exposed to an unfavorable microclimate, assess the risk of colds and exacerbation of chronic inflammatory processes.

Documents regulating the parameters of the indoor microclimate

When assessing microclimate parameters, the following documents are used:

¨ SanPiN 2.2.4.548-96 "Hygienic requirements for the microclimate of industrial premises".

¨ SanPiN 2.1.2.1002-00 "Sanitary and epidemiological requirements for residential buildings and premises".

Sanitary rules establish hygienic requirements for indicators of the microclimate of workplaces in industrial and other premises, taking into account the intensity of energy consumption of workers, the time of work and periods of the year. Microclimate factors should ensure the preservation of the thermal balance of a person with the environment and the maintenance of an optimal or acceptable thermal state of the body.

Optimal microclimatic conditions provide a general and local feeling of thermal comfort during an 8-hour work shift with minimal stress on thermoregulation mechanisms, do not cause deviations in health status, and create prerequisites for high level performance and are preferred in workplaces.

Vertical and horizontal air temperature fluctuations, as well as air temperature changes during the shift, should not exceed 2 ° C and go beyond the values ​​\u200b\u200bspecified in tables 1, 2.

Table 1

Microclimate parameters in the premises of medical institutions

table 2

Microclimate parameters in residential premises

Classification of microclimate types

Optimal- a microclimate in which a person of the appropriate age and state of health is in a sense of thermal comfort.

Permissible- a microclimate that can cause transient and rapidly normalizing changes in the functional and thermal state of a person.

Heating- microclimate, the parameters of which exceed the permissible values ​​and can cause physiological changes, and sometimes cause the development of pathological conditions and diseases (overheating, heat stroke, etc.).

Cooling- microclimate, the parameters of which are below the permissible values ​​and can cause hypothermia, as well as related pathological conditions and diseases.

RESEARCH PROCEDURE

Determination of atmospheric pressure

Barometric pressure on the Earth's surface is uneven and unstable. As you go up to a height, there is a decrease in pressure, when you go down to a depth - an increase. The change in pressure in the same place depends on various atmospheric phenomena and serves as a well-known harbinger of a change in the weather.

Under normal conditions, fluctuations in atmospheric pressure (10–30 mmHg) healthy people transfer easily and imperceptibly. However, some patients (people with minor and significant health disorders) are very sensitive to even small changes in atmospheric pressure - those suffering from rheumatic diseases, nervous diseases, some infectious diseases: the exacerbation of the course of pulmonary tuberculosis coincided with sharp fluctuations in barometric pressure.

In the special conditions of life and labor activity deviations from normal atmospheric pressure can serve as a direct cause of human health problems. Let's consider some of them.

In mountainous regions located at an altitude of 2500–3000 m above sea level and above, a significant decrease in barometric pressure is observed, accompanied by a corresponding decrease in the partial pressure of oxygen. This circumstance is the main reason for the mountain (altitude) illness, expressed in the appearance of shortness of breath, palpitations, dizziness, nausea, nosebleeds, pallor of the skin, etc. The clinical signs of mountain sickness are based on hypoxia.

Increased atmospheric pressure is found in caissons (fr. caisson letters. box) - special devices for diving operations. If the necessary preventive measures are not observed, high blood pressure can cause dramatic physiological changes in the body, which can take on a pathological character with the development decompression sickness: during a rapid transition from an atmosphere with high pressure to an atmosphere with ordinary pressure, an excess amount of nitrogen dissolved in the blood and tissue fluids (mainly in adipose tissue and in the white matter of the brain) does not have time to be released through the lungs and remains in them in the form of gas bubbles. The latter are carried by the blood throughout the body and can cause gas embolisms in various parts of the body. Clinical manifestations decompression sickness are musculo-articular and retrosternal pain, skin itching, coughing, vegetative-vascular and cerebral disorders. The entry of a gas embolus into the coronary vessels of the heart can cause death.

Thus, barometric pressure measurements are of great practical importance in preventing the serious consequences of these changes for human health.

Atmospheric pressure is measured using mercury barometer or aneroid barometer. For continuous recording of atmospheric pressure fluctuations, barograph(Fig. 1). Atmospheric pressure fluctuates on average within 760±20 mm Hg.

Fig 1. Barograph

Determination of air temperature

Air temperature has a direct impact on human heat transfer. Its fluctuations significantly affect the change in the conditions of heat transfer: high temperature limits the possibility of heat transfer by the body, low temperature increases it.

The perfection of thermoregulatory mechanisms, the activity of which is carried out under constant and strict control by the central nervous system, allows a person to adapt to various temperature conditions environment and for a short time to endure significant deviations in air temperature from the usual optimal values. However, the limits of thermoregulation are by no means unlimited and their transition causes a violation of the thermal balance of the body, which can cause significant harm to health.

Prolonged stay in a highly heated atmosphere causes an increase in body temperature, an acceleration of the pulse, a weakening of the compensatory ability of the cardiovascular apparatus, and a decrease in the activity of the gastrointestinal tract due to a violation of heat transfer conditions. In such conditions of the external environment, rapid fatigue and a decrease in mental and physical performance are noted: attention, accuracy and coordination of movements decrease, which can cause traumatic injuries when performing work in production, etc.

Low air temperature, increasing heat transfer, creates the danger of hypothermia of the body. As a result, prerequisites are created for colds, which are based on a neuroreflex mechanism that causes certain dystrophic changes in tissues due to an imbalance in the regulation of metabolic processes.

Moderate fluctuations in temperature can be considered as a factor that provides the physiologically necessary training of the body as a whole and its thermoregulatory mechanisms.

The most favorable air temperature in residential premises for a person at rest is 20–22 ° C in the cold season and 22–25 ° C in the warm season at normal humidity and air speed.

Method for assessing the temperature regime

Air temperature is measured with mercury And alcohol thermometers.

To determine the temperature regime of the room, the air temperature is measured vertically and horizontally at three points: at the outer wall (10 cm from it), in the center and at the inner wall (10 cm from it). Measurements are carried out at a level of 0.1–1.5 m from the floor. Readings are taken 10 minutes after the thermometer is installed. The arithmetic mean value is calculated from the six obtained temperature values, which are recorded in the protocol and analyze the temperature drops vertically and horizontally.

The horizontal average room temperature is calculated from three measurements at different points taken at a height of 1.5 m.

The change in temperature horizontally from the outer wall to the inner wall should not exceed 2 ° C, and vertically - 2.5 ° C for each meter of height. Temperature fluctuations during the day should not exceed 3 ° C.

Determination of air humidity

Each air temperature corresponds to a certain degree of saturation with water vapor: the higher the temperature, the greater the degree of saturation, since warm air accommodates large quantity water vapor than cold air.

The following concepts are used to characterize humidity.

Absolute humidity- the amount of water vapor in g in 1 m 3 of air.

Maximum humidity- the amount of water vapor in g required to completely saturate 1 m 3 of air at the same temperature.

Relative Humidity- the ratio of absolute humidity to maximum, expressed as a percentage.

saturation deficit is the difference between maximum and absolute humidity.

Dew point- the temperature at which water vapor in the air saturates the space.

Relative humidity and saturation deficiency are of the greatest hygienic importance, which give a clear idea of ​​the degree of saturation of the air with water vapor and the rate of evaporation of moisture from the surface of the body at a given temperature.

Absolute humidity gives an idea of ​​the absolute content of water vapor in the air, but does not show the degree of its saturation, and therefore is a less indicative value than relative humidity.

Humidity is determined by devices called psychrometers. They are of two types: August psychrometer And Assmann psychrometer.

To determine air humidity with the August psychrometer, the device should be installed at a level of 1.5 m from the floor and observations should be made for 10–15 minutes.

When using the August psychrometer, the absolute humidity is calculated using the Regnot formula:

TO = f – a (t-t 1) IN, Where

TO is the absolute humidity in mm. rt. Art.;

f- maximum humidity at wet bulb temperature (its value is taken from table 4);

A– psychrometric coefficient (for room air 0,0011);

t- dry bulb temperature;

t1 is the temperature of the wet bulb;

IN- Atmosphere pressure.

Relative humidity is calculated using the formula:

R– relative humidity in %;

TO– absolute humidity;

F-maximum humidity at dry bulb temperature (taken from table 4).

Example: during the study it was found that the temperature of a dry thermometer is 18 o C, and a wet one 13 o C; barometric pressure - 762 mm Hg. According to table 4 "Maximum elasticity of water vapor at different temperatures (mm Hg)" we find the value f - the maximum voltage of water vapor at 13 ° C, which is equal to 11.23 mm Hg, and substitute the found values ​​into the formula:

TO= 11.23–0.0011 (18–13) 762 = 7.04 mmHg

We will convert absolute humidity into relative humidity using the formula:

R = (K/ F) 100,

In our example F at 18 ° C according to Table 4 it is equal to 15.48 mm Hg, from where:

R = (7,04 / 15,48) 100 = 45%

For more accurate measurements, an Assmann aspiration psychrometer is used (Fig. 2). The Assmann psychrometer has two mercury thermometer enclosed in a metal case that protects the device from exposure to thermal radiation. One of the thermometers (its lower part) is covered with matter and requires humidification before the device works. Mechanical suction device - a fan located at the top of the psychrometer provides constant speed air movement near the thermometers, which allows measurements to be taken under constant conditions.

Before determining the air humidity, the matter on the tank of one of the thermometers (“wet”) is moistened with water, then the fan clock mechanism is started for 3–4 minutes. Thermometer readings are taken at the moment when the temperature of the wet bulb becomes minimal.

Fig 2. Assmann psychrometer

Absolute humidity is calculated using the Shprung formula:

(Notation and formula for determining relative humidity, see above).

Example: Let's assume that after the operation of the device for 3-4 minutes the temperature of the dry thermometer was 18 o C, and the wet 13 o C. The barometric pressure at the time of the study was 762 mm Hg. According to table 4 "Maximum elasticity of water vapor at different temperatures (mm Hg)" we find the value F- the maximum elasticity of water vapor at 13 ° C, which is equal to 11.23 mm Hg, and, substituting the found value into the formula, we obtain:

TO\u003d 11.23 - 0.5 (18-13) (762/755) \u003d 8.71 mm Hg.

We translate the found absolute humidity into relative humidity using the formula:

R = (TO/ F) 100,

In our example:

R = (8,71 / 15,48) 100 = 56,3%

In addition to the calculated determination of relative humidity by formulas, it can be found directly from psychrometric tables 5 and 6, using the data obtained using the August and Assmann psychrometer.

Relative humidity in residential and industrial premises allowed in the range from 30 to 60%.

Determining the speed of air movement

The speed of air movement has a certain effect on the heat balance of the human body. In addition, the high mobility of air in hospital rooms contributes to the rise of settled dust into the air, its movement and, together with microorganisms, creates conditions for possible infection of people.

Anemometers are used to determine high air velocities in the open atmosphere (Fig. 3). They measure the speed of air movement in the range from 1 to 50 m / s.

Fig 3. Anemometer

The determination of low air velocities from 0.1 to 1.5 m / s is carried out using a catathermometer (from the Greek kata - movement from top to bottom) - a special alcohol thermometer (Fig. 4). This device allows you to determine the amount of heat loss by a physical body, depending on the temperature and speed of the surrounding air.

In this case, the cooling capacity of the air is first determined. To do this, immerse the device in hot water until the alcohol rises to half of the top expansion of the capillary. Then it is wiped dry and the time in seconds of the decrease in the alcohol level from 38 ° C to 35 ° C is determined.

Figure 4. Catathermometer

Calculation of the cooling capacity of air in millicalories from 1 cm 2 per second ( H) is carried out according to the formula:

F- device factor - a constant value showing the amount of heat lost from 1 cm 2 of the catathermometer surface during the lowering of the alcohol column from 38 ° C to 35 ° C (indicated on the back of the device);

A- the number of seconds during which the alcohol column drops from 38 ° C to 35 ° C.

Air speed in m/s. ( V) is determined by the formula:

, Where

H is the cooling capacity of the air.

Q- the difference between the average body temperature of 36.5 ° C and the ambient air temperature;

0.2 and 0.4 are empirical coefficients.

The air velocity can also be determined from Table 7.

The normal speed of air movement in residential and educational premises is considered to be 0.2–0.4 m/s. The speed of air movement in the wards of medical institutions should be from 0.1 to 0.2 m/s.

Table 3

Summary data of conducted studies

Hygienic conclusion. Based on the results obtained, the compliance of microclimate factors is assessed optimal conditions. In case of deviation from the standards, recommendations are made for their improvement.

Control questions:

1. Microclimate. The concept, the factors that determine it.

2. Weather-dependent diseases.

3. The influence of low and high atmospheric pressure on the human body.

4. The influence of low and high air temperature on the human body.

5. Air humidity. hygienic value.

6. Optimal values temperature, relative humidity and air velocity in medical institutions. Documents regulating them.

7. Instruments for assessing the indoor microclimate.

8. Advantages of the Assmann aspiration psychrometer over the August psychrometer.

9. Devices for continuous, long-term recording of temperature, humidity and atmospheric air pressure.

Table 4

Maximum water vapor pressure at different temperatures (mmHg)

Table 5

Determination of relative humidity according to the readings of the August psychrometer at an air velocity in the room of 0.2 m / s

Table 6

Determination of relative humidity according to the readings of the Assmann psychrometer

Table 7

Air velocity less than 1 m/s (adjusted for temperature), H=F/a

The internal environment of the premises affects the body by a complex of factors: thermal, air, light, color, acoustic. Acting in combination, these factors determine the well-being and performance of a person in an enclosed space.

thermal factor is a collection of four physical indicators: air temperature, humidity, air velocity and temperature of the internal surfaces of the room (ceiling, walls).

Air environment premises are the gas and electrical composition of the air, dust (mechanical impurities), anthropogenic chemicals and microorganisms
Optimization of the microclimate in large rooms contributes to a favorable course and outcome of the disease. The patient's compensatory capabilities are limited, sensitivity to adverse environmental factors is increased.

The norms of the microclimate of the wards and other premises of the hospital should take into account:
- age of the patient;

Features of heat transfer in patients with various diseases;

Functional purpose of the premises;

Climatic features of the area.

The temperature in most wards of general hospitals is 20°; The age characteristics of children determine the highest temperature standards in the wards of premature babies, newborns and infants -25 °; Features of heat transfer in patients with impaired thyroid function cause a high temperature in the wards for patients with hypothyroidism (24 °). On the contrary, the temperature in the wards for patients with thyrotoxicosis should be 15°. Increased heat generation in such patients is the specificity of thyrotoxicosis: “sheet” syndrome, such patients are always hot; The temperature in the halls of physiotherapy exercises is 18 °.

Air environment premises: the chemical composition of air and bacterial pollution are normalized.

Chemical composition indoor air

Standards for bacterial contamination depend on the functional purpose and class of cleanliness of the premises. Three types of sanitary and bacteriological indicators are monitored: before the start of work and during work.

The total number of microorganisms in 1 m of Air (CFU m)

The number of Staphylococcus aureus colonies in 1 m 3 of air

The number of molds and yeasts in 1 dm3 of air

Heating. In medical institutions during the cold period of the year, the heating system should provide uniform heating of the air throughout the entire heating period, exclude pollution by harmful emissions and unpleasant odors indoor air, do not create noise. The heating system should be easy to operate and repair, linked to ventilation systems, and easily adjustable. Heating devices should be placed near the outer walls under the windows, which ensures their higher efficiency. In this case, they create a uniform heating of the air in the room and prevent the appearance of cold air currents above the floor near the windows. It is not allowed to place heaters near the inner walls in the chambers. The optimal system is central heating. Only water with a temperature limit of 85° is allowed. Heaters only with a smooth surface are allowed in hospital rooms. Devices must be resistant to daily exposure to cleaning and disinfecting solutions, not to adsorb dust and microorganisms.

Heating devices in children's hospitals are protected. From a hygienic point of view, radiant heating is more favorable than convective heating. It is used for heating operating rooms, preoperative, resuscitation, anesthesia, childbirth, psychiatric departments, as well as intensive care and postoperative wards.

As a heat carrier in central heating systems medical institutions water is used with a maximum temperature of heating appliances 85°C. The use of other liquids and solutions as a heat carrier in the heating systems of medical institutions is prohibited.

Ventilation. Buildings of medical institutions should be equipped with three systems:

·
supply and exhaust ventilation with mechanical impulse;

·
natural exhaust ventilation without mechanical stimulation;

·
conditioning

Natural ventilation (aeration) through the windows, transoms is required for all medical facilities, except for operating rooms.

The intake of outdoor air for ventilation and air conditioning systems is carried out from a clean zone of atmospheric air at a height of at least 2 m from the ground. The outside air supplied by the supply units is cleaned with coarse and fine filters.

The air supplied to operating rooms, anesthesia, delivery, resuscitation, postoperative wards, intensive care wards, as well as to wards for patients with burns, AIDS patients, must be treated with air disinfection devices that ensure the effectiveness of inactivation of microorganisms and viruses present in the treated air, not less than 95%.

There are methods for a comprehensive assessment of the microclimate and its effect on the body:

1) Assessment of the cooling capacity of the air. The cooling capacity is determined using a catathermometer and is measured in mcal / cm "s. The norm (thermal comfort) for a sedentary lifestyle is 5.5-7 mkal / cm 2 s. With a mobile lifestyle - 7.5-8 mkal / cm 2 -s. For large rooms, where heat transfer is higher than the rate of cooling capacity, it is approximately 4-5.5 µcal / cm s.

2) Determination of EET (equivalent effective temperature) - an indicator that characterizes the complex effect on a person of temperature, humidity and speed of movement

ambient air, as well as infrared (thermal) radiation of the environment; determined using

nomograms or tables for equivalent effective and radiation temperatures, radiation temperature and RT (resultant temperature).

Microclimate Control Systems in Medical Institutions

A. P. Borisoglebskaya, Candidate of Engineering

keywords: medical and preventive treatment facility, air distribution, microclimate

Controlling of microclimate in Medical and Preventive Treatment Facilities is a complex task requiring special knowledge, experience and regulatory documents, since the same building includes rooms of different cleanness category and regulated air bacterial loads. Therefore, the design process requires serious discussions, studying of the best national practices and foreign experience.

Description:

Ensuring a microclimate in medical buildings or medical institutions is a complex task that requires special knowledge, experience and regulatory documents due to the presence of premises in the volume of one building various classes purity and standardized levels of bacterial contamination of the air. Therefore, the design process requires serious discussion, study of the best domestic practices and foreign experience.

A. P. Borisoglebskaya, cand. tech. Sci., editor of the issue on the topic "Organization of the microclimate of health care facilities"

Ensuring a microclimate in medical buildings or medical and preventive treatment facilities (HCF) is a complex task that requires special knowledge, experience and regulatory documents due to the presence in the volume of one building of premises of various cleanliness classes and standardized levels of bacterial contamination of the air. Therefore, the design process requires serious discussion, study of the best domestic practices and foreign experience.

Development of the domestic regulatory framework

After analyzing the history of the design of healthcare facilities, it can be seen that until the beginning of the 90s, there was a production of projects for hospital buildings, the main share of which belonged to standard design. Medical technologies of the treatment process almost did not develop and did not require the modernization of architectural and planning and, accordingly, engineering solutions. Therefore, the projects were rather monotonous, the typification of planning decisions led to the typification of decisions in the field of engineering systems design, such as ventilation and air conditioning. So, for a long time in the projects, planning decisions were made for such basic structures as hospital wards without locks with direct access to the corridor of the ward section. And only at the very end of the 70s and the beginning of the 80s did the first projects appear with the installation of lock rooms at the wards, which led to a novelty in the adoption of sanitary and technical solutions. The design technology was based on the relevant regulatory documentation. In 1970, SNiP 11-L.9-70 “Hospitals and polyclinics. Design standards”, which for 8 years has been the main standard for designers in the narrow specialization “medical institutions”. It has not yet traced the requirement for the layout of wards with a lock, with the exception of wards for newborns and boxes, semi-boxes of infectious diseases hospitals. In 1978, it was replaced by SNiP 11-69-78 "Treatment and preventive care institutions", in which there is a reasonable requirement for the need to equip the wards with a gateway. Thus, a fundamentally new approach to the design of wards and ward sections arose. Moreover, joint architectural and planning and sanitary solutions are recommended as the main way to ensure the required microclimate. Also by 1978, “Instructive and methodological guidelines for organizing air exchange in ward departments and operating blocks of hospitals” were developed, where the requirement was voiced to create an isolated air regime of the wards through planning decisions - the creation of gateways in the wards. Both documents were the result of new research in the field of organization of air exchange in hospitals. Later, in 1989, SNiP 2.08.02–89 “Public Buildings and Structures” was published, which included requirements for the design of healthcare facilities as types of public buildings, and in 1990, an addition to it in the form of a manual for the design of healthcare facilities. This document provided indispensable assistance to designers until 2014, despite the age of origin, until it was replaced by SP 158.13330.2014 “Buildings and premises of medical organizations”. Then came out sequentially in 2003 and 2010, replacing each other, SanPiN 2.1.3.1375-03 "Hygienic requirements for the placement, arrangement, equipment and operation of hospitals, maternity hospitals and other medical hospitals" and SanPiN 2.1.3.2630-10 "Requirements for organizations engaged in medical activities. Thus, an overview of the main regulatory documents that accompanied project activities in the field of medicine for several decades to the present.

The outbreak of interest in the hygienic aspects of the air environment was especially acute in the 70s. Not only specialists in the design of engineering systems, but also specialists in the field of sanitation and hygiene began to intensively study the quality of the air environment in medical facilities, the state of which was considered unsatisfactory. A large number of publications have appeared on the topic of organizing measures to ensure clean air in the premises of healthcare facilities. Among epidemiologists, for a long time it was believed that the quality of the air environment is determined by the quality of anti-epidemic measures. There is a concept of specific and non-specific infection prevention. In the first case, these are disinfection and sterilization (anti-epidemic measures), in the second case, ventilation and architectural and planning measures. Over time, studies have shown that against the background of specific prevention, current medical and technological processes in health facilities continue to be accompanied by the growth and spread of nosocomial infections. The emphasis began to be placed on sanitary and architectural and planning solutions, which among hygienists began to be considered the main method of non-specific prevention of nosocomial infection (HAI), and they began to play a dominant role.

Design features of health care facilities

During the entire period, especially from the mid-90s to the present, there has been a development of technologies to ensure clean air, starting with the sterilization of air and surfaces of premises and up to the application of modern technical solutions and the introduction of the latest equipment in the field of microclimate provision. Appeared modern technologies, allowing to provide and maintain the required conditions of the air environment.

The design of engineering systems in health care facilities has always been and still is a difficult task compared to the design of a number of other objects related, like health care facilities, to public buildings. Features of the technology for designing heating, ventilation and air conditioning systems in these buildings are directly related to the features of the health facilities themselves. Features of LPU are as follows. The first feature of LPU should be considered a wide range of their names. These are general hospitals and specialized hospitals, maternity hospitals and perinatal centers. The complex of health care facilities includes: infectious diseases hospitals, polyclinics and dispensaries, treatment and diagnostic and rehabilitation centers, medical centers for various purposes, dental clinics, research institutes and laboratories, dispensaries and sanatoriums, ambulance substations and even dairy kitchens and sanitary and epidemiological stations. This entire list of institutions of completely diverse purposes implies the same set of various medical technologies that accompany the operation of buildings. In recent years, medical technologies have been growing rapidly: new and incomprehensible processes are being carried out in operating rooms, laboratories and other premises, complex modern equipment is being used. For design engineers, misunderstood names and abbreviations in the explication of premises become frightening, which cannot be understood without qualified technologists, with the presence of which, as a rule, there are difficulties. On the other hand, the improvement of medical and technological solutions requires new, directly related engineering solutions, often unknown without the support of technologists or their lack of proper qualifications. All this adds to the complexity of production. design work and often even for an engineer with a long experience in the field of medicine, each new building being designed presents newly set, sometimes research, technological and engineering tasks.

The second feature of LPU should be considered a feature of the sanitary and hygienic state of the air environment of the premises, which is characterized by the presence in the air of the premises of not only mechanical, chemical and gas pollution, but also microbiological contamination of the air. The standard criterion for the cleanliness of indoor air in public buildings is the absence of excess heat, moisture and carbon dioxide in it. In healthcare facilities, the main indicator for assessing air quality is nosocomial infection (HAI), which is of particular danger, the source of which is the staff and the patients themselves. It has the peculiarity, regardless of the planned disinfection measures, to accumulate, grow rapidly and spread throughout the premises of the building, and in 95% of cases by air.

The next feature is the nature of the architectural and planning solutions of medical facilities, which have changed qualitatively. There was a time when the hospital building assumed the presence of a group of different buildings located at a distance from each other and separated, respectively, by air from each other. This made it possible to isolate clean and dirty medical and technological processes and patient flows. Clean and dirty rooms were located in separate buildings, which helped to reduce the transmission of infection. In modern times of saving building space in the design, there is a tendency to increase the number of storeys, compactness in terms of and capacity of hospitals, which leads to a reduction in the length of communications and, of course, more economically. On the other hand, this leads to a close mutual arrangement of rooms with different cleanliness classes and the possibility of contamination from dirty rooms to clean rooms both vertically and in floor plan.

To justify the recommended requirements for the design of engineering systems in health facilities, it is necessary to dwell on the air regime of buildings (VRZ). Here it is necessary to consider the boundary value problem of the VRZ regarding the nature of the movement of air through the openings in the external and internal enclosures of buildings, which directly affects the sanitary and hygienic state of the air environment and can be considered as one of the features of the medical facility. The air mode of the medical facility, as in any high-rise building, is unorganized (chaotic) in nature, that is, arising spontaneously due to natural forces. Under VRZ in this case, one should understand the nature of the movement of air flows through the enclosing structures of the building. On fig. 1 shows a schematic section of the building. The section shows a stairwell (elevator shaft), which, as a single high room, is vertical connection between the floors of the building and is of particular danger, since it is a channel through which air flows are transferred. Through the leakage of external fences (windows, transoms) there is an unorganized movement of air due to the difference in pressure outside and inside the premises of the building. As a rule, the movement of air at the level of the lower floors occurs from the street into the building, and as the number of storeys increases, the amount of incoming air gradually decreases and approximately at the middle of the height of the building changes its direction to the opposite, and the amount of outgoing air increases and on the top floor becomes maximum. In the first case, this phenomenon is called infiltration, in the second - ex-filtration. The same patterns are valid for the movement of air through the openings or their leaks in the internal enclosures of the building. As a rule, on the lower floors of the building, air flows move from the corridor of the floor to the volume of the staircase, and on the upper floors, on the contrary, from the staircase to the floors of the building. That is, the air coming from the premises of the lower floors of the building rises up and is distributed through stairwell to the upper floors. Thus, there is an unorganized flow of air between the floors of the building, and, consequently, the transfer of WFI with its flows. As the number of storeys increases, air pollution in the staircase and elevator units increases, which, if the air exchange is not properly organized, leads to an increase in bacterial contamination of the air in the rooms of the upper floors.

There is also an unorganized flow of air between the rooms located on the windward and leeward facades of the building, as well as between adjacent premises in the floor plan or between compartment sections. On fig. 2 shows the plan of the ward section of the hospital and indicates (arrows) the direction of air movement between the rooms. This is how air flows from the rooms of the wards located on the windward facade of the building to the rooms of the wards located on the windward facade, bypassing the ward lock. It is also obvious that there is a flow from the corridor of one ward section to the corridor of another. The circle shows the required organization of the movement of air flows in the ward block, excluding the flow of air from the ward to the corridor, and from the corridor to the ward.

Under the floor plan there is a fragment of the corridor with the image of active locks - additionally provided rooms with supply or exhaust ventilation in them to prevent air from flowing between the corridors of different sections. In the first case, the lock is considered "clean", since clean air flows from it into the corridor, in the second - "dirty": air from neighboring rooms will flow into the lock. Thus, assessing the phenomenon of VRZ as a difficult task, it becomes necessary to solve it, which should be reduced to the organization of flows of overflowing air and their control.

The features of hospital buildings are taken into account as a whole, since all the considered parameters are interconnected and interdependent, and affect the requirements for the organization of air exchange, architectural, planning and technical solutions, isolation of ward departments, sections, wards for patients and premises of operating blocks, which should be nosocomial infection prevention and control measures.

When organizing a rational scheme for the distribution of air flows, it is necessary to take into account the purpose of the premises, especially such as ward departments and operating blocks.

Planning and sanitary-technical solutions of ward departments should exclude the possibility of air flows from stair-elevator nodes to departments and, conversely, from departments to stair-elevator nodes, in departments - from one ward section to another, in ward sections - from the corridor to wards for patients and, conversely, from the wards to the corridor. Such solutions in the field of organizing the movement of air flows imply the exclusion of air flow in an undesirable direction and the spread of infectious agents with air flows. On fig. 3 shows a diagram of the organization of air flows, excluding the flow of air between floors.

Thus, the tasks of designing heating, ventilation and air conditioning systems of health facilities should be as follows:

1) maintaining the required parameters of the microclimate of the premises (temperature, speed, humidity, the required sanitary norm of oxygen, the specified chemical, radiological and bacterial purity of indoor air) and eliminating odors;

2) exclusion of the possibility of air overflow from dirty areas to clean ones, creation of an isolated air regime of wards, ward sections and departments, operating and generic blocks, as well as other structural divisions of healthcare facilities;

3) preventing the formation and accumulation of static electricity and eliminating the risk of an explosion of gases used in anesthesia and other technological processes.

Literature

1. Borisoglebskaya A.P. Medical and preventive institutions. General requirements for the design of heating, ventilation and air conditioning systems. M.: AVOK-PRESS, 2008.
2. Borisoglebskaya A.P. // ABOK. - 2013. - No. 3.
3. Borisoglebskaya A.P. // ABOK. - 2010. - No. 8.
4. Borisoglebskaya A.P. // ABOK. - 2011. - No. 1.
5. // ABOK. - 2009. - No. 2.
6. Tabunshchikov Yu. A., Brodach M. M., Shilkin N. V. Energy efficient buildings. M.: AVOK-PRESS, 2003.
7. Tabunshchikov Yu. A. // ABOK. - 2007. - No. 4.

As a result of the introduction of new services to patients of dental clinics, the activities of any medical institution require a qualitatively different approach to compliance sanitary standards microclimate. We understand in the article what the microclimate in medical institutions affects and what work should be done to optimize it.

Microclimate in a medical facility

All sanitary rules and norms in dentistry, which enterprises in the medical field are required to follow, are specified in the Decree of the Chief State Sanitary Doctor of the Russian Federation dated May 18, 2010 No. 58 (Resolution “On Approval SanPiN 2.1.3.2630-10"Sanitary and epidemiological requirements for organizations engaged in medical activities"). Microclimate requirements are described in Chapter 6 "Requirements for heating, ventilation, microclimate and indoor air".

The formed market of medical services is quite wide, and constant interaction both between patients and between patients and dentists leads to two unfavorable moments:

• cross-infection of clinic clients
• occupational infection of dental workers who carry out appropriate manipulations

The influence of the microclimate in a medical institution affects the productivity of clinic staff. First of all, it is an indicator of the quality of the hospital environment for the patient.

Relevant requirements are formed depending on the layout of the buildings of medical institutions. If it meets all the requirements, then the microclimate is satisfactory in terms of microbiological indicators. To comply with such requirements, pay attention to the properties of the room. Let us clarify that if the clinic employees spend half of their time in this building or more than two hours from their work activity (that is, constantly), this room is called a workplace.

Requirements for creating a microclimate in rooms with the regular presence of an employee

Requirements for the creation of a microclimate in the premises where the clinic staff is periodically

In addition, the clinic is not allowed to exceed dangerous and harmful substances, respectively, properly working and ventilation systems. Moreover, the sanitary rules and norms of the Russian Federation indicate that if they break down, urgent repairs are required. Finally, the ventilation systems of dental offices need preventive maintenance to avoid their unforeseen failure.

The situation of the spread of infections in the medical business is largely due to the general epidemiological situation in Russia; thus, an increase in the incidence among people living in the country also increases the risk of infection of dental patients in medical institutions.

At the same time, we also note the economic losses that accompany the growth of infectious diseases: in European countries, these figures are approximately 7-7.5 billion euros, while in our country these figures are almost twice as high. Objectively, it can be judged that such a situation directly affects the quality of life of Russians, and also forms a negative reputation in individual dental clinics.

Now there are about 350 different pathogens; they can cause an infectious process in the patient and provoke the illness of medical personnel in the provision of services.

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• Production control program of the dental clinic

Nosocomial infections and air purification technologies

Informing about the features of the spread of nosocomial infections in various medical institutions is very inactive, however, there are a lot of patients who come to dentists in the maxillofacial departments with characteristic complications. Often, the presence of microorganisms in the air in dental clinics exceeded the standards for the total number of colonies in 58% of cases, and in the autumn-winter period in 67.2% - from total number exceeding the standards.

When a dentist works with a drill, especially during various invasive procedures, the local concentration of pathogens in the air increases several times, at the same time, microorganisms are sprayed from the patient's oral cavity in the form of tiny particles. They settle on the skin of the face and hands of the dentist, end up on the mucous membrane of the nasopharynx and eyes. Finally, they also settle on the surface, equipment in the cabinet.

On average, 1 ml of saliva can contain up to 5 billion microorganisms; 1 gram of plaque contains 10-1000 billion microorganisms. Moreover, if a microorganism exhibits stable antibiotic resistance and resistance to disinfectants, this exacerbates the situation with infectious diseases in dental institutions. Accordingly, innovative ways to purify the air environment are also needed.

Now devices appear on the market that almost completely solve the problems of microbiological air purity. These are devices based on Bioinactivation technology, they disinfect, disinfect and carry out fine filtration indoor air, as well as reduce microbial contamination of various surfaces.

Using the unit, you can prepare a local "clean" area (for example, an operating table) or process the entire room - on average, one such mobile unit covers 40–50 m3.

This technology is based on the phenomenon of cell membrane electroporation, that is, the formation of pores in the cell membrane under the influence of an electric field. The process of electroporation is irreversible, as a result, we observe the inactivation of pathogenic microorganisms. The cell is affected electric field given orientation and tension, which destroys it. Now this technology has become actively used in the medical business, including dentistry, including surgery.

We thank Olga Konina, Ph.D., doctor of the 2nd category, for her help