METHODICAL INSTRUCTION FOR  2^nd YEAR BSN STUDENTS

LESSON # 1

(PRACTICAL – 6 HOURS)

Theme:  

1.    The hygienical estimation of the complex influencing of parameters of microclimate on the heat exchange of man.

2. Hygienic estimation of natural and artifficial illumination.

 Aim:

1. To study classification of methods, use in hygiene for investigation of environment and its influence on people’s health.

2. To learn the method of determination and hygienic estimation of air temperature  and  atmospheric  pressure

3.     To master the methods of hygienic estimation of air humidity in apartments of houses and hospital.

4. To learn method of determination and hygienic estimation of direction and speed air motion

5. To study the general methods of hygienic estimation of influence microclimate on human heat exchange and determination method of effective temperatures.

6. To learn to define light by lighting engineering and geometrical methods and to give a hygienic evaluate to the obtained outcomes.

7. The familiarity with geometrical and objective method of artificial illumination.

8. To give hygienic evaluation to different sources of artificial illumination and to levels of illumination

PROFESSIONAL ORIENTATION OF STUDENTS

The Hygiene is a branch of the medical knowledge, the science dealing with protecting and consolidating social (collective) and personal (individual) health by means of prophylactic measures.

Prophylaxis is one of the basic principles of public health service. The main duty of the medical workers is the taking of the disease prevention measures for healthy people and exacerbation, complication and relapse prevention for the ill.

Preventive means the wide system of state, public and medical measures for preserving and strengthening people’s health, the upbringing of the healthy young generation, work capacity and people’s longevity increasing.

The visible part of the solar spectrum has large biological significance. Day light has favourable influences on mental condition of the person, in particular on ill. One under the influence of light the metabolism in an organism strengthens, the synthesis of some vitamins is carried out. The mode of lighting influences a regulation of biological rhythms. The intensity of light upon a job place matters for preventive maintenance of violations of vision. The no rational light assists to the development of a near-sightedness, reduces mental hardworking.

 Visible part of sun spectrum has the large physiological value. Therefore all medicinal and prophylactic apartments must have sufficient natural illumination. In the case of insufficient natural illumination (in evening time, at a bad weather), and also for creation of additional intensive illumination on a workplace the sources of lamplight must be used. The modern condition of science gives the possibility to approve the artificial illumination with its biological positive features to natural by means of introduction the new fountains of illumination. “Light actually continues conscious existence of man, and herein foremost its large value”, – the academician S.I Vavilov wrote.

METHODOLOGY OF PRACTICAL CLASS (9⁰⁰-12⁰⁰ hour).

Theme 1. The hygienical estimation of the complex influencing of parameters of microclimate on the heat exchange of man.

 Work 1. Studying the temperature condition of the indoor air

The temperature is measured in 6 or more points to fully characterize the temperature conditions of premises.

Thermometers (mercurial, alcohol, electric or psychrometer dry thermometers) are placed onto support racks at three points 0.2 meter high above the floor, at three points 1.5 meters high (points t_2, t_4, t₆ and t_1, t_3, t₅ respectively) and at 20 cm from the wall along the diagonal section of the laboratory.

The thermometer data are fixed after 10 minutes of the exposition at the point of measurement.

The air temperature parameters in premises are calculated using following formulas:

а) the average temperature in the premises:

а) t_aver.= ,

b) the vertical variation of the air temperature:

Dt_vert.. = –  ,

c) the horizontal variation of the air temperature:

Dt_hor..=   –  

Diagrams and calculations are written down into the protocol, the hygienic assessment is made. It is necessary to consider the following data: the optimal air temperature must be from +18 to +21^оС in residential and class–room premises, wards for somatic patients, the vertical temperature variation must be no more than 1.5-2.0^оС, horizontal – no more than 2.0-3.0^оС. The daily temperature variations are determined using the thermogram, prepared in laboratory using the thermograph. The daily temperature variation must be no more than 6^оС.

The allowable and optimal standards of the temperature, presented in the table 1 are the hygienic assessment criteria for residential and public premises.

Table 1

The temperature standards for residential, public and administrative premises

The radiant temperature and the wall temperature determination

The spherical thermometers are used for the radiant temperature determination in premises, wall thermometers – for the wall temperature determination .

The spherical thermometer consists of the thermometer located inside the hollow sphere 10-15 cm in diameter and covered with porous polyurethane foam layer. This material has similar coefficients of the infrared radiation adsorption as the human skin.

The radiant temperature is also determined at 0.2 and 1.5 meters above the floor.

The device has the considerable inertia (up to 15 min.), that is why the thermometer data must be takeo earlier than after that time.

The spherical thermometer data at the height of 0.2 and 1.5 m must not vary by more that 3^оС in comfortable microclimate conditions.

 Work 2. The methods of hygienic estimation of air humidity.

1.To study the structure and principle of work of psychrometers of Аssman and August

Determination of the air humidity using psychrometers

The absolute and relative air humidity is determined using the August stationary psychrometer.

The reservoir of the psychrometer is filled with water. One of the device’s thermometers is wrapped with the fabric. The fabric is put down into the water so that the reservoir is located about 3 cm above the water surface. After this the psychrometer is hanged onto the support at the determination point. The wet and dry thermometer data are taken 8-10 minutes later.

The absolute humidity is calculated using the Regnault formula:

А = f – a · (t – t₁) · B,

where, А – the air absolute humidity at the current temperature in Hg mm;

            f – maximum pressure of water vapour at the wet thermometer’s temperature (see the table of saturated water vapours, table 3);

            а – psychrometric coefficient is 0.0011 for enclosed spaces;

            t – temperature of the dry thermometer;

            t₁ – temperature of the wet thermometer;

            В – barometric pressure during the humidity determination, Hg mm.

The relative humidity is calculated using the following formula:

P = ,

where,  Р –the value of relative humidity to be found, %;

            А – absolute humidity, Hg mm;

             F – maximum pressure of water vapour at the dry thermometer temperature, Hg mm (see the table of saturated water vapours).

Table 3

Maximum pressure of the air water vapour of premises

Determination of the air humidity using the Assmann aspiration psychrometer

The significant disadvantage of August psychrometer is its dependence on the air velocity. The air velocity influences the evaporation intensity and the device’s wet thermometer cooling.

This disadvantage has been eliminated in Assmann psychrometer due to the usage of the ventilator . The ventilator produces the constant air movement at the 4 m/sec speed near thermometers’ reservoirs. As a result data does not depend on the air velocity either inside or outside of the premises. Furthermore, thermometers;’ reservoirs of this psychrometer are protected with reflecting cylinders around psychrometer’s reservoirs from the radiant heat.

The cambric of Assmann aspiration psychrometer wet thermometer is dampened using the pipette, the spring of the aspiration devise is set or the psychrometer with electrical ventilator is plugged in. After these procedures the psychrometer is hung up onto the support at the determination point. The data of wet and dry thermometers are taken 8-10 minutes later.

The absolute air humidity is calculated using the Sprung formula:

,

where: А – absolute air humidity in Hg mm;

            t – maximum pressure of water vapour at the wet thermometer temperature (see the table of saturated water vapours);

           0.5 – constant psychometric coefficient;

            t – temperature of the dry thermometer;

            t₁ – temperature of the wet thermometer;

            В – barometric pressure at the determination moment in Hg mm.

 Relative humidity is determined using the following formula:

,

where: Р –the value of relative humidity to be found, %;

           А – absolute humidity, Hg mm;

           F – maximum humidity at the dry thermometer temperature, Hg mm.

Relative humidity is determined using the psychrometric tables for aspiration psychrometers. The value of the relative humidity is found at the intersection point of the dry and wet thermometer data (see table 3).

Hair or membrane hygrometers are used for the determination of the relative humidity of the air. These devices measure the relative humidity directly. The hygrometer operation is based on the facts, that the degreased hair lengthens, and the membrane/diaphragm weakens when it’s damp, and vice-versa when they are dry.

Humidity deficit (the difference between the maximum and absolute air humidity) is determined using the table of saturated water vapours. The absolute air humidity, calculated using Regnault or Sprung formulas is subtracted from the value of maximum air humidity according to the dry psychrometer’s thermometer.

Physiological humidity deficit (the difference between the maximum air humidity at 36,5^оС body temperature and absolute air humidity) is determined using the same table of saturated water vapours (see table).

Dew point (temperature when the absolute air humidity is maximum) is determined using the same table of saturated water vapours (see table 3 ) in reverse direction. The temperature when the absolute air humidity is equivalent to the maximum, is found using the value of absolute humidity.

Interdependency between different air humidity indices can be seen on the diagram

Work 3.To calculate the following indexes in an educational room and give hygienic estimation to the got results.

          A – absolute humidity (mm of mercury column);

          M  –  maximum humidity (mm of mercury column);

          R  – relative humidity (%);

          Dew point ( ⁰ C ). 

 

Hygienic norm of microclimate in the different rooms

Theme 2. Hygienic estimation of natural and artifficial illumination.

Work 1. To define the coefficient of depth (CD) of room in study room.

To define the coefficient of depth room to calculate by formula:

CD = W/H,

Where: W is distance from a window to the opposite wall, in meter,

      H is distance from a floor to the overhead edge of window, in meter,

Hygienically norm of the coefficient of depth room is less that 2.

 Work 2. To define a light coefficient in study room and of situation task.

The area of windows should correspond to area of room. Therefore a widespread method of evaluate of a daylight is geometrical, at which one calculate light coefficient (LC), i.e. attitude of a glass area of windows to area of a floor of room. The more size of light factor, the better is lighting. For living rooms LC = 1:6 – 1:8, for hospital wards, the doctors cabinets, educational classes 1:5 – 1:6, for operational, birth wards, observation, dressing rooms, labs 1:3 – 1:4, for extra locations 1:10 – 1:12.

 Work 3. Measure daylight on a workplace by luxmeter and calculate coefficient of daylight.

The basic lighting engineering parameter for a normalization of daylight is coefficient of daylight (CDL). This attitude of lighting indoors to simultaneous lighting outdoor, expressed in %.

Objective method of research of natural illumination in room:

а) To define illumination by luxmeter in the apartment (in the distance 1 meter at an internal wall), Ei;

b) To define external illumination by luxmeter, Ee;

c) To calculate the coefficient of natural illumination is

CDL = (E _i / E _e ) x 100 %

          For living rooms CDL must be not less than 0,5 %, for hospital wards – not less than 1 %, for school classes – not less than 1,5 %, for operational – not less than 2,5 %.

The estimation of illumination is made on an illumination level of a horizontal surface on a job place with the help of a luxmeter. An accepting part of the instrument is the photocell conversing a quantity of light in electrical. A recording part is the sensing galvanometer calibrated in luxs. The obtained result is compared to the established norms.

 Work 4. To determinate of illumination by the method “WATT”.

For definition of illumination by ”WATT” method or by proper power we need:

          -to measure the area of the apartment (A)

          -to indicate the total power of lamps in Wt (Σ Wt)

          -to calculate the proper power in apartment  Σ Wt / A (m² ) = Wt / m²

The quantity of proper power depends on the height of hanging of lamps, square of the apartment and level of illumination, which is necessary to create in this apartment .

On the table 1 and 2 we indicate that this quantity reply to the smallest normative illumination for this groups of apartment (the cabinets of dentist, therapeutics, gynaecologists and other specialities, for inspection rooms, ets).

Table 1

 

The (E_tab) minimum horizontal illuminance values at the specific capacity (P) of 10 Wt/m²

The electric lamp capacity, Wt	The direct light		Half-reflected light
	Voltage, V
	100…127	220	100…127	220
40	26	23	16.5	19.5
60	29	25	25	21
100	35	27	30	23
150	39.5	31	34	26.5
200	41.5	34	35.5	29.5
300	44	37	38	32
500	48	41	41	35

 

Table 2

Standards of the general artificial illumination (BNaR II-69-78 and BNaR II-4-79)

 

Premises	The smallest illumination, lux
	Luminescent lamps	Incandescent lamps
Rooms and kitchens of dwelling houses	75	30
Classrooms	300	150
Rooms of technical drawing	500	300
School workshops	300	150
Public reading halls	300	150
Operating and sectional rooms		200
Delivery room, dressing ward, manipulation room	400	200
Pre-operative room	300	150
Surgeon’s, obstetritian-gynecologist’s, pediatrician’s, infectionist’s, dentist’s room	500	200
X-ray room	–	150
Functional diagnostics room	–	150
Wards for newly-born babies, postoperative rooms	150	75

 

Work 5.

 Determine uniformity of artificial illumination in the apartment by measuring of illumination in three points bias and in a place which has maximal illumination. Then calculate, in how many times illumination in a dark place less, than illumination of bright place. In a norm this index E_max / E_mіn is evened 1,5 – 2   for different types of lamps.

 Work 6.  To define evenness of lamplight in the apartment on the work place.

In evening time the artificial illumination is measured by luxmeter too. In daytime – by means of curtains-darkening of the room or by the approximate calculation:

E_ARTIFICIAL = E_SUMMARY – E_NATURAL

that is so, first of all we indicate the level of summary illumination with the inclusion of lamps, then indicate the level of natural with the interrupted lamps and at last for their difference we receive the result of approximate level of  artificial illumination.

Hygienic norms of natural and artificial lighting (illumination) in different rooms

 

INDIVIDUAL STUDENTS PROGRAM

Theme 1. “The hygienical estimation of the complex influencing of parameters of microclimate on the heat exchange of man.”

Control questions:

1.  Temperature scales (Celsius, Kelvin, Fahrenheit) and types of thermometers.

2.  Methods of determination and hygienic estimation of air temperature 

3.  Methods of determination and hygienic estimation of atmospheric  pressure.

4.  The consists parts and principles of the work of thermograph and barograph.

5.  Hygienic significance of air humidity and types of humidity.

6.  Methods of determination and hygienic estimation of humidity.

7.  Instruments to Measure Humidity. The consists parts and principles of the work of hygrograph.

8            Notion about microclimate and factors, which its form. Heat exchange of organism with environment.

9.            Cooling microclimate and its influence on human organism.

10.            Overheating microclimate and its influence on human organism.

Theme 2.” Hygienic estimation of natural and artifficial illumination”.

Control questions:

1.     Physiology role of natural illumination of apartments.

2.     Sanitary-hygienic value of natural illumination of apartments.

3.     Method of determination of indexes for estimation of natural illumination (light coefficient, coefficient of day lighting, angle of incidence, corner of opening, coefficient of depth). Method of their determination and hygienically norms.

4.     Principle of work of luxmeter.

5.     Hygienic value of artificial illumination.

6.     Classification of sources of artificial illumination.

7.     Description of varieties of lighting armature of lamps of incandescence.

8.     Lacks of luminescent lamps (by comparison to the lamps of incandescence).

9.     Advantages of luminescent lamps above the lamps of incandescence.

10.           Methods of determination of lamplight of apartments (on specific power, evenness of illumination, by an objective method).

SEMINAR DISCUSSION OF THEORETICAL ISSUES (12³⁰ – 14⁰⁰ hour).

1. Temperature scales (Celsius, Kelvin, Fahrenheit) and types of thermometers.

2.     Methods of determination and hygienic estimation of air temperature

3.     Methods of determination and hygienic estimation of atmospheric pressure.

4. The principles of the work of thermograph and barograph.

5. Hygienic significance of air humidity and types of humidity.

6.     Methods of determination and hygienic estimation of humidity.

7. Instruments to Measure Humidity. The principles of the work of hygrograph.

8. The role of sun radiation and earth surface type in appearing of winds. Using of “ rose of wind” in preventive sanitary control.

9. Classification and characteristics of instruments for measuring of direction and speed of air movement.

10. Methods of determination and hygienic estimation of the velocity of air movement by Kathathermometer.

11. Notion about microclimate and factors, which its form. Heat exchange of organism with environment.

12. Cooling microclimate and its influence on human organism.

13. Overheating microclimate and its influence on human organism.

14. Physiology role of natural illumination of apartments.

15. Sanitary-hygienic value of natural illumination of apartments.

16. Method of determination of indexes for estimation of natural illumination (light coefficient, coefficient of day lighting, angle of incidence, corner of opening, coefficient of depth). Method of their determination and hygienically norms.

17. Principle of work of luxmeter.

18. Hygienic value of artificial illumination.

19. Classification of sources of artificial illumination.

20. Description of varieties of lighting armature of lamps of incandescence.

21. Lacks of luminescent lamps (by comparison to the lamps of incandescence).

22. Advantages of luminescent lamps above the lamps of incandescence.

23. Methods of determination of lamplight of apartments (on specific power, evenness of illumination, by an objective method).

TEST EVALUATION AND SITUATIONAL TASKS

TEST QUESTIONS:

1.  The most fatal complication which can occur to divers (under high atmospheric pressure)

A.                       Pulmonary oedema;

B.                       Air embolism; 

C.                       Rupture of spleen;

D.                       Myocardial infarction;

E.                        None of above.

2. One of the earliest temperature scales was that devised by

A.   Celsius;

B.   Fahrenheit;  

C.   Kelvin;

D.   Reaumur;

E.    None of the above.

3. Graphical diagram, which characterizes number of a wind in the given district, measured by long-term observations name

A.   Wind direction;

B.    Rose of winds;  

C.   Air velocity;

D.   Speed of the wind;

E.    Cooling power of air.

4.  In condition of comfortable microclimate human feels himself good, because

A.A room is well lighted.

B. Present air moving in room;

C. Absent psycho emotionally stress;

D.Atmospheric pressure is low;

E. Heat production equal to heat loss. 

5. Norm of L.C. (light coefficient) in study room

     A .1: 5

     B.1: 8

      C.1:10

       D.1:2

       E.1:12

SITUATION TASK

Situational task №1.

 Indoors air humidity was measured with a help of August psychrometer.  A temperature of the dry thermometer is 19 ⁰ C, and humid is 13 ⁰ С, barometric pressure is 752 mm Hg. Calculate an absolute, maximum and relative humidity, and dew point. 

Situational task №2.

 The light area of two windows in a bedroom is 2,4 m ², area of a floor is 25 m ².  To calculate the light coefficient.

Light coefficient calculate by formula:

LC=A/B,

where: A is glass area of windows, B is area of a floor of room.

LC = 2,4/25 =1/10,42 = 1:10,

Situational task №3

The distance from the window to the opposite wall (B) is 5,6 m. The distance from a floor to the upper edge of the window (Н) is 3,0 m. To calculat coefficient of depth of a living room:

CORRECT ANSWERS OF TEST EVALUATIONS AND SITUATIONAL TASKS:

1.     B;

2.     B;

3.     B;

4.     B;

5.     A;

 Answer on situation task1:   

The absolute humidity is calculated using the Regnault formula:

А = f – a · (t – t₁) · B,

where, А – the air absolute humidity at the current temperature in Hg mm;

            f – maximum pressure of water vapour at the wet thermometer’s temperature 11,23 mm Hg ;

            а – psychrometric coefficient is 0.0011 for enclosed spaces;

            t – temperature of the dry thermometer (19 ⁰ C)

            t₁ – temperature of the wet thermometer (13 ⁰ C)

            В – barometric pressure during the humidity determination, 752 Hg mm.

where:

A = 11,23 – 0,0011 х (19 – 13) х 752 = 6,27 mm Hg

The relative humidity is calculated using the following formula:

 ,

where,  Р –the value of relative humidity to be found, %;

            А – absolute humidity, Hg mm;

             F – maximum pressure of water vapour at the dry thermometer temperature, Hg mm (see the table of saturated water vapours).

              Maximum humidity (F) we find on table. It is equal to16,48 mm Hg

Relative humidity ( R ) calculate according to the formula :

                  R = 6,27 / 16,48 x 100 = 38 %          

A dew  Point is determine after the table of maximum strain of water steams:

                              dew  Point   = 4,4 ⁰С.

Relative humidity can be defined with the table method after indexes of dry and humid thermometers. In our example relative humidity according to the table = 40 %.

So, a quantity of relative humidity, which we have got, corresponds to the hygienic standards indoors (30 – 60 % when the temperature is 18-21 ⁰С).

Answer on situation task 2: 

Light coefficient in bedroom is hygienic norm for living accommodations.

Answer on situation task #3

Coefficient of depth is В/Н. CD= 5,6/3,0 = 1,87, that corresponds to norm. The size of hygienic norm coefficient of depth   is no more 2.

Individual student work (14¹⁵-15⁰⁰ hour)  are checked by solving situational tasks for each topic, answers in test evaluations and constructive questions (the instructor has tests & situational tasks).

 

 

 INITIAL LEVEL OF KNOWLEDGE AND SKILLS

are checked by solving situational tasks for each topic, answers in test evaluations and constructive questions.

(the instructor has tests & situational tasks)

 The student must know:

1.    Basics of the mathematical processing of medico-biological research results.Definition of «microclimate» and factors, which influence its formation.

2.    Physiological basics of human heat exchange and thermoregulation, their dependence on the microclimate: physiological reactions in the comfortable or uncomfortable (hot or cold) microclimate.

3.     Hygienic significance of the atmospheric and indoor air, its role in the microclimate formation and mechanisms of the organism heat exchange.

4.    Methods and devices for determination of the air movement direction and speed outdoors and indoors.

5.    Value of natural illumination of apartments.

6.     Method of determination and hygienically norms LC, CNI, CD, that are used for estimation of natural luminosity.

7.    Methods of determination of artificial illumination of apartments.

8.     Principle of work of luxmeter

The student should be able:

1.    To measure the indoor air temperature, radiant temperature, air humidity and to assess the temperature and humidity conditions of different premises (residential, public/social, industrial).

2.    To determine the air movement direction and speed, wind strength.

3. To draw the hygienic conclusions and assess the results of the outdoor and indoor air movement direction and speed measurement.

4. To define LC, CNI, CD in the apartments of a different type and to give hygienic estimation to the got results.

5. To define the indexes of lamplight by luxmeter.

6. To estimate artificial illumination by a computation method.

7. To estimate a brightness and uniformity of lamplight.

REFERENCES:

Principal:

1.        Practical classes materials http://intranet.tdmu.edu.ua/data/kafedra/internal/distance/classes_stud/English.htm

2.        Hygiene and human ecology. Manual for the students of higher medical institutions/ Under the general editorship of V.G. Bardov. – K., 2009. – PP. 14-34, 71-106. http://www.nmu.edu.ua/kaf55-8.php

3.        Datsenko I.I., Gabovich R.D .Preventive medicine. – K.: Health, 2004, pp. 14-74.

4.        Lecture on hygiene.

additional:

1.        Kozak D.V., Sopel O.N., Lototska O.V. General Hygiene and Ecology. – Ternopil: TSMU, 2008. – 248 p.

2.        Dacenko I.I., Denisuk O.B., Doloshickiy S.L. General hygiene: Manual for practical studies. –Lviv: Svit, 2001. – P. 6-23.

3.        A hand book of Preventive and Social Medicine. – Yash Pal Bedi / Sixteenth Edition, 2003 –  p. 26-36, 92-97.

 

Methodical instruction has been worked out by: ass-prof. Lototska O.V.,  ass-prof. Sopel O.M.

 

Methodical instruction was discussed and adopted at the Department sitting

28 august 2013, Minute № 1