METHODICAL INSTRUCTION FOR STUDENTS OF THE 3 COURSE

MEDICAL FACULTY

LESSON № 2 (PRACTICAL – 6 HOURS)

                                                                                                         

Themes:  

1. Ultraviolet radiation and lighting. Hygienic estimation of radiation energy. Methods of determination of intensity and preventive dose of ultraviolet (UVR) radiation and its use with the purpose of prophylaxis of diseases and air sanation - 3 hours.

2. Method of determination and hygienic estimation of natural and artificial illumination. - 3  hours.

 

Aim: 1.To learns how to make the recommendations for prevention of ultra-violet insufficiency of children and adult.

2.      To learn methods of air disinfection with the UV-rays and to learn how to control its effectiveness.

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

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

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

 

PROFESSIONAL ORIENTATION OF STUDENTS

Ultra-violet portion of solar spectrum has high physiologic meaning. Under its influence exchange processes intensify in the organism, nutrition and tissue regeneration intensify, vitamin D is produced. In condition of insufficiency UV-radiation in the organism there occur changes that are connected with sufficient formation of vitamin D (rickets, osteoporosis, osteomalation, lowering of organism resistibility), besides with the disturbances of phosphor-calcium exchange (myopia, scoliosis).

That's why for prophylactic of ultra-violet insufficiency we should use not only the natural solar radiation but also the artificial sources of ultra-violet radiation. Especially artificial UV-sources are important for disinfection of hospital workplaces: surgical blocks, patrimonial halls, chambers etc.

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. Ultraviolet radiation and lighting. Hygienical estimation of radiation energy. Methods of determination of intensity and preventive dose of ultraviolet (UVR) radiation and its use with the purpose of prophylaxis of diseases and air sanation - 3 hours

 

Work 1.

The defining of the effectiveness of the UV-radiation  with the help of the biological method ( the defining of the erythemic dose).

The biological method is widely used to measure the intensity of ultra-violet irradiation. The unit of measurement is biodose. It is the smallest quantity of ultra-violet irradiation, provoking hardly visible hyperaemia of untanned skin in 6-20 hours after the irradiation.

The measuring instrument is ultra-violetmeter (UVmeter).Ultra-violetmeter is a special device, used in medicine. Ultraviolet irradiation is absorbed by photoelement and the generated electrical current is registered by galvanometer. The scale of galve- nometer is graduated by mcW/sm2. 1 biodose is equal to 600-800 mcW/sm2. Consequently, minimal physiological request of white man is 100 mcW/sm2, optimal - 200-400 mcW/sm2. These indices make 250-500 and 500-2000 mcW/sm2 correspondingly for black man. The intensity of UV-irradiation makes 15-20 mcW/sm2 per min.

 

Work 2.

To calculate physiologic and prophylactic dose by situation task.

The minimal daily prophylactical dose, preventing rachitis in people with the white skin, is 1/8 of biodose. The optimal dose with the adaptagenous meaning is 1/4 - 1/2 of biodose . This is physiologic dose.

The prophylactic dose UV-raying while using the erythemic lamp LE-30 of power 30 Wt  is provided at the irradiation of patient during 3 mines in the distance 1,5 m from a source. To calculate, how many times is needed for the receipt of prophylactic dose. if a patient will be found in the distance 3 m from a source.

The prophylactic dose is accounted by the formula:

X=(B/C) ² x A,

where: B is the distance in meters, on which the patients will be located;

            C is the standard distance in meters, by which the erythemic dose was defined;

A is the erythemic dose on the standard distance, min.

 

Work 3.

To estimate of efficiency of disinfections of air (situation task).

 

Microbial number calculates with the formula:

 M.n. =А х 1000/ Т х V,

 Where:

M. n. is amount of microbe bodies in 1m³ air, and amount of colonies on Petri cup:

Т is air taking time, min;

V is speed air passing, l /min.

Bactericidal action of ultra-violet radiation characterizes by effectiveness degree, which shows, on how much percentages decreased a number of microorganisms in 1m³ of air after disinfection or by effectiveness coefficient,  which shows, how much  decreased microorganisms  in  that volume .

A disinfection defers effective, if effectiveness degree is 80%, and

an effectiveness coefficient is not less than 5.

Air microbe number, which has got after disinfection, weighs also with

recommendations of admissible bacterial contamination air closed of workplaces, which is represented into table.

 

Basic indexes for estimation of microbe pollute (stage of cleanness) air
of some workplaces.

 

 

Theme 2. Method of determination and hygienic estimation of natural and artificial 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 (table 35-36, page 110. The recommendation for practical classes on hygiene Y.P.Pivovarov).

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).

 

Work 5.

To determinate of brightness on the example of situation task.

Determination of brightness. The bright sources of artificial light can unfavourably affect the organ of sight and nervous system. The brilliant filaments of unscreened lamp of incandescence at their contemplation give feeling of illumination which lasts still long since eyes left off to look. The presence of bright source of light not only before eyes, but also in lateral parts of eyeshot gives the decline of all visual functions (sharpness of sight, speed of perception and etc), diverts attention, tires eyes, nervous system and ability as a result goes  down to work. Therefore the brightness of sources of light is subject to setting of norms and control.

Brightness can be defined by the special device - brightness meter,   either by visual luxmetra, or to calculate on a formula:

B = (n x l² / 10³ x S ) knt;

 where, n-index of galvanometer in luxes

             l-distance in sm. from research surface

10³- re-calculation in kilonits (knt);

By luxmeter the illumination is determined in lux.  The result of measuring is multiplied on 27 х 10^-6; the result of brightness is got in nits.

         The brightness of visible lamp’s parts of general illumination in schools and

 hospitals must not  be more than 2000nits,and in other cases(public apartments, theatres, concert’s halls)-5000nits.During the presence of local  illumination the brightness of visible parts of fountains more than 2000nits (for the table lamps).

 

Work 6.

 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 7.

 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. Ultraviolet radiation and lighting. Hygienical estimation of radiation energy. Methods of determination of intensity and preventive dose of ultraviolet (UVR) radiation and its use with the purpose of prophylaxis of diseases and air sanation.

 

Control questions:

1. Characteristic of the UV-rays, features of their on an organism and environment.

2. Biodoza and method of its determination.

3.Erythemal, physiologic and preventive ultraviolet radiation doses

4. Sign of UV- insufficiency and “sun starvations”.

5. Indication and contra-indication for UV - exposure of the people.

6. What is the case a necessity in the irradiation of objects of environment?

7. Types of the artificial sources of UV-radiation, their description, master technical data.

8. Vehicles and devices for UV irradiation of people.

9. Methods of measuring of the UV- radiation.

 

Theme 2. Method of determination and hygienic estimation of natural and artificial 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.     Characteristic of the UV-rays, features of their on an organism and environment.

2.     Biodoza and method of its determination.

3.     Sign of UV- insufficiency and “sun starvations”.

4.     Indication and contra-indication for UV - exposure of the people.

5.     What is the case a necessity in the irradiation of objects of environment?

6.     Types of the artificial sources of UV-radiation, their description, master technical data.

7.     Vehicles and devices for UV irradiation of people.

8.     Methods of measuring of the UV- radiation.

9.     Physiology role of natural illumination of apartments.

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

11. 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.

12. Principle of work of luxmeter.

13. Hygienic value of artificial illumination.

14. Classification of sources of artificial illumination.

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

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

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

18. 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 minimal daily optimal (physiological) dose, preventing rickets of children with the white skin, is

A. 1 / 2 of biodose;

B. 1 / 6 of biodose;

C. 1 / 5 of biodose;

D. 1 / 8 of biodose;

E.  1 / 3 of biodose;

2. One of the following is contraindication for UV-exposure of people

A.  Chill,

B.  Diseases of respiratory organs;

C.  Rickets;

D.  Malignant tumors;

E.   Osteoporosis.

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

                  A .1: 5

                  B.1: 8

                  C.1:10

                  D.1:2

                  E.1:12       

4. Coefficient of daylight  is:

           A. a ratio of a glass area of windows to area of a floor

           B. a attitude of distance from the upper edge of the window to a floor to distance from the window to the opposite wall

           C. a ratio of lighting indoors to simultaneous lighting outdoor

            D. angle between a horizontal surface of a table, and line conducted from this surface to the upper edge of the window

           E. an angle between a horizontal surface of a table, and line conducted from this surface to the upper edge of the object with darken the window

5. For measuring of daily lighting use

                   A. Kata termometer.

B. Psychrometr.

C. Anemometer

D. Barometer

 E. Luxmeter

 

SITUATION TASK

Situational task № 1.

During the inoculation of air in operation room by aspiratory-sedimental method of Yu. Krotov on Petri dish with meat-peptone agar in 24 hours in thermostat there were grown 98 colonies of microorganisms. After air disinfection by 4 lamps WAS-30 during 6 hours  one more inoculation was made. Conditions of inoculation in both cases are the same - speed of aspiration is 10 liters per minute during 5 minutes. After second inoculation there were grown 6 colonies. Evaluate the air cleanly in operation room before and after the disinfection.

 

 

Situational task №2.

For air disinfection  in school class-room (square is 50 m², height is 3,5 m ) during the period of influenza epidemy the radiator (of the lamp WAS-30) during one hour. the inoculation of air before and after the exposure was made by aspiratory-sedimental method of Krotov (aspiration speed is 20 liters per minute, time is 5 minutes). Give the hygienic evaluation to disinfection effectiveness if the quantity of microorganism colonies before the disinfection was 86, and after - 64.

 

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:

 

Situational task №4.

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,

 

CORRECT ANSWERS OF TEST EVALUATIONS AND SITUATIONAL TASKS:

1.     A;

2.     D;

3.     A;

4.     A;

5.     E.

 

Answer on situation task: 

Situational task № 1.

Answer:

Microbe number before the disinfection = A x 1000/T x V = 98 x 1000/5 x 10= = 1960

Microbe number after the disinfection = A x  1000/T x V = 6 x 1000/5 x 10 = =120  

Effectiveness degree is 90%, and effective coefficient is 16%, therefore air disinfection is effective.

 

Situational task №2.

Answer:

Microbe number before the disinfection = A х 1000/T х V = 86 х 1000/ 5 x 20= 86.

Microbe number after disinfection= A х 1000/Т х V = 64 х 1000/5 х 20 == 64.0

Effectiveness degree is 25,5%, and effectiveness coefficient is 1,3,  disinfection is unsatisfactory.

 

Situational task №3

Answer: 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.

Situational task №4.

Answer: Light coefficient in bedroom is hygienic norm for living accommodations.

 

 

 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.Basic types of biological action of the UV- radiation and changes in an organism, caused by it.

2. Artificial sources of the UV- radiation.

3. Possibility of the use UV - radiations for the prophylaxis of diseases and disinfection of air and objects of environment.

4.  Physiological value of components of air and their contamination.

5. Physical, chemical and bacterial indexes of cleanness of air in apartments.

6. Value of natural illumination of apartments.

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

8. Methods of determination of artificial illumination of apartments.

9. Principle of work of luxmeter

The student should be able:

1.  To calculate prophylactics dose the UV- radiation.

2. To calculate time and distance, which are needed for the receipt of the prophylactic dose UVR at the use of eritemnic lamps?

3. To use the Yu. Krotova device for taking away of tests of air and determine the level of microbes number of air (from data of count of colonies on the Petri cup with a nourishing environment).

4. To estimate efficiency of disinfection of air by ultraviolet rays.

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

6. To define the indexes of lamplight by luxmeter.

7. To estimate artificial illumination by a computation method.

8. To estimate a brightness and uniformity of lamplight.

 

REFERENCES:

Principal:

1.                                         Practical classes materials http://intranet.tdmu.edu.ua/data/kafedra/internal/hihiena/classes_stud/en/med/lik/ptn/hygiene%20and%20ecology/3/02.%20Ultraviolet%20radiation%20and%20lighting.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. 34-70.

http://www.nmu.edu.ua/kaf55-8.php

3.                                         Datsenko I.I., Gabovich R.D. Preventive medicine. - K.: Health, 2004, pp. 98 - 106,278-281, 445-446.

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. 74-104.

3.          A hand book of Preventive and Social Medicine. – Yash Pal Bedi / Sixteenth Edition, 2003 –  p. 361.

 

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

Methodical instruction was discussed and adopted at the Department sitting

30 august 2011, Minute № 1

Methodical instruction was adopted and reviewed at the Department sitting

28 august 2013, Minute № 1