Fundamentals of General and Pharmaceutical Hygiene - Dykyi I.L. 2003

Room lighting and ventilation
Hygienic evaluation of natural and artificial indoor lighting

Working in pharmacy settings involves a significant strain on the visual analyzer, which is why ensuring rational indoor lighting is of great hygienic importance. Inadequate or poorly designed workplace lighting reduces visual and general performance, increases the likelihood of errors and injuries, and creates conditions for The Development of eye disorders. All pharmacy premises must be provided with both natural and artificial lighting.

The main hygienic requirements for indoor lighting are:

— an adequate intensity level, taking into account the functional purpose of the room;

— uniform illumination across the entire area of the room;

— absence of a blinding (glare) effect on the eyes;

— spectral characteristics of artificial lighting that closely approximate natural light.

The main indicators of natural indoor lighting are: the light coefficient, the angle of incidence of light rays, the aperture angle, and the natural lighting coefficient.

Hygienic evaluation of indoor artificial lighting, including in pharmacies, includes: assessing the light source, its power and Location, the intensity and uniformity of illumination, and the absence of glare.

However, the potential NEGATIVE IMPACT OF light on medications during their storage must be taken into account. Direct sunlight can initiate racemization reactions, accompanied by the appearance of optical isomers in the drug that exhibit reduced pharmacological action, as well as other effects. The simultaneous action of light and oxygen leads to the rapid degradation of medications, rendering them unsuitable and sometimes dangerous to health. Given the destructive effect of light on Pharmaceuticals, appropriate storage conditions have been developed.

Objective: to understand the hygienic requirements for pharmacy lighting depending on the functional purpose of the premises, to be able to assess natural and artificial indoor lighting, and to develop hygienic recommendations for optimizing lighting parameters.

QUESTIONS FOR INDEPENDENT PREPARATION

1. Lighting concepts and units of illumination.

2. Impact of inadequate workplace lighting on visual function and the body as a whole.

3. Effect of light On the Stability of medications during storage.

4. Hygienic requirements for natural and artificial indoor lighting.

5. Graphical Methods for evaluating natural indoor lighting.

6. Lighting engineering methods for evaluating natural and artificial indoor lighting.

7. Design and operating principle of an objective lux meter.

8. Evaluation of indoor artificial lighting using the computational “watt method”.

Task 1. Hygienic evaluation of natural indoor lighting

Graphical and lighting engineering methods are used for the hygienic evaluation of natural lighting. Graphical methods include determining the light coefficient, the angle of incidence of light rays, and the aperture angle, whereas lighting engineering methods involve determining the natural lighting coefficient.

1.1. Determining the light coefficient

The light coefficient (LC) is The ratio of the glazed window area to the floor area. To determine it, a tape measure is used to measure the glazed surface area of all windows in the room (excluding window frames) and the floor area. The light coefficient is expressed as a simple fraction with a numerator of 1 and a denominator representing the quotient of the floor area divided by the glazed surface area.

Example. The glazed surface area in a pharmacy dispensing/preparation room is 4 m², and the floor area is 20 m². Therefore, the light coefficient is 1/5 (20: 4 = 5).

In pharmacy areas where intensive visual work is performed (dispensing room, aseptic room, packaging room), the LC should be at least 1/4, and in other rooms — 1/6.

1.2. Determining the Angle of Incidence

This indicator characterizes the angle at which light rays strike the working horizontal surface in a room. The angle of incidence ∠ ABC (Fig. 1) is formed by two lines originating from a single point (the workplace) and extending to the upper (AB) and lower (BC) edges of the window. Since triangle ABC is a right-angled triangle, the angle of incidence can be determined using the tangent:

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To determine it, measure the window height (AC) and the distance from the center point of the desktop surface to the window (BC).

Using the table of natural tangent values, find the corresponding angle of incidence (Table 10).

Fig. 1. Lighting angles:

∠ ABC — angle of incidence;

∠ ABD — aperture angle.

The angle of incidence of light rays at the workplace must be at least 27°.

Table 10. Natural Tangent Values

1.3. Determining the Aperture Angle

The aperture angle (∠ ABD) characterizes the area of the celestial dome that directly illuminates the workplace under study. The larger the visible sky area through the window, the higher the illumination level. To determine it, mentally draw a line from the desktop surface to the highest point of the opposite building (or tree) and mark the point on the Glass through which it passes (D). Measure the legs DC and CB, find tg ∠ DBC from their ratio, and then determine the natural values of tg ∠ ABC and tg ∠ DBC from Table 13. The aperture angle (∠ ABD) is equal to the difference between the angles ∠ ABC and ∠ DBC.

The aperture angle must be at least 5°.

1.4. Determining the Daylight Factor (DF)

The daylight factor is the ratio (expressed as a percentage) of the illumination of a horizontal surface inside a room (P₁) to the illumination of a horizontal surface under an open sky (P₂):

The illumination level is determined using a Yu-116 objective luxmeter. The device consists of a selenium photocell, a needle galvanometer, and light filters. When light rays strike the photocell, light energy is transformed into electrical energy in its active layer (selenium), which is then registered by the galvanometer.

When measuring illumination, the photocell is set horizontally, connected to the galvanometer terminals, and the switch button located on the measuring panel is pressed. Pressing the right button allows readings to be taken using the upper scale (0-100 lx), while the left button uses the lower scale (0-30 lx). If the galvanometer needle goes off the scale—in case of a high illumination level—one of the light filters marked with a light attenuation coefficient is used. When assessing the illumination level, the number of divisions by which the instrument needle has deflected is multiplied by the light attenuation coefficient, thereby determining the illumination in lux.

The DF in pharmacy premises where intensive visual work is performed (dispensing, aseptic, analyst-provisor room, and packaging room) should be 2%, and in other rooms, 1–1.5%.

Task 2. Hygienic assessment of Artificial Lighting

The artificial illumination level in rooms is determined using a photometric method (with a luxmeter) and a calculation method ("watt method"), comparing the obtained illumination level with the standards given in Table 10 of the Appendix.

2.1. Determining the Artificial Illumination Level by Calculation ("Watt Method")

Since the luminous flux depends on the power of the light sources, the specific power of the light sources for a given room (P) is first determined—that is, The amount of energy in watts per unit of illuminated surface.

where n is the number of lamps in the room;

u is the lamp power, W;

Sn is the floor area, m².

Next, the illumination level (E) in the room is determined. If the room area is less than 50 m², the calculation is performed using the formula

E = P ∙ e,

where E is the illumination level (lx);

P is the specific power, W/m²;

e is the coefficient indicating the illumination level in lux provided by a specific power of 1 W per 1 m² (at a mains voltage of 220 V for lamps with a capacity of up to 100 W, the coefficient is 2.0; for lamp capacities of 100 W and above, it is 2.5).

If fluorescent lamps are used as light sources, the calculation is performed taking into account that a specific power of 10 W/m² corresponds to an illumination level of 100 lx.

The illumination level in lux is compared with the standards given in Table 10 of the Appendix.

2.2. Determination of Illumination Uniformity

Using a luxmeter, the illumination levels in the room at workstations are determined, recording the lowest and highest illumination levels in a given area. Then, the illumination non-uniformity coefficient is calculated:

where K_н is the illumination non-uniformity coefficient;

E_min is the minimum illumination;

E_max is the maximum illumination.

K_н is expressed as a simple fraction showing how many times the minimum illumination is less than the maximum. Over an area of 5 m, K_н must be at least 1 : 3; over 0.75 m, it must be 1 : 2.

PROTOCOL OUTLINE

Topic of the practical session.

1. Hygienic assessment of natural lighting.

Determination of the light coefficient (LC).

Number of windows in the room ... .

Glazed surface area ... .

Floor area ... .

Calculation of SC ... .

SC standard for rooms where intensive visual work is performed ... .

Determination of the angle of incidence.

Distance from the desk to the window ... .

Window height ... .

Drawing (scale 1 m = 1 cm) ... .

Tangent of the angle of incidence ... .

Angle of incidence ... .

Standard angle of incidence ... .

Determination of the aperture angle.

Distance from the desk to the window ... .

Window height ... .

Height of the segment from the lower edge of the window to the point fixed on the glass ... .

Intersection of the line from the table surface to the highest point of the opposite building (tree) ... .

Drawing (scale 1 m = 1 cm) ... .

Calculation of the aperture angle ... .

Standard aperture angle ... .

Determination of the daylight factor.

Instrument ... .

Upper or lower scale (underline) ... .

Number of divisions by which the galvanometer needle deflected ....

Light filter used with a light attenuation coefficient ... .

Indoor illumination (E_in) ... .

Outdoor illumination (E_out) ... .

DF calculation ... .

DCC standard for assistant pharmacies ... .

2. Hygienic assessment of artificial lighting.

Determination of the artificial lighting level using the "watt method".

Light sources ... .

Number of lamps ... .

Power rating of a single lamp ... .

Floor area of the room ... .

Calculation of specific power (P) ... .

Mains voltage ... .

Calculation of the artificial lighting level (E) ... .

Standard artificial lighting level for rooms involving intensive visual work ... .

Determination of lighting uniformity.

Minimum illumination level ... .

Maximum illumination level ... .

Calculation of K_n ... .

Standard ... .

Conclusion. Based on Sanitary and hygienic studies conducted in the room ..., it has been established that the daylight factor is ..., the angle of incidence of light rays at the workstation is ..., the aperture angle, the daylight factor is ...%, the artificial lighting level is ... lx, and the lighting non-uniformity factor is ... . The following indicators do not meet the hygienic requirements ... .

Recommendations.

TASKS FOR INDEPENDENT WORK

1. Test control of knowledge.

2. Solving situational problems.

TESTS

1. The unit of measurement for luminous flux is:

A. Lumen (lm).

B. Lux (lx).

B. Candela (cd).

Г. Watt (W)

2. The unit of measurement for lighting level is:

A. Lumen (lm).

Б. Lux (lx).

B. Candela (cd).

Г. Watt (W).

3. The optimal insolation regime for the pharmacy customer service area in the temperate zone is achieved by orienting the windows:

A. South, east, southeast.

Б. South, southwest, west.

B. North, northeast, northwest.

Г. North, west, southwest.

4. The optimal insolation regime for the pharmacy washing room in the temperate zone is provided by orienting the windows:

A. South, east, southeast.

Б. North, northeast.

B. Southeast, southwest.

Г. Northeast, northwest.

5. The optimal insolation regime for the pharmacy dispensing/assistant room in the temperate zone is provided by orienting the windows:

A. South, east.

Б. North, west.

B. West, southwest.

Г. Southeast, southwest.

6. The optimal insolation regime for pharmacy storage rooms in the temperate zone is provided by orienting the windows:

A. North, northeast.

Б. South, southeast.

B. West, southwest.

Г. East, southeast.

7. What is the term for the indicator that characterizes the percentage ratio of indoor illumination to outdoor illumination?

A. Daylight factor (DF).

Б. Light coefficient.

B. Angle of incidence of light rays.

Г. Aperture angle.

8. What is the name of the instrument used to determine the level of illumination?

A. Krotov apparatus.

Б. Anemometer.

B. Objective luxmeter.

Г. Rheometer.

9. What is the term for the indicator that characterizes the distance of a workstation from a window?

A. Light coefficient.

Б. Aperture angle.

B. Uniformity ratio.

Г. Angle of incidence.

10. Indicate the effect that is the main disadvantage of fluorescent light sources:

A. Hypertensive.

Б. Stroboscopic.

B. Glare.

Г. Hyperthermic.

SITUATIONAL PROBLEMS

Problem 1.

In the pharmacy assistant room, the distance from the workstation to the window is 4 m, and the window height is 2.5 m. Determine the angle of incidence of light rays and provide a hygienic assessment.

Problem 2.

There are three windows in the analytical pharmacist's office. Each window is 2.2 m high and 1.4 m wide.

The floor area is 12 m². Determine the lighting coefficient and provide a hygienic assessment.

Problem 3.

The pharmacy compounding room has two windows. Each window is 2.5 m high and 1.5 m wide. The floor area is 15 m². Determine the lighting coefficient and provide a hygienic assessment.

Problem 4.

What is the maximum distance from the window at which a desk can be placed in the compounding room to ensure an adequate level of illumination, given that the window height is 2.5 m? The desk is positioned at the level of the lower edge of the window.

Problem 5.

An imaginary line drawn from The surface of the desk in the prescription department of the customer service hall to the highest point of the opposite building intersects the window at a point 1.8 m above the lower edge of the window. The window height is 2 m, and the distance from the workstation to the window is 2.4 m. Determine the angle of aperture and provide a hygienic assessment.

Problem 6.

In the pharmacy packaging room, the illumination of the work surface furthest from the window is 40 lx, and the outdoor illumination is 1,500 lx. Determine the daylight factor and provide a hygienic assessment.

Problem 7.

In a pharmacy washing room with an area of 10 m², lighting is provided by 4 incandescent lamps of 75 W each. The mains voltage is 220 V. Determine the illumination in lux and provide a hygienic assessment.

Problem 8.

In a pharmacy compounding room with an area of 20 m², lighting is provided by 10 fluorescent lamps of 60 W each. Determine the illumination in lux and provide a hygienic assessment.

Problem 9.

In the aseptic unit of a pharmacy with an area of 10 m², there are 6 fluorescent lamps of 40 W each in operation. Determine the illumination in lux and provide a hygienic assessment.

Problem 10.

How many 60 W fluorescent lamps need to be installed in the customer service hall (visitor area) to achieve the regulated level of illumination?