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TEM Journal. Volume 7, Issue 4, Pages 829-836, ISSN 2217-8309, DOI: 10.18421/TEM74-21, November 2018.

TEM Journal – Volume 7 / Number 4 / 2018. 829

Quality Assessment of the University Classroom

Lighting - A Case Study

Ivana Tureková 1, Danka Lukáčová

1, Gabriel Bánesz

1

1 Constantine the Philosopher University in Nitra, Faculty of Education, Department of Techniques and

Information Technologies, Dražovská 4, Post code: 949 74, Nitra, Slovakia

Abstract - The purpose of this study is to prove that

the quality of the school environment significantly

influences students’ academic performance. The

factors affecting the work environment are accurate

lighting which plays an important role in visual tasks,

resulting in either visual comfort or visual fatigue. This

study presents the results of lighting objectification of a

selected university classroom. Specifically, it focuses on

detection of the daylight factor, which is a significant

criterion for the amount of daylight in the classroom.

Its value is a relative magnitude and depends on the

correct spatial layout of the classroom. The results of

the study indicate the insufficient values of this

indicator. At the end, with a software, the solution for

replacing the artificial lighting in the classroom is

designed, which is a possible alternative for improving

the visual comfort of the classroom.

Keywords – daylighting assessment, visual comfort,

daylight illumination coefficient, DIALux.

1. Introduction

Daylight plays an essential and irreplaceable role

in human life. It affects one’s productivity, comfort,

mood and overall health. Its effects apply in mental,

as well as physical terms. The controlling body of

humans is directly stimulated and regulated by

daylight [1, 2]. Suitable illumination is vital in

DOI: 10.18421/TEM74-21 https://dx.doi.org/10.18421/TEM74-21

Corresponding author: Ivana Tureková, Constantine the Philosopher University in Nitra, Faculty of Education, Nitra, Slovakia Email: [email protected]

Received: 21 June 2018. Accepted: 10 October 2018. Published: 26 November 2018.

© 2018 Ivana Tureková, Danka Lukáčová, Gabriel Bánesz; published by UIKTEN. This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License.

The article is published with Open Access at www.temjournal.com

children’s education, hence the strict regulations

governing the natural and artificial lighting in child

care and educational facilities. The majority of

children and students spend most of the day in

enclosed spaces where the sun penetrates in limited

quantities only. Most problematic is the winter time,

when the lack of light is most critical, although

a number of buildings struggle with proper amount of

daylight throughout the whole year. The main

struggle of educational buildings in Slovakia

nowadays is inappropriate thermal insulation,

inadequate microclimatic conditions in the

classrooms, absence of mechanical ventilation

systems or insufficient natural daylight [3]. Besides

lifestyle, genetic dispositions and healthcare quality

level, environmental conditions are amongst the

basic parameters that affect human health. The

impact of environmental factors (15 – 20 %) is the

second most important element influencing public

health [4]. This comes immediately after the

population lifestyle impact (50 %).

Daylighting is considered a resource of primary

importance in schools: it’s a key factor for

occupants’ health and well-being, enhancing the

indoor environmental quality and reducing the

energy consumption for electric lighting [5]. The

impact of natural light on learning has physiological,

psychological and behavioural influences on school

children as well as workers [6].

Humans are affected both physically and

psychologically by light [7]. As shown in Table 1.

there is a multitude of physiological and

psychological benefits resulting from building

daylighting [8].

Table 1. Natural light and human body

Natural light and human body

Physically Psychologically

Improve Decrease Improve Decrease

Vitamin D Cancer

Possibility

Mood Depression

Visual

System

Abnormal

Bone

Formation

Mental

Performance

Stress

Circadian

Rhythms

Alertness Sadness

Sleep

Quality

Brain

activity

Violent

Behavior

https://dx.doi.org/10.18421/TEM74-21

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830 TEM Journal – Volume 7 / Number 4 / 2018

There is no doubt that people find daylight more

pleasant than electric lighting as their primary source

of light. Foreign studies confirm [9, 10, 11, 12, 13,

14], that a high percentage of respondents surveyed

prefer working in daylight. Similarly, people prefer

to sit at tables located next to windows as opposed to

further in the room, especially when these windows

have access to direct sunlight [15, 16, 17, 18].

Thanks to light we are able to receive visual

information about the environment that we are

surrounded by 75 % to 90 % of these are received

through eyesight. The mental state in which the

visual system fulfils its function optimally is called

visual comfort. Suitable lighting is an essential

element here. Visual comfort is directly affected by

the lighting source, type and layout of the lights,

evenness, and level of luminance and brightness

distribution in space [14].

In terms of evaluation of work conditions, the

geometrical parameters of the space and surface

features, including colour, matter as well as whether

or not there is glare [19]. Lighting should be

sufficient and even, without excessive brightness or

contrast. If there is proper lighting distribution,

objects appear to be plastic. In suitable lighting

conditions one has a feeling of clear vision even after

a longer time. The opposite of visual comfort is

visual fatigue. This is a complex state due to

shortcomings in lighting. Symptoms include burning

eyes, headaches and conjunctivitis [20].

Even when it’s cloudy the lighting changes rapidly

over the course of the day. This is done to a greater

extent than we are able to realize as a result of the

adaptive ability of our vision (Figure 1.).

Figure 1. Changes in daylight illumination throughout a

cloudy day and the perception of these changes

The variability of daylight is an advantage to us, as

in a physiologically acceptable course it forces our

vision to adapt [21]. However, in terms of lighting

evaluation, the instability of daylight is a problem

most relevant in quality assessment (evenness,

brightness distribution throughout our vision field,

exclusion of silhouette effect or glare). Illumination

quality can be impaired at any state of sky, however,

mainly at direct sunlight. For instance, evenness

evaluation according to STN 73 0580-1/Z2 brings

inaccuracies because it is based on daylight factor

values set for evenly cloudy sky [22]. Therefore, at

this time there is no exact evaluation method, due to

instable daylight.

The daylight factor D (%) is determined by the

daylight rate coefficient in conditions of a cloudy

winter day according to formula [23]:

(1)

Where E (lx) represents illumination at the

observed location on a levelling plain and Eh (lx)

represents external illumination of the horizontal

unshaded plain (Figure 2.).

The daylight rate coefficient D (%) is a relative

value and therefore, unlike luminance E (lx), its

value is not so much subject to changes in the

brightness of the cloudy sky [19]. Relative simplicity

of the winter-cloudy model and its independency of

sun position or point of the compass enables us to

estimate D (%) by calculation and mathematical and

graphic methods [24] as well and by using a software

or measurements [25].

Figure 2. Illumination rates for a horizontal unshaded

plain with a cloudy sky in course of a day and a year

2. Method

The aim of our study was to determine the values

of illumination, the daylight illumination coefficient

and the expression of similarity or inaccuracy of the

results achieved with the limit values in the

representative classroom. Using the DIALux model a

new lighting system was designed [26].

For our experiment we selected a small university

classroom located in the building of the Faculty of

Education at Constantine the Philosopher University.

The room is situated on the ground floor and lectures



take place here frequently. It holds 24 students and 1

teacher. 15 meters far from the building there is

another building which could have an impact on the

daylight intensity in the measured classroom (Figure

3.). The foreside of the building where the classroom

is located is heat cladded and the whole building has

plastic windows.

Figure 3. A classroom where all measurements were done

- position of windows and the nearby building,

arrangement of furniture

The room orientation is north-west. Table 2. shows

description data of the space.

Table 2. Characteristics of sunlight and artificial lighting

system

Description of the office place

Walls Ceiling Floor

colour white colour white colour light

gray

material plaster material plaster material PVC

state of

surface

clean state of

surface

clean state of

surface

clean

Description of lighting system

Natural lighting

system:

2 windows 800 x 1100 mm

Artificial lighting

system:

4 pieces of lamps

number of light

sources in lamps: 4

pieces

Type of light

sources:

TESLA, PHILIPS

TL-D

Power input: 36 W

Position of light

sources:

regular, symmetric

Located 15 meters from the researched classroom,

there is another building which significantly affects

the daylight intensity in the school.

Particular measurement was performed by a light

meter Testo 545 (Figure 4.). It was extremely

accurate measurement since the permissible

deviation defined by producer was ±2% (according

to DIN 5032, part 6).

Figure 4. Apparatus Testo 545 that was used for lighting

measurement

The lighting measurements were executed in

March 8.00 - 15.00 hour. This included 8

measurements of sunlight, 8 measurements of

compound lighting and 3 measurements of artificial

lighting.

The aim of objectification was to detect the current

state of a workplace. Illumination was measured

within the net of 20 selected control points [27].

Height of the datum plane was 0.85 m above the

floor, distances between measuring points were 1 m

and the outer points of the net were less than 1.5 m

from the wall.

Other control points were distributed in regular

distances so that they can adequately monitor the

whole measured place, changes in lighting and also

places with the highest and lowest intensity of

lighting. External conditions were measured by

anemometer (psychrometer) AN 340.

3. Results

Table 3. shows the results of external conditions in

which the measurements took place.

Table 3. External conditions in measurements

Temperature

(°C)

Humidity

(%)

Wet

thermometer

temperature

(°C)

Condensation

point

(°C)

23.6 32.8 13.9 6.2

Average daylight values are presented in Figure 5.

At 11 o’clock the daylight amounted to a maximum

value measured (507,4 lx). In the morning and in the

afternoon the values were considerably lower (100 –

200 lx).



0.00

200.00

400.00

600.00

800.00

1000.00

1200.00

1400.00

1600.00 1563.63

1189.38

958.25 831.38

1413.13

1147.88

978.25 882.38

1214.25 1172.75

1044.13 905.63

1488.63

1277.63 1184.38

933.63

1557.38

1243.50

1046.50

781.50

Figure 5. Average daylight values in the classroom from 8 am to 3 pm

Table 4. presents daylight values, measurement

uncertainty and illumination requirements by STN

EN 12464-1 : Light and Illumination.

Table 4. Measurement results and Illumination

Requirements.

Ē

(lx)

U

(%)

Ē – U

(lx)

Ē + U

(lx)

Illumination

requirements by

STN EN 12464-1

426.13 34.09 392.04 460.22 500 lx

At the same time, measurement of combined light

was carried out by turning on every light source in

the classroom in the same measuring points. We have

determined the average illumination of the classroom

(Ē) based on the arithmetic mean of the measured

values of the overall scaled horizontal illumination in

the whole of the measured space or combined

illumination on the comparison plain (Figure 6.).

The lowest values were on average about 1000 lx,

which meets the illumination requirements

(minimum of 500 lx) for educational spaces [28].

Figure 6. Average combined illumination values in the course of a day in the classroom.

0.00

200.00

400.00

600.00

800.00

1000.00785.25

443.13

243.13 176.875

790.38

438.50

290.88 193.63

559.57

439.71

302.29 210.63

835.25

466.63

297.63 187.38

902.63

476.25

312.25

170.63



Table 5. presents the values of combined

illumination, measurement uncertainty and

illumination requirements by STN [28].

Table 5. Combined Illumination Values.

Ē

(lx)

U

(%)

Ē – U

(lx)

Ē + U

(lx)

Illumination

requirements by

STN EN 12464-1

1140.71 91.26 1049.45 1231.97 500 lx

Table 6. summarizes the values of 20 measuring

points of average daylight values, external

illumination at cloudy sky in winter (there was a set

of 20 measuring points constructed, similar to the

one in the classroom) and artificial lighting in the

classroom by using only the existing lighting sources.

The last column contains the daylight illumination

coefficient D (%) calculated by using the formula

(1).

Table 6. Results of measuring daylight and artificial light, calculation of daylight illumination coefficient

Measuring

point

Average

daylight values

(classroom)

Ē (lx)

Average values of

combined lighting

Ē (lx)

Artificial

lighting values

Ēartificial (lx)

Average

daylight values

outside

Ēoutside (lx)

Daylight

illumination

coefficient

D (%)

1. 785.25 1563.63 840.15 12520 6.3

2. 443.13 1189.38 820.35 14310 3.1

3. 243.13 958.25 894.71 14170 1.7

4. 176.88 831.38 829.53 13880 1.3

5. 790.38 1413.13 1003.23 14210 5.6

6. 428.50 1147.88 1033.44 13250 3.2

7. 290.88 978.25 1057.53 13780 2.1

8. 193.63 882.38 999.92 14010 1.4

9. 559.57 1214.25 825.74 13360 4.2

10. 438.71 1172.75 894.58 13450 3.3

11. 302.29 1044.13 943.16 13780 2.2

12. 210.63 905.63 873.06 13970 1.5

13. 835.25 1488.63 751.22 12890 6.4

14. 466.63 1277.63 720.81 13580 3.4

15. 297.63 1184.38 852.14 13560 2.2

16. 187.38 933.63 753.26 12790 1.4

17. 902.63 1557.38 790.78 14120 6.4

18. 476.25 1243.50 767.83 13480 3.5

19. 312.25 1046.50 786.21 12780 2.4

20. 170.63 781.50 730.34 13010 1.3

Average

value 425.58 1040.71 858.40 13354 3.2

Table 7. present artificial daylight values,

measuring uncertainty, and illumination requirements

by STN EN 12464-1: Light and Illumination.

Daylight illumination coefficient D (%) as one of

the criteria of daylight amount has to meet the

following requirements:

Inside the premises or in their functionally

specialized parts where employees spend a lot of

time the minimum values of the daylight illumination

coefficient must be:

a) At side illumination Dmin = 1,5 %

b) At top and combined illumination Dmin = 1, 5

% and Dm = 3 %, where: Dmin is the minimum

value of the daylight illumination coefficient

on the comparison plain (%);Dm – the average

value of the daylight illumination coefficient

on the comparison plain (%).

Table 7. Artificial daylight values and illumination

requirements

Ē

(lx)

U

(%)

Ē – U

(lx)

Ē + U

(lx)

Illumination

requirements by

STN EN 12464-1

857.95 68.64 789.31 926.59 500 lx

The values of average illumination we obtained by

the measurements and calculations were rectified by

measurement uncertainties set against the

illumination requirements. Technical solutions for

improving lighting systems are relevant while project

processing and reconstruction. Various modelling

programmes offer a range of lighting system

solutions. Through DIAlux programme a new

lighting system was drafted using LED lights, while,

preserving the arrangement of the existing lighting

system (Figures 7., 8.).



The lights were selected from the options in the

programme - 12 pcs of PHILIPS CR200B 2xTL5-

54W HFP GT_452 (luminous flux 5852 lm; Lamp

power: 118.0 W).

Figure 7. Modelling room arrangement.

Figure 8. 3D model of the classroom and the proposed

lighting.

Figure 9. Rendering of place by false colours

4. Discussion

The results obtained can be summarized within the

the following conclusions:

a) The lighting in the selected classroom cannot be

sufficiently illuminated by daylight alone as

daylight cannot provide the required lighting

intensity.

b) Combined lighting values as well as artificial

lighting values meet the required minimum.

Hence, with lighting units turned on, the required

limit values are met.

c) The obtained values of artificial lighting are

sufficient, as none of the values dropped below

500 lx.

d) The amount of daylight measured by the daylight

illumination coefficient appears to be sufficient

because 3 of the values have fallen below 1, 5.

This means that the space is not provided with

sufficient light for mental and physiological

influences as well as for contact with the outside

environment. If, for some reason, lighting is

higher than daylight, the lighting of daylight

must be supported by artificial lighting, which is

not considered as combined lighting.

e) Optimal working temperature in the room met

the required parameters for temperature –

humidity microclimate for cooler seasons (from

18 °C to 26 °C).

f) Required relative air humidity in the classroom

in cooler seasons should amount to 30 % -70 %.

Our values are between 30,3 % to 35,9 % which

means the humidity requirements have been met

as well.



It is necessary to mind the ceiling lighting sources

besides external daylight, considering that the values

of daylight alone without using the support of any

artificial light did not meet the required lighting

intensity and required value of daylight illumination

coefficient. Especially in winter months, daylight

alone is not sufficient and needs to be supported by

artificial lighting sources in order to prevent visual

fatigue and other health issues.

The natural light penetration into the classroom

must be ensured by regularly cleaning the covers of

the lighting systems and window openings,

maintaining clean wall surface, ceiling and floor.

Designers, teachers and all people who are

involved with educational environments must

consider the lighting and controlling it. Physical area

in designing is very important and lighting is one of

the most important features in physical area in all

environments especially in educational and working

environments [29]. Despite the fact that good lighting

makes workspace more efficient, the lighting system

is always regulated by the human factor. Modern

technologies already offer lighting based on natural

daylight. For example, the light is automatically

adjusted by the control system. The sensor inside

measures the daylight amount and maintains the

lighting level for a given time, depending on daylight

availability which guarantees energy savings.

Different scenarios (with varying degrees of

chromaticity and light intensity ratios) are presented

in the control system [1].

5. Conclusions

Good lighting is a key to creating successful living,

working and learning environment, and is necessary

to ensure safety, as well as, well-being, health and

quality of life. By objectivizing the lighting, we

pointed out the deficiencies in the internal

environment of the university classroom. A major

shortcoming in the design of the classroom is due to

another building being immediately adjacent to the

researched building. This causes shadowing and

insufficient daylight flow into the room even though

the daylight coefficient met the required values. At

the moment, only alternative solutions can be taken,

which can bring not only light comfort but also

energy savings. However, other parameters such as

humidity, air flow, temperature, noise or chemical

factors are very closely related to the building's

suitability. Therefore, improving the lighting is

important, however, at the same time, maintaining

the classroom with both appropriate air conditioning

and regeneration systems is necessary, so that the

inner environment well-being, impacts the

performance of the student and the teacher positively,

and does not result in discontent.

Acknowledgements

This article was supported by the Grant Agency

Ministry of Education SR KEGA - project no.

014UKF-4/2016.

References

[1]. Nevrklová, J., (2017). Světlo pro naši budoucnost.

Světlo, 6 (12).

[2]. Kotus, M., Bujna, M., (2015). Bezpečnosť a ochrana

zdravia pri práci. Nitra: SPU, 2015. 148 p.

[3]. Šolc, M., Kliment, J., Divoká, A. & Forrai, F.,

(2017). Faktory ovplyvňujúce kvalitu a bezpečnosť

pracovného prostredia doktoranda pri realizovaní

experimentov. In. Doktorandské štúdium - súčasný

stav a perspektívy. Prešov : pp. 82-97.

[4]. Lalonde, M., (1974). A new perspective on the health

of Canadians. Ottawa, ON: Minister of Supply and

Services Canada. Retrieved from Public Health

Agency of Canada website: http://www.phac-

aspc.gc.ca/ph-sp/pdf/perspect-eng.pdf

[5]. Veitch, J. A., & Newsham, G. R. (1998). Lighting

quality and energy-efficiency effects on task

performance, mood, health, satisfaction, and

comfort. Journal of the Illuminating Engineering

Society, 27(1), 107-129.

[6]. Bellia, L., Bisegna, F., & Spada, G., (2011). Lighting

in indoor environments: Visual and non-visual effects

of light sources with different spectral power

distributions. Building and Environment, 46(10),

1984-1992.

[7]. Boubekri, M., (2008). Daylighting, Architecture and

Health, NY: Architectural Press, 143 p.

[8]. Shishegar, N., & Boubekri, M. (2016, April). Natural

light and productivity: Analyzing the impacts of

daylighting on students’ and workers’ health and

alertness. In Proceedings of the International

Conference on “Health, Biological and Life

Science”(HBLS-16), Istanbul, Turkey (pp. 18-19).

[9]. Wells, B. W. P. (1965). Subjective responses to the

lighting installation in a modern office building and

their design implications. Building Science, 1(1), 57-

68.

[10]. Manning, P., (1967). Windows, environment and

people, Interbuild/ Arena, 20-25 (Oct. 1967).

[11]. Markus, T.A., (1967). The significance of sunshine

and view for office workers, in Sunlight in buildings,

Proc. CIE conference, Rotterdam, 59-93.

[12]. Cuttle, C. (1983, June). People and windows in

workplaces. In Proceedings of the people and

physical environment research conference,

Wellington, New Zealand (pp. 203-212).

[13]. Heerwagen, J. H., & Heerwagen, D. R. (1986).

Lighting and psychological comfort. Lighting Design

and Application, 16(4), 47-51.

[14]. Veitch, J. A., & Newsham, G. R. (1998). Lighting

quality and energy-efficiency effects on task

performance, mood, health, satisfaction, and

comfort. Journal of the Illuminating Engineering

Society, 27(1), 107-129.

http://www.phac-aspc.gc.ca/ph-sp/pdf/perspect-eng.pdf

http://www.phac-aspc.gc.ca/ph-sp/pdf/perspect-eng.pdf



[15]. Aldworth and Bridgers, D., (1971). Desing variety in

lighting. Lighting research and Technology, 3, 8-23.

[16]. Collins, B., (1990). The Psychological Aspects of

Lighting: A Review of the Work of CIE TC3.16.

Gaithersburg, MD: National Institute of Standards

and Technology.

[17]. Ludlow, A. M. (1976). The functions of windows in

buildings. Lighting Research & Technology, 8(2),

57-68.

[18]. Veicht, J. A., (1993). End user knowlage, beliefs, and

preferences for lighting. Journal of Interior design,

19, 15-16.

[19]. Tureková, I., Lukáčová, D. & Bánesz, G., (2017).

Monitoring of lighting in a school classroom. In:

WOS 2017. Proceedings from 9h International

Conference on the Prevention of Accidents at Work,

Prague, London: Taylor&Francis, 339-344.

[20]. Moore, T. (1998). Harvesting daylight inside

buildings. EPRI Journal, 23(4), 18-19.

[21]. Kaňka, J. (2016) Požadavky na denní osvětlení

budov. TZB journal online: http://stavba.tzb-

info.cz/denni-osvetleni-a-osluneni/15093-pozadavky-

na-denni-osvetleni-budov

[22]. STN 73 0580-1/Z2 .(2007). Daylighting in buildings.

[23]. Regulation MZ SR n. 541/2007 Z. z. about details

and requirements for lighting during work.

[24]. Vychytil, J., (2015). Stavební světelná technika.

ČVUT Praha 2015,158 p.

[25]. Buday, F., (2012). Požiadavky na osvetlenie pri

práci.

http://www.aos.sk/spe/seminare/spe_2012/08_buday_

bp2012.pdf

[26]. DIALux v 4.6, DIAL GmbH, (2008). from

http://urlm.co/www.dial.de

[27]. STN EN 12464-1 .(2012). Light and

lighting.Lighting of work places. Part 1:Indoor work

places.

[28]. Stanko, L., (2017). Objektivizácia vnútorného

prostredia vo vysokoškolských učebniach.

[Bakalárska práca]. PF UKF 2017. 58 p.

[29]. Knez, I., & Kers, C. (2000). Effects of indoor

lighting, gender, and age on mood and cognitive

performance. Environment and Behavior, 32(6), 817-

831.

http://stavba.tzb-info.cz/denni-osvetleni-a-osluneni/15093-pozadavky-na-denni-osvetleni-budov



http://www.aos.sk/spe/seminare/spe_2012/08_buday_bp2012.pdf

http://www.aos.sk/spe/seminare/spe_2012/08_buday_bp2012.pdf

http://urlm.co/www.dial.de

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