The effect of sound on job performance
V. Siskova1,*, M. Juricka2, 3
1
Department of Industrial Engineering and Management, Tomas Bata University, Zlín, Czech Republic
2
Department of Physics and Materials Engineering, Tomas Bata University, Zlín, Czech Republic
(vsiskova@fame.utb.cz, juricka@ft.utb.cz)
3
Centre of Polymers Systems, Nad Ovčírnou 3685, 76001 Zlín, Czech Republic
Abstract – Industrial factories involves in their
equipment or machinery can be noisy places and exposing
employees to conditions can affect their job performance
and health quality. Noise exposure in the workplace might
have resulted in long-term workers´ health problems;
occupational diseases. Designers, managers or people
responsible for safety of work should take into account
possible danger of sound effect during designing future
workplaces. This article reports the results of a
questionnaire survey that investigated sound as a physical
factor and if its effect is solved in production factories. The
sample of 69 respondents included especially production
factories having mostly assembly workplaces. The results
confirm the hypothesis solving a workplace assessment and
sound impact on job performance. Results of the survey
were confirmed by case study that was carried out in the
processing plastics manufacturing company.
Keywords – Assembly Workplaces, Human Factors
Industry, Job Performance quality, Noise, Sound
I. INTRODUCTION
Noise, which is often defined as unwanted sound, is a
phenomenon that confronts human factors professionals
in many settings and applications [1]. The World Health
Organization defines noise as any unwanted noise [2].
According to Berry [3] sound is vibration of air or other
elastic media in certain frequency range. Sound
vibrations can occur, possibly spread in gases, liquids and
solids. Noise can do operate as a stressor to individual
employees. Sound can be physically described at
resources (emission) or it spreads across the environment
(imission). Sound waves that a subject is able to hear as
sound have frequency in the range of 16 – 16 000 Hz.
Experts agree that it is not possible to define noise
exclusively based on physical parameters of sound. Noise
is defined as audible acoustic energy unfavourably
affecting or influencing physiological and psychological
people comfort [4]. Sound energy emitted by the sound
source per the time unit (measured in W) is referred to as
sound power. And sound power measured on the unit
surface (in W/m2) is defined as the sound intensity or
sound wave energy. Sound intensity can be also defined
as a size of air pressure variation caused by spreading of
sound wave. The range of sound intensity perceived by a
man is cca 12 ranks (from the audibility threshold at 1012 W/m2 to the hurtfulness limit 1 W/m2). The level of
sound intensity is defined as:
Li  10 lg
L
in dB .
l0
(1)
Where l0 is noise intensity at bottom limit of audibility set
for l0=10-12 W/m2. Measurement unit of sound is decibel
(dB) [3].
When the noise fluctuates significantly with time
there cannot be possible characterized the noise exposure
by sound pressure level A. There is normally used
equivalent sound pressure level A LAeq,T [dB] for the
evaluation variables of acoustic signals. It is stable sound
pressure level that has got the same effect on human
during the time period T as variable sound pressure level
at the same time.
L p  10 lg
p
in dB 
p0
(2)
Where p0 is acoustic reference pressure = 2.10-5 Pa and p
is effective value of sound pressure (Pa) [5].
t2
LAeq,T  10 log
1 p A (t ) 2
dt in dB 
T t1 p02
(3)
Where LAeq is equivalent value of sound pressure level A
in time range T = t2 – t1 in dB; pA (t) in sec instantaneous
acoustic pressure of sound signal [5].
Many researches describe effects of noise on
productivity [6]. Results of studies prove effects of noise
on a subject that can be changing over time. Absence of
adequate acoustic conditions can affect object
performance. Erret at all [7] found out the noise on
background can effect on performance on employee’s
daily task. People encounter high noise is annoyed during
performance of tasks and their quality of job performance
of worker is fitfully influenced. The exposure to high
levels of sound might lead to cardiovascular disease,
endocrine and digestive reactions especially in complex
tasks not in simple task [8]. On the other hand some
levels of noise can improve worker efficiency or also
disturb his concentration during performance. Cohen and
Weinstein [9] have confirmed this statement by declaring
the fact that worker efficiency is higher during lower
level of noise and on the other hand higher level disturbs
his performance.
After time the noise can unfavourably effect worker´s
health. The workplace noise may arise as a by-product of
stationary or mobile equipment, construction machinery,
transport equipment, electronic appliances and equipment
used in the workplace. Protection of employee against
acute or chronic impaired hearing is the primary problem
that should be solved in the workplace. Such protection is
very important especially during physical work with hand
tools or machinery service. Effects are expressed as
auditory and non-auditory. Technical researches
examining occupational diseases show how that longterm intensive exposure to noise during daily working
hours for several years, causing hearing loss.
Diseases caused by noise are very debate topic in the
Czech Republic. Many operators end up their work in
early years. The researchers attempt to find causes which
are the most frequent on the workplaces and pursue those
problems. Solving problems connected with health
diseases are in the competence of NIPH. The National
Institute of Public Health (NIPH) is a health care
establishment for basic preventive disciplines - hygiene,
epidemiology, microbiology and occupational medicine
[10]. Its main tasks are health promotion and protection,
disease prevention and follow-up of environmental
impact on the health status of the population.
Cohen and Weinstein [9] argues that subjects were
exposed to noise intensity of 93 dB, showed higher
physiological effort than subjects who worked on the
quieter workplaces. Effects of noise on worker´s health
can lead to long-term disorder, his absence and bad
quality of work. Lower performance adversely affects the
work where certain quantity of products should be
produced in set time [11]. Aamondt [12] found out in his
researches to understand relations and effects of noise on
performance and classified seven factors specifying
interference effects on a worker´s performance; difficulty
of task, continuity of noise level, continuity of noise,
sound frequency, noise foreseeability, noise necessity and
sensitivity to noise. Regardless of whether noise has a
significant impact on job performance of the individual
worker or, conversely, it is still debatable issue. It
depends on each worker sensation of noise. Significant
hearing loss is caused by the higher frequencies of sound
effects, rarely hearing can be damaged at low
frequencies. Studies show that low-frequency noise
causes human fatigue, headache, irritation, which leads to
a reduction in the job performance [11].
Health hazards related to hearing damage are clearly
measurable and observance. Hearing loss caused by noise
effects includes injury of inner ear. These damages are
caused by vibrations being transferred from outside
environment. Immediate damage of structure of inner and
middle ear and breaking of eardrum are caused by
explosions and other intensity sounds. Raising intensity
and long-term noise effect lead to gradual shortage of hair
cellules and hearing loss [13]. Studies showed the level of
acoustic pressure between 85 and 88 dB is harmful for
ear. Long-time exposition to noise of levels between 85
and 90 dB and higher can cause risk of definitive hearing
loss [14]. The employer is obliged to get the premises
professionally ensured against noise and name workers
for which there is a risk of hearing damage due to effects
of noise. Noisy areas have to be identified when assessed
level reaches 90 dB or exceeds the maximum noise level
of 140 dB. Workers who are employed in a noisy
environment or are exposed to overreached noise level of
85 dB, have to be provide with suitable hearing
protection. If the assessed level exceeds 90 dB, the
worker must wear personal protective equipment (e.g.
cotton wool swab into the ear capsule and hearing
protection) [15]. Size of the noise energy is depended on
the average noise level and duration of exposure.
Hygienic limit is understood as a noise limit fixed for the
place of residence of persons for the protection of their
health from the adverse effects of noise. In the day time
values of noise are set for eight continuous successive
noisiest hours, in the night time only for noisiest hour.
According to the timing sounds are divided on steady,
fluctuating, intermittent or pulsed. Table I shows the
recommended values of noise on selected types of
workplaces [16]. This review has indicated that a possible
relation exists between noise and job performance. A
questionnaire is a direct method for measuring job
performance using self-assessment approach. The first
step was a questionnaire survey carried out in the
production company verifies that the currently addressed
noise in the workplace and whether the noise is
considered to be a significant factor in the working
environment.
TABLE I
Recommended values of noise on selected types of workplaces.
Type of workplace
The creative workplace - concentration
Recommended
values (dB)
50
Noise is caused by rating or air-conditioning
55
Rooms for rests, emergency and in surgery
60
Workplace for routine activities
65
Production and storage - noise is caused by
ventilation or heating
Average level of noise warranting health safety
for all workers
Maximum level of noise to which workers can
be exposed without protection during working
day.
Limit of steady and variable noise during
physical work (8 hours)
Need to mark the area as noisy: suitable means
to protect.
The noise levels in industrial plants.
Acute hearing loss danger of exposure to
impulsive noise
Need to mark the area as noisy; the occurrence
of these levels is rare.
70
75
80
85
90
100
135
140
Two hypotheses were defined:
 H1: More than 30% of surveyed companies deal with
the design of workplaces (in terms of physical
factors).
 H2: A third of the companies surveyed considered
noise as a factor that interferes with job performance.
The next step was verified if results are valid in the
production company which was chosen by researchers.
II. METHODOLOGY
Manufacturing companies in the Czech Republic
were selected as the preliminary survey companies.
Manufacturing company was chosen where questionnaire
survey was carried out. The results are described below.
The aim of the preliminary survey was to confirm or
refuse the two hypotheses set out above. The
questionnaire was electronically sent to 300 companies.
The target respondents were production managers, or
persons responsible for the production. Manufacturing
company with prevailing assembly plants was addressed.
Assembly workplace was selected because of easier
detection of operators’ job performance. Of 300
questionnaires sent, 75 were returned (25% return). Six
questionnaires were excluded because of incompleteness.
Total return usable questionnaires were thus 23%.
Fig. 2: Results of LAeq analysis of noise exposure in the workplace.
III. RESULTS
TABLE III
Results of LAeq analysis of noise exposure in the workplace
More than 60% of companies evaluate their work
visually (naked eye). 27% of respondents said that the
workplace did not evaluate at all. 30% of companies use
checklists to evaluate their workplaces. Companies can
tick more than one possible answer; hence the total
percentages exceed 100%. Only 3% of the assessment
centres use an external company. For this case the
hypothesis H1 has been confirmed. Respondents
answered the question: "Does noise disturb the
performance of your employees? Follow the instructions
in the questionnaires a question was evaluated as in the
school; from 1 (not very disturb) to 5 (very disturb). The
graph in Figure 3 shows the results. The above chart
shows that the H2 hypothesis was confirmed. Red bars
indicate that more than one third (25% and 19%)
companies consider the noise rather disturbing and
intrusive.
Fig. 1: Graph of the noise assessment in the workplace
TABLE II
Evaluation of the effects of the job performance
Scale
1
2
3
4
5
Noise disturbance
Not very disturb
Rather not disturb
Neutral
Rather disturb
Very disturb
Results (%)
15
18
23
25
19
Quantity
11
12
16
17
13
Place
number
LAeq
[dB]
Colour
label
Scale
LAeq
[dB]
2
87,3
87,0-87,9
10
86,6
86,0-86,9
4
86,3
86,0-86,9
8
86,2
86,0-86,9
3
85,5
85,0-85,9
11
85,4
85,0-85,9
5
85,2
85,0-85,9
6
84,8
84,0-84,9
9
84,7
84,0-84,9
7
84
84,0-84,9
1
83,3
83,0-83,9
12
81,9
81,0-81,9
13
81,9
81,0-81,9
Results of the preliminary survey should be
confirmed by case study. The manufacturing plastic
products company was selected as a case study company.
This factory was chosen as the representative
manufacturing plant in the country. The company has two
large facilities. The questionnaire survey and
measurements were made in the noisier facility. There is
the average noise exposure in the workplace more than 87
dB in the facility. Operators are exposed to noise for the
whole 8-hour shift. The company is located in the
industrial zone close to the bigger city. Facility B is
equipped with machines that produce irregular, loud and
annoying noise. Facility does not have any anti-noise
barriers; operators are required to wear noise protection
(earplugs). Height of the facility is prescribed to 5 meters.
Based on a pilot observation by the research team, a
place of main sound sources was identified and marked
into the list fig. 2. Such sound sources covered a range of
frequencies, including low frequencies, which could be
important factor for noise annoyance.
Measurements were carried out during the normal
working day lasting 8 hours with a half hour break;
measuring equipment Bruel and Kjaer (BaK) Mediator
2238 was used. Statistically evaluated questionnaires
were used to determine subjective opinions of individual
operators
All 40 operators working in the facility were chosen.
In terms of gender, the percentage of males was 100%. In
terms of age, the majority of the interviewees, 50%, were
aged 25-34. They were asked about a number of
structured questions, covering the following aspects:
demographic data, evaluation of the acoustic condition
and comfort of the working environment, job satisfaction.
The case study results are described below.
The number of questions was aimed at various aspects of
the sound environment, including: How do you perceive
noise at your workplace? Does noise influence your job
performance? Do you think if your workplace was
optimised would your job performance get better? In
which period do you feel your job performance your job
performance declines.
In Fig.4 may be obvious that in terms of the
importance of the acoustic environment at work, 40.0%
of respondents think it is "very noise" as some as 40.0%
“noisy” and 7.5% think that it is "acceptable", that the
percentage of respondents who think the acoustic
environment "very quiet" is only 12.5.%. Regarding the
impact of noise on job performance 47.5 % of
respondents think it is "medium”, only 22.5% think there
is no influence on their performance and 17.5%
respectively 12.5% perceive noise as “important”
respectively “very importance” can be seen in fig. 5. 75%
of respondents stated that if the workplace was better
adjusted to the operators’ conditions, their performance
would be higher, 5 % operators do not see the
improvement their job performance due to optimizing
workplaces and 20%think that sound is independent on
their job performance. This means significant effects of
noise on the performance of the work environment.
Fig. 3: Results of LAeq analysis of noise exposure in the workplace.
Fig. 4: The impact of noise exposure in the workplace on operators’ job
performance
IV. DISCUSSION
The study indicates relationship between noise and
employee performance. At present, the company does not
sufficiently solve the physical factor - noise, which
proves the hypothesis H1, which was confirmed. More
than 30% of companies do not evaluate their workplaces.
Hypothesis H2 if managers consider noise as a factor that
affects work performance was also confirmed. The results
clearly show that noise is considered as rather intrusive
and distorting factor. This statement also indicates that
managers are aware of the negative impact of physical
factors on employee’s performance. A number of
respondents in open-ended questions whether deficient
state of workplaces want to solve and will solve, said yes.
Another problem issued from open questions in the
questionnaire was the current legislation. This was
mainly assessed as comprehensive and obscure. Further
studies will continue these challenges and focus on
addressing workplace design, in terms of physical factors
on employee performance.
V. CONCLUSION
People encounter noise often in their everyday
environments – in work, during sleeping, in leisure time.
This type of noise can be characterized as excitable,
dispersed concentrations, defending in job performance,
it can cause work injury. It is noise from heating, airconditions, ventilation. Noise can cause disorders of a
worker concentration and decrease in job performance.
Based on the preliminary survey in the
manufacturing company and a case study in typical
plastics manufacturing company in the Czech Republic
found that, compared with other physical factors of the
environment, operators are mostly influenced by noise
exposure in the workplace. The impact of noise in
monitoring the work environment is quite significant in
terms of the sound pressure level inside the production
facilities. About 30-50% of those surveyed believe that
the various noise sources in the work area are "very
troubling" and "disturbing" and the most annoying sounds
are the noise of machines handlers of plastic, using a
panel hanging from the ceiling insulation of buildings and
machinery are considered effective measures to improve
the introduction of natural sounds to mask undesirable
noise appears that is not preferred. Some of satisfaction
with work-related statements and assessing the
effectiveness of different acoustics related factors
indicate that "I am very sensitive to noise" is significantly
correlated with the acoustics of the working environment.
If conditions in facilities were acceptable operators
could improve their job performance. This fact is related
to finances, which reduces the number of health workers.
If a worker´s outgoing is caused by excessive noise
the cost could be increased by payment of sick
employees, the education new employees, the cost
penalties etc. These effects on the health of the operators
are reflected in a long time, for several years and
additional surveys are important.
ACKNOWLEDGMENT
The authors are thankful to the Operational
Programme Education for Competitiveness co-funded by
the European Social Fund (ESF) and national budget of
the
Czech
Republic,
the
grant
No.
CZ.1.07/2.4.00/31.0096 - “Building partnerships and
strengthening cooperation in the field of lean
manufacturing and services, innovations and industrial
engineering with the emphasis on the competitiveness of
the Czech Republic”, which provided financial support
for this research.
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