Introduction
Exposure in place that have a high noise level for a long time
must hazard to hearing. In this measurement, a Chinese
restaurant and a peak dining hour has been chosen to conduct the
measurement, the aim of chosen peak hour and Chinese restaurant
to conduct the measurement is to investigate the workplace noise
level and how high level of noise level are impact to workers
who need to exposure in noise for a long time, generally the
noise level will be high in lunch peak dining hour, the data
that collect in peak dining time will be representative to noise
pollution impact to workers who work in restaurant. In this
measurement, parameter Leq, L10 and L90 will be collect and
conduct a comparation after measurement. And the noise exposure.
On the other head, possible noise source has been observed due
to measurement.
Methodology
In this measurement, precision sound level meter, calibrator and
tripod are necessary in measuring procedure. Before measurement,
calibration of sound level meter must be conduct to ensure the
sensitive of sound level meter, to increase the accuracy of data
measured. Parameter Leq, L10, L90 are necessary to measure at
two location inside restaurant to show the different noise level
inside a same restaurant, after a measurement at a place, it
should repeat the same measure procedure at another position.
Then, background noise level are also need to measure. At the
end of measurement, a calibration of sound level meter is
necessary to conduct once.
Result
In the measurement, two location: 501 and 606 are chosen as the
measuring position inside restaurant, the result in Leq, L10 and
L90 measured will be show below:
In 606, 30 minutes Leq was 78.3dB, and L10 and L90 were 80.9dB
and 73.6dB respectively. To view the trend, the trend of noise
level change at 606 was ups and downs. Overall, there were 5
downward and 4 upward trend at the measure interval. For the
aspect of downward trend, downward trend had present in minute 0
to 3, 9 to 12, 15 to 18, 21 to 24 and 27 to 30 with noise level
79.6dB to 72.8dB, 79.3dB to 76.4dB, 78.3dB to 70.7dB, 74.7dB to
73.7dB and 77.2dB to 75.5dB respectively, the decrease rate were
1.3% to 10.7%. For the aspect of upward trend, upward trend was
present tin minute 3 to 9, 12 to 15, 18 to 21 and 24 to 27 with
noise level 72.8dB to 79.3dB, 76.4dB to 78.3dB, 70.7dB to 74.7dB
and 73.7dB to 77.2dB respectively, the increase rate were 2.5%
to 8.9%. Minute 9 to 15 had the highest noise level at whole
measure interval.
In 501, 30 minutes Leq was 79.5dB and L10 and L90 was 101.4dB
and 76.4dB respectively. To view the trend, the trend of noise
level change at 501 was ups and downs. Overall, there were 4
upward trend and downward trend during the measurement. For the
aspect of downward trend, downward trend was present in minute 0
to 3, 9 to 15, 18 to 21 and 24 to 27 with noise level 81.5dB to
76.1dB, 77dB to 73.6dB, 80.5dB to 79.5dB and 87.6dB to 73.2dB
respectively, the decrease rate was 1.2% to 16.4%. For the
aspect of upward trend, upward trend was present in minute 3 to
9, 15 to 18, 21to 24 and 27 to 30 with noise level 76.1dB to
77dB, 73.6dB to 80.5dB, 79.5dB to 87.6dB and 73.2dB to 75.6dB
re4spectively, the increase rate were 1.2% to 10.2%, minute 24
had the highest noise level at whole measuring interval.
For the aspect of possible noise source, the noise source
observed can be divide into 8 types: noise from diners talking,
noise from porcelain collision, noise from working of restaurant
workers (delivery of foods) noise from television, noise from
ventilation system, noise from cooking in the kitchen, noise
from cleaning dining tools and noise from working.
Sampling location: Dragon Delight
Date of sampling:1/3/2019 Time of sampling: 13:15
List of possible noise source
|
1
|
Noise from diners talking
|
||
|
2
|
Noise from porcelain collision
|
||
|
3
|
Noise from working of restaurant workers
(delivery of foods)
|
||
|
4
|
Noise from television
|
||
|
5
|
Noise from ventilation system
|
||
|
6
|
Noise from cooking in the kitchen
|
||
|
7
|
Noise from cleaning dining tools
|
||
|
8
|
Noise from walking
|
||
|
|
Measuring position 1 (606):
|
|
|
Calibration before measurement: 92.5dB
|
Time (min)
|
Leq
|
L10
|
L90
|
Leq (30 min)
|
|
0
|
79.6
|
80.9
|
73.6
|
|
|
3
|
72.8
|
|
||
|
6
|
75.5
|
|
||
|
9
|
79.3
|
|
||
|
12
|
76.4
|
|
||
|
15
|
78.3
|
|
||
|
18
|
70.7
|
|
||
|
21
|
74.7
|
|
||
|
24
|
73.7
|
|
||
|
27
|
77.2
|
|
||
|
30
|
75.5
|
78.3
|
Leq,L10 and L90 against time at 606
|
Measuring position 2 (501):
|
|
|
|
|
|
|||
|
|
|
|
|
|
|
|
|
|
|
|
Time
|
Leq
|
|
L10
|
|
L90
|
Leq
|
Lmax
|
|
|
(min)
|
|
|
|
|
|
(30-min)
|
(30-min)
|
|
|
0
|
81.5
|
|
|
|
|
|
|
|
|
3
|
76.1
|
|
|
|
|
|
|
|
|
6
|
76.4
|
|
|
|
|
|
|
|
|
9
|
77
|
|
|
|
|
|
|
|
|
12
|
76.7
|
|
|
|
|
|
|
|
|
15
|
73.6
|
101.4
|
|
|
76.4
|
|
|
|
|
18
|
80.5
|
|
|
|
|
|
|
|
|
21
|
79.5
|
|
|
|
|
|
|
|
|
24
|
87.6
|
|
|
|
|
|
|
|
|
27
|
73.2
|
|
|
|
|
|
|
|
|
30
|
75.6
|
|
|
|
|
79.5
|
104.9
|
Leq, L10 and L90 against time at 501
Discussion
In a restaurant, the location of seat will be a possible
factor that may affect the representativeness of data.
If choosing the seat that is far from other diners in
the restaurant, the result measured is not
representative because the result cannot reflect the
real situation of noise level, due to the fact that
sound pressure level will be decrease if the sound level
meter is far from the sound source, molecules suspend in
air will adsorb the energy of sound, sound will
gradually weaken. On the other hand, the time slot of
conduct measurement may affect the representativeness of
data, it should not measure in latest afternoon base on
restaurant will have a break in the latest afternoon
generally, the number of diners are rare at that time,
sound level of sound source are not stronger than at
lunch time or dinner time, lead the noise level keep
continue low, it is not representative to the noise
level in the real situation of a restaurant.
The sensitive of sound level meter may be the factor
that affect the representativeness of data, the
sensitive of sound level meter will affect the accuracy
of data measure directly, the data which are not
accuracy is not representativeness. So, to ensure the
sound level meter is sensitive, calibration should be
conduct before measurement and after measurement.
To view about the daily personal noise exposure level,
according to the noise dose set by the International
Organization of ISO, the allowable noise dose set by ISO
will be noise level 85dB during 8 hours currently. The
noise exposure and noise dose that restaurant workers
experience daily are calculate below;
Daily personal noise exposure level: LEP,d=10 log
1/8(10^7.83x8) =78.3
Noise dose：T1=8/2^((78.3-90)/5)
T1=8/0.197510328
T1=40.50421101
D=100x(8/40.50421101)
D=19.7510328%
Daily noise exposure level: 40.50421101dB
Noise dose: 19.7510328%
Noise dose: T2= 8/2^((79.5-90)/5)
T2= 8/0.2332582479
T2= 34.2967507988
D=100x(8/34.2967507988)
D= 23.32582479%
Daily noise exposure level: 34.2967507988dB
Noise dose: 23.32582479%
To comparing the result with the allowable noise dose set by
the International Organization of ISO, the allowable noise
dose set by ISO will be noise level 85dB during 8 hours
currently, at this situation, the noise dose will be 100%.
Look back to the result calculated, the noise dose just
about 19.8% and 23.3% at two measuring position, if an
employee is working in the monitoring location for 8 hours,
it is much lower than the ISO standard.
If the employee work at the workplace with high noise dose
for a long time, it is estimated that the hearing of
employees will be damage. So, if the noise dose of workplace
exceed ISO standard 100% and noise level 85dB during 8
hours, employer should decrease the noise dose exposure
time of employees, make the average level of labor noise
exposure on the eight-hour day of work no more than the
specified value or equivalent dose value to avoid the
hearing damage of employees. For laborers with an average
sound pressure level of more than 85 dB or an exposure dose
of more than 50% on an eight-hour day, workers should wear
effective earplugs, earmuffs and other soundproofing
protective gear.