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Measurement of Noise in the Workplace: Area Monitoring The Purpose of the Assessment: •

To conduct an area monitoring (noise monitoring) at Utusan Melayu factory, Bangi, Selangor.

Objectives: i.

To define the noise problem and provide the source for a noise measurement and control plan.

ii.

To identify the specific noise sources within the area.

iii.

To draw a layout of the area with machinery location.

iv.

To sketch noise contours of below 80dB(A), 80dB(A) to 84dB(A), 85dB(A) to 89dB(A) and 90dB(A) and above on the layout plan.

v.

To determine whether any of the employees are exposed to noise greater than action level of 85 dB(A) at a particular workplace.

Introduction: Physically, there is no difference between sound and noise.

Sound is a

sensory perception and noise corresponds to undesired sound. By extension, noise is any unwarranted disturbance within a useful frequency band (NIOSH, 1991).

Noise is present in every human activity, and when assessing its

impact on human well-being it is usually classified either as occupational noise (i.e. noise in the workplace), or as environmental noise, which includes noise in all other settings, whether at the community, residential, or domestic level (e.g. traffic, playgrounds, sports, music) (de Hollander et al., 2004). Occupational noise exposure occurs when the ears of an exposed employee is subjected to sound from background noise and vibrating objects such as high speed rotating machines, air flow and friction or mechanical

impacts involved in machine operation. From the source, noise spread out as a series of air pressure fluctuations known as sound waves.

When a

sound waves strikes our ear, then hearing mechanism takes place (Frederick, 1975). Area monitoring is an assessment of identifying the noise created by the machineries operation within the particular area which may greater than action level of 85 dB(A) or exceeding the Permissible Exposure Limit (PEL) of 90 dB(A). The assessment of noise survey has been conducted at Utusan Melayu factory. A walk through assessment was done for the beginning in order to define the noise problem and provide some basis for noise measurement and control plan. Besides that, we want to be familiarized with the plant and machine’s location. This assessment can be considered as an informal audit of noise source, possible noise controls and also the management action taken in order to reduce noise exposure. The purpose of this area monitoring assessment is to determine whether any of employees working surround or merely near with the printing machine is exposed to noise greater than the action level of 85 dB(A). The Factory & Machinery (Noise Exposure) Regulation 1989 clearly stated that all employers are to reduce and control the workers exposure to a noise level below the permissible exposure limit of 90 dB (A) for 8 working hours. The higher the sound level, the shorter the duration of exposure is permitted.

In an area monitoring, measurements of environmental noise levels are recorded using a sound level meter to identify work areas where employees' exposures may be above hazardous levels, and where more thorough exposure monitoring may be needed. Area monitoring is conducted using a calibrated sound level meter set to the A scale, slow response. Within the area of interest, several different locations will be measured. Typical measurement locations would include the hearing zone at the employee's normal work location, next to the noise source(s), at the entrance(s) to the work area or at other locations within the area where the employee might work. A rough sketch of the area will be included with the results showing the locations where the noise readings were obtained. The collected data was interpreted into noise contour mapping. The purpose of work field assessment by providing the noise contour mapping is to identify the source of noise and the exposure levels at different locations within the workplace. However, since our group only done an assessment at one source of noise (the machine), thus our purpose for making a noise or sound contour mapping is to identify the exposure levels

from a source of noise at that particular workplace area. The instrument which has been used to measure the noise exposure level is Sound Level Meter (SLM). A sound level meter (SLM) is a device that we used to measures the intensity of sound at a given moment. Since sound level meters provide a measure of sound intensity at only one point in time, it is generally necessary to take a number of measurements at different times during the day to estimate noise exposure over a workday. If noise levels fluctuate, the amount of time noise remains at each of the various measured levels must be determined. To estimate employee noise exposures with a sound level meter it is also generally necessary to take several measurements at different locations within the workplace.

After appropriate sound level meter readings are

obtained, people sometimes draw “maps” of the sound levels within different areas of the workplace. By using a sound level “map” and information on employee locations throughout the day, estimates of individual exposure levels can be developed. This measurement method is generally referred to as area noise monitoring. As an overall, this area monitoring can be used to estimate noise exposure when the noise levels are relatively constant and employees are not mobile. In workplaces where employees move about in different areas or where the noise intensity tends to fluctuate over time, noise exposure is generally more accurately estimated by the personal monitoring approach.

Figure: Part of Sound Level Meter Problem Statement: The review of the literature indicates that noise has a series of health effects, in addition to hearing impairment. Some of these, such as sleep deprivation, are important in the context of environmental noise, but are less likely to be associated with noise in the workplace. Other consequences of workplace noise, such as annoyance, hypertension, disturbance of psychosocial wellbeing, and psychiatric disorders have also been described (de Hollander et al., 2004). For occupational noise, the best characterized health outcome is hearing impairment.

The first effects of exposure to excess noise are

typically an increase in the threshold of hearing (threshold shift), as assessed by audiometry.

This is defined as a change in hearing thresholds of an

average 10 dB or more at 2000, 3000 and 4000 Hz in either ear (poorer hearing) (NIOSH, 1998). The consequences of noise induced hearing loss (NIHL) includes social isolation, impaired communication with coworkers and family, decreased ability to monitor the work

environment (warning signals, equipment

sounds), increased injuries from impaired communication and isolation, anxiety, irritability and decreased self-esteem, lost productivity, and also

expenses for workers’ compensation and hearing aids (de Hollander et al., 2004).

Methodology: The area monitoring was conducted at Utusan Melayu factory in Bangi, Selangor which performed at 30th September 2009. A walk-through assessment was done first by all group members in order to define the noise problem and the source for noise measurement and control plan. Once the source was identified, then the layout of the area with machinery location is drawn. The data which come out from the instrument used were jotted down. Then, the noise contours of below 80 dB(A), 80 dB(A) to 84 dB(A), 85 dB(A) to 89 dB(A), and 90 dB(A) and above were sketched on the plan which later are colored for identification. The measurement was conducted by walking with the meter (SLM) through the marks distance from the noise source (the machine) for each noise contour being measured. Then, all the points for each contour are jointed to complete the zone. Instrument: Sound Pro Quest SLM was used along our assessment in order to identify the sound level of noise around the source (machine) that generates hazardous levels of noise. Quality Control: The SLM was calibrated first according to the user manual using “Quest Standard Calibrator” before use. When measuring the noise emitted from the machine, background noise was taken into consideration. Background noise was measured when the machine was turned off while the sound level

of machine was measured when the machine was turned on.

The sound

level obtained will be corrected using a curve provided in the user manual to eliminate the background noise

Results: i)

To define the noise problem and provide the source for a noise measurement and control plan. Based on our walk-through assessment, we managed to identify the

machine as the source of noise. Noise level surround the machine were around 80 dB(A) to 90 dB(A). The working area (WA) that the worker have to be is divided into WA1 and WA3 which noise exposure are in range 80 dB(A) to 84 dB(A) while the WA2 is in range 85 dB(A) to 89 dB(A). There are two workers were working at WA1, two worker were working at WA2 and six to eight worker were perform their work at WA3. This finding indicates that some control measure must be done to reduce the risk of hearing loss among the workers whose perform their work at WA2 which noise exposure are in range 85 dB(A) to 89 dB(A). Based on Noise Regulation, this is an action limit which the hearing conservation program should be done for that worker.

ii)

To identify the specific noise sources within the area.

We have found and identified a noise source within the area. It is comes out from a machine which the only one that run on that moment on that particular monitoring area. iii)

To draw-out a layout of the area with machinery location.

The wall

The run machine (noise source) Scale Scale is is 11 cm cm :: 11 m m

iv)

To sketch noise contours of below 80dB(A), 80dB(A) to 84dB(A), 85dB(A) to 89dB(A) and 90dB(A) and above on the layout plan.

WA 2 WA 3

WA 1

v)

To determine whether any of the employees are exposed to noise greater than action level of 85 dB(A) at a particular workplace.

Since there are two workers whose perform their work at WA2 which noise exposure is range between 85 dB(A) to 89 dB(A), thus both of them are exposed to noise greater than action level. There are no any worker who work at area with 90 dB(A) and above based on our observation during workthrough survey.

Discussion: The assessment of noise exposure monitoring was done successfully by making a noise contour mapping based on the data and information given from reading which directly shown on the screen of Sound Pro Quest SLM on 30th September 2009 (the day where the assessment was done). This result is actually totally depends on the working conditions during the days. This is because, although there are lot of operational machines such as for printing

and transferring the paper, but not the entire machine were runs simultaneously. In our point of view and also based on our study, we are assume that, if there are lot of machines were operated in the same time, the noise exposure level might be arise over the action level at 85 dB(A) or possibly exceed than Permissible Exposure Limit (PEL) at 90 dB(A) or above. But, since there is only one machine was operated on that time (period of the assessment was done), thus the noise exposure level might be possibly low and acceptable. However, if this result was not complied with daily occupational noise exposure, then this report can be considered as null and void. Based on the result, there are only two routine workers which exposed to noise exposure which greater than action level of 85 dB(A). Therefore, there is need for periodic personal noise exposure monitoring to be carried out for them in order to indicate the extent of the severity of an employee’s noise exposure. Fortunately, there is no any worker need to perform their work at area which exceeded PEL of 90 dB(A) and also not too many worker were expose to noise exposure which greater than action level of 85 dB(A). Most of the worker were perform their work routinely at the acceptable area which noise exposure level is in range between 80 dB(A) to 84 dB(A). By referring to the map, we can see that there is an area with noise which reach or exceed 90 dB(A)(red zone). From our observation then followed by some interview session, there were two additional motors which functioning as additional power supply to the machine. Besides that, the location of the machine near to the concrete wall might be a contributor to the high level of noise (green zone as 85 to 89 dB(A). Fortunately, there are no workers in red zone.

noise level at or exceed

concrete wall

Based on the requirement of Factory and Machinery (Noise Exposure) Regulation 1989, if the noise levels are below 85 dB(A) on a time-weighted average basis in the area, no further routine monitoring will be required for that area. Should any of the noise measurements equal or exceed 85 dB(A), records shall be maintained as to the noise levels recorded, where they were taken, and the source(s) of the noise. These records shall be updated at least once every two years to determine if any changes have occurred that would warrant re-monitoring of exposed personnel. If any of the measurements equal or exceed a noise level of 85 dB(A), employees who work in or near the high noise area or equipment shall have their noise exposure determined through personnel monitoring using noise dosimeters (NDM).

Since only two workers are exposed to noise exposure at or greater than action level of 85 dB(A) while most of them working at acceptable noise exposure, their employer still provide the personal protective equipment (PPE) like ear plug or ear muff in order to prevent all the employees from suffering or exposed to noise which possibly harm the hearing ability at the future. There is a scenario at Utusan Melayu factory which we were told by the employer

itself

that

there

is

some

control

measure

which

already

implemented on that particular area (which noise exposure level was taken). At first, the employees were provided an ear plug for each of them. However, the employees refuse to use in order the difficulties to communicate with each other to perform their task because they need to remove the ear plug first. This action increases another awareness which is the contamination of ear plug because they need to touch the ear plug with contaminated hand or finger (since they also have contact with a lot of solvent). Thus, the employees than were provided with ear muff. However, they claim that the ear muff likely to gift some stress towards their head (bone around ears) which causing headache since they need to used it almost 8 hours per day. Then, the employees were provided other type of ear plug which likely more preferable (although less efficient from the first one). But still, most of the workers still not use the PPE given because they might not aware about their health especially the hearing site which might be possibly affected day by day because of expose to noise (which sometime reach action level or exceed PEL)routinely. Recommendations:

There is some recommendation that we would like to suggest for the employer for this Utusan Melayu factory which listed as below. However, if not practicable the suggestion can be neglected. Since the elimination of noise source (the machine) likely not practicable for this factory, the substitution of the machine with the new machine which produce a lower sound might be practicable if the financial status is good. However, if that particular machine is a new one, then no need to replace it. An installation of noise absorbing material in the wall then can be applied as one of the engineering control. The reason for this suggestion is an absorbing material such as acoustical foam. This noise absorber is designed to reduce reflected noise and dissipate noise energy. The open cell structure of acoustical foam dissipates noise energy to control harsh reflected noise and reverberations in enclosed surroundings (Netwell: Noise Control Solutions, 2000). Since there are only involve a small range of worker around the machine, may be the exposure duration of the employee can be decreased by applying a work-shift. However, if all of these are not practicable, the Personal Protective Equipment (PPE) should be introduced. Type of PPE is hearing protection devices (HPDs) which are earplugs and earmuffs. Earplugs can be made of foam or a polymer. Foam plugs are shaped like small cylinders that you roll and compress then insert into your ear canal. Polymer plugs are "rubbery" and have flanges or fins. Earmuffs have a cup design with noise dampened cushions that surround the ear to seal off noise. Some earmuffs are designed to accommodate hardhats. Some allow radio communication with others who have the same type of earmuffs. Custom earplugs are custommade for your ears by an audiologist. Custom earplugs are comfortable and provide maximum protection.

However, the factory should choose an appropriate noise reduction rating of the ear plug. NRR is the greatest amount of sound reduction that a hearing protection device can provide. A higher NRR decibel (dB) rating means a greater amount of noise reduction. For example, an earplug with a noise reduction rating of 29 dB provides more protection than an NRR 25 earplug. We would like to suggest the appropriate NRR is NRR 20 which can reduce the exposure toward noise until 83.5 dB(A) ≈ 84 dB(A), which is under action level for noise.

The NRR calculation:NRR – 7 = x x/2=w SPL – w = y

20 – 7 = 13 13 / 2 = 6.5 90 – 6.5 = 83.5 ≈ 84 dB(A)

It is known that the PPE is already introduced to the whole worker. However, most of them are not using the PPE given (ear muff or ear plug) until some of them require a medical treatment due to the hearing loss (told by the employer itself). Thus, we would like to suggest that the implementation of using PPE should be more stringent to ensure that entire worker follow the direction. It is more worthy if the factory only spends the money to buy the PPE rather than the payment of medical fees which possibly increases from times to times. Conclusion: Our assessment of noise exposure of area monitoring which done at Utusan Melayu factory have indicated that most point of measurement are in range between 80 dB(A) to 84 dB(A) which no further routine monitoring will be required for that particular area. However, for the area which noise exposure level above action level of 85 dB(A) likes WA2, further personal noise monitoring must be carried out for those workers to indicate the extent of

the severity of an employee’s noise exposure by using noise dosimeter (NDM) instrument (under the Factories and Machinery (Noise Exposure) Regulation 1989). References: 1) Part 380. Occupational Noise Exposure (online). Retrieved September 4, 2009 from The Department of Labor & Economic Growth, Michigan Occupational Safety and Health Administration. Available at http://www.michigan.gov/mioshastandards 2) Campbell-Lendrum, D. (n.d.). (2004). Occupational Noise: Assessing The Burden of Disease From Work-Related Hearing Impairment at National and Local Levels (series no. 9) (online). Retrieved October 28, 2009 from World Health Organization, Protection of the Human Environment, Geneva 2004. Available at http://www.who.int/quantifying_ehimpacts/publications/en/ebd9.pdf 3) John Wertel (May, 2000). Experimental Analysis of Noise Reduction: Properties of Sound Absorbing Foam by Scotty. Retrieved November 5, 2009 from The Graduate College University of Wisconsin-Stout. Available at http://www.uwstout.edu/lib/thesis/2001/2001wertels.pdf 4) NIOSH (1972). “Criteria for a Recommended Standard: Occupational Exposure to Noise (Revised Criteria 1998).” U.S. Department of Health, Education, and Welfare, National Institute for Occupational Safety and Health, DHEW (NIOSH) (Publication No. HSM 73-ll00l, Cincinnati, OH). 5) Nims D. K. (1999). Basics of Industrial Hygiene. Canada: John Wiley & Sons, Inc.

6) Martin B. Stern, S. M. (1999). Applications & Computational Elements of Indutrial Hygiene. U.S.A: Lewis Publisher (imprint of CRC Press LLC).