Are Machinists at Risk from Continuous Exposure to Load Noise during CNC Operations

Document Type:Dissertation

Subject Area:Other

Document 1

This becomes an added cost to the factories, hence the need for proper assessment and consequential control. These hearing problems had been indicated in several industries across the world. This, for instance, Pakistan showing vast implications of noise pollution on its population within the industries. The noise pollution indicates severe consequences on the workers within the industries, with no specific methodology on their damaging capability (Islam 2014, p. This results in problems of increased noise within the industries, that needs some control, to safeguard the workplace and its workers. To be able to provide reliable hearing protectors in protecting the machine operators at the workplace, in ensuring healthy working conditions, from the case CNC Machine sound levels. Literature Review Oishi and Scacht (2011, p.

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237) present the excessive noise causing damage on the ears’ especially on the hair cells presented to them. This indicates the damage caused on the cochlea on the ear of the person. This begins gradually, with encroachment in the verge of increased sound levels. The sound intensity or loudness is measured in Pascal (Pa) or decibels (dB). Human beings indicate acceptance of up to 50 dB. Decibels often show ease at which sound is compressed, within a logarithmic scale of measurement. Noise refers to the undesired or some unattractive sound on machines or planes. This comes from various sources without a proper organisation for instance; computers, television, traffic, human beings and dog barking alongside aeroplanes, animal sounds and industrial machinery. This from the different textile industries in Pakistan, with the workers showing frustrations regarding audibility damages, harming their health standards.

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Working within noisy conditions beyond the acceptance limits promotes health challenges, associated with respiration, nervous system challenges with psychological issues in place. This also increases the chances of cardiovascular diseases having harm on the body of the people working within such settings, especially in case the noise being above 65 dB with its values between 80 to 85 dB (Fritschi et al. 2011, p. Noise pollution comes with challenges of negative responses regarding increased ageing chances, excitement cases, distraction and anger, what may alter the social relations between the different groups of people, and hence behavioural change, as compared to those groups not exposed to the problem of noise pollution. This showed the need for safer working environments in terms of the challenges associated with noise in the different settings at the workplace.

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This backed by the results of the studies from the various scholars conducting the various studies on noise and its effects on people. Babisch et. al (2005, p. 33) in Geneva in the study of noise within the different industries presented interesting findings. This has indicates the need for researchers to focus much on the causes of impairment on the individual workforce, alongside the noise problems through the use of sound lever or dosimeter in measuring the decibel levels of sound. The sound level meter gives another use regarding the collection of frequency information on the frequency information on the octave bands with the varied tonal aspects. This from the differentiated characteristics of noise exposure on different machine users within the industries. This study presents the assessment of the different octave bands that is generated in the operation of the different machines, CNC Machines in particular, on measuring the volume of sound from the different machines.

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This presented within regular working days in establishing the extent of the sound, in terms of noise on the people around the structures within the manufacturing firm. The sources of noise shall be keenly identified, with further analysis of the sound levels by the use of sound level meter in determining the measurements of the Octave Band. 7 Method of Investigation i. In measuring and recording the Octave Band levels from the CNC Machine, the researcher placed the Sound Level Meter at different locations using a tripod standing at 160cm (Human Ear Level) , to enhance the overall measurements of the Octave Band frequencies on the characteristics of noise produced within the workplace, from the CNC Machines while in operation. ii. Mapping of the noise was defined in the form of generation of layout designs that was divided into 18 locations, with the use of the Sound Level Meter, to measure the different Octave Bands from the CNC Machines in operation.

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9 Risks The operation of the CNC Machines may tend to produce tool fragment emissions or flying objects, with the possibility of causing harm to the researcher (CNC Masters 2017, p. Also, CNC Masters (2017, p. 2) indicate the interference of the different moving parts of machines likely to cause them to break down, during the research process. This calls for a machinist with proper knowledge on the working of the CNC Machines involved in the study for technical and engineering support. The machinists must ensure that they put on their personal safety equipment such as footwear hearing guards and safety glasses to protect them against the risks associated with the site in operation. 3 C 48 53 71 81 85 84 81 76 89. 5 D 46 57 74 84 88 87 84 78 92. 5 E 51 51 70 80 84 82 80 74 88. 1 F 54 52 71 81 83 81 75 68 86. 7 G 49 49 68 77 81 79 76 69 84. 5 R 53 53 65 71 75 74 68 59 79. 0 *For Detail Calculation using Hearing Protection Calculator Excel Sheet & Octave Band Method for Location A-R (Refer to Appendix) From the overall result above, the records had shown that from 63 Hz to 125 Hz having an average of 44.

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0 dB to 55. 0 dB. On the other hand, from 250 Hz, 500 Hz, 1 kHz and 2 kHz showing a gradual and consequential increase in dBs respectively only to gradually decrease from 4 kHz to 8 kHz. 1 3 Hours 11 Minutes 8 F 86. 6 6 Hours 21 Minutes 8 G 84. 9 8 Hours 8 H 85. 2 6 Hours 21 Minutes 8 I 81. 5 16 Hours 8 J 87. For Location H and Location J, although the A – Weighted are above 85 dB, both points are located along the walkway. Octave Band Method. Using the Hearing Protection Calculator Excel Sheet downloaded from http://www. hse. gov. 0 dB, then 125 Hz having 57. 0 dB. On the other hand, 250 Hz recorded 74. 0 dB, 500 Hz indicating 82 dB with I kHz and 2 kHz showing the highest record of 87 and 86 Db respectively. Consequential increase in frequency beyond 2 kHz to 4 kHz indicated 81. 7 dB (A). Octave Band Centre Frequency 63 125 250 500 1000 2000 4000 8000 LA' (dB) 18.

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3 To work out the SPL of at the ear, we shall use all the values in the table using the formula: = 69. 91 dB 12 Discussions 1- Comparison between the Current Hearing Protection Model and another Leading Hearing Protection Model for more appropriate hearing protector selection for the machinists. Current Brand - 3M Clear E-A-R Earplugs Attenuation Values: Other Brand – Moldex Rockets Attenuation Values Using the SNR method The Single Number Rating (SNR) method is the simplest form of calculation. Avoid protectors resulting in less than 70 dB at the ear - this is 'over-protection' Based on the results for both brands, its indicates that the current brand hearing protection gives adequate protection and does not ‘over-protected’ the employees. But for the other leading brand, it shows that hearing protection is ‘over-protected’ the employees.

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Simply ‘Providing the Best’ and ‘over-protected’ the employee will generate other associated problems. Excessive reduction of the noise can instill a feeling of loneliness in which the employees may need to remove their Personnel Hearing Device in order to communicate with other fellow employees. 2- Comparison between using the Octave Band Method and SNR (Single Number Rating) Method for more appropriate hearing protector selection for the machinists. 6 A- Weighting factors 26. 1 To get the LA’, A-weighting factors, we use the Assumed protective value and Sound Pressure Level. For instance, for 63 Hz frequency, we have: LA’=46-2. 7 dB (A). Octave Band Centre Frequency 63 125 250 500 1000 2000 4000 8000 LA' (dB) 17. The current hearing protection used by the machinists is currently sufficient based on the research but the mandatory period on the use of the hearing protection indicated only during the operating of the CNC Machines.

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Also, from the research stated, if the machinists are wearing the hearing protection at other locations, they are overprotected. In many cases, it is shown that ‘overprotected’ employees are incapable of communicating with each other efficiently, it’s not unusual for the Hearing protection to be removed for oral communications. These defeats the resolution of the hearing protection and jeopardises the employee from needless noise experience. Incapability to communicate with each other may also lead to misinterpretation among employees, triggering blunders, loss of production, amplified stress among the employees, and may increase workplace accidents (Alan Davis, 2015). Warning Signages The organisation should also put up additional proper warning signage to mark out in the workplace the hearing protection zones where Hearing Protection must be worn.

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Emphasis should be placed on strategic locations such as machine area, production entrances or worktable. A copy of the noise map to be placed on the entrances of the premises, notice boards and rest areas so create awareness/remind the machinists and other employees to take appropriate action prior entering these zones. Hearing Protection Training The main objective for this training aims to ensure that the employees know how to use, select, maintain, and wear correctly. It’s also trained the employees on how to check for defects and acquire new Hearing Protection. sensear. com/blog/hearing-protection%E2%80%93can-you-have-too-much Babisch, W. , Beule, B. , Schust, M. , Kersten, N. cncmasters. com/blog/safety-tips-for-operating-a-cnc-machine. html. Accessed 19 Jul. Fritschi, L. D. , & Langdon, F. J. Subjective response to road traffic noise.

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Journal of Sound and Vibration, 8(1), 16-32. Noise and vibration characteristics of permanent-magnet synchronous motors using electromagnetic and structural analyses.  IEEE Transactions on industry applications, 50(5), pp. Klaboe, R. , Engelien, E. , Steinnes, M. Masterson, E. A. , Tak, S. , Themann, C. L. Oishi, N. and Schacht, J. Emerging Treatments for Noise-Induced Hearing Loss. Expert Opinion on Emerging Drugs, 16(2), pp. 235-245 Ristovska, G. Stansfeld, S. A. and Matheson, M. P. Noise Pollution: Non-Auditory Effects on Health. 16 Appendix Octave Band Report & Octave Band Method - Location A – R (Full Calculation) The individual research shows the results recorded at the different locations of the CNC Machine environment. The Octave Band will be calculated using Hearing Protection Calculator Excel Sheet downloaded from http://www. hse. gov. uk/noise/calculator.

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0 dB and 16 kHz indicating 64. 0 dB. This graph indicates that the situation in the CNC Machines provided for the highest frequency at 1 and 2 kHz frequencies, showing the highest levels of sound recorded. Octave Band Calculation for location A: Octave band Calculation for Location A. Based on the calculation, the current hearing protection gives adequate protection and does not ‘over-protected’ the user. 0 dB, then 125 Hz having 56. 0 dB. On the other hand, 250 Hz recorded 72. 0 dB, 500 Hz indicating 81. 0 dB with I kHz and 2 kHz showing the highest record of 86. 6 A- Weighting factors 26. 1 To get the LA’, A-weighting factors, we use the Assumed protective value and Sound Pressure Level. For instance, for 63 Hz frequency, we have: LA’=43-2. 7 dB (A). Octave Band Centre Frequency 63 125 250 500 1000 2000 4000 8000 LA' (dB) 14.

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0 dB respectively. Consequential increase in frequency beyond 2 kHz to 4 kHz indicated 81. 0 dB, 8 kHz showing 76. 0 dB and 16 kHz indicating 63. 0 dB. 94 dB Location D Output for location D From the graph, the record begins at 31. 5Hz showing 50. 0dB, followed by 63 Hz having 46. 0 dB, then 125 Hz having 57. 0 dB. Octave Band Calculation for location D: Octave band Calculation for Location D. Based on the calculation, the current hearing protection gives adequate protection and does not ‘over-protected’ the user. Calculation Formula for Location D: Table 4: Sound Intensity Results Octave Band Centre frequency 63 125 250 500 1000 2000 4000 8000 Sound pressure Level (dB) 46 57 74 84 88 87 84 78 or the protection equipment found, we have: Octave Band Centre Frequency 63 125 250 500 1000 2000 4000 8000 Assumed Protection value APV (dB) 2. 6 A- Weighting factors 26. 1 To get the LA’, A-weighting factors, we use the Assumed protective value and Sound Pressure Level.

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0 dB, 500 Hz indicating 80. 0 dB with I kHz and 2 kHz showing the highest record of 84. 0 and 82. 0 dB respectively. Consequential increase in frequency beyond 2 kHz to 4 kHz indicated 80. 7 dB (A). Octave Band Centre Frequency 63 125 250 500 1000 2000 4000 8000 LA' (dB) 22. 3 To work out the SPL of at the ear, we shall use all the values in the table using the formula: = 66. 84 dB Location F Output for location F From the graph, the record begins at 31. 5Hz showing 46. 0 dB and 16 kHz indicating 51. 0 dB. This graph indicates that the situation in the CNC Machines provided for the highest frequency at 1 and 2 kHz frequencies, showing the highest levels of sound recorded. Octave Band Calculation for location F: Octave band Calculation for Location F. Based on the calculation, the current hearing protection gives adequate protection and does not ‘over-protected’ the user.

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0 dB, then 125 Hz having 49. 0 dB. On the other hand, 250 Hz recorded 68. 0 dB, 500 Hz indicating 77. 0 dB with I kHz and 2 kHz showing the highest record of 81. 6 A- Weighting factors 26. 1 To get the LA’, A-weighting factors, we use the Assumed protective value and Sound Pressure Level. For instance, for 63 Hz frequency, we have: LA’=49-2. 7 dB (A). Octave Band Centre Frequency 63 125 250 500 1000 2000 4000 8000 LA' (dB) 20. 0 dB respectively. Consequential increase in frequency beyond 2 kHz to 4 kHz indicated 77. 0 dB, 8 kHz showing 72. 0 dB and 16 kHz indicating 60. 0 dB. 53 Db Location I Output for location I From the graph, the record begins at 31. 5Hz showing 46. 0dB, followed by 63 Hz having 50. 0 dB, then 125 Hz having 44. 0 dB. Octave Band Calculation for location I: Octave band Calculation for Location I. Based on the calculation, the current hearing protection is ‘over-protected’ the user.

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Calculation Formula from Location I: Table 9: Sound Intensity Results Octave Band Centre frequency 63 125 250 500 1000 2000 4000 8000 Sound pressure Level (dB) 50 44 68 75 78 75 72 65 or the protection equipment found, we have: Octave Band Centre Frequency 63 125 250 500 1000 2000 4000 8000 Assumed Protection value APV (dB) 2. 6 A- Weighting factors 26. 1 To get the LA’, A-weighting factors, we use the Assumed protective value and Sound Pressure Level. 0 dB, 500 Hz indicating 79. 0 dB with I kHz and 2 kHz showing the highest record of 83. 0 and 82. 0 dB respectively. Consequential increase in frequency beyond 2 kHz to 4 kHz indicated 80. 7 dB (A). Octave Band Centre Frequency 63 125 250 500 1000 2000 4000 8000 LA' (dB) 21. 3 To work out the SPL of at the ear, we shall use all the values in the table using the formula: = 65. 99 dB Location K Output for location K From the graph, the record begins at 31.

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5Hz showing 46. 0 dB and 16 kHz indicating 57. 0 dB. This graph indicates that the situation in the CNC Machines provided for the highest frequency at 1 and 2 kHz frequencies, showing the highest levels of sound recorded. Octave Band Calculation for location K Octave band Calculation for Location K. Based on the calculation, the current hearing protection is ‘over-protected’ the user. 0 dB, then 125 Hz having 48. 0 dB. On the other hand, 250 Hz recorded 69. 0 dB, 500 Hz indicating 75. 0 dB with I kHz and 2 kHz showing the highest record of 76. 6 A- Weighting factors 26. 1 To get the LA’, A-weighting factors, we use the Assumed protective value and Sound Pressure Level. For instance, for 63 Hz frequency, we have: LA’=53-2. 7 dB (A). Octave Band Centre Frequency 63 125 250 500 1000 2000 4000 8000 LA' (dB) 24. 0 Db respectively. Increase in frequency beyond 2 kHz to 4 kHz indicated 74.

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0 dB, 8 kHz showing 67. 0 dB and 16 kHz indicating 51. 0 dB. 8 dB Location N Output for location N From the graph, the record begins at 31. 5Hz showing 50. 0dB, followed by 63 Hz having 50. 0 dB, then 125 Hz having 55. 0 dB. Octave Band Calculation for location N Octave band Calculation for Location N. Based on the calculation, the current hearing protection is ‘over-protected’ the user. Calculation Formula from Location N: Table 14: Sound Intensity Results Octave Band Centre frequency 63 125 250 500 1000 2000 4000 8000 Sound pressure Level (dB) 50 55 70 76 80 77 74 69 or the protection equipment found, we have: Octave Band Centre Frequency 63 125 250 500 1000 2000 4000 8000 Assumed Protection value APV (dB) 2. 6 A- Weighting factors 26. 1 To get the LA’, A-weighting factors, we use the Assumed protective value and Sound Pressure Level. 0 dB, 500 Hz indicating 74. 0 dB with I kHz and 2 kHz showing the highest record of 77.

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0 and 74. 0 Db respectively. Increase in frequency beyond 2 kHz to 4 kHz indicated 71. Octave Band Centre Frequency 63 125 250 500 1000 2000 4000 8000 LA' (dB) 15. 3 To work out the SPL of at the ear, we shall use all the values in the table using the formula: = 60. 51 dB Location P Output for location P From the graph, the record begins at 31. 5Hz showing 50. 0dB, followed by 63 Hz having 51. 0 dB. This graph indicates that the situation in the CNC Machines provided for the highest frequency at 1 and 2 kHz frequencies, showing the highest levels of sound recorded. Octave Band Calculation for location P Octave band Calculation for Location P. Based on the calculation, the current hearing protection is ‘over-protected’ the user. Calculation Formula from Location P: Table 16: Sound Intensity Results Octave Band Centre frequency 63 125 250 500 1000 2000 4000 8000 Sound pressure Level (dB) 51 56 71 77 82 78 74 69 or the protection equipment found, we have: Octave Band Centre Frequency 63 125 250 500 1000 2000 4000 8000 Assumed Protection value APV (dB) 2.

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0 dB. On the other hand, 250 Hz recorded 66. 0 dB, 500 Hz indicating 72. 0 dB with I kHz and 2 kHz showing the highest record of 77. 0 dB each. For instance, for 63 Hz frequency, we have: LA’=52-2. 7 dB (A). Octave Band Centre Frequency 63 125 250 500 1000 2000 4000 8000 LA' (dB) 23. 3 To work out the SPL of at the ear, we shall use all the values in the table using the formula: = 59. 8 dB Location R Output for location R From the graph, the record begins at 31. 0 dB, 8 kHz showing 59. 0 dB and 16 kHz indicating 47. 0 dB. This graph indicates that the situation in the CNC Machines provided for the highest frequency at 1 and 2 kHz frequencies, showing the highest levels of sound recorded. Octave Band Calculation for location R Octave band Calculation for Location R.

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