NOISE
Human being has five sense organs that can take the information from the environment in order to process in to your brain. Hearing belongs to five senses, our ears have the ability to detect sound even if it’s unwanted sound like noise but it can’t impede the sound passing through it.
Noise is unwanted sound and common occupational hazard in large number of workplaces like manufacturing, foundries, steel industry etc. The Industrial noise generate by different sources such as crushing, punching, shearing, pressing, grinding, milling and drilling. Also, Industrial machinery generates noise by using compressor, rotors, electrical machines etc.
According to studies in Germany and other industrialize country, 12% to 15% of employed person exposed in noise or more than 85 dB(A) on average daily working operation. After a few years of exposure, unfortunately results into noise-related hearing impairment and that portion would equivalent to 4 to 5 million persons in Germany.
Type of Noise:
1. Continuous Noise is the type of noise level generated by the machine which is running continuously without interruption. This noise could be heard usually in manufacturing industry.
2. Intermittent Noise is the type of noise level that rapidly changes and increases or decreases. This noise could be heard usually in factory equipment that operates.
3. Impact Noise is the type of noise level generated when an object impacts transmitted to other things that can generate sound.
Why we need to measure the noise on the workplace?It’s important to measure the noise level considering the duration of worker performing the activity near the source of noise. In order to know who may need a noise control program and also it helps to identify the work locations that can generate the noise. Did you know that you are not noise safe even if you don’t work in manufacturing industry?
Based on the study of Indoor Air Quality Health and Safety Guide, CCOHS, even if you’re not in this type of industry you are affected by noise like in offices. In addition, the noise level in office environment is not enough to cause a hearing loss. In contrast, this level of sound can contribute to stress, discomfort, reduce productivity and cause disruption of work.
Based on Indoor Air Quality Health and Safety Guide, (CCOHS) very few people, when the noise level below 45 dB(A) feels disturbed, also 55 dB(A) about half of people feel some amount of disturbance. Considering all this factors the recommended noise level in offices should not exceed 50 dB(A).
There are no specific noise regulations in offices. But there are guidelines recommended noise limits in offices. In contrast, this is not legal requirement in terms of noise level in offices.
Noise readings were taken on areas with processes and equipment that generate noise. Sound levels are measured by holding the measuring instrument near the worker’s hearing zone when conducting the activity. Evaluations of results are in accordance to the Permissible Noise Exposure Limit or PNEL for continuous noise under Rule 1074 of the Occupational Safety and Health Standards, as shown below. Exposure to impact or impulsive noise must not exceed 140 dB sound level.
Permissible Noise Exposure Limit, OSHS Rule 1074 (Table 8b)
| Duration per day, hours | Sound Levels, dBA |
| 8 | 90 |
| 6 | 92 |
| 4 | 95 |
| 3 | 97 |
| 2 | 100 |
| 1 ½ (90 mins) | 102 |
| 1 | 105 |
| ½ (30 mins) | 110 |
| ¼ (15 mins) | 115 |
However, the PNEL values do not apply for offices. The Canadian Centre for Occupational Health and Safety (CCOHS) recommends a maximum of 50 dBA for offices based on the Indoor Air Quality Health and Safety Guide.
POSSIBLE HEALTH EFFECTS OF NOISE
Hearing impairment is the worst effect of occupational noise. Permanent hearing loss is caused by long-term exposure to excessive noise.
The scientific evidence that excessive noise causes physiological damage to the human hearing mechanism is incontrovertible. Such hearing impairment is known as noise induced hearing loss (NIHL) that often progresses slowly over many years and may go unnoticed until permanent damage has occurred.
Excessive exposures to noise are probably the most common cause of hearing loss due to damage of the inner ear. In general terms, prolonged exposure to sound levels of more than 85 dB(A) (based on international standard) is potentially hazardous although the important factor is the total amount of exposure given by the level and length of exposure time.
The World Health Organization states “noise-induced hearing loss is insidious, permanent, and irreparable. In a developed country, exposure to excessive noise is at least partially the cause in more than one third of those in the population who have hearing loss.
Noise-induced hearing loss is the most prevalent irreversible industrial disease and noise is the biggest compensable occupational hazard”.
Noise prevention measures designed into machines, workstations and places of work and the selection of work equipment, procedures and methods so as to give priority to reducing the noise at source is the more effective method for reducing exposure to noise.
The approach of collection preventive measures over personal protection measures should be strongly promoted; particularly as recent research results have shown that the overall application of personal hearing protection is generally not very successful in avoiding hearing losses.
Employers should make adjustments in the light of technical progress and scientific knowledge of risks related to exposure to noise, with a view to improving the health and safety protection of workers.
An effective noise reduction program includes:
- Noise control by engineering and design;
- Organizational and administrative noise control measures;
- Adequate information and training to instruct workers to use work equipment correctly in order to reduce their exposure to noise to a minimum and only as a last resort;
- Individual protection measures.
References:
https://www.who.int/occupational_health/publications/noise5.pdf
https://www.ccohs.ca/oshanswers/phys_agents/noise_measurement.html
https://www.cirrusresearch.co.uk/blog/2015/01/4-different-types-noise/
IAQ Health And Safety Guide - CCOHS.pdf
