It can often be difficult to control noise in a workplace
Although health and safety personnel would like all owners of every workplace to control decibel levels, i.e. control noise, this is not always practical. There are certain places where it is not possible to control db levels, although things can be done to try and minimise the impact of the noise.
The decibel (abbreviated dB) is the unit used to measure the intensity of a sound. The decibel scale is a little odd because the human ear is incredibly sensitive. Your ears can hear everything from your fingertip brushing lightly over your skin to a loud jet engine. In terms of power, the sound of the jet engine is about 1,000,000,000,000 times more powerful than the smallest audible sound. That is quite a big difference if you stop to consider.
On the decibel scale, the smallest audible sound (near total silence) is 0 dB. A sound 10 times more powerful is 10 dB. A sound 100 times more powerful than near total silence is 20 dB. A sound 1,000 times more powerful than near total silence is 30 dB.
Before taking field measurements, it is important to determine the type of information required. The person making the measurement must understand certain things such as;
The purpose of measurement: compliance with noise regulations, hearing loss prevention, control noise, community annoyance etc.
The sources of noise, and times when the sources are operating.
The temporal pattern of noise - continuous, variable, intermittent, impulse.
Locations of exposed persons.
The main purposes of noise measurement in occupational settings are to;
Identify overexposed workers and quantify their exposures and
Assess the need both for engineering noise control and the other types of control that are indicated.
Other uses of noise measurement are to evaluate the effectiveness of particular noise controls and to determine the background levels in audiometric rooms.
Measuring Instruments
Sound level meters have built-in frequency weighting devices, which are filters that allow most frequencies to pass while discriminating against others. The most commonly used filter is the A-weighting network, which was developed to simulate the response curve of the human ear at moderate listening levels.
The noise dose meter or “dosimeter” is a form of integrating sound level meter that can be worn in the shirt pocket or attached to the worker’s clothing. Data from the noise dosimeter may be computerized and printed out. Specifications for sound level meters may be found in national and international standards, such as the International Organization for Standardization (ISO).
Some places where it may be difficult to control db level, or control decibel level are things such as the factory floor in a manufacturing plant or the noise near an airport to which employees are exposed. Also some activities when noise levels have to be measured can carry certain risks of exposure to high levels of noise and where it is not possible to control decibels. These activities include: Helmet/cabin/cockpit noise assessment, human acoustic and vibration monitoring, urban, airport, industrial and construction noise monitoring, and vehicle noise mapping.