The most crucial aspect of a workplace hearing conservation and noise control program is measuring noise levels and workers' noise exposures, which helps identify work locations with noise issues, employees who may be exposed to noise levels that can cause hearing loss, where additional noise measurements need to be made, and where appropriate noise control measures need to be implemented.
How is noise in the workplace measured?
The first step is to determine if there is a noise problem in the workplace. This document briefly outlines the steps involved in the noise measurement. For details, you should consult the most recent edition of the Canadian Standard CSA Z107.56-13 ().
How might noise issues at work be identified?
The first step is to ascertain whether or not noise is a potential issue in your workplace. A walk-through survey is advised. The indicators of potentially hazardous noise level include: Noise is louder than busy city traffic. People must raise their voice to speak to someone at one metre (3 feet) away. At the end of work shift, people must turn up their radio or TV to a level that is too loud for others. After working there for a few years, it becomes difficult to concentrate on work.
What factors are taken into account while planning a noise measurement?
The person taking the measurement must understand the following before taking field measurements: The purpose of measurement: compliance with noise regulations, hearing loss prevention, noise control, community annoyance, etc. The sources of noise, and times when the sources are operating. The temporal pattern of noise - continuous, variable, intermittent, impulse.
What kind of equipment is used to measure noise?
The sound level meter (SLM), integrating sound level meter (ISLM), and noise dosimeter are the three most popular instruments used to measure noise. It is crucial that you comprehend the calibration, operation, and reading of the instrument you use. The user's manual provided by the instrument manufacturer provides the majority of this information. Table 1 provides some instrument selection guidelines.
What is an SLM, or sound level meter?
The SLM is made up of a microphone, electronic circuitry, and a readout display. The readout displays the sound level in decibels after the instrument's electronic circuitry processes the electrical signals that the microphone converts into after being processed by it. The SLM measures the sound pressure level at a specific location and time while being held at arm's length at the ear.
An ISLM stands for an integrating sound level meter.
The major distinction between the integrating sound level meter (ISLM) and the dosimeter is that the ISLM determines equivalent sound levels at a specific location, yields a single reading of a given noise, even if the actual sound level of the noise changes continuously, and does not provide personal exposures because it is hand-held like the SLM and not worn.
A noise dosimeter is what?
A noise dosimeter is a small, lightweight device that the worker wears, with the microphone placed above the outside edge of the wearer's shoulder, close to their ear. The dosimeter stores the noise level information and performs an averaging process. It is useful in industry where noise typically varies in duration and intensity, and where the person changes locations.
When should a windscreen be used?
To prevent the impact of wind, one employs a windshield or windscreen to cover the microphone in regions with significant air movement. Wind shields or screens are available from manufacturers of sound level meters. When air blows by the microphone, the noise reading is altered.
What methods are employed to measure noise?
In a bottle washing and filling facility in Ontario, for example, the noise levels vary over the course of the work shift. Instantaneous noise measurements, taken with an SLM (Type 2, SLOW RESPONSE, A-filter), at one person's work station, ranged from 63 dBA to 135 dBA.
How is impact/impulse noise analyzed?
Before measuring impulse or impact noise, make sure that the equipment can measure this type of noise. Typically measurements of either peak noise levels together with the actual number of peaks, or percentage dose, or equivalent sound levels are required. Where there is little background noise, as there might be on an outdoor rifle range, the measuring of peak peak noise levels with the actual number of peaks is required.
A frequency analysis is what?
Frequency analysis is the process of measuring noise level at each frequency or pitch. Frequency analysis is not necessary when the goal of noise measurement is to determine compliance with regulatory exposure limits or to determine the risk of hearing loss; instead, the A-weighted noise level in dBA, percent noise dose, or time-weighted average (TWA) equivalent sound level will suffice.
When should you adjust for background noise, and how?
When determining whether background noise is affecting the total noise level measured with the noise source ""on,"" it is sometimes necessary to take two readings of the noise level, one with the noise source ""on"" and the other with the noise source ""off."" The following table can be used to determine the noise level due to the noise source. For instance, if the total noise level is 97 dB and the background noise is 90 dB, the noise due to source I is 5 dB.
A noise survey is what?
Noise surveys provide very useful information that enables us to identify:Areas where employees are likely to be exposed to harmful levels of noise and personal dosimetry may be needed.Machines and equipment that generate harmful levels of noise.Employees who may be exposed to unacceptable noise levels.Noise control options to reduce noise exposure.Variability i.
When and how should you use a noise dosimeter to assess employee noise exposure?
The need for measuring the employees' noise exposure arises when noise survey indicates the possibility that the employees may be exposed to noise exceeding the noise exposure limits set by noise regulations or the limits set by the company. Personal noise exposure of employees is measured using a noise dosimeter. The dosimeter is worn by the employee during the entire or part of the shift. The employee does not need to be followed by the person responsible for taking the noise measurements during the entire measurement period. However, the worker should keep a log detailing tasks performed, areas visited, and any other important information that can help with understanding results, especially if noise levels are high. Any unwitnessed peaks in noise levels (if a logging dosimeter is used) should also be investigated. The reliability of the noise data will depend on the employee's cooperation in the proper use of the dosimeter. The following are some helpful tips to ensure employee's cooperation in noise dosimetry.Inform the employees about the purpose of measurement.Explain the importance of the accuracy of noise data in assessing the need for noise control.Emphasize the importance of wearing it all the time during the measurement period.Explain the consequences of tampering with the microphone - shouting in it, using it to knock on doors, etcReassure the employee that the device records sound levels only, not actual words or conversations..Usually, the manufacturer electronically adjusts dosimeters to the criterion level and exchange rate in use. You may have to adjust them to suit the exposure guidelines/standards in force in your jurisdiction. The manufacturer’s instructions for proper use must be followed. The dosimeter is to be calibrated before and after each measurement. If, after the measurement, calibration is off by more than 0.5 dB, resampling may be needed as the results may not be accurate. The start and stop times of the dosimeters must be noted. It is also important to talk with the worker and supervisor to ensure conditions during the day of sampling are typical of a normal shift. If conditions are not typical, this variation should be noted and resampling may be required.
How can we measure equivalent noise level using an Integrating Sound Level Meter (ISLM)?
The integrating sound level meter (ISLM) can be used to measure equivalent noise level averaged over the measurement period which could be several minutes, a few hours or an entire work shift. In this respect it is similar to a dosimeter used as area monitor. An ISLM does not provide personal exposure level because it is not worn on person. It gives equivalent sound levels at a particular location. The ISLM uses a pre-programmed exchange rate, with a time constant that is equivalent to the SLOW setting on the SLM."""