Noise Monitoring – Procedure & Monitoring Equipment

Noise monitoring is the act of checking noise levels to ensure that the levels are within the set guidelines and that workers are protected from risk of hearing damage at their place of work.

Excessive noise can result to a long-term negative health effects such as hearing loss, tinnitus, sleep disturbances, a rise in blood pressure, an increase in stress and vasoconstriction, and an increased incidence of coronary artery disease, this is why noise measurement is important.

How To Conduct Noise Survey

Noise survey is used to establish whether employees are being exposed to occupational noise levels exceeding the exposure limits set by the regulations. It provide useful information which enables a safety professional to identify:

Areas where employees are likely to be exposed to harmful levels of noise
Machines and equipment which generate harmful levels of noise
Operatives who might be exposed to unacceptable noise levels
Determine noise control options to reduce noise exposure.

Noise survey is carried out using a sound level meter which reads Sound Pressure Levels (SPLs) in dB(A) and the highest noise level reached, the peak sound pressure in Pascal (Pa).

Standards For Noise Measurement

There are a number of standards for noise measurement, each with a different goal or focus, including:

Standard:ITU-R BS 468 widely used in Broadcasting and professional Audio.
Standard:IEC A-weighting is widely used in Environmental Noise measurement.
Standard:CCIR recommendation 468-4 is now maintained as ITU-R BS 468

How To Measure Noise Level In The Workplace

There are two basic types of sound level meter which could be used to measure noise level – Integrated and direct reading meters.

In order to collect data on noise, investigators must identify the sampling equipment that will best suit the objectives of the study.

Below are different noise monitoring equipment:

Sound Level Meter:The sound level meter shown is an instrument that measures sound pressure level. It can be used to identify and evaluate individual noise sources for abatement purposes and can aid in determining the feasibility of engineering controls for individual noise sources. Another use of the sound level meter is to spot-check noise dosimeter performance.
Noise Dosimeter:This is very similar to a sound level meter except that it can be worn by an employee to determine the personal noise dose during the workshift sampling period. it is also known as Personal Sound Exposure Meter (PSEM).They are often used to comply with OSHA noise standards. They can measure an employee’s exposure to noise and automatically compute the necessary noise dose calculations.
Octave band analyzer: This is a sound level meter that divides noise into its frequency components. This allows for further characterization of noise beyond a simple measure in decibels. The analysis allows for more detailed information regarding the breakdown of frequencies that make up the noise. It helps determine the effectiveness of various types of frequency-dependent noise controls, such as barriers and personal protective equipment (PPE). The special signature of any given noise can be obtained by taking sound level meter readings at each of the center frequency bands.

NOTE: The sound level meter, or indeed any noise measurement device, must be calibrated before and after each measurement session. To take measurements, the sound level meter is held at arm’s length at the ear height for those exposed to the noise. Remember to make a measurement at each ear.

In conclusion, to carry out a successful noise monitoring, below are steps to follow:

Carry out noise survey in the area of interest
Choose appropriate noise measurement equipment that will meet your objective for the measurement.
Carry out the monitoring

If the noise level after measurement exceeds the compliance level, then measures should be put in place to reduce it using the hierarchy of risk control.