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Method of Noise Risk Assessment (NRA)

Noise Risk Assessment (NRA)

Noise risk assessment is important to conduct at the workplace to ensure workers will not be exposed to any excessive noise which can affect them. A Noise Risk Assessor is a person who can conduct a noise risk assessment at the workplace.

Area monitoring during noise risk assessment using sound level meter.
Area Monitoring during Noise Risk Assessment (NRA)

How to conduct Noise Risk Assessment (NRA)?

The methodology to conduct Noise Risk Assessment was clearly explained in the guidelines from the Industry Code of Practice (ICOP) for Management of Occupational Noise Exposure and Hearing Conservation 2019.

The noise risk assessment consists of the area and personal monitoring;

1. Area monitoring

Area monitoring is needed in noise risk assessment to determine the sources of noise which will be monitored and recorded using a sound level meter. This includes noise emitted from machines such as in manufacturing sectors. Area monitoring can measure noise levels and determine the sources to ensure the priority of noise controls.

2. Noise mapping

Noise mapping is important to visualize workplace location and noise exposure levels on a layout plan. During noise risk assessment, when noise levels were measured in area monitoring by spot measurements of each machine, the average sound pressure level will be used to include in the noise mapping. Noise mapping will be prepared by setting up the workplace in the form of a colour zone.

3. Personal monitoring

Personal monitoring can measure and identify the exposure of excessive noise to workers during their working hours. Personal monitoring in noise risk assessment should include every employee who may be exposed to excessive noise during their working shift by grouping the employees who have similar noise exposure into similar exposure groups (SEG).

Installing Dosimeter on workers to monitor personal noise exposure during Noise Risk Assessment (NRA)
Personal Monitoring during Noise Risk Assessment (NRA)

SEG can be created with a consultation between NRA, HCA, supervisor and employees based on workers who;

a) performs the same tasks,

b) has similar job functions, or

c) work in the same area.

The most exposed workers from each SEG defined will be selected for personal noise monitoring based on the criteria:

  1. work directly with the noise source

  2. work near or pass through areas with noise exposure

  3. work in a noise area for a long period of time

During the measurement, employees will be observed and the validity will be examined by:

a) Interviewing supervisors and workers

b) Taking spot measurements to verify the levels measured using noise dosimeter

c) An examination of the noise dosimeter log (time history) at the end of shift.

Daily noise exposure level will then be calculated for the effective duration of the working day.

4. Noise risk evaluation

After the noise measurements, risk evaluation needs to be conducted in noise risk assessment by comparing the personal monitoring result to the NEL from Occupational Safety and Health (Noise Exposure) Regulations 2019.

Examples of Sound Level Meter
Sound Level Meter for Area Monitoring in Noise Risk Assessment

Equipment used for Noise Risk Assessment (NRA)?

  1. Sound level meter (SLM): To conduct area monitoring at the workplace.

  2. Dosimeter: To monitor personal noise exposure to the exposed workers.

  3. Sound level calibrator: To calibrate the noise exposure equipment.

Examples of Personal Dosimeter
Dosimeter for Personal Monitoring in Noise Risk Assessment

Our NRA Services?

Need to conduct Noise Risk Assessment (NRA) at your workplace? Our Noise Risk Assessor will provide you the best services in conducting the Noise Risk Assessment. Contact us at 013-2419000 or email [email protected] now. We will always be committed to help you.


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