Noise Monitoring and Hearing Conservation Support in Singapore
IEH supports organisations with workplace noise monitoring, personal noise dosimetry, machine noise measurement, area noise mapping and practical recommendations to manage occupational noise exposure and hearing risk.
Better noise assessment gives you better control decisions.
Clients often approach IEH because they need to conduct noise monitoring for regulatory, operational or hearing conservation purposes. A good noise assessment should not only provide a number; it should help the organisation understand who is exposed, where the significant sources are, and what practical controls should be prioritised.
IEH plans workplace noise monitoring based on operations, worker groups, facility layout, shift patterns, machinery, work activities and likely exposure duration. This helps provide more representative results for management action, noise control and hearing conservation.
When organisations usually engage IEH
- Noise monitoring is required under Singapore workplace safety and health requirements.
- Workers may be exposed to high, intermittent, fluctuating or impact noise.
- The workplace needs to review its Hearing Conservation Programme.
- New machines, tools, processes or work areas have been introduced.
- Management needs evidence for engineering controls, PPE selection or work planning.
- There are concerns about worker hearing, complaints, or noisy work areas.
Three complementary approaches for a more complete workplace noise profile.
IEH may combine personal noise dosimetry, machine noise measurement and area noise mapping so that the organisation can understand both worker exposure and workplace noise sources.
Personal noise dosimetry
Personal dosimeters are worn by selected workers to estimate noise exposure during their work shift or representative monitoring period.
- Worker exposure profile
- Similar Exposure Group support
- Full-shift or representative monitoring
- Noise dose and exposure interpretation
Machine noise measurement
Machine and equipment noise measurements help identify significant noise sources and support control planning at source or along the transmission path.
- Machine or process source review
- Sound level measurement
- Priority source identification
- Noise control recommendations
Area noise mapping
Area measurements help visualise noisy zones, support workplace planning and identify where signage, controls or hearing protection zones may be needed.
- Work area noise survey
- Representative noise map
- Noisy zone identification
- Control and communication support
Noise monitoring should be planned around actual work exposure and Singapore WSH requirements.
MOM states that hygiene monitoring includes toxic substance monitoring and noise monitoring, and that monitoring must be carried out by a competent person. Noise monitoring includes workplace noise monitoring and personal noise monitoring.
Where there are 10 or more persons in the workplace likely to be exposed to excessive noise, the workplace is required to engage a Noise Monitoring Officer, who is a competent person, to conduct noise monitoring and submit the results to MOM once every 3 years.
Where there are 50 or more persons in the workplace likely to be exposed to excessive noise, the workplace is required to appoint a Noise Control Officer to advise on proper noise control measures.
MOM states that the permissible exposure limit for noise is an equivalent sound pressure level of 85 dB(A) over an 8-hour workday, or a peak sound pressure level exceeding 140 dB(C).
References: MOM Requirements for Hygiene Monitoring, MOM FAQ on PEL for Noise, Workplace Safety and Health (Noise) Regulations 2011, and WSH Guidelines on Hearing Conservation Programme. This page provides general service information and should not be treated as legal advice.
How IEH plans representative noise monitoring using Similar Exposure Groups.
IEH reviews the workplace, operations and work patterns to decide a suitable monitoring strategy. For personal noise dosimetry, workers may be grouped into Similar Exposure Groups where they perform similar tasks, have similar job functions, work in the same area, and are expected to have similar noise exposure.
What is a Similar Exposure Group?
According to MOM, the number of personal noise dosimetries required depends on the number of workers in the Similar Exposure Group, or SEG. MOM describes an SEG as a group of workers who perform the same job tasks, have similar job functions and work in the same area.
- Workers should perform the same or similar job tasks.
- Workers should have similar job functions.
- Workers should work in the same or similar work area.
- The SEG should be verified with workers and supervisors where practicable.
- The competent person should justify the SEG classification in the noise monitoring report.
Why SEG planning matters
SEG planning helps ensure that personal noise dosimetry is representative. Instead of measuring every worker individually, selected workers from each SEG can be monitored to estimate the daily noise exposure profile for that group.
The WSH Guidelines on Hearing Conservation Programme state that workers from the SEG should be randomly selected, and that the sampling approach should not exclude workers simply because their exposure may be lower than normal on a particular day.
| Total number of workers in Similar Exposure Group (N) | Required number of personal noise dosimetry samples (n) | Planning note |
|---|---|---|
| 1 to 6 | n = N | Monitor all workers in the SEG. |
| 7 to 8 | 6 | Randomly select 6 workers from the SEG. |
| 9 to 11 | 7 | Randomly select 7 workers from the SEG. |
| 12 to 14 | 8 | Randomly select 8 workers from the SEG. |
| 15 to 18 | 9 | Randomly select 9 workers from the SEG. |
| 19 to 26 | 10 | Randomly select 10 workers from the SEG. |
| 27 to 43 | 11 | Randomly select 11 workers from the SEG. |
| 44 to 50 | 12 | Randomly select 12 workers from the SEG. |
Source: Table 4, WSH Guidelines on Hearing Conservation Programme. The guideline notes that the maximum number of workers per SEG is 50. For groups larger than 50, the competent person should review whether the group should be further divided into more representative SEGs.
Monitoring duration
For practical reasons, it may not always be possible to measure noise levels over the entire working day. Where representative personal monitoring is used, measurements should as far as possible cover the major part of the day, approximately 80% of the work shift, and include all significant periods of noise exposure.
Information to include in the report
The WSH Guidelines state that competent persons conducting dosimetry should include key dosimeter settings and worker information in the noise monitoring report.
- Criterion level
- Exchange rate
- Threshold
- Name and identification number of the worker monitored
- SEG number and number of persons in the SEG
- LAeq,T, running time, exposure duration, LAeq,8h and percentage dose
Information that helps IEH prepare a practical noise monitoring quotation.
The correct quotation depends on the facility layout, number of exposed workers, number of Similar Exposure Groups, working hours, machine inventory and whether the client needs personal dosimetry, machine noise measurement, area noise mapping or broader HCP support.
| Planning consideration | Why it matters | How IEH uses the information |
|---|---|---|
| Facility size and layout | Noise levels can vary significantly between departments, production lines and work areas. | Helps decide area noise measurement points and whether noise mapping is needed. |
| Number of workers | Workers need to be reviewed by work group and possible Similar Exposure Group. | Supports personal dosimetry planning and SEG sample size estimation. |
| Working hours and shifts | Noise exposure depends on both sound level and exposure duration. | Helps decide monitoring duration and interpretation approach. |
| Machine and process list | Noisy sources need to be identified for control planning. | Supports machine noise measurement and prioritisation of controls. |
| Previous noise reports | Previous findings help identify trends, gaps and high-risk areas. | Supports more targeted assessment planning and better continuity. |
| Existing controls | Controls affect actual exposure and future improvement priorities. | Supports recommendations on engineering, administrative and PPE controls. |
If you are not sure how many dosimetry samples are needed, IEH can first review the worker groups and likely SEGs before confirming the most appropriate monitoring scope.
Structured support from assessment planning to practical controls.
IEH’s noise monitoring work is designed to help clients move from compliance-driven monitoring to practical workplace improvement.
Understand
Review the workplace, process flow, noisy activities, work groups, shifts and available previous monitoring information.
Plan
Define the monitoring scope, including personal noise dosimetry, machine noise measurement, area noise measurements and SEG-based sampling requirements.
Measure
Conduct suitable noise monitoring using calibrated instruments and representative monitoring arrangements based on the assessment objective.
Improve
Provide clear recommendations for noise control, hearing protection, signage, training, monitoring follow-up and HCP improvement.
Clear reporting for management, WSH teams and operations.
IEH’s noise monitoring deliverables help clients understand exposure risk, communicate findings and take practical action.
Noise monitoring report
Summary of monitoring objective, methods, workplace conditions, results, findings and interpretation.
Personal exposure results
Personal noise dosimetry findings for selected workers or work groups, including exposure interpretation and SEG information where applicable.
Machine and area findings
Identification of noisy machines, activities and work areas to support workplace noise control priorities.
Noise map support
Area noise data may be presented to help visualise noisy zones and support communication with stakeholders.
Control recommendations
Practical advice on source control, engineering measures, administrative controls, signage, hearing protection and follow-up monitoring.
Programme support
Support for Hearing Conservation Programme improvement, worker communication and ongoing occupational hygiene management.
Noise monitoring is part of broader occupational hygiene management.
IEH can support clients beyond one-off monitoring by reviewing the overall noise risk management system and workplace health programme.
Hearing Conservation Programme support
- Noise exposure monitoring and trend review
- Hearing protection review and fit-for-purpose advice
- Noise control and risk reduction recommendations
- Worker communication and training support
- Follow-up monitoring and programme review
Practical tool
For quick estimation and learning, IEH also provides a practical Noise Exposure Calculator for users to better understand how noise level and exposure duration affect noise dose.
Noise monitoring questions clients commonly ask.
What is the difference between personal noise dosimetry and area noise measurement?
Personal noise dosimetry estimates the noise exposure of selected workers during work. Area noise measurement assesses sound levels at fixed locations or work areas. Both are useful, but they answer different questions.
How many workers need to wear personal noise dosimeters?
The number depends on the number of workers in each Similar Exposure Group. The WSH HCP Guidelines provide a sample size table where groups of 1 to 6 require all workers to be monitored, while larger groups require representative sample numbers up to 12 samples for a 44 to 50 person group.
Why is machine noise measurement useful?
Machine noise measurement helps identify significant noise sources. This is important because effective control should focus not only on exposed workers, but also on the source of the noise where practicable.
Will noise dosimetry affect normal work?
Personal noise dosimeters are designed to be lightweight and should generally cause minimal interference to normal work. Workers will usually be briefed on how to wear the instrument and continue their usual tasks.
Can IEH support noise control recommendations after monitoring?
Yes. IEH can provide practical recommendations covering source control, engineering measures, administrative controls, hearing protection, signage, training and follow-up monitoring where required.
Is this page a substitute for professional advice?
No. This page is intended as a general guide. The final monitoring plan, SEG classification, sampling strategy and interpretation should be determined by a competent person after reviewing the workplace and work activities.
Singapore references used for this page.
This service page is written with reference to the following official sources. Clients should review the latest official requirements and consult a competent person for workplace-specific interpretation.
- MOM Requirements for Hygiene Monitoring
- MOM FAQ: How many personal noise dosimetries do I need to carry out?
- MOM FAQ: Permissible Exposure Level or Permissible Exposure Limit for Noise
- Workplace Safety and Health (Noise) Regulations 2011
- WSH Guidelines on Hearing Conservation Programme
Need noise monitoring for your workplace?
Share your facility size, number of workers, working hours, major noise sources, previous monitoring reports and monitoring objective with IEH. We can help you plan a suitable noise monitoring scope covering personal dosimetry, machine noise measurement, area noise mapping and Hearing Conservation Programme support.
Request a quotation or technical discussion
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