Noise at work: what supervisors need to know

Why it matters

Loud noise damages the hair cells in the inner ear. They do not grow back. The loss creeps up over years, and workers rarely notice until it is severe. By then, conversation, phone calls and warning alarms are hard to hear.

Noise-induced deafness is a reportable occupational disease in Singapore. You cannot cure it once it sets in. You can prevent it with a few steady habits on site.

How loud is too loud

A simple field test: if you must raise your voice to talk to someone two metres away, the noise may be harmful. If you must shout at arm's length, it is almost certainly too loud. Get it measured.

Decibels climb fast. Every 3 dB rise doubles the sound energy reaching the ear. So the safe exposure time halves. Grinders, jackhammers, piling rigs, chainsaws, compressors and press machines often run well above 90 dB(A).

Order of controls

The WSH Council puts it in this order: control noise at the source, then along its path, then at the worker.

• Eliminate or substitute: pick a quieter method or machine. Buy low-noise equipment and write noise limits into purchase orders.
• At the source: fit silencers and mufflers. Damp vibrating panels. Balance, lubricate and maintain machines.
• Along the path: enclose noisy machines. Put up barriers. Move people further away. Add sound-absorbing panels.
• Administrative: schedule noisy work when fewer people are near. Rotate jobs. Mark hearing protection zones and provide quiet rest areas.
• Hearing protectors: issue them while other controls are being put in place, or where nothing else works.

Choosing and using hearing protectors

Earplugs and ear muffs both work when worn correctly. Earplugs are cooler in hot, humid areas and fit with other PPE. Ear muffs are quicker to fit and easier to check from a distance. Glasses can break the muff seal.

Pick a protector that brings the noise at the ear below 85 dB(A). Where noise reaches 100 dB(A) or more, the WSH Council says to wear earplugs and ear muffs together. Singapore Standard SS 549 covers selection, use and care.

• Roll foam plugs thin, pull the ear up and back, insert, and hold until they expand.
• Clean reusable plugs and muff cushions often. Replace them when they are damaged or hard.
• Wear protection before you enter the zone. Keep it on until you leave.

What the rules require

The WSH (Noise) Regulations apply to all workplaces. A person counts as exposed to excessive noise if, without hearing protection, they would exceed the permissible exposure limit. That means 85 dB(A) over an 8-hour day or a peak above 140 dB(C). These points come from the WSH Guidelines for Hearing Conservation Programme:

• Where 10 or more persons are or may be exposed to excessive noise, the occupier must appoint a competent person to monitor noise. Monitoring is due at least every three years, and sooner after changes.
• The occupier keeps the noise monitoring report for at least 10 years and submits it to the Commissioner for WSH.
• Under the WSH (Medical Examinations) Regulations, exposed workers need a check by a Designated Workplace Doctor. It takes place before or within three months of starting the job. After that they need a hearing test every year, paid for by the employer.
• Medical examination reports are kept for at least five years.
• Noise-induced deafness must be reported to the Commissioner within 10 days of receiving the doctor's written diagnosis.
• Where more than 50 workers are exposed to excessive noise, a Noise Control Officer is required.

Training and signs

The WSH Council guidelines say to train exposed workers every year. New workers should be trained within three months of starting. Cover the effects of noise, how to fit and care for protectors, and why the hearing tests matter. Teach in a language each worker understands.

Post warning signs at every entrance to a noisy area. Show the typical noise level and the need for hearing protection. Walk the zones and correct anyone not wearing protection.

Warning signs in your crew

Listen for workers who say their ears ring after a shift. Ringing or dull hearing after work means the ear took damage that day. Watch for people who ask others to repeat themselves, turn the radio up high, or miss calls on the phone.

Send these workers for a hearing check. Then look at the task they do. One person's symptoms often point to a noise problem for the whole crew.

Common mistakes

These are the gaps auditors find most often.

• Handing out earplugs and calling it a noise programme.
• Earplugs pushed half in, or muffs worn over a cap or hood.
• No new monitoring after adding a compressor, generator or new line.
• Missing the three-month window for a new worker's first hearing test.
• Workers taking protection off to talk or to use the phone.
• Signs posted inside the zone instead of at the entrance.

In other countries

• Malaysia: The Occupational Safety and Health (Noise Exposure) Regulations 2019 treat a daily exposure above 82 dB(A) as excessive noise. That triggers a noise risk assessment by a registered assessor. The exposure limit is 85 dB(A) daily, 115 dB(A) maximum and 140 dB(C) peak. Above the limit, employers must mark a "HEARING PROTECTION ZONE" and arrange yearly audiometric tests. Exposed workers get training at least once a year.
• Indonesia: Permenaker No. 5 of 2018 sets the noise threshold value at 85 dBA for 8 hours a day. Allowed time halves for each 3 dBA rise, for example 88 dBA for 4 hours.

Use it on site: the noise at work checklist and the toolbox talk to brief your crew.

Sources

1. WSH Guidelines for Hearing Conservation Programme (2024), WSH Council.
2. What is a Hearing Conservation Programme (HCP)?, Ministry of Manpower.
3. Occupational Safety and Health (Noise Exposure) Regulations 2019, DOSH Malaysia.
4. Peraturan Menteri Ketenagakerjaan No. 5 Tahun 2018 tentang K3 Lingkungan Kerja, Kemnaker.

This is practical guidance, not legal advice. Laws and codes of practice change; always check the current official text and your site's own procedures.