10.1 Physical Hazards: Noise, Vibration, Heat Stress, Radiation and Lighting

Physical hazards on construction sites

Physical hazards are forms of energy that harm the body: sound, vibration, heat, radiation and poor lighting. They are easy to underestimate, because damage such as noise-induced hearing loss or vibration white finger develops slowly and is permanent.

Noise: the OSH (Noise Exposure) Regulations 2019

The 2019 Regulations (P.U.(A) 60/2019) replaced the repealed FM (Noise Exposure) Regulations 1989.

Key definitions and limits

Employer duties

1. Noise risk assessment (regulation 4):

   • carried out by a noise risk assessor registered with the Director General, using IEC-standard equipment
   • the report is given to the employer within one month
   • exposed employees are told the findings within 14 days
   • recommendations are carried out within 30 days
   • the assessment is reviewed within five years or when directed

2. Information, instruction and training for exposed workers, at least once a year (regulation 5).

3. Reduce noise above the limit (regulation 6). First assess what is practicable, then apply controls in this order:

   • engineering control
   • engineering control together with administrative control
   • administrative control alone
   • other effective measures, including personal hearing protectors

   Keep engineering controls in good working order.

4. Personal hearing protectors (regulation 7): suitable, maintained, available, giving enough attenuation, and approved by the Director General.

5. Hearing protection zones (regulation 8): areas above the limit are marked "HEARING PROTECTION ZONE", and everyone entering uses hearing protectors.

6. Audiometric testing (regulations 9 and 10):

   • annual testing for employees exposed above the limit, at a DOSH-approved centre, interpreted by an occupational health doctor, at no cost to the employee
   • the first test within three months of starting work in the area, after 14 hours without noise above 80 dB(A)
   • a temporary threshold shift is retested within three months
   • noise-induced hearing loss is notified to DOSH within 7 days

7. Records (regulation 11): noise risk assessment reports kept at least 30 years; audiometric reports kept for the period of employment plus five years.

The maximum penalty is RM10,000 or one year or both. Noise-induced hearing loss is also a reportable occupational disease under the NADOPOD Third Schedule.

Construction noise controls

The decibel scale is logarithmic. Doubling the sound energy adds 3 dB, so two identical 90 dB(A) machines together produce about 93 dB(A). Because daily noise exposure is an energy average, each 3 dB increase halves the time it takes to reach the same daily dose.

Vibration

DOSH has published guidelines for work involving vibration (2003). Internationally, the EU Physical Agents (Vibration) Directive 2002/44/EC sets:

• for hand-arm vibration, a daily exposure action value of 2.5 m/s² A(8) and a limit value of 5 m/s² A(8)
• for whole-body vibration, an action value of 0.5 m/s² and a limit value of 1.15 m/s²

These are useful benchmarks when planning exposure times.

Controls:

• Choose different methods, for example crushing or diamond cutting instead of breaking.
• Use low-vibration tools and anti-vibration mounts, and maintain tools with sharp bits.
• Limit trigger time and rotate workers.
• Keep hands warm and dry.
• Fit suspension seats in plant and maintain haul roads.
• Report early symptoms and arrange health surveillance where exposure is high.

Disease caused by vibration is in the NADOPOD Third Schedule (item 36).

Heat stress: DOSH Guidelines on Heat Stress Management at Workplace 2016

Malaysia's hot, humid climate, with work on exposed decks and roofs, makes heat stress a daily construction hazard.

Heat illnesses (from mild to life-threatening)

• Heat rash
• Heat cramps: replace fluid and salt; the guideline suggests drinking water or electrolyte drinks every 15 to 20 minutes
• Heat syncope: fainting
• Heat exhaustion: heavy sweating, weakness, nausea
• Heat stroke: a medical emergency, with hot dry skin, confusion, convulsions and loss of consciousness

The WBGT index

The wet bulb globe temperature (WBGT) combines air temperature, humidity, radiant heat and air movement:

• Outdoors with sun: WBGT = 0.7 Tnwb + 0.2 Tg + 0.1 Tdb
• Indoors or without sun: WBGT = 0.7 Tnwb + 0.3 Tg

Here Tnwb is the natural wet-bulb temperature, Tg the globe temperature and Tdb the dry-bulb temperature. A clothing adjustment is added. The adjusted WBGT is compared with ACGIH action limits and threshold limit values for the workload and work-rest regime.

Acclimatisation: complete heat acclimatisation generally takes seven to fourteen days. Heat tolerance falls even after a long weekend, so very hot work on the first day of the week is not advisable. New workers should build up gradually.

First aid for heat stroke:

1. Call 999.
2. Move the casualty to shade.
3. Cool them rapidly with water and fanning.
4. Monitor until help arrives.

Radiation

• Solar ultraviolet: long outdoor exposure causes sunburn, skin cancer and eye damage. Provide shade, schedule heavy work earlier where possible, and supply helmet neck flaps, long sleeves and UV-filtering safety glasses.
• Welding arc ultraviolet and infrared: causes arc eye and burns (Section 9.2). Use screens to protect passers-by.
• Ionising radiation: from industrial radiography, such as weld testing on pipelines and steelwork, and from some density gauges. Its use is licensed under the Atomic Energy Licensing Act 1984 (Act 304). Fourth Schedule work in CDM 2024 includes ionising radiation that requires controlled or supervised areas. Keep everyone outside the radiographer's barriers and follow their warning signals.

Lighting

CDM 2024 regulation 37 requires:

• suitable and sufficient lighting, natural where practicable, on the site, its surroundings and traffic routes
• artificial lighting that does not change how safety signs look
• secondary lighting where failure of the main lighting would create risk

Poor lighting causes trips, falls and errors in basements, stairwells and night work.

Scenario: the basement breaking crew

Two workers spend most of each shift breaking concrete with pneumatic breakers in a basement, beside an unsilenced compressor, at 34 °C with poor ventilation. Neither wears hearing protection. The SSS:

1. Arranges a noise risk assessment by a registered assessor. Exposure is clearly above 85 dB(A), so the area is marked as a hearing protection zone and approved hearing protectors are issued at once as an interim measure.
2. Has the employer consider engineering controls first: a remote-controlled demolition robot or hydraulic crusher, moving the compressor outside, and an acoustic enclosure.
3. Rotates the breaker operators to limit vibration exposure, and plans audiometric testing.
4. Applies heat controls: water at the work face, a cool rest area, ventilation, a work-rest schedule, and buddy checks for heat illness symptoms.