DRS1713 – Chapter 2 : Physical Hazards (Noise, Vibration, Heat Stress, Radiation)

38 question-and-answer flashcards summarising the key facts, definitions, health effects, control measures and legislation for Noise, Vibration, Heat Stress and Radiation hazards as presented in DRS1713 Chapter 2.

Q1. Which four physical hazards are emphasised in Chapter 2 of DRS1713?

Noise, Vibration, Heat (Heat Stress) and Radiation.

Q2. At what equivalent continuous sound level over an 8-hour workday is noise considered hazardous according to Malaysian regulations?

85 dB(A).

Q3. What is the ceiling limit for instantaneous noise exposure under the Occupational Safety and Health (Noise Exposure) Regulations 2019?

140 dB(A).

Q4. State the ‘3-dB exchange rule’ for safe noise exposure time.

For every 3 dB increase above 85 dB(A), the permissible exposure time is halved.

Q5. According to the rule in Q4, what is the maximum safe exposure time at 106 dB(A)?

About 4 minutes (7.5 min at 103 dB, halved again at 106 dB).

Q6. Give two manufacturing sectors typically recording noise >92 dB(A).

Examples: metal forging & stamping; basic metal industry; manufacture of machinery; metal cans & containers; structural metal products.

Q7. List three individual health or performance effects linked to prolonged noise exposure.

Possible answers: Depression, hypertension, stress, reduced attention span, communication interference, drop in work performance.

Q8. Arrange the preferred control measures for noise from most to least effective.

Substitute/Eliminate → Engineering controls → Administrative controls → Personal Protective Equipment (earmuffs/earplugs).

Q9. Differentiate sound from noise in occupational hygiene terms.

Sound is any pressure vibration detected by the ear; noise is unwanted or harmful sound that can pose a risk when levels and exposure duration are high.

Q10. Name the Malaysian regulation that specifically governs workplace noise exposure.

Occupational Safety and Health (Noise Exposure) Regulations 2019.

Q11. Define ‘vibration hazard’.

Harm arising from movement of solid objects where the amplitude and frequency cause harm to exposed persons.

Q12. What does HAV stand for and what causes it?

Hand-Arm Vibration; caused by regular use of vibrating hand tools such as grinders, chainsaws, power drills, or by holding workpieces during cutting/grinding.

Q13. Name two common health symptoms linked to prolonged HAV.

Tingling & numbness in fingers, weakened grip strength, blanching/discolouration of fingers (vibration white finger).

Q14. What is Whole-Body Vibration (WBV) and give one occupational source.

Vibration transmitted to the entire body from sitting, standing or lying on vibrating surfaces; sources include heavy equipment operators, truck or subway drivers.

Q15. State two health effects associated with WBV.

Headaches, motion sickness, chronic back pain, stomach problems, sleep or visual disturbances.

Q16. Outline two engineering controls for vibration hazard.

Isolate/dampen the vibration and keep machines well-maintained or balanced.

Q17. Under OSHA 1994, which objective supports control of vibration and heat stress hazards?

Objective 3 – to promote a working environment conducive to workers’ psychological and physiological needs.

Q18. Define ‘heat stress hazard’.

A condition where retained body heat exceeds the body’s ability to dissipate it.

Q19. List three typical symptoms of heat stress progression.

Heat rash/skin irritation, muscle cramps from electrolyte loss, excessive fatigue or heat exhaustion, and—at extreme—heat stroke with collapse.

Q20. Give one example of an occupation involving severe heat stress.

Examples: foundry work, smelting, outdoor road paving, firefighting, kitchen/catering near ovens, glass blowing.

Q21. Mention three employer responsibilities to prevent heat stress.

Evaluate heat risk, supply sanitary drinking water & encourage hydration, schedule hot tasks for coolest times, implement work–rest cycles, provide shaded or air-conditioned rest areas.

Q22. State two personal preventive actions workers should take against heat stress.

Drink plenty of water, seek shade, wear loose/light clothing, take regular breaks.

Q23. What PPE modification can help reduce solar heat on a worker’s head?

Use vented, full-brim hard hats.

Q24. Define ‘radiation hazard’.

Hazard from emission of energy as electromagnetic waves or moving sub-atomic particles, especially ionising radiation capable of producing ionisation and tissue damage.

Q25. Which part of the electromagnetic spectrum marks the transition from non-ionising to ionising radiation?

The ultraviolet band (beyond UV into X-rays and gamma becomes ionising).

Q26. Name the four primary types of ionising radiation.

Alpha particles, Beta particles, Gamma rays/X-rays, and Neutron radiation.

Q27. Which simple material can stop alpha particles?

A sheet of paper or the dead outer layer of human skin.

Q28. What shielding is typically required for beta radiation?

Thick clothing or thin aluminium to stop beta particles.

Q29. How is gamma radiation normally shielded effectively?

With dense, thick materials such as lead (~1.3 ft) or equivalent concrete (~6.6 ft) or water (~13.8 ft), depending on energy.

Q30. State three potential health effects of high-dose ionising radiation exposure.

Cancer, central nervous system syndrome, skin burns, eye damage, infertility, hair loss, mutagenesis, mental retardation in offspring.

Q31. Explain the ALARA principle.

‘As Low As Reasonably Achievable’—minimise radiation dose through optimised Time, Distance, and Shielding.

Q32. List the three key variables used to obey ALARA.

Minimise time exposed, maximise distance from source, and apply adequate shielding.

Q33. Identify the two Malaysian regulations issued under the Atomic Energy Licenses Act 1984 that govern radiation safety.

Radiation Protection (Licensing) Regulations 1986 and Radiation Protection (Basic Safety Standards) Regulations 1988.

Q34. In noise control, give one example of a substitution measure.

Replacing a noisy production machine with a quieter model or method.

Q35. For vibration, what administrative practice is recommended to limit HAV exposure?

Rotate between vibrating and non-vibrating tasks and allow 10- to 15-minute rests each hour.

Q36. Which PPE is most common for HAV reduction?

Thick, vibration-damping fabric gloves.

Q37. Provide two examples of non-occupational noise sources that can exceed 85 dB(A).

Personal audio systems at high volume, concerts/music performances, exotic cars with loud engines, nightclubs.

Q38. What laboratory-oriented question does the lecture pose to encourage reflection on physical hazards?

‘Which of the four physical hazards might you face during laboratory sessions, and what control measures would you apply?’