Question 2 of 7: Hazard Sources, Control Priorities, and Warning Devices

Question 2: Hazard Sources, Control Priorities, and Warning Devices (20 marks: 7/6/7)

Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.

(i) Sources of Hazards

• Mechanical (moving parts, nip points), electrical (shock, arc flash), chemical (toxic, corrosive, flammable), physical/energy (noise, vibration, heat, radiation, pressure), fire/explosion, ergonomic (manual handling, repetition), biological, environmental/workplace (housekeeping, lighting, height, confined spaces), human/organizational (fatigue, training, supervision).

(ii) Priority Order of Controls (Hierarchy)

1. Elimination — remove the hazard (most effective).
2. Substitution — replace with something less hazardous.
3. Engineering controls — guarding, isolation, ventilation, interlocks.
4. Administrative controls — procedures, training, rotation, signage.
5. PPE — last line, protects only the individual.

(iii) Steps for Effective Use of Warning Devices

• Use only after higher-order controls; identify the specific hazard and required response.
• Select a device suited to the hazard and environment (visual/audible/both).
• Make it clearly perceptible (above background), understandable and standardized.
• Give it in time to react; train workers to recognize and respond; test/inspect/maintain; avoid warning overload.