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, electrical, chemical, physical/energy (noise, vibration, heat, radiation, pressure), fire/explosion, ergonomic, biological, environmental/workplace (housekeeping, lighting, height, confined spaces), and human/organizational (fatigue, training, supervision).

(ii) Priority Order of Controls (Hierarchy)

1. Elimination — remove the hazard entirely.
2. Substitution — replace it with something less hazardous.
3. Engineering controls — isolate people from the hazard (guarding, enclosure, ventilation, interlocks).
4. Administrative controls — change the way people work (procedures, training, rotation, signage, permits).
5. Personal protective equipment (PPE) — the last line of defence.

Control at source and as close to elimination as practicable; higher levels don't depend on behaviour.

(iii) Effective Use of Warning Devices

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