Question 5 of 7: Risk Management and Chemical Risk Assessment

Question 5: Risk Management and Chemical Risk Assessment (20 marks: 6/7/7)

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) Components of the Risk-Management Process

• Establish the context; risk identification; risk analysis (likelihood × consequence); risk evaluation (against criteria); risk treatment/control (hierarchy; may transfer/avoid); monitoring and review; communication and consultation throughout.

(ii) Steps in Chemical Risk Assessment

1. Identify the chemicals and hazards (inventory, SDS, classification).
2. Identify exposure scenarios (who, tasks, routes, frequency, duration).
3. Assess exposure (measure/estimate concentration; compare with exposure limits).
4. Characterize the risk (hazard × exposure; is it acceptable?).
5. Determine controls (hierarchy); re-assess residual risk.
6. Document, communicate, review.

(iii) Risk Reduction in Chemical Processing Plants

• Inherent safety — minimize inventory, substitute safer chemicals, moderate conditions, simplify.
• Engineering — containment/closed systems, ventilation, pressure relief, interlocks/trips, automation/remote operation, gas detection and alarms, containment for spills.
• Process hazard analysis — HAZOP, what-if, layers-of-protection analysis.
• Administrative — procedures, permits, management of change, training, maintenance; plus PPE and emergency preparedness ("defence in depth").