Guide to Understanding the Risk Assessment Matrix
Basic concepts, methodology, and application in occupational safety.
How does the 5x5 matrix work?
In occupational safety, a 5x5 matrix is most commonly used, which crosses two main components of risk:
- Likelihood (1-5): How likely it is that a hazardous event will occur (from "extremely rare" to "almost certain").
- Severity (1-5): How severe the injury or damage would be if the event occurs (from "negligible" to "fatal / catastrophic").
By multiplying these factors (L x S), we get the risk level (1-25), which tells us how urgently we need to act.
Risk Levels and Required Actions
Depending on the resulting number, risks are typically divided into several categories:
- Low Risk (1-4): Acceptable risk. No additional measures are required, but monitoring is needed.
- Medium Risk (5-12): It is necessary to plan and implement risk reduction measures within a reasonable timeframe.
- High Risk (15-25): Unacceptable risk! Work must be stopped immediately until measures to reduce the risk are implemented.
Hierarchy of Controls
When you identify a high risk, you must apply reduction measures in the following order: 1. Elimination (most effective), 2. Substitution (replacing the hazard with a safer one), 3. Engineering Controls (physical changes to the workplace), 4. Administrative Controls (procedures, training), and finally 5. Personal Protective Equipment (PPE) as the last line of defense.
Frequently Asked Questions (FAQ) about Risk Assessment
What is a risk assessment matrix?
A risk assessment matrix is a tool used in occupational safety to visualize and categorize risks based on two variables: the likelihood of an adverse event occurring and the severity of its consequences. It helps organizations prioritize which hazards need immediate attention.
What is the difference between a hazard and a risk?
Hazard is anything that has the potential to cause harm (e.g., working at height without guardrails, exposed electrical wires, toxic chemicals). Risk is the likelihood that the hazard will actually cause harm, combined with the severity of that harm. By implementing controls, we can reduce the risk, even if the hazard itself remains.