Risk Assessment

Risk Assessment

Hazard Identification

Hazard Identification is, as the name suggests, a process of identifying hazards; where a hazard is a potential source of harm. Hazard Identification is most effective when it follows a structured process, systematically considering components of the system and their function. Terms such as HAZID and HAZOP are often used to describe types of hazard identification processes.

The Assessment

The expected outcome of an accident or event associated with an identified hazard, including the range of possible outcomes, is assessed as the central task of a risk assessment.

Quantitative risk assessment involves assigning rates and probabilities to events to determine the total risk of an outcome. For example, in a diving context, a quantitative risk analysis related to omitted decompression might determine a rate for the accident of omitting decompression and a probability that treatment in the onsite chamber provides full resolution. Such quantitative risk assessments often suffer from a lack of reliable data and from significant complexity.

Qualitative risk assessment involves assigning categories to hazard probabilities and outcomes. The figure below shows an example qualitative risk assessment matrix extracted from MIL-STD-882E, Page 12, which is available via the link to the left.

Risk Assessment Matrix

As can be seen categories have been assigned to the severity and probability parameters. The combination of these parameters determines the assessed risk which again is categorized; in this case with categories of High, Serious, Medium, Low and Eliminated. For this example, MIL-STD-882E provides definitions for each of these categories.

Whether a qualitative or quantitative method is used, or something in between, the end result is an assessment of the risk associated with each hazard. Combining assessed risk for all hazards produces an assessed risk for the entire system or operation under review. The assessed risk is associated with a given set of assumptions related to system design, environment and external mitigations. For example, a certain diving operation might be deemed High risk without a recompression chamber onsite, but Low risk with a chamber in place.