Risk Assessment. Marvin Rausand

Risk Assessment

2.28 (Asset)

Something we value and want to preserve.

Assets are also called targets, vulnerable targets, victims, recipients, receptors, and risk‐absorbing items. Examples of assets are listed in Table 2.6 . Observe that the sequence of the assets in Table 2.6 does not imply any priority or ranking.

Table 2.6 Some types of assets.

– Humans (first, second, third, and fourth parties)– Community– The environment (animals, birds, fish, air, water, soil, landscape, natural preserve areas, and built environment)– Performance (e.g. availability of a production system, punctuality of a railway service)– Material assets (e.g. buildings, equipment, and infrastructure)

– Historical monuments, national heritage objects– Financial assets– Intangibles (e.g. reputation, goodwill, and quality of life)– Timing or schedule of activities (project or mission risk)– Organizational behavior

2.5.2 Categories of Human Victims

In most risk assessments, humans are considered to be the most important asset. The possible victims of an accident are sometimes classified according to their proximity to and influence on the hazard (Perrow 1984):

1 (1) First‐party victims. These are people directly involved in the operation of the system. Employees in a company where accidents may occur are typical examples of first‐party victims.

2 (2) Second‐party victims. These are people who are associated with the system as suppliers or users, but exert no influence over it. Even though such exposure may not be entirely voluntary, these people are not innocent bystanders, because they are aware of (or could be informed about) their exposure. Passengers on airplanes, ships, and railways, for example, are considered to be second‐party victims.

3 (3) Third‐party victims. These are innocent bystanders who have no involvement in the system, for example, people living in the neighborhood of a plant.

4 (4) Fourth‐party victims. These are victims of yet‐unborn generations. The category includes fetuses that are carried while their parents are exposed to radiation or toxic materials, and all those people who will be contaminated in the future by residual substances, including substances that become concentrated as they move up the food chain.

Example 2.10 (Victims of Railway Accidents)

The railway industry sometimes classifies human assets in five categories:

1 (a)Passengers

2 (b)Employees

3 (c)People on the road or footpath crossings of the line

4 (d)Trespassers (who are close to the line without permission)

5 (e)Other persons

2.5.3 Consequence Categories

In addition to distinguishing between different assets, the adverse effects may also be classified into several categories related to the assets. Some examples are given in Table 2.7 .

Table 2.7 Some types of harm to different assets.

– Loss of human life– Personal injury– Reduction in life expectancy– Damage to the environment (fauna, flora, soil, water, air, climate, and landscape)– Damage to material assets– Investigation and cleanup costs– Business‐interruption losses– Loss of staff productivity

– Loss of information– Loss of reputation (public relations)– Insurance deductible costs– Fines and citations– Legal action and damage claims– Business‐sustainability consequences– Societal disturbances– Reduction of human well‐being– Loss of freedom

For harm to people, it is common to distinguish between:

1 – Temporary harm/injury. In this case the person is injured but will be totally restored and able to work within a period after the accident.

2 – Permanent disability. In this case, the person gets permanent illness or disability. The degree of disability is sometimes given as a percentage.

3 – Fatality. The person dies, either immediately or because of complications. The fatality may sometimes occur a long time after the accident, for example, due to cancer caused by radiation after a nuclear accident.

2.5.4 Consequence Spectrum

A hazardous event (or end state) images may lead to a number of potential consequences images , images , …, images . The probability images that consequence images will occur depends on the physical situation and whether or not the barriers are functioning. The possible consequences and the associated probabilities resulting from the hazardous event are shown in Figure 2.5 .

c02f005 Figure 2.5 Consequence spectrum for a hazardous event.

The diagram in Figure 2.5 is called a consequence spectrum, a risk picture, or a risk profile related to hazardous event images . The consequence spectrum may also be written as a vector:

(2.8) equation

In Figure 2.5 and in the vector (2.8), we have tacitly assumed that the consequences can be classified into a finite number ( images ) of discrete consequences. This is often a simplification that we make in risk analysis.

A study object may lead to several potential hazardous events. It may therefore be relevant to establish the consequence spectrum for the study object rather than for a single hazardous event. Each hazardous event then has a consequence spectrum, as shown in Figure 2.5 . Combining the consequence spectra for all the relevant hazardous events yields the consequence spectrum for the study object. This consequence spectrum has the same form as for a hazardous event. The consequence spectrum may also be presented in a table, as shown in Table 2.8 .

Table 2.8 Consequence spectrum for a study object

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