EuroWire November 2015

Technical article

when protection. Repairability, data safety and backup strategies are just a few of them. 3.2 Risk Assessment Quantitative risk assessment requires calculations of two components of risk: the magnitude of the potential loss, and the probability that the loss will occur. So risk (R) is determined as a product of two factors: The probability of any failure (p) is multiplied by the magnitude of the potential loss (L) caused by that failure, further shortly called impact of failure. This is common knowledge according to Wikipedia [5] and is used in standard engineering methods as the well known failure method and effect analysis (FMEA) [3] as well as in insurance risk assessment procedures. Insurance companies use the risk calculation according to Equation (1) in risk assessment which is basic to determine insurance premiums. Here both factors – probability and impact of failure- are taken into account, too. Equation (1) indicates that it is worth taking both factors into account. In many realistic cases both factors of risk depend on each other. To name an example taken from this fire protection topic, the use of halogenated materials reduces the probability of failure but increases the possible impact on personal health by asphyxiation or something else. Experience from FMEA practice reveals the advantage to keep both factors on a similar low level. If both factors may vary in a range from 1 to 10, the risk varies from 1 to 100. If the probability is reduced down to 4 and the impact down to 5, a risk level of 20 as a product of the factors 4*5 is achieved. If the impact remains on its high level of 10, the probability must be reduced down to 2 to achieve the same risk level. Keeping in mind the Pareto principle, it will be clear that the effort to achieve this extremely low level of one factor will exceed the effort to keep both factors on a medium level. The advantage to distribute the efforts of risk reduction to both factors (avoidance and impact reduction) is shown in Figure 2 . The dashed line shows the risk depending on reduction efforts if all efforts are invested into threat avoidance. The continuous line shows the risk if the reduction efforts are distributed to both avoidance and impact reduction in the same quantity. Some simplifying assumptions are done in this approach to show the basic principle easily. It can be clearly seen that just in the medium part of the range, the distribution of efforts to both factors brings clear advantages. considering fire R=p*L Equation (1 )

Power distance

Masculinity

Individualism

Germany Japan USA

Uncertainty avoidance

Long-term orientation

▲ ▲ Figure 1 : Cultural relativity for three selected nationalities according to Hofstede [1]

Risk vs Effort

Risk (2 factors) Risk (1 factor)

Remaining Risk

Total Effort

▲ ▲ Figure 2 : Remaining risk versus total effort for reduction efforts on one factor or both factors

orientation and not find the emergency exit. In the same way smoke may restrict the work of rescue teams. Further acid fumes cause asphyxiation which is the most often lethal consequence of a fire. 3.1.2 Damage of Goods In case of fire, damage of goods might happen by combustion but also by corrosion effects due to the presence of acid smoke. Smaller damages by acid smoke often remain undetected when a halogenated material burns and a layer of acid radicals covers some electronics. When weeks or months later humidity increases due to weather changes or else, this film reacts to an acid and causes failures by corrosion which are not detected as a long-term consequence of that fire some time ago. 3.1.3 Economic Loss The financial damage caused by a fire might be much higher than the real value of any devices burnt down. In the industrial field we know a production downtime caused by machinery damage may exceed the cost of the machinery itself many times over. Especially in banking and finance the loss of information is another important economic threat of a fire event. Thus additional aspects are to be included

This is also valid in respect to fire safety. For this reason the threat of fire is estimated differently. This results in different national or regional approaches for fire protection. To look deeper into these approaches it is important to understand the threats of fire and the theory of risk.

3 Risk of Fire 3.1 Threats of Fire Events

In occurrence of fire there are different aspects that people are to be protected against. In almost all cultures the most important aspect should be the protection of life and the avoidance of personal injuries. Protection of goods against combustion or secondary damages such as corrosion are important. This depends on the value of these goods, which might be estimated differently in different cultures. Further economic loss can be caused by less physical effects of a fire such as loss of information or downtime of any infrastructure. 3.1.1 Personal Health The threats for personal injury by a fire are much more than suffering burns. Huge danger in case of fire is generated by smoke. In dense smoke people may lose

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November 2015