Civil Engineering Reference
In-Depth Information
Quantitative analysis
In this method risk is evaluated, not by subjective judge-
ment, but by numerical data. Quantitative evaluation of
the risk is therefore more demanding than a qualitative
approach but provides a more rigorous evaluation.
A quantitative approach, when used to recalculate
the effectiveness of controls (after implementation of
risk control measures) also provides clear evidence that
confi rms that risks have in fact been reduced.
It should be noted that specifi c raw data is required
when using this technique to analyse the magnitude of
risk. Data that will be required to allow a quantitative
evaluation of risk will be found in the local and national
records of:
insurance industry via the statistics produced by the Fire
Protection Association (FPA) and from the fi re services
via DCLG is available. Generally the statistics produced
by the insurance industry focus upon estimated fi nancial
losses, whereas those produced by DCLG relate to fi re
deaths and injuries.
Both sets of statistics provide information on the
causes of fi re and the numbers of fi res occurring in
given areas or sectors. As the severity rating or potential
outcome of a fi re is death or multiple deaths, reducing
the likelihood of a fi re occurring and managing the
secondary hazards associated with fi re (not being able
to escape, etc.) must be seen as being a high priority.
Gathering meaningful data that gives a clear indica-
tion of frequency and severity is very often diffi cult
(unless the industry, sector, or organisation is large
enough to have suffi cient statistics available).
While personal injury accident data and ill-health
data are generally readily available due to the frequency
of events, the statistics relating to the numbers of fi res
and false alarms refl ect the relatively low numbers of
incidents; however, the outcomes are quite often more
severe, so pure quantitative analysis can be very often
diffi cult to achieve.
Pure quantitative analysis is generally only needed
in a small select group of high risk industries, such as
nuclear and offshore. The fi nal and probably most widely
used evaluation of risk is a combination of the qualitative
and quantitative approaches and is referred to as 'semi-
quantitative' risk.
➤
Hazard reports
➤
Injury accidents and incidents
➤
Ill health and sickness
➤
Health monitoring systems
➤
Environmental monitoring systems
➤
Fire-related incidents.
Details relating to the types of safety events that occur
together with the likelihood of occurrence gathered from
such records are an essential tool when evaluating risk
as they provide statistics that confi rm the severity (or
potential severity if a near miss) and how frequently the
event occurs.
For most organisations gathering statistics in
relation to fi re to provide a quantitative evaluation of fi re
risk can be diffi cult to achieve. However, data from the
How the £250 000 plus fires in 2004-2005 started
70
60
50
40
30
20
10
0
source
Figure 5.11
Graph showing the initiators of fi res that resulted in more than £250 000 damage
