Page 307 - Pipelines and Risers

280 Chapter I6

Probability reducing measures shall, to the extent possible be given priority over
consequence reducing measures.
Subsea pipeline systems shall be to a reasonable extent, be protected to prevent
mechanical damage to the pipeline due to other activities along the route, including
fishing and shipping activities.

Individual corporations may choose to implement internal acceptance criteria. These
acceptance criteria may be based on the relative cost between implementing a risk reducing
measure and the potential loss. Also many projects specify a pipeline availability requirement.
Thus total losses must be such to ensure required availability.

If the risk estimation arrived at is not within the acceptable risk, then it is necessary to
implement alterations. This new system should then be analyzed and compared with the risk
acceptance to ensure adequate risk levels. This is an iterative process, which will eventually
lead to a system/ design, which is acceptable.

16.2.2 Individual Risk
The FAR (Fatal Accident Rate) associated with post commissioning activities (the installation
and retricval of pigging equipment) has been evaluated.

The FAR acceptance criteria are defined to be 10 fatalities per lo8 working hours.

The maximum FAR (Fatal Accident rate, No. of fatal accidents per lo8 hours worked) for the
operational phase should be I 10. The maximum FAR for the installation phase should be I
20.

16.2.3 Societal Risk
The society risk is 3rd Party (Societal) Risks posed to passing fishing vessels and merchant
shipping.

Acceptance of 3d party risks posed by pipeline should be on the basis of the F-N curves
shown in Figure 16.2 below.