Page 531 - Marine Structural Design

Chapter 28 Probability and Risk Based Inspection Planning 507

The person (inspector) who carries out an inspection can greatly influence the inspection
performance. Performance varies not only from inspector to inspector, but also from
inspection to inspection with the same inspector based on his mental and physical condition.
Factors associated with the inspector include experience, training, fatigue, and motivation.
The environment, in which the inspection is carried out, has a major influence on performance.
The environmental factors can be divided into two categories: external factors which cannot be
modified by inspection procedures and procedure factors that can be modified. External
factors include weather and location of the vessel, that is, whether the inspection is performed
while underway, while in port, or while in dry-dock. Procedural factors reflect the condition
during the inspection (lighting, cleanliness, temperature, ventilation), the way in which the
inspection is conducted (access method, inspection method, crew support, time available), and
the overall specification for inspection (inspection type).
Inspection Strategies
Inspections, data recording, data archiving (storage), and data analysis should all be a part of a
comprehensive and optimum inspection system. Records and thorough understanding of the
information contained in these records are an essential aspect of inspection programs.
Inspection is one part of the ‘system’ that is intended to help disclose the presence of
‘anticipated’ and ‘unanticipated’ defects and damage. Development of inspection programs
should address:

Elements to be inspected (where and how many?)
Defects, degradation, and damages to be detected (what?)
Methods to be used to inspect, record, archive, and report results (how?)
Timing and scheduling (when?)
Organization, selection, training, verification, conflict resolution, and responsibilities
(who?)
Objectives (why?)
Where and How Many?
The definition of the elements to be inspected is based on two principal aspects:
Consequences of defects and damage
Likelihood of defects and damage
The consequence evaluation essentially focuses on defining those elements, and components
that have a major influence on the quality and safety of a FPSO. Evaluation of the potential
consequences should be based on historical data (experience) and analysis to define the
elements that are critical to maintaining the integrity of a FPSO. The likelihood evaluation
focuses on defining those elements that have high likelihood’s of being damaged. Experience
and analyses are complementary means of identifying these elements.