As a result of recent developments it is expected that Formal Safety Assessments will have to be performed for all offshore installations in the UK Sector of the North Sea in this paper the main elements of these assessments and application to pipeline design are briefly introduced. The information required for these assessments is discussed and sources of historical data and information that are available are presented Finally incidents which have caused damage to pipelines m the past are described.
The design of a system is regulated in order to ensure that it can perform its expected function safely This is usually achieved by following appropriate Codes and Standards which have been formulated over the years on the basis of experience However, for some time there has been concern that reliance on good engineering practice, the application of approved standards and certification and inspection are not by themselves always sufficient to identify and highlight hazards and sequences of events that can lead to a major hazard [I], and thus ensure that required levels of safety are achieved and maintained
Following the issue of a discussion document by the UK Department of Energy [I], it is anticipated that Formal Safety Assessments will have to be performed for all offshore installations In the UK Sector of the North Sea The perceived objective of these studies is to confirm that all possible hazards have been recognised and steps taken to prevent or minimise their occurrence and the consequences of such an occurrence
Hazards to be considered for an installation include product release from pipeline systems and therefore the safety assessments will need to include hazards to pipelines and their consequences The analysis techniques that it is suggested should be used in these assessments include Quantified Risk Analyses, Detailed Safety Evaluation Studies, Evacuation Studies, Ship Collision Studies and Safety Audits The main elements of these assessments will be the identification of potential hazards, the analysis of their consequences and the determination of their expected frequency. In this paper these steps and their use in pipeline design are briefly discussed.
Three main areas of difficulty in the quantification of risk have been identified by the Department of Energy [l] These are the limited statistical data on equipment failure rates on which to predict overall failure criteria, the level at which acceptability criteria for failure rates can be set and the assessment of human factors and their contribution to such risks The information that would be required to overcome these difficulties for pipelines is discussed and the sources of historical data and information that are available are presented
The use of methods such as HAZOP and FMECA and reliability analysis techniques such as Fault and Event Trees is well established. However, they have only been used to a limited extent in pipeline design During the design process hazard and risk analysis techniques have been used mostly as a decision making tool to assist In the choice between design solutions.