PIPELINE QRA SEMINAR
PIPELINE RISK ASSESSMENT
RISK REDUCING MEASURES
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INTRODUCTION TO RISK REDUCING
MEASURES
“selecting one or more options for modifying risks and
implementing those options”
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INTRODUCTION TO RISK REDUCING
MEASURES
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Depending on the outcome of the risk evaluation
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Decision-making (i.e. to take mitigating actions or not)
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Decision could also be to not proceed – showstopper!
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Mitigating actions (risk reducing measures) influencing
the frequency or consequence of the risk
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Given the implementation of risk reducing measure – is
the residual risk tolerable?
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INTRODUCTION TO RISK REDUCING
MEASURES
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We know that the frequency and consequence is
combined to the risk in the QRA
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Reduction in risk through influence the frequency of the
scenario or the consequence of the scenario
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Preferable to influence the frequency (i.e. avoid any
kind of accident)
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INTRODUCTION TO RISK REDUCING
MEASURES
What could be a risk reducing measure?
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INTRODUCTION TO RISK REDUCING
MEASURES
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There are always a number of barriers to prevent the
accident from happen (or mitigate the consequences from
the accident)
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When discussing risk reducing measures – we add a barrier
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In order for the accident to happen the barriers must fail
- Active failure – directly linked to the accident (e.g. human
error or safety valve failing on operation)
- Latent conditions – existing for days, weeks or months
(e.g. unsufficient design and insufficient maintenance)
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INTRODUCTION TO RISK REDUCING
MEASURES
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Decreasing effectiveness in risk reducing measures
- Elimination (e.g. reduce the number of valves on the
pipeline)
- Substitution (e.g. re-think the pipeline routing)
- Engineering/isolation (e.g. place the control panel
outside the process room)
- Administration/training (e.g. establish procedures for
shut-down off pipeline and maintenance)
- Protective equipment (e.g. respirators and helmet)
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Increasing success in risk reducing measures!
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INTRODUCTION TO RISK REDUCING
MEASURES
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Preferable risk reducing measure – elimination!
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Preferable risk reducing measure – already implemented
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HSE design – cross-disciplinary activities on design, risk reduction and operability
- Increasing focus area
- Previously design (engineering) and risk assessment (engineering) separated
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The earlier risk reducing measures could be specified (compare with risk identification for early stage projects) – the
easier implemented
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EXAMPLE OF RISK REDUCING MEASURES
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San Bruno, September 2010
- rupture gas pipeline
– flawed weld during construction
- lack of quality control (construction)
- inadequate integrity management programme
(inspection and maintenance during operation)
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Suggestion to risk reducing measures?
- Review of integrity management programme (e.g.
what could inspections actually find and frequency of
inspection and maintenance)
- RFO (pressure testing of system)
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EXAMPLE OF RISK REDUCING MEASURES
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New Mexico, August 2000
- rupture gas pipeline
– internal corrosion
- inadequate integrity management programme
(inspection and maintenance during operation)
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Suggestion to risk reducing measures?
- Review of integrity management programme (e.g.
what could inspections actually find and frequency of
inspection and maintenance)
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EXAMPLE OF RISK REDUCING MEASURES
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Michigan, July 2010
- rupture oil pipeline
– external corrosion (under coating)
- undetected for 17 hours
- inadequate integrity management programme
(inspection and maintenance during operation)
- inadequate detection system and adequate
preparedness/training/education of operators
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Suggestion to risk reducing measures?
- Review of system for detection of leakages
- Establish emergency procedures and conduct exercises
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EXAMPLE OF RISK REDUCING MEASURES
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Wonowon, June 2012
- leak compressor station
- replacement of safety device (not same function)
- inadequate knowledge of process equipment (safety
device function)
- no personal gas detectors and no process room gas
detection
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Suggestion to risk reducing measures?
- Review procedures for maintenance (and changes to
the process equipment)
- Install system for detection of leakages (flashing light)
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EXAMPLE OF RISK REDUCING MEASURES
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Carthage, February 2011
- leak compressor station
- failing check-valve
- inadequate design of ESD-system
- impingement of process equipment
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Suggestion to risk reducing measures?
- Typical example where HSE design could have been
applicable!
- Installation of passive fire protection (resist fire for
certain period of time)
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EXAMPLE OF RISK REDUCING MEASURES
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Natural hazards (e.g. earthquakes, erosion, landslides
and flooding)
- Studies (e.g. location and environment) before
pipeline routing
- Design (i.e. criteria for earthquake impact)
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3rd party interference (e.g. excavation and collision with
vehicle)
- Warning signs
- Protection (e.g. rocks)
- Buried or exposed (depending on situation)
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EXAMPLE OF RISK REDUCING MEASURES
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Process conditions (e.g. moisture and changed
conditions)
- Internal inspections (e.g. pigging)
- Internal corrosion protection
- Management of change (i.e. what could be the
consequences of this change?)
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EXAMPLE OF RISK REDUCING MEASURES
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Risk reducing measures for urban areas?
- Valves on the pipeline (limiting the possible release)
- Increased wall-thickness (resistance to 3rd party
interference and damages due to overpressure at other
locations)
- Ensure ventilation (density lower than air)
- Public education (awareness of gas pipelines and
possible detection of pending accidents – sound/smell)
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EXAMPLE OF RISK REDUCING MEASURES
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Awareness of multiple effects (and possible opposite
effects) of risk reducing measures
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Valves on the pipeline
- Advantage – limit the release
- Disadvantage – increasing release points
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Buried or exposed pipeline
- Easy to see or not?
- Exposed to 3rd party or not?
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RISK REDUCING MEASURES
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When is a risk tolerable (acceptable)?
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What is a risk intolerable (unacceptable)?
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How much risk reduction is possible?
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How safe is safe enough?
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QUESTIONS?
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