Page 269 - Pipeline Risk Management Manual Ideas, Techniques, and Resources

la246 Offshore Pipeline Systems
High outside forces. The protecting structure’s frame geometry and
Area has high vessel traffic and/or shore approaches withpopu- embedment depth are significant factors in determining the
lation nearby, or is a commonly dredged area. Normal possibility of fouling from fishing gear.
anchoring nearby creates potential for damaging anchor In general, score the presence of surface facilities as 0 pts
loads. If a fishing area, the use of potentially damaging and then add points for all measures that would reduce the like-
equipment is normal. Construction activity, third-party dam- lihood of third-party damage, up to a maximum of IO pts (see
age that has occurred in the past, and the presence of other Chapter 3).
offshore structures suggest a higher threat level.
Medium D. Damage prevention (weighting: 20%)
Area has shore approaches with occasional human visitation,
some vessel traffic, a fishing area where mostly nonthreaten- A damage prevention program for an offshore pipeline can
ing equipment is being used, is only an occasional anchoring have many of the same aspects of its onshore counterpart. Risk
area for higher anchor loads, and an anchoring area for variables that can be evaluated in order to assess the quality and
smaller (low-damage-potential) vessels. effectiveness of a damage prevention program include public
Low education, notification systems, and patrol. The first two are
Areas with rare human visitations and due to water depth or discussed here and patrol will be discussed as an separate
other factors, potentially damaging activities are possible, variable.
but very rare. There is little or no vessel traffic, no anchoring,
and no dredging. Public education
None
This category is assigned where essentially no potentially Public education is often an integral part of a damage preven-
damaging activity can occur. An example might be very tion program (see Chapter 3). The public to be educated in this
deep water where no other activities (no anchoring, drilling, case includes boaters of all kinds, fishermen, offshore con-
diving, cable or pipeline installations, etc.) are possible. structors, supply boats, recreational craft, and law enforce-
ment. Pipeline route maps could be supplied and informal
As an alternative to the scoring approach above, individual training given to groups to alert them to signs such as bubbles
contributors to activity level can be weighted, assessed, and or sheens indicating possible pipeline damage. Training
combined into an activity score. For example, a possible list of should emphasize the susceptibility to damage by anchors or
contributors and weightings is shown below: dredging. There is often a misconception that a steel pipeline,
especially when concrete coated, is unharmed by anchors and
Foreign crossings (pipelines, cables, etc.) 10% nets.
Fishingicrabbing area 15% The quality of the public education program can be assessed
Recreation area 15% by evaluating components such as:
Vessel traffic 15%
Distance from shore 10% Mailouts Maximum points are appropriate for regular, effec-
Dumping site 10% tive mailed communications to people engaged in potentially
Anchoring areas 15% harmful activities.
Water depth 10%
Presentations Maximum points can be awarded for quality
These factors make up 100% ofthe activity score, in this exam- programs targeting audiences that engage in potentially harm-
ple. Each would be assessed, assigned apoint value, adjusted by ful activities.
a respective weighting, and summed with all other factors.
Advertisements While not as specific as other measures, this
C. Aboveground facilities (weighting: 10%) may reach a wider audience. Maximum points are appropriate
where there is evidence of advertisement effectiveness.
As with its onshore counterpart, exposed facilities offshore can
be a good or bad thing, from a risk standpoint. Being in clear Route maps Maximum points can be awarded for high qual-
view, the facilities are less exposed to certain types of acciden- ity, accurate route maps that are widely distributed and effec-
tal damage, but they are more exposed to intentional damage or tive in reducing third-party intrusions.
use for unintended purposes. Many offshore platforms are
unmanned and visited infrequently. Platforms are susceptible to Notijication systems
ship traffic impact and are sometimes convenient locations for
temporary mooring of vessels, especially recreational fishing One-call systems are probably not meaningful in the offshore
boats. Warning signs, lights, and on-site or remote monitoring environment. An exception would be a program that dupli-
(alarmed motion detectors, video surveillance, sound monitors, cates the intent of the land-based one-call program. Such a
etc.) with adequate response offer a degree ofprotection. program would require anyone performing potentially
When considering third-party damage potential, submerged pipeline-damaging activities in the water to contact a central
but unburied pipelines can be evaluated in the same way as clearinghouse that would notify owners of facilities of the
surface facilities. Where valve assemblies are located on the impending activity. To be effective, such a program must
seafloor, it is common practice to use subsea valve protectors- be regularly used by all parties concerned, contacts to the
structures placed around the valves to protect them from clearinghouse must indeed be made prior to any work, and