Page 251 - Pipeline Risk Management Manual Ideas, Techniques, and Resources

11/228 Distribution Systems
Public education/locatingprcess larly available along pipelines under pavement. Placement of
pipelines is consistent relative to sidewalks, roadways, etc.
The approach to public education in a distribution system Routings of service lines are uniform (standard design) and
might be slightly different than that of a transmission system. marked wherever practical.
The higher concentration of people allows for the effective use Average
of certain communications media. With a distribution system, ROW conditions are inconsistent, More markers are needed.
most of the pipeline neighbors are also customers, and they are More opportunities for leak detection are needed. Signs are
easily reached through information included in the customer not always in legible condition.
bill. Other common methods of public education include news- Poor
paper ads and public service broadcasts (radio, TV). Points No markers present anywhere. Placement of lines is inconsis-
should be awarded based on how effective the program is. tent. Areas of vegetation are overgrown. Debris or structures
Effectiveness is best measured by results: the number ofpeople cover the pipelines. Very difficult for anyone to know of
near the pipeline who understand that the pipeline system presence of buried utility line. See also page 54.
exists, what constitutes possible threat to pipe integrity, and
appropriate reactions to threats or evidence of leaks. Especially Patrol
in a high population density situation, knowledgeable and
cooperative neighbors add a great deal to pipeline security from Formal patrols might not be part of a distribution system
third-party damage. owner’s normal operations. However, informal observations in
A significant number of serious accidents occurs in service the course of day-to-day activities are common and could be
lines-those pieces of pipe between a distribution main and a included in this evaluation, especially when such observations
building. These lines are not always owned by the distribution are made more formal.
company-the service line may be owned and maintained by Much of an effective system patrol for a distribution system
the building owner or property owner. From a risk standpoint, it will have to occur at ground level. Company personnel regu-
is important that the maintainers know the safety issues larly driving or walking the pipeline route can be effective in
involved. Depending on the boundaries of the risk assessment, detecting and halting potentially damaging third-party activi-
the evaluator may check that reasonable steps are taken to ties. Training or other emphasis on the drive-by inspections
ensure the proper maintenance of the distribution system that could be done to heighten sensitivity among employees and
leads to the customer’s equipment. contractors. Other patrolling concepts are discussed beginning
Public education for water systems often focuses more on on page 54.
customer health issues such as contamination potential. A point scale can be created to assess how much of the sys-
Outside of the one-call system advertisements, public educa- tem is being examined and on what frequency. The following
tion is not commonly done as a means to protect water systems equation provides such a scale. Note that issues regarding
from third-party damage. In this case (and any case where pub- patrol effectiveness should be incorporated into this score. That
lic education scoring is not applicable), the evaluator can sim- is, a less effective patrol performed more frequently is basically
ply award no points for this variable. Alternatively, he can equivalent to a more effective but less frequent patrol.
change the risk model so that a replacement variable is used or
the public education points can be redistributed among the (Number of weekly patrols + 5) x (% of system observed on each patrol)
other variables. A candidate replacement variable might be x 15 =point score (if 15 points is the maximum point level)
locating process-an evaluation of the process for receiving
notification of pending activity and response to that notifica- Using this equation, maximum points (15) are awarded for
tion including marking, oversight, and follow-up. This would patrols occumng five times per week that observe 100% of the
overlap the one-call variable to some extent. system on each patrol. Twice per week patrols that view 80% of
Modifications to the suggested point scale on page 53 can the system would be equivalent to patrols four times per week
reflect the use of education practices for distribution systems. seeing 40% of the system on each patrol (approximately 5
points).
ROW condition
A distribution system ROW is usually quite different from a VI. Corrosion index
transmission line ROW. It is impractical to mark all locations of
the distribution pipes because many are under pavement or on Depending on the material being used, the same corrosion
private property. Nonetheless, in some areas, markers and clear mechanisms are at work in a distribution system as are found in
ROW postings are practical and useful in reducing incidences transmission pipelines. It is not unusual, however, to find older
of third-party intrusions. Included in this item are inspection metallic distribution lines that have no coating or other means
opportunities designed to assist in leak detection surveys. of corrosion prevention. In certain countries and in certain time
A qualitative scale can be devised to assign points to a periods in most countries, corrosion prevention was not under-
section of distribution piping being evaluated: taken. As would be expected, corrosion leaks are seen more
often in such pipes where no or little corrosion prevention steps
Excellent are taken. The presence of unprotected iron pipe and non-
ROW is clear and unencumbered. Signs are present wherever is cathodically protected steel lines is statistically correlated with
practical. Signs are clear in their warning and phone num- a higher incidence of leaks [5 11 and a primary consideration in
bers are prominent. Leak detection survey points are regu- many “repair-and-replace” models.