Page 193 - Pipeline Risk Management Manual Ideas, Techniques, and Resources

7/170 Leak Impact Factor
Historzcal areas. Areas valuable to the public, especially Table 7.20 Sample high-value area scoring
when they are irreplaceable due to historical significance, ~
may carry a high price if damaged due to a pipeline leak. This HVA description Paints
high price might be seen indirectly in terms of public opinion
against the company (or the industry in general) or increased None 0
5
regulatory actions. Archaeological sites may fit into this School 3.5
Church
category. Hospital 5
High-use areas. The areas are generally covered by popula- Historic site 2
tion density classifications (high-occupancy buildings such Cemetery 2
as churches, schools, and stores cause the class location to Busy harbor
rise to Class 3 in U.S regulations, if not already there) or by Airport (major)
environmentally sensitive areas such as state and national Airport (minor)
parks. Evaluators may wish to designate other high-use areas University
such as marinas, beaches, picnic areas, and boating and fish- Industrial center 3.5
3
ing areas as high-value areas due to the negative publicity Interstate highway 2
Recreational arealparks
that a leak in such areas would generate. Special agriculhrre
Water treatmenthource
Identification and scoring of HVAs can be done by Multiple
determining the most consequential conditions that exist Other
and scoring according to the following scale (or according to
the scale of Table 7.21, shown later). Note that the probability
of a leak, fire, and explosion is not evaluated here-nly
potential consequences should such an event occur. Inter- nary conditions along the lines that merit special treatment in a
polations between the classifications should be done. The fol- risk assessment.
lowing classifications use qualitative descriptions of HVA’s
and environmental sensitivities to score potential receptor Equivalencies of receptors
damages.
A difficulty in all risk assessments is the determination of a
Neutral (default) 0 damage state on which to base frequency-of-occurrence esti-
No extraordinary environmental or high-value considerations. mates. This is further complicated by the normal presence of
Because all pipeline leaks have the potential for environmen- several types of receptors, each with different vulnerabilities to
tal harm and property damage, the neutral classification a threat such as thermal radiation or contamination. The overall
indicates that there are no special conditions that would difficulty is sometimes addressed by running several risk
significantly increase the consequences of a leak, fire, or assessments in parallel, each corresponding to a certain recep-
explosion. tor or receptor-damage state. In this approach, separate risk val-
Higher 0.1-0.6 ues would be generated for, as an example, fatalities, injuries,
Some environmental sensitivity. A spill has a fair chance of groundwater contamination, property damage values, etc. The
causing an unusual amount of environmental harm. Values of advantage of this approach is in estimating absolute risk values.
surrounding residential properties are in the top 10% of the The disadvantage is the additional complexity in modeling and
community. High-value commercial, public, or industrial subsequent decision making. An example of this type approach
facilities could be impacted by a leak’s fire or explosion. is shown in Appendix E
Remediation costs are estimated to be about halfway Another approach is to let any special vulnerability of any
between a normal remediation and the most extreme remedi- threatened receptor govern the risk assessment. An example of
ation. this approach is shown in Appendix E Appendix F presents a
Extreme 0.7-1.0 protocol for grouping various receptor impacts into three sensi-
Extreme environmental sensitivity. Nearly any spill will cause tivity areas: normal, sensitive, and hypersensitive. This was
immediate and serious harm. High-cost remediation is antic- developed to perform an environmental assessment (EA) of a
ipated. High-value facilities would almost certainly be dam- proposed gasoline pipeline. Receptors considered and the basis
aged by a leak, fire, or explosion. Widespread community of their evaluation in this EA are shown in Table 7.21. Under
disruptions would occur, as well as long-term or permanent this categorization, an area was judged to be sensitive or hyper-
environmental damage. sensitive if any one of the receptors is defined to be sensitive or
hypersensitive. This conservatively uses the worst case ele-
Another sample of scoring HVAs is shown in Table 7.20. In ment, but does not consider cumulative effects-when multiple
this scheme, various high-value areas are “valued” on a 0- to 5- sensitive or hypersensitive elements are present.
point scale with higher points representing more consequential A third option in combining various receptor types into a risk
or vulnerable receptors. assessment is to establish equivalencies among the receptors.
Attempts to gauge all property values and land uses along the The following scheme is an example scoring of receptors for a
pipeline may not be a worthwhile effort, especially since such hazardous liquid pipeline:
evaluations must be constantly updated. The HVA designation
can be reserved for extraordinary situations. Experienced Population 0-10 pts
pipeline personnel will normally have a good feel for extraordi- High-value areas 0-10 pts