Page 279 - Pipeline Risk Management Manual Ideas, Techniques, and Resources

121256 Offshore Pipeline Systems
(see page 159). Some additional considerations, specific to off- Other spill-limiting conditions such as emergency block val-
shore spills, are as follows. ues and secondary containment are covered in the basic model
The need for quick detection is important in most offshore (see Chapter 7) and can apply to an offshore analysis as well.
environments because of the potential for contaminant
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spread coupled with the remote locations of many off- Example 12.2: Leak impact factor
shore installations. In situ burning of oil on water is often
attractive as a means of mitigating a spill. The need for A pipeline transporting light crude oil is being evaluated. The
physical collection, transportation, storage, and disposal of product hazard is evaluated as described on pages 136142.
spilled product is reduced. Drawbacks include the visible The worst case section has strong subsurface currents and
smoke plume containing soot and other combustion by- strong prevailing winds close to shore. These will tend to
products and the lack of knowledge about heat and radiation spread the product as it rises from the submerged pipe and
from large fires. again as it pools on the water surface. The range is therefore
Response plans should take full advantage of spill cleanup scored to be nearly the highest dispersion score. (The highest
technology. Oil spill chemical treating agents include disper- score for this company is reserved for spills into fast flowing
sants, emulsion breakers, beach cleanup agents, biodegrada- freshwater streams.) Receptors combine the population density
tion agents, and surface-washing agents. Although these have (rural) and known recreational and commercial use areas with
been proven to be effective in specific cases, wide differences the environmental and the high-value areas, of which there are
in oil type and composition complicate attempts to identify none in this case, except for near-shore approaches. Those
agents that are effective across a wide range of products [78]. areas indicate higher consequence potential and hence, higher
Knowledge of available agents and their application to specific overall risk. Response capabilities, including a state-of-the-art
spills is required to make the best use ofthe agents. This is a rel- SCADA-based leak detection system, are considered to be
evant knowledge area for the evaluator to explore with the fairly robust and should facilitate minimization of conse-
pipeline operator when assessing response capabilities. quences in all areas distant from the shore approach.