TABLE OF CONTENTS As noted earlier in this chapter, two pipeline activities that can contribute to consequence reduction are secondary containment and emergency response. Both are useful only as consequence reducers since both are reactionary to a release that has already occurred and neither provides an opportunity to prevent a failure. There is little argument that, especially in scenarios involving more chronic consequences, secondary containment and emergency response can indeed minimize damages. They are therefore included as modifiers to the dispersion portion of the leak impact factor. The amount of the contribution to the overall risk picture is arguable, however, and must be carefully evaluated.
Chronic hazards have a time factor implied: potential damage level increase with passing time. Actions that can influence what occurs during the time period of the spill will therefore impact the consequences.
Acute hazard scenarios offer much less opportunity to intervene in the potentially consequential chain of events. The most probable pipeline leak scenarios involving acute hazards suggest that the consequences would not increase over time because the driving force (pressure) is being reduced immediately after the leak event begins and dispersion of spilled product occurs rapidly. This means that reaction times swift enough to impact the immediate degree of hazard are not very likely. We emphasize immediate here so as not to downplay the importance of emergency response. Emergency response can indeed influence the final outcome of an acute event in terms of loss of life, injuries, and property damage. This...
