TABLE OF CONTENTS A release of pipeline contents can impact a very specific area, determined by a host of pipeline and site characteristics. The relative size of that impacted area is the subject of this portion of the consequence assessment.
As modeled by physics and thermodynamics, spilled product will always seek a lower energy state. The laws of entropy tell us that systems tend to become increasingly disordered. The product will mix and intersperse itself with its new environment in a nonreversible process. The spill has also introduced stress into the system. The system will react to relieve the stress by spreading the new energy throughout the system until a new equilibrium is established.
The characteristics of the spilled product and the spill site determine the movement of the spill. The possibilities are spills into the atmosphere, surface water, soil, groundwater, and man-made structures (buildings, sewers, etc.). Accurately predicting these movements can be an enormously complex modeling process. For releases into the atmosphere, product movement is covered in the discussion of vapor dispersion. Liquid dispersion scenarios cover releases into other media. Some spill scenarios involve both the spill of a liquid and vapor generation from the spilled liquid as it disperses.
For purposes of many assessments, accurate modeling of the dispersion of spilled product will not be necessary. It is the propensity to do harm that is of interest. A substance that causes great damage even at low concentrations, released into an area that allows rapid and wide-ranging spreading, creates the...
