What assumptions would PHMSA Pipeline Safety find acceptable for analysis of spilled product transport by waterway or topographical features?
Because the physical characteristics near pipelines can vary dramatically, PHMSA Pipeline Safety does not believe that any single set of assumptions would be applicable in all cases. For example, waterways may be broad, slow-moving rivers or fast-moving mountain streams. Topography near a pipeline can vary between a flat prairie and steep gullies. Ground cover can also affect the speed of product transport. Operators are responsible for considering the specific circumstances of their pipeline in the vicinity of high consequence areas, and determining the analytical assumptions that are appropriate. Operators are expected to consider the effect of extreme conditions (e.g., floods), and to use recognized sources for data regarding stream flow rates, etc. Operators should assure their analyses are reasonably conservative. PHMSA Pipeline Safety may review the technical basis for these assumptions during integrity management inspections.
Related Questions
- Should operators inform PHMSA Pipeline Safety of changes they determine are needed to HCAs as defined in the National Pipeline Mapping System (NPMS)?
- What assumptions would PHMSA Pipeline Safety find acceptable for analysis of spilled product transport by waterway or topographical features?
- What type of risk analysis process would PHMSA Pipeline Safety prefer, quantitative or qualitative?
