Data - Information that is specific to the facility being analyzed but is unlikely to
have already been compiled in other documents. Such information is generally
needed only for aircraft crash analysis and would therefore not be readily available
unless a previous analysis has been performed.
Derived - Information that results from the application of this standard. Generally,
a derived input was an output of one of the previous steps of the analysis.
Exposure Screening. Exposure screening consists of performing a simplified,
conservative analysis of the potential hazardous material exposure to any member of the
public resulting from an aircraft crash into a facility. For the purpose of this screening, it is
assumed that the building is destroyed and all of the hazardous material available in the
building is impacted; conservative values for the amount of material that can be
transported and ingested are used, and it is assumed that the most direct and harmful
path is taken to the site boundary. Exclusions of well-confined material from the
hazardous materials inventory may be made, but should be justified on the basis of the
robustness of the material containment in a postulated aircraft impact environment. The
purpose of this step is to determine whether there is sufficient hazardous material
inventory in the facility that the worst possible release could cause measurable harm to a
member of the public (or, in certain cases, to a worker near the facility). The guidelines
(given in Section 4.1) are expressed in terms of a dose (for radioactive materials) or a
concentration (for chemical hazards) to the maximally exposed individual at or beyond the
site boundary. The methodology for the analysis is provided in Section 7.2.
The result of the analysis allows the analyst to determine what amount of radioactive or
hazardous chemical material would have to be present in the facility to exceed the
guidelines at or beyond the site boundary (see Chapter 4). The analyst can then
determine whether the facility inventory would exceed those guidelines. If the facility
inventory does not exceed the thresholds, the risk is deemed to be small and the results
are documented. If the facility inventory does exceed the thresholds, the analysis should
proceed to the next step.