hazardous material, the location of the affected material, and the
failure modes that could lead to the release.
b. For each target SSC or its barrier selected above, more than one
impact location should be considered so that the worst adverse
effects can be determined. It is possible that the impact location that
produces the worst global response is different from the location that
produces the worst local damage or SSC functional failure.
c. The angle of impact should be based on the orientation of the SSC or
barrier being evaluated, the worst impact angle from SSC/barrier
vulnerability considerations, and the most probable angle of impact for
the aircraft subcategory to which the critical missile belongs.
Local Response Evaluation. The local response of the target will be initiated with
spalling and subsequently result in penetration, scabbing of target material from
the back face of the target, and the eventual perforation of the target, transporting
the missile through the target (Figure 3).
Empirical formulas validated by tests have been used to predict these local
responses for predominantly rigid (nondeformable) missiles (see Table I). Empirical
formulas are for the case of normal (90-degree) impact. When the impacting
missile strikes normal to the target face, the local responses are maximized. The
angle of strike can substantially influence the extent of local damage and should be
appropriately considered. For further guidance see the technical support
document for SSC evaluation (Reference 1).
Typically, spalling is not of any safety concern, and it is sufficient to evaluate
safety-related targets against only scabbing and perforation (i.e., full penetration)
using the methods provided herein. If the results of such evaluation do not meet
Section 4.3 guidelines, it is not necessary to perform global response or building
collapse evaluation, and the evaluation should proceed to consequence analysis in
accordance with Chapter 7.