<45> Is risk acceptable? If the PDT plus ingress/egress times for
one or more of the building components does not equal or exceed the guard
response, the designer should decide if the risk is acceptable considering
other factors such as the cost of additional hardening, etc.
<46> Select construction of first layer.
If the designer reaches
here, it means: (a) the minimum prescribed construction of the innermost
layer for one or more building components does not meet delay time
requirements; (b) one or more components of the exterior layer design for
blast, standoff weapons, etc., does not meet minimum delay time requirements;
(c) inner and exterior layers in combination do not meet delay time
requirements; or (d) there is no previously prescribed inner or exterior
layer construction and the design must start at this point. The data in par.
5.5 provides design options and PDT for new construction and par. 5.6 for
existing and retrofit construction. These should be selected and entered
appropriately into Columns C and D of the worksheet for new construction
(Table A-1) and Rows C, D, E, and F for each component for retrofit
construction (Table A-2). If possible, one should identify those choices
that achieve an equivalent penetration time over all building components,
i.e., walls should be about equally as hard as the roof, doors, etc. In some
cases, the use of multiple doors may be required as shown in Figure 10.
<47> Is the PDT plus ingress/egress time greater than or equal to
the guard response time for all components and layers? If one or more of the
building component penetration (Column D for Table A-1, Column 6 for Table A-
2) plus ingress/egress times (both interior and exterior to the building)
does not equal or exceed the guard response time, additional delay is
required. In this case, the flow chart branches to Element <48>, otherwise
to Element <55>.
<48> Is risk acceptable? If the penetration delay plus
ingress/egress times for one or more of the building components does not
equal or exceed the guard response, the designer should decide if the risk is
acceptable considering other factors such as the cost of additional
<49> Are any more layers possible? If the preliminary layout of
the building permits more layers to be hardened to achieve the needed delay,
the flow chart branches to Element <53>, otherwise to Elements <50>, <51>, or
<52>. Here, the designer has the option of redesigning the layout of the
building interior (Element <52>), reevaluating the guard operating procedure
to reduce the response (Element <50>), or adding CCTV to reduce the threat
assessment time (Element <51>).