DESCRIPTION
Security-related costs arise from ISC requirements that influence the design of structural components and non-structural components. For example, the requirements for consideration of blast threats to the facility impact the design, and thus cost, of the structural frame and façade elements including walls, roof, and windows.
The impact of design explosive threat level on cost is reflected in the increased requirements of structural components, e.g., thicker walls, additional reinforcement, blast-resistant glazing and frames, etc. The two primary blast-related factors that influence the design of a structural component are the design threat magnitude (e.g., lbs TNT) and the distance between the potential explosion and the structural component, i.e., the standoff. Note that standoff is the distance to the structure from a defended perimeter, i.e., the closest distance to the design threat.
An increase in explosive weight or a decrease in standoff generally increases structural requirements. Since the ISC Security Criteria impose the design explosive weight magnitude for each level of protection, the building design is influenced by the amount of standoff available. For the defined threat level in the criteria for a particular facility, the designer must balance the effect of available standoff by incorporating blast-resistant design and/or hazard mitigation measures.
The effects of standoff on various structural and non-structural components are illustrated in Fig. 1. This figure generally illustrates, at no particular scale, the general trends and relationships between standoff and cost of protection. A number of the various components of incremental security cost are shown, including structural and non-structural component contributors.