Henri Sullivan's classic and now somewhat worn cliché adage came to mind when I recently participated in the Building Security Symposium, sponsored be the Architectural Engineering Institute, the Steel and Ornamental Metal Institute of New York and the Infrastructure Security Partnership at the McGraw-Hill conference center in New York City. The trust of the symposium was to review available design options and risk analysis for an effective resistance to terrorist threats. Buildings with simple geometric shapes and clear lines are obviously less vulnerable to the impact of dynamic blast loads, than the ones with intricate and often convoluted shapes of architectural expression.
Following is a short synopsis of what I learned. While the most common threats are from explosives, the threats from chemical, biological and radioactive agents are real and must be considered. In addition we must stay focused that terrorist threats can come from within as well as from overseas, from misguided political activists as well as disgruntled employees and psychopaths.
Security planning starts with consideration of a specific threat and assessing the associated vulnerability from which the appropriate level of protection may be determined, based on an acceptable level of risk. While a building owner’s defense against chemical or biological agents is limited to control utility access points and installation of expensive detection equipment, more practical options are available to mitigate blast threats from explosives. Explosive charges are limited by the load carrying capacity of the conveyance vehicle from 50 pounds by a personal carrier (satchel) to 5000 pounds of a truck. Controlling / restricting physical access by establishing stand-off zones can be very effective and is less costly than the alternative of structural hardening.
However in an existing urban environment, stand-off zones may not be feasible and hardening may have to be achieved via retro fitting of...