Some guidelines already exist, particularly for military structures. Documents are also available from our industry's European counterparts, who sadly have more experience in this area.
The most critical information needed for system designers, most agreed, is risk assessment levels for various types of buildings. Hospitals, schools, and public event facilities (arenas, etc.) are likely high-risk targets in the commercial-industrial sector. How do you help building owners plan for possible events if their structure is down the street from a high-risk target?
Moreover, how do you get building owners to even get an assessment without having them run from the potential liability, when they don't even want an IAQ assessment? One possibility is to slip it into general operations.