This chapter is intended to be an overview of HVAC security considerations relative to natural events, accidents, terrorism, and national threats, as well as addressing chemical, biological, radiological, and explosive (CBRE) incidents that do not cause major structural damage to a building or its infrastructure. This added focus on CBRE incidents, either accidental (e.g., an industrial spill) or premeditated, is intended to be a general overview and not used as design guidelines. OWNER’S PROJECT REQUIREMENTS RISK EVALUATION HVAC SYSTEM SECURITY AND ENVIRONMENTAL HEALTH AND SAFETY DESIGN CHEMICAL INCIDENTS BIOLOGICAL INCIDENTS RADIOLOGICAL INCIDENTS EXPLOSIVE INCIDENTS