This presentation is a discussion about the HVAC, electrical, and plumbing systems commonly found in commercial buildings and will revolve around topics firefighters should understand from an engineering design perspective. We all know the importance of being familiar with structures located in our first due from a basic fire protection standpoint. That’s why we pre-plan. As firefighters, we tend to focus on construction and life safety systems such as sprinklers, fire alarms, and high hazard areas. This is all very important. However, I believe this process should go beyond these topics. Firefighters need to understand how important it is to know how buildings work. Familiarity and control of building systems is essential for effective tactics, scene stability and, most importantly, safety of occupants and firefighters on the fireground. The goal of this presentation is to provide firefighters with a basic understanding of what to look for both before, and during, an incident with respect to building systems. They will also learn ideas to gather information and develop relationships to improve their strategies and operations. At the conclusion, firefighters will have an “awareness level” of how these systems can impact fireground tactics and safety and how to prepare for and handle them.