What do you know about building systems? You may not realize how much you do know. Often times, the systems located in our own homes are great examples for understanding what we may find in a commercial structure.

The first picture shown is a typical residential HVAC unit. There's a fan at the bottom, a heating section above the fan, and a cooling section above that. The fan pushes the air through the supply duct and the air is heated or cooled as needed. The fan also draws return air back to the unit where it is filtered and sent back through the system.

Conceptually, this is not really different than a commercial HVAC unit. It's just a much smaller scale, but there will be differences. The unit orientation may be different. The unit may be located on a roof and draw in outside air. Heating and cooling can be accomplished with hot or chilled water instead of electric, natural gas, or refrigeration.

The main intent of HVAC systems is to provide comfort. They may also offer some type of "environmental protection" to occupants or to a process. For example, they may use air pressurization to keep contaminants out of a pharmaceutical manufacturing area or contain biologics in a laboratory. A properly engineered system can also provide protection to firefighters and building occupants by controlling airflow to contain fires and preventing the transmission of smoke containing harmful contaminants. What happens if the system is not engineered, installed, or maintained correctly? A system failure can make a bad situation worse and lead to inefficient use of time on the fireground.

Firefighters should be able to recognize these units and understand how they operate in the event they need to get control of them. In a light commercial structure, this may not be a complicated task. In a more complicated installation, this may not be easy. The units may not be as easy to gain control of and shutting them down could create other issues or concerns. In these situations it is good to have a strong working relationship with building personnel that can help firefighters get control of the equipment and the situation. The units may even be controlled to provide smoke removal in lieu using fans and openings in the buildings.

If you understand the system in your home you can relate it to a larger system. If you don't understand the system, ask your service technician to explain it to you the next time they come out to do preventative maintenance. For larger more elaborate systems, have a working relationship with the facility to be able to understand and operate these units. We all know that if you can control the air, you can control the fire. The HVAC system can be your control point so it's important for firefighters to understand how the system operates and how to gain control of it.

Be Smart - Stay Safe!