What should be installed in return air systems with a design capacity greater than 2000 cfm?

In return air systems with a design capacity greater than 2000 cfm, the installation of smoke detectors is essential for ensuring safety and compliance with building codes. Smoke detectors play a critical role in identifying the presence of smoke in the air, which could indicate a fire hazard. These devices provide early warning signals, allowing for timely evacuation and response to fire incidents within the building.

The requirement for smoke detectors in larger air handling systems aligns with safety regulations that emphasize the importance of early detection in minimizing risks associated with fires. By monitoring the return air, smoke detectors can effectively alert occupants and allow for necessary safety measures to be implemented. This consideration is particularly important in high-capacity systems where the potential for greater risk is present.

While air filters, carbon monoxide detectors, and fire dampers also have important functions in HVAC systems, they do not specifically address the critical need for smoke detection in return air systems above the threshold of 2000 cfm. Air filters help maintain air quality, carbon monoxide detectors monitor for toxic gas, and fire dampers are used to control the spread of smoke and fire, but they do not serve the primary function of detecting smoke. Thus, the installation of smoke detectors is the most appropriate and relevant choice in this context.