CO2 sensors in mechanically ventilated areas must be calibrated to be accurate within how many ppm or percentage of the reading?

The correct choice emphasizes the importance of calibrating CO2 sensors in mechanically ventilated spaces to ensure accurate monitoring of indoor air quality. The calibration threshold of 75 ppm or 5% is specified to ensure that sensors can effectively detect and respond to varying levels of CO2 concentration, which is critical for maintaining a healthy indoor environment.

In mechanically ventilated areas, appropriately calibrated sensors help in optimizing ventilation rates based on actual occupancy and air quality conditions. This contributes to effective energy management while ensuring that the indoor air quality meets health and comfort standards. Accurate sensor readings are essential for the timely adjustment of ventilation systems in response to CO2 levels, thus facilitating better occupant comfort and IAQ (Indoor Air Quality).

The choice highlights how a range that balances precision (75 ppm) with a practical percentage (5%) supports both operational efficiency and comfort. This level of calibration allows for effective real-time monitoring, ensuring that the systems in place are functioning optimally.

In contrast, other choices suggest calibration limits that either do not meet the necessary accuracy or offer lesser thresholds, which might not sufficiently cover the fluctuations that can occur in CO2 levels in various occupancy scenarios. The selected option strikes an optimal balance necessary for maintaining air quality and supporting ventilation system performance.