temperature density correction

Temperature density correction accounts for the fact that warmer air has lower density, which changes ventilation fan performance compared with standard test conditions. In mining, temperature effects can be significant in deep operations, hot climates, and high-heat production areas. If selection is based only on standard curves without correction, the fan may not produce the required static pressure (Ps) at the target airflow (Q), or the motor may be incorrectly sized for continuous duty.

Mining ventilation should always be specified by Q@Ps duty point at the location that matters—often the end of duct for auxiliary ventilation or a defined district location for network airflow. When temperature rises, the system still demands pressure to overcome resistance, but the fan’s pressure rise capability at a given speed is influenced by density. That is why corrected curves and power checks are needed before final approval.

Common scenarios where temperature correction matters include:

• Deep mines where geothermal heat and equipment heat loads increase air temperature.
• Hot surface environments where intake air enters at elevated temperature.
• High heat/humidity zones where ventilation must remove heat while maintaining airflow targets.

In practical selection, temperature correction is frequently combined with altitude correction to get a realistic density value. The corrected duty point helps determine whether a fan should operate at a different speed range (often with VFD), whether additional margin is needed for future resistance growth, and whether the motor has adequate kW and thermal reserve.

Bottom line: temperature density correction prevents under-delivery of airflow and avoids motor loading surprises. It ensures the selected mining fan package can achieve required Q@Ps and remain stable under real underground temperature conditions.