Continuous measurement of confined animal housing ventilation rates for determining pollutant emissions

Measuring aerial pollutant emissions from mechanically ventilated animal housing can be very challenging due to the large number of wall-mounted fans and their fluctuating ventilation rates. Even when the concentration of the pollutant is known, the total building emission is difficult to quantify because flow rate has to be continuously measured. In addition, EPA established standard source testing methods are designed for in-stack measurement and are not directly applicable for mechanically ventilated livestock buildings. It was found that a single vane anemometer can be used to accurately measure the ventilation rate of agricultural fans on a continuous basis. This is important since the ventilation rate can vary by a factor of tens of times over the course of a day. Calibration of the vane anemometer is necessary, as the fan design and ventilation configuration can alter the measurements. Overall, this instrument provides a relatively reliable and economical means to measure the flow rate from mechanically ventilated animal houses.