While the EasyOne does not require calibration, it is important to note that the American Thoracic Society, NIOSH/OSHA, and others recommend that the accuracy of the spirometer be verified on a regular basis. This verification is easily done using the ndd 3-liter syringe.
The following two main characteristics make the EasyOne Sirometer calibration free:
a) The EasyOne spirometer determines flow by measuring the flight time of ultrasonic pulses. The time measurement is performed digitally using a precision quartz clock.
b) The transducers that are used for this time measurement are mounted outside of the flow tube. Changing the flow tube does not change the characteristics of the transducers.
In addition, the ultrasonic flow measurement is inherently independent of temperature, humidity, pressure, and gas composition.