Pressure Effect
Readings from the MAXO2 Monitor are proportional to the partial pressure of oxygen. The partial pressure of Oxygen (PO2) is equal to the percentage of oxygen (%O2) times the absolute pressure (AP) at which the sample enviroment is measured. (PO2=%O2 x AP). Thus the readings are proportional to the concentration if the pressure is held constant. Flow rate of sample gas can affect pressure at the sensor in that back pressure at the sensing point may change. For these reasons, the following is recommended:
1)Calibrate the MAXO2 Monitor at the same pressure as the sample gas.
2)If sample gases flow through tubing, use the same apparatus and flow rates when calibrating as when measuring.
3)The MAXO2 Monitor oxygen sensor has been validated at pressures up to 2 atmospheres absolute. Calibration or operation above this pressure is beyond the intended use.
Humidity Effect
Humidity has no effect on the performance of the MAXO2 Monitor other than diluting the gas, as long as there is no condensation. Depending on the humidity, the gas may be diluted by as much as 4%, which proportionally reduces the oxygen concentration from the dry concentration. Environments where condensation may occur are to be avoided since condensate may obstruct passage of gas to the sensing surface, resulting in erroneous readings and slower response time. For this reason, the following is recommended:
1)Avoid usage in environments greater than 95% relative humidity.
2)When used in a breathing circuit, place the sensor upstream of the humidifier.
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