text: There are two commonly used ways to specify expected sensor life span: The time in months at room temperature in air, or volume percentage oxygen hours (Vol%O2h). Storage at low oxygen partial pressure when not in use would seem an effective way to extend cell life, but when stored in anoxic conditions the sensor current will cease and the surface of the electrode may be passivated, which can lead to sensor failure. High ambient temperatures will increase sensor current, and reduce cell life. In diving service a cell typically lasts for 12 to 18 months, with perhaps 150 hours service in the diving loop at an oxygen partial pressure of about 1.2 bar and the rest of the time in storage in air at room temperature.
  Failures in cells can be life-threatening for technical divers and in particular, rebreather divers. The failure modes common to these cells are: failing with a higher than expected output due to electrolyte leaks, which is usually attributable to physical damage, contamination, or other defects in manufacture, or current limitation due to exhausted cell life and non linear output across its range.
  Shelf life can be maximised by keeping the cell in the sealed bag as supplied by the manufacturer until being put into service, storing the cell before and between use at or below room temperature, - a range of from 10 to 22 °C is recommended by a manufacturer - and avoid storing the cell in warm or dry environments for prolonged periods, particularly areas exposed to direct sunlight.