Instruction manual

Oxygen Sensor Specifications
Environment and Oxygen Sensor Readings
A number of environmental factors may affect the oxygen sensor
readings, including changes in pressure, humidity and
temperature. Pressure and humidity changes affect the amount of
oxygen actually present in the atmosphere.
Pressure Changes
The FiveStar Alarm has a built-in pressure sensor to rapidly
compensate for ambient pressure changes in the area of
instrument operation. If pressure changes rapidly (e.g., stepping
through airlock) the oxygen sensor reading may temporarily shift,
and possibly cause the detector to go into alarm. Allow up to 30
seconds for the pressure sensor to update the oxygen sensor
reading; then, reset any alarms. While the percentage of oxygen
may remain at or near 20.8%, the total amount of oxygen present
in the atmosphere available for respiration may become a hazard
if the overall pressure is reduced to a significant degree.
Humidity Changes
If humidity changes to any significant degree (e.g., going from a
dry, air conditioned environment to outdoor, moisture laden air),
oxygen levels can change up to 0.5%. This is due to water vapor
in the air displacing oxygen, thus reducing oxygen readings as
humidity increases. The oxygen sensor has a special filter to
reduce the affects of humidity changes on oxygen readings. This
effect will not be noticed immediately, but slowly impacts oxygen
readings over several hours.
Temperature Changes
The oxygen sensor has built-in temperature compensation.
However, if temperature shifts dramatically, the oxygen sensor
reading may shift. Zero the instrument to within 30
o
C of the
temperature-of-use for the least effect.
Table 4-4. OXYGEN - Typical Performance Specifications
RANGE
0 to 25% O
2
RESOLUTION
0.1% O
2
REPRODUCIBILITY
0.5% O
2
, for 18 to 25% O
2
; 0.8% for less than 18%
RESPONSE TIME
90% of final reading
30 seconds (normal temperature range)*
3 minutes (extended temperature range)
*See TABLE 4-1, NOTE 1.
Chapter 4, Performance Specifications Instruction Manual
4-4 FiveStar Alarm