Dräger MQG 02 0 Series - Page 5

Technical manual | X-am
®
2800 / X-am
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5800 5
Safety-related information
Oxygen enriched atmospheres
Explosion protection is not ensured in oxygen enriched atmospheres (>21 Vol%
O
2).
► Remove the device from the explosion-hazard area.
Oxygen deficient atmospheres
The CatEx sensor may display false readings and incorrect measured values when
used for measurements in an oxygen deficient atmosphere (<12 Vol% O2). In this
case the CatEx sensor cannot provide a reliable measurement.
► The CatEx sensor is intended to measure flammable gases and vapours mixed
with air (i.e. O
2 content ≈ 21 Vol%). If the O2 content falls below 12 Vol% and an
operational O2 sensor is available in the gas detector, a channel error is
triggered on the CatEx channel due to oxygen deficiency.
► A CatEx sensor should preferably be operated with an active XXS O2 or O2 PR
sensor so that oxygen deficiency can be evaluated by the gas detector.
► Remove the gas detector from the area and discontinue measurement.
Incorrect calibration
CAUTION: An incorrect calibration leads to incorrect measured values.
► CSA requirement (Canadian Standard Association): The sensitivity must be
checked daily before first using the device, with a known concentration of the
gas to be measured that corresponds to 25 to 50 % of the final concentration.
The accuracy must be 0 to +20 % of the actual value. The accuracy can be
corrected by calibration.
NOTICE
Damage to the CatEx sensor!
Fractions of catalytic poisons in the measuring gas (e.g. volatile silicon, sulphur,
heavy metal compounds or halogenated hydrocarbon) can damage the Cat Ex
sensor.
► If the CatEx sensor can no longer be calibrated to the target concentration,
replace the sensor.
WARNING
Risk of explosion!
If the CatEx sensor is exposed to hydrogen and low temperatures (< -10 °C) for a
long time (> 1 h), measured values that are too low may be displayed. This also
applies if hydrogen is being measured but the measured gas set is not hydrogen.
► The CatEx sensor should be set to the measured gas “hydrogen”for regular and
planned measurements of hydrogen. Measuring tasks which last less than
30 min. are not affected by this.
Increased hydrogen concentrations within the measuring range of the
DrägerSensor XXS H2 HC and CatEx sensor may trigger false alarms by additively
influencing Dräger sensors XXS H
2S and XXS CO, XXS H2S-LC and XXS CO-LC,
and negatively influencing DrägerSensor XXS O2 and XXS O2 PR.