Check Response Time (T90) - Dräger X-am 2800 Gebrauchsanweisung

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Maintenance
5. Wait until the detector displays the test gas concentration with sufficient
tolerance.
 Ex: ±20 % of the test gas concentration
 O
: ±0.6 Vol%
2
 TOX: ±20 % of the test gas concentration
6. Close the test gas cylinder valve and remove the gas detector from the
calibration adapter.
7. If the concentrations have fallen below the A1 alarm thresholds, the gas
detector automatically switches back to measuring mode after 10 s.
Further steps
If the displays are outside of the above-mentioned ranges, have the gas detector
calibrated by service personnel.
5.5

Check response time (t90)

The test can also take place in calibration mode in which case the values are
not displaced by alarms. If necessary, the values can subsequently be
discarded, if the gas detector already has a valid calibration.
1. Carry out a bump test and conduct a simplified check of the response time.
a. Connect the test gas cylinder to the calibration adapter and open the
valve on the test gas cylinder so that the calibration adapter is purged
with test gas.
b. Insert the switched-on gas detector into the calibration adapter and press
it down until it locks into place. Record the starting time.
c. Determine the time until 90 % of the test gas concentration is reached.
2. Compare the measured response time with the previous bump tests and
with the t90 values indicated in the supplementary documentation (part
number 9033890) provided.
The determined t90 setting time may differ from the certified setting time,
as this simplified procedure does not conform to the standard.
The X-dock maintenance station provides the option of automatically
checking the response time.
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X-am 2800