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Revision 3
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Gasurveyor 700
USER MANUAL
5.2. Time-averaged Toxic Gas Alarms
In the Confined Space Monitor (CSM) mode the monitor also calculates the Short-Term and Long-
Term Exposures for toxic gas ranges. If these exceed the STEL or LTEL then alarms are activated.
Note: A time-averaged value is the mean average gas level over a rolling period.
The STEL is 15 minutes and the LTEL/TWA is 8 hours. In accordance with legislation,
this requires the time weighted averages to be averaged over a full period whether
the monitor is ON or OFF. Such averaging essentially makes the monitor single user
applicable.
Note: Because readings are averaged, it is possible to get a ‘live reading’ of zero and
have a LTEL or STEL alarm active.
5.3. Ticker (Geiger) Gas Alarm
An audible and visual Geiger alarm, enabled in the PPM Flammable range, provides indication of
increasing or decreasing gas concentration via a variable rate sounder and LED flashes.
User can change the operation of the Ticker (Geiger) alarm. Refer to
for
more details.
Note: Ticker (Geiger) gas alarm is available only in Search mode.
5.4. Available Gas Alarms
Modes
GLO / GLI
CSM
Purge
Search
Instantaneous alarms
✓
Non Latching
✓
Latching
✓
Non Latching
Time-averaged alarms
✓
Latching
Ticker (Geiger)
✓
5.5. Gas Alarms Examples
Figure 47: LOLO Oxygen Alarm
