Toxic Alarm Limits - GMI PS500 Manual Del Usuario

USER HANDBOOK

3.1.4 Toxic Alarm Limits

Each toxic range has 2 instantaneous alarm set points.
Additionally, toxic ranges also have user exposure alarms.
The instrument calculates the Short Term Exposure Limit
(STEL) and Long Term Exposure Limit (LTEL), known as Time
Weighted Average (TWA) readings.
Note: A Time Weighted Average (TWA) value is the mean
average gas level over a specific period. The STEL is
15 minutes and the LTEL is 8 hours. This averaging
makes the instrument single user applicable.
A option is available to reset the averaging after each
instrument switch-off, allowing multiple user use.
Note: It is important that the user ensures all alarm levels
are in accordance with their company's procedures
and with regional health and safety legislation.
In the following examples, Fig. 3.1 shows a 'LOLO' Oxygen
alarm and Fig. 3.2 shows a 'HIHI' LEL alarm.
If more than one gas alarm level is exceeded, the gas value
will flash for each gas type in alarm.
Each alarm can be latching or non-latching.
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