Oxygen (O2) Alarm Limits; Toxic Alarm Limits - GMI V!SA Manual De Instrucciones

V!SA - USER HANDBOOK
3.1.3 Oxygen (O ) Alarm Limits
2
Up to one (1) upper and two (2) lower alarm limits are
programmable, each with different pitch and tone. All
alarms are user configurable to meet the specific needs
of different companies.

3.1.4 Toxic Alarm Limits

When operating normally, the instrument records minimum
and maximum readings for each gas and calculates the
Short Term Exposure Limit (STEL) and Long Term Exposure
Limit (LTEL), known as Time Weighted Average (TWA)
readings , for each toxic gas range as appropriate. Up to
two (2) instantaneous and two (2) TWA alarms are
programmable for each toxic range fitted to the instrument.
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. In accordance with UK
legislation, this requires the time weighted averages to be
averaged over a full 24 hour period whether the instrument
is On or Off. Such averaging essentially makes the
instrument single user applicable. The option is available
to restart the averaging after each instrument switch-off,
thus allowing for multiple user application.
All alarms are user configurable to meet the specific needs
of different companies.
Note: The toxic gas alarm levels – instantaneous, STEL
and LTEL are set at the time of instrument manufacture. It
is important that the user ensures that the levels are in
accordance with their company's alarm levels and with
health and safety legislation. The alarm levels may be
3-2