Gas Exposure Of 100% Lel - MSA Altair 5X Mode D'emploi

2.8.2 Gas Exposure of 100% LEL

When the reading from the catalytic combustible sensor reaches 100%
of the lower explosive limit (LEL), the instrument enters a LockAlarm
state and displays "XXX" in place of the actual reading.
A catalytic combustible gas reading of "XXX" indicates the
atmosphere may be above 100% LEL or 5.00% Vol CH 4 and
an explosion hazard exists. Leave the contaminated area
immediately.
For ALTAIR 5X IR instruments with an enabled 100% Vol methane IR
sensor, the LockAlarm will clear, and the catalytic combustible again
displays combustible concentrations when the gas sample drops to a
lower level.
For instruments without an enabled 100% Vol methane IR sensor, the
user can clear the LockAlarm state only by turning the instrument OFF,
and then ON again in a fresh air environment.
When catalytic combustible gas reading digits appear, the instrument is
available for measuring gases once again.
NOTE: LockAlarm of the catalytic combustible sensor occurs during
Bump Testing and calibration of a % Vol combustible IR sensor.
After the IR sensor Bump Test, the LockAlarm must be cleared
(as described above) before the catalytic combustible sensor is
again able to measure and provide readings.
2-18
! WARNING
TM