Alarm Warnings And Calculations - Trolex XD One User Manual

13. ALARM WARNINGS AND
CALCULATIONS
The XD One uses two LED icons alongside audio sequences to alert users to changing levels
of airborne particulates as highlighted below.
If a threshold is breached during operation, the following alarm sequence is used to alert
users.
'Icon 1': Short-term exposure limit (STEL) alarm
The XD One will flash the amber STEL icon alongside an audible alarm (two beeps per
second).
'Icon 2': Long-term exposure limit/time-weighted average (TWA) alarm
The XD One will flash the red TWA icon alongside an audible alarm (three beeps per second).
In the event that both alarms are triggered simultaneously, the TWA alarm will take priority.
Note: The XD One is factory programmed with the following default STEL and long-term
exposure limit/TWA alarm warning thresholds:
• STEL alarm warning threshold – 1,000 µm/m³ over 15 minutes
• TWA alarm warning threshold – 1,000 µm/m³ over 8 hours
The default threshold limits have been defined based on a quarter of the permissible limit for
most respirable dusts as outlined in the EH40/2005 guidelines.
34 XD ONE USER MANUAL
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