Trolex XD1+ - 13. ALARM WARNINGS AND CALCULATIONS; Alarm Indications and Thresholds

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XD1+_User manual_P5650.1600_Rev A
The D1
+
uses 2 LED icons alongside audio sequences to alert users to changing levels of
airborne particulates as highlighted below.
13. ALARM WARNINGS AND
CALCULATIONS
If a threshold is breached during operation, the following alarm sequence is used to alert
users to act based on the change in the working environment.
‘Icon 1’: Short-term exposure limit (STEL) alarm
The D1
+
will flash the amber STEL icon alongside an audible alarm (2 beeps per second).
‘Icon 2’: Long-term exposure limit / time-weighted average (TWA) alarm
The D1
+
will flash the red TWA icon alongside an audible alarm (3 beeps per second).
In the event that both alarms are triggered simultaneously, the TWA alarm will take priority.
Note: The D1
+
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.
Advice outlined in EH40/2005 states that where no specific short-term exposure limit is listed,
a figure three times that of long-term exposure limit should be used. However, always refer to
local guidelines and legislation to ensure that alarm warning thresholds are set at appropriate
and permissible values for the intended operating environment.
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