User's Manual
G7 TECHNICAL USER MANUAL || 23
TWA TIME WEIGHTED AVERAGE ALERT
When does G7 trigger a TWA alert?
If a toxic sensor detects you have exceeded the average allowable amount of gas during
an eight-hour period.
NOTE: The two TWA measuring methods available for use on your G7 are:
OSHA (United States Department of Labor Occupational Safety and Health Administration)
or ACGIH (American Conference of Governmental Industrial Hygienists).
OSHA is defined as a rolling average of gas exposure accumulated over an eight-hour
period of operation. If the worker is in the field longer, the most recent eight-hour
cumulative value is used.
ACGIH is dened as the total accumulated average, from four to 16 hours as congured
by your safety supervisor.
OL OVER LIMIT ALERT
When does G7 trigger an OL alert?
If a gas sensor detects an excessive amount of gas and can no longer give you an
accurate reading.
NOTE: STEL, LEL and peak readings are reset on power cycle unless configured to
resume readings in G7’s configuration profile in Blackline Live.
Evacuate the area and follow your
emergency safety protocol. Read the
information on your G7 screen. Press and
hold the up and down arrow buttons at the
same time to mute the sound and vibration.
The sound and vibration will return after one
minute. This will continue until gas levels
or averages have reduced or returned to
acceptable concentrations.
For real-time users, red alerts are immediately
communicated to monitoring personnel.
Muting sound and vibration does not cancel
the remote alert sent to monitoring personnel.
What do I do in the case of a red alert?