Alarms

Table 7. describes the detector alarms and corresponding screens. During an alarm condition, the detector activates the backlight, audible/ visual/vibrator alarms, and displays the current ambient readings. If more than one type or level of alarm occurs simultaneously, a multi-gas alarm results. If Stealth is enabled, the audible and visual alarms are disabled, and only the vibrator alarm activates.

To change the factory-defined alarm setpoints, refer to Low Alarm, High Alarm, TWA Alarm, and STEL Alarm.

Alarm	Screen
Low Alarm Slow siren Slow alternating flash and target gas bar flash Vibrator alarm activates
High Alarm Fast siren Fast alternating flash and target gas bar flash Vibrator alarm activates
TWA Alarm Slow siren Slow alternating flash and target gas bar flash Vibrator alarm activates
STEL Alarm Fast siren Fast alternating flash and target gas bar flash Vibrator alarm activates

Note

If Low Alarm Acknowledge is enabled, the audible alarm can be disabled during a low alarm condition. The vibrator and visual alarm indicators remain active until the alarm condition changes or the detector deactivates. Press Gas alarm to acknowledge the low alarm and deactivate the audible alarm. If the alarm escalates to a high, TWA, or STEL alarm, the audible alarm reactivates.

If enabled, Latched Alarms causes the low and high gas alarms (audible, visual, and vibrator) to persist until the alarm is acknowledged (by pressing ) and the gas concentration is below the low alarm setpoint. The LCD displays the peak concentration and the audible, visual, and vibrator indicators persist until the alarm condition no longer exists. Enable/disable Latching Alarms in Fleet Manager II. Local regulations may require Latching Alarms be enabled.

Alarm	Screen
Multi-Gas Alarm Sequence alternating low and high alarm siren and flash and gas bars flash Vibrator alarm activates
Sensor Alarm During startup sequence Error [sensor name] displays During normal operation Err displays (must be acknowledged by press )
Low Battery Alarm Sequence of 10 rapid sirens and alternating flashes with 7 seconds of silence in between (continues for 15 minutes) and flash, LOW BAT displays, and the vibrator alarm activates After 15 minutes, of the Low Battery alarm, the Automatic Shutdown Alarm sequence begins OFF displays before deactivating
Over Limit (OL) Alarm Fast siren and alternating flash and gas bar flash Vibrator alarm activates OL displays
Confidence Beep and IntelliFlash One beep and flash every second Note The detector is shipped with Confidence Beep disabled and IntelliFlash enabled
Automatic Shutdown Alarm Sequence of 10 rapid sirens and alternating flashes with 1 second of silence in between (sequence reactivates seven times) LOW BAT and display Vibrator alarm activates OFF displays before deactivating
Normal Shutdown Sequence of two sirens and alternating flashes Vibrator alarm activates Countdown initiates OFF displays

Computed Gas Exposures

Warning

To avoid possible personal injury, do not deactivate the detector during a work shift. TWA, STEL, and MAX readings reset once the detector is deactivated.

Table 8. Computed Gas Exposures

Gas Exposures	Description
TWA (H₂S and CO only)	Time-weighted average (TWA) based on accumulated exposure to toxic gases averaged over a workday according to US OSHA method. OSHA: 8 hour moving average
STEL (H₂S and CO only)	Short-term exposure limit (STEL) to gas based on a 5-15 minute user-defined period.
Peak* (maximum)	Peak concentration encountered during work shift.

* For oxygen, it is the highest or the lowest concentration encountered.

Viewing Gas Exposures

To view the TWA, STEL, and peak (maximum) readings, press Gas alarm twice. The LCD first displays the TWA gas exposures.

Then the LCD displays the STEL gas exposures.

Finally the LCD displays the peak (maximum) readings.

Clearing Gas Exposures

Caution

Follow all safety procedures as defined by your employer. Confirm with your supervisor before clearing TWA and STEL alarms.

To clear the TWA, STEL, and peak exposure readings, press Gas alarm when the LCD displays RESET.

Gas Alarm Setpoints

Gas alarms are activated when detected gas concentrations are above or below the user-defined setpoints. Gas alarms are described below.

Table 9. Gas Alarm Setpoints

Alarm	Condition
Low	Toxics and combustibles: Ambient gas level above low alarm setpoint. Oxygen: Ambient gas level may be set above or below 20.9% (or 20.8%).
High	Toxics and combustibles: Ambient gas level above high alarm setpoint. Oxygen: Ambient gas level may be set above or below 20.9% (or 20.8%).
TWA	Toxics only: Accumulated value above the TWA alarm setpoint
STEL	Toxics only: Accumulated value above the STEL alarm setpoint.
Downscale	Toxics only: If sensor reading is negative (half of the TWA setpoint)
Multi-gas	Two or more gas alarm conditions
Downscale	Toxics only: If sensor reading is negative (half of the TWA setpoint)
Over Limit (OL)	OL displays when readings are above or below the sensor detection range. Refer to Specifications for detection ranges.

Factory Gas Alarm Setpoints

Note

Standard factory alarm setpoints may vary by region.

Table 10. lists the factory alarm setpoints as defined by Occupational Safety and Health Association (OSHA).

Table 10. Sample Factory Alarm Setpoints

Gas	TWA	STEL	Low	High
O₂	N/A	N/A	19.5% vol.	23.5% vol.
LEL	N/A	N/A	10% LEL	20% LEL
CO	35 ppm	50 ppm	35 ppm	200 ppm
H₂S	10 ppm	15 ppm	10 ppm	15 ppm

Note

To disable an alarm, set the alarm setpoint to 0 (zero) in Fleet Manager II. Refer to Using Fleet Manager II to Configure the Detector for complete instructions.

Changing Alarm Setpoints

To change alarm setpoints, use the base station or IR Link and refer to the following under Sensor Configuration:

Stopping a Gas Alarm

The low and high alarms stop when the ambient gas concentration returns to the acceptable range.

Note

If alarms are set to latch, press Gas alarm to reset the alarms.

The detector calculates the TWA value based on OSHA standards and the STEL value based on a user-defined 5 to 15 minute period. Refer to STEL Interval.

To stop a TWA or STEL alarm, perform one of the following:

1. Deactivate and reactivate the detector.

2. Reset the TWA/STEL/peak exposure readings. Refer to Viewing Gas Exposures).

Warning

Follow all safety procedures as defined by your employer. Confirm with your supervisor before clearing TWA and STEL alarms.

Sensor Alarm

The detector tests for missing or defective sensors during the startup self-test and continuously thereafter.

During start-up if a sensor fails, Error and the sensor name displays.
If a sensor fails the self-test, Err displays above the gas type of the failed sensor. The detector will enter alarm. Press to acknowledge the sensor alarm and stoop the alarm. Refer to Troubleshooting.

Low Battery Alarm

Battery power is continually displayed during normal operation. If battery power is low, and flashes. The detector performs a sequence of 10 rapid sirens and alternating flashes with 7 seconds of silence in between (continues for 15 minutes).

If battery power becomes critically low, and LOW BAT display. The detector performs a sequence of 10 rapid sirens with 1 second of silence in between (sequence reactivates seven times). The detector then displays OFF and the detector deactivates.

Charge the battery immediately. Refer to Charging the Battery.

Note

Confidence Beep automatically disables during a low battery alarm.

Automatic Deactivation Alarm

An automatic deactivation alarm will occur if

the battery voltage is too low to operate the detector,
calibration is due but not performed (when the Force Calibration option is enabled),
bump test is due but not performed (when the Force Bump options is enabled) and
all sensors fail during the startup self-test.

The detector performs a sequence of 10 rapid sirens with alternating flashes with 1 second of silence in between (sequence reactivates seven times). OFF then displays and the detector deactivates.