Oxygen Instrument (O ); Toxic Gas Measurements; Short Term Exposure Limits - MSA ORION plus Betriebsanleitung

2 Using the ORION plus
2.8.2 Oxygen Instrument (O
plus
The ORION can be equipped to detect the amount of
oxygen in the atmosphere.
Two conditions trigger the alarm:
- Too little oxygen (deficient)
- Too much oxygen (enriched).
- For monitoring lack of excess of oxygen, HI alarm
(self-locking) should be used.
When the alarm setpoint is reached for either of the above:
- Alarm sounds.
- Alarm lights flash.
- % O label above the concentration flashes.
2
If the Oxygen alarm condition is reached while using the instrument as a personal or
area monitor, leave the area immediately; the ambient condition has reached a preset
alarm level. If using the instrument as an inspection device, do not enter the area
without proper protection.

2.8.3 Toxic Gas Measurements

plus
The ORION can be equipped to detect Carbon
Monoxide (CO), Carbon Dioxide (CO
Sulfide (H S) in the atmosphere.
2
When one of the alarm setpoints is reached for CO,
CO and/or H S:
2 2
- Alarm Sounds.
- Alarm lights flash.
- PPM CO, CO or H
2
flashes.
2.9 Short Term Exposure Limits (STEL)
The STEL flag appears in the upper portion of the display to show the average exposure
over a 15-minute period. When the amount of gas detected by the ORION
than the STEL limit:
- Alarm sounds.
- Alarm lights flash.
- The STEL flag flashes.
The STEL alarm is calculated over a 15-minute exposure. Calculation examples are as follows:
Assume the ORION
15 minutes exposure of 35 ppm: (15 minutes x 35 ppm) = 35 ppm
Assume the ORION
5-minute exposure of 15 ppm: (5 minutes x 15 ppm) + (10 minutes x 0 ppm) = 5 ppm
12
)
2
) and/or Hydrogen
2
S label above the concentration
2
plus
has been running for at least 15 minutes.
15 minutes
plus
was turned on 5 minutes ago.
15 minutes
plus is greater