MSA ORION - Time Weighted Average (TWA) (FIGURE 3-13); Warning

•
10-minute exposure of 35 PPM
5-minute exposure of 5 PPM:
(
10
minutes x
35
PPM
) + (
5
minutes
x
5
PPM
)
15
minutes
=
25
PPM
Assume the Orion Multigas Detector was turned on five minutes ago.
•
5-minute exposure of 15 PPM:
(
5
minutes x
15
PPM
) + (
10
minutes
x
0
PPM
)
15
minutes
=
5
PPM
º
WARNING
If the STEL alarm condition is reached while using the
instrument as a personal or area monitor, leave the
contaminated area immediately; the ambient gas
concentration has reached the preset STEL alarm level.
Failure to follow this warning will cause over-exposure to
toxic gases, which can result in serious personal injury or
death.
Time Weighted Average (TWA) (FIGURE 3-13)
•
The TWA flag will
appear in the upper
portion of the display
to show the average
exposure since the
TWA reading was
reset.
•
When the amount of
gas detected by the
Orion Multigas
Detector is greater
than the eight-hour
TWA limit:
•
Alarm Sounds
•
Alarm Lights
Flash
•
The TWA
flag flashes.
Figure 3-13. Exposure Page with TWA
Alarm
Operating Manual Chapter 3, Using the Orion Multigas Detector
3-15