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APPENDIX B
B - 2
Compound
LEL Sensor
LEL CF
LEL/TC Sensor
LEL CF
LEL
(Vol%)
Methane
1.0
1.0
5
Methanol
1.5
6
Methyl ethyl ketone
1.7
2.6
1.4
Octane, n-
2.9
1
Pentane
1.8
3.4
1.5
Propane
1.5
1.9
2.1
Propene
1.5
2.5
2
Toluene
1.9
4.4
1.1
Vinyl chloride
1.8
3.6
Xylene, m-
2.7
1.1
Xylene, o-
3.0
0.9
Xylene, p-
2.8
1.1
The LEL correction factors are measured relative to
methane gas. All gases are measured at less than 5% relative
humidity and 25oC. These factors may change at higher
concentration level or different temperature. The factors are
to be multiplied by the reading to obtain the actual
concentration or %LEL of the gas when the monitor is
calibrated to a known %LEL of methane. If the correction
factor of a gas is <1.0, then the sensitivity to the gas is
higher than that of methane.
Note:
The LEL CF is different when using the LEL-only
sensor compared to the LEL/TC sensor. Therefore it is
important to enter the proper CF in the programming mode
when the measurement gases is changed (Section 4.8).
Similarly, the CF for the LEL-only sensor should be
checked for recent updates in Technical Note 156 on our
website
www.raesystems.com
.