Scott Safety Protege ZM, System Manual

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APPENDIX B: SENSOR INFORMATION
087-0048 REV B SCOTT SAFETY
Gas Interferences
There are known gas interferences to a limited number of chemical compounds. Scott
Safety attempts to identify possible gas interferences to which gas sensors may be
exposed; however, not all chemical compounds that presently exist have been tested.
Table 29 provides known toxic gas interferences.
Table 29 does not show, nor should it be implied, that no additional interferences may
occur. These selectivity ratios are used as guides only. They are not to be used as
calibration factors. The gas species’ actual cross-sensitivities may vary from the
values shown.
Keys for Table 29 .
•
Zero – Indicates tested and confirmed no interferences
•
Blank – Indicates not tested
•
Neg – Indicates gas produces a negative signal
•
Two values in a cell – Indicates initial peak and finish offset (unstable or transition
gas) and should not be used for cross calibration
Table 29 Gas Interferences
SENSOR TYPES (ALL VALUES IN PPM)
CO
H
2
S
Interference Gas
CO
1
< 0.02
H
2
S < 0.02
1
SO
2
0 =0.3
NO <0.1
H
2
<0.4 <0.1
C
2
H
5
OH 0 = -0.005
Key: < Less than; ~ Approximate.
For each sensor type, the table shows how 1ppm of an Interference Gas
appears on that specific sensor type. For example, 1ppm CO appears as
less than <0.02ppm on a H
2
S sensor.