SCOTT Protege - Gas Interferences

Protégé Portable Gas Monitor
Instruction Manual
40 of 61
P/N 087-0038 Rev. J 02/10
4.5. Gas Interferences
There are known gas interferences to a limited number of chemical compounds. Scott H & S
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 4-2 displays known toxic gas interferences.
NOTE
T
ABLE 4-2 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.
Table 4-2. Toxic Gas Interference
All values in PPM
~ Approximate
< Less than
</= Less than
or equal to
Sensor Types
Dual Tox Sensors
CO H
2
S H
2
S CO
CO </= 0.5 ~ 1 100
H
2
S < 3 100 100 -20
SO
2
0 ~ 20 ~ 2 < 1
NO < 10 < 2 < 10 ~ 15
NO
2
</= -20 ~ -20 ~ -20 ~ -25
CL
2
O 0 ~ -5 ~ -5
H
2
< 40 < 0.2 ~ 30
HCN
HCL