Carbon Monoxide Alarm User Manual

Page 43
Appendix E PhD
2
Toxic Sensor Cross Sensitivity Data
1
The table below lists the cross sensitivity of electrochemical toxic sensors used in Biosystems portable gas
detectors to gases other than their target gas. Depending on the nature of the reaction each gas has with
the sensor, the effect can either decrease the signal (negative cross sensitivity) or increase the signal;
(positive cross sensitivity). Each figure represents the reaction of the sensor to 100 PPM of gas, thus
providing a percentage sensitivity to that gas relative to its target gas.
CO H
2
SSO
2
NO NO
2
Cl
2
H
2
HCN HCl NH
3
Ethyl-
ene
TOX 1
(broad
range)
2
100 ~280 ~45 ~200 0 ~ -65 0 0 0 0 50 min.
Carbon
monoxide(
CO)
100 <10 <10 <30 <15 <10 <60 <15 <3 0 ~50
Hydrogen
sulfide
(H
2
S)
<10 100 ~15 <5 ~ -20 < -25 <0 0 0 0 0
Hydrogen
sulfide
(H
2
S)
3
<10 100 <20 0 ~ -20 ~ -20 <5 0 0 0 0
Sulfur
dioxide
(SO
2
)
0 0 100 0 ~ -120 <5 0 <50 0 0 0
Nitric oxide
(NO)
0 ~35 ~5 100 <40 0 0 0 <15 0 0
Nitrogen
dioxide
(NO
2
)
0 ~ -20 < -0.5 0 100 90 0 <1 0 0 0
Chlorine
(Cl
2
)
0
~ -20
0 0 120 100 0 0 0 0 0
Hydrogen
cyanide
(HCN)
<5 ~1100 ~39 5 0 ~ -120 ~ - 14 0 0 100 ~65 0 ~50
Hydrogen
chloride
(HCl)
<5 ~660 ~100 ~285 ~-20 ~ -30 ~ 0 <25 100 0 2
Ammonia
(NH
3
)
0 ~130 ~70 ~20 ~ 0 ~ -50 0 ~30 ~ -5 100 0
1
Data derived in part from City Technology Limited, Product Data Handbook Oct. 1, 1992
2
Tox1 data obtained from sensors calibrated with 50 PPM carbon monoxide in air.
3
Extended range Hydrogen sulfide sensor (0-500 PPM).