Emerson Net Safety ST3, Reference Manual

Page: 23 / 32

4 Maintenance
4.1 Cross sensitivities
Certain compounds and or gases can cause a reaction and hence some effects or response
from the sensor.
See Cross sensitive gases for hydrogen sulfide sensor (Net Safety ST320) and Cross
sensitive gases for carbon monoxide sensor (Net Safety ST360) for a list of these cross
sensitive gases/compounds. For more information, please contact Net Safety.
Note
The values listed below are typical values and should not be used as a basis for cross
calibration. Cross sensitivities may not be linear and should not be scaled either. The data
provided is based on gassing for a minimum of five minutes using the gas sensor
manufacturer's test equipment. Some cross interference break through will occur if gas is
applied for a longer period of time.
4.1.1 Cross sensitive gases for hydrogen sulfide sensor (Net
Safety ST320)
Table 4-1: Cross-Sensitive Gases/Compounds
Cross sensitive gas
Cross sensitive gas
concentration
Reading
Carbon monoxide 300 ppm < 3 ppm
Sulfur dioxide 5 ppm < 1 ppm
Nitrogen dioxide 5 ppm < ±0.5 ppm
Nitric oxide 50 ppm < 1 ppm
Hydrogen 100 ppm < 1 ppm
Chlorine 1 ppm 0 ppm
Ethylene 100 ppm 0 ppm
Carbon dioxide 5000 ppm 0 ppm
4.1.2 Cross sensitive gases for carbon monoxide sensor (Net
Safety ST360)
Table 4-2: Cross Sensitive Gases/Compounds
Cross sensitive gas
Cross sensitive gas
concentration
Reading
Hydrogen sulfide 15 ppm < 0.1 ppm
Sulfur dioxide 5 ppm 0 ppm
Reference Manual Maintenance
00809-0100-4303 November 2020
Net Safety ST3 23