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Appendix D
Calibrating Sensors
EVM Series User Manual
Sensor Type
Zero Calibration
Advanced calibration (correction
factors)
CO
2
sensor
Performed with Nitrogen
CO
2
gas with a 1 Liter/minute flow rate
*NOTE:
The range of the CO
2
sensor is 0 to
5,000 ppm. It is recommended to span cal
to the value you will be measuring (i.e.,
4,500 ppm) for best results.
Note settling time with 1 L/min gas flow has
a response time of <90 seconds.
PID ppm
sensor
Performed with Pure Air or Nitrogen
*NOTE:
Room air can be applied In
clean air environments (such as a
school with no toxic cleaners present).
Isobutylene is used when the VOCs are
unknown.
*NOTE:
in order to measure a specific
VOC, you will use the relevant VOC for your
calibrated gas source.
PID ppb
sensor
No user cal performed in the field.
(Factory cal. only.)
PID sensor ppb – span: 10 ppm (or
10,000 ppb) of Isobutylene whether the gas
of interest is known/unknown.
Carbon Monoxide
(CO)
Performed with Pure Air or Nitrogen
CO gas
Chlorine
(CL
2
)
Performed with Pure Air or Nitrogen
CL
2
gas
Ethylene Oxide
(EtO)
Performed with Pure Air or Nitrogen
EtO gas
Hydrogen Cyanide
(HCN)
Performed with Pure Air or Nitrogen
HCN gas
Hydrogen Sulfide
(H
2
S)
Performed with Pure Air or Nitrogen
H
2
S gas
Nitrogen Dioxide
(NO
2
)
Performed with Pure Air or Nitrogen
NO
2
gas
Nitric Oxide
(NO)
Performed with Pure Air or Nitrogen
NO gas
Oxygen
(O
2
)
Performed with Nitrogen
Room air
*NOTE:
The range of the O
2
sensor is
0 to 30% with a typical span of 20.9%.
Sulphur Dioxide
(SO
2
)
Performed with Pure Air or Nitrogen
SO
2
gas
