Sensor Performance Factors - Teledyne Meridian User Manual

B.2. Sensor Performance Factors
Factor
Target Gas Identify target gases that have a potential for providing a haz-
ard in the process. Most sensors are applicable to mostly
toxic or mostly combustible gas monitoring. However, some
sensor types are capable of monitoring for either. Situations
where several gases may pose a threat may be monitored for
a presence.
Sensor Sensor placement directly impacts sensor effectiveness. No
Placement sensor can detect a hazard if placed too far from release or
receptor points. Use zoned or voting coverage areas, where
multiple sensor points effectively provide a maximum, redun-
dant coverage area (to minimize false alarms) and account
for barriers, air currents, and all potential gas release points.
Temperature/ Severe environments can affect certain sensor types. All sen-
Humidity sor types are rated for specific temperature ranges. High
humidity environments, where water vapors can interfere with
readings, can affect some sensors.
Oxygen In applications where oxygen may be displaced or not pres-
Content ent in a gas sample, the sensor type should be considered.
Power Some sensor types consume much more power than others.
Consumption This is important when considering if a technology is appropri-
ate for a fixed or portable detection device. Fixed detection
systems need appropriate power supplies to maintain the cur-
rent necessary for sensor operation.
Cross Gases other than target gases can interfere with nearly all
Interference sensor types. Sensor manufacturers employ different methods
to counter the effects using filters, sensor construction materi-
als, and preprogrammed expected response functions based
on target gas characteristics. In some technologies, a sensor
is calibrated with an appropriate cross interference gas, if the
target gas is unobtainable or difficult to apply in field condi-
tions. In this case, apply a K-factor to the calibration values.
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Table B-2: Sensor Performance Factors
Description
USE AND DISCLOSURE OF DATA
prohibited.
MERIDIAN
UNIVERSAL GAS DETECTOR
GAS SENSOR INFORMATION
Sensor Type
Generally Toxic
• Electrochemical
Generally
Combustible
• Infrared
• Catalytic Bead
Application specific
Varies
Cat bead and most E-Chem
sensors will not perform as
designed without oxygen
present.
Varies
Varies
B-3