Low-Cost Flammable Catalytic Methane / Natural Gas Sensor

General Description:

The NAP-50A Gas Sensor is a low–cost Catalytic Flammable Gas Sensor designed for the detection and measurement of Methane or Natural Gas in the range 0-50% LEL. It is a slightly modified version of the original NAP55A sensor, to reduce the effect of potential cross sensitive gases likely to be encountered in domestic premises, particularly Ethanol, in compliance with the European standard for Residential Gas Detectors EN 50194.

The NAP-50A should therefore only be selected if high sensitivity to Natural Gas or Methane only is required, and the lowest cross sensitivity to other flammable gases and vapours is desirable. Where maximum sensitivity to all flammable gases is required, The NAP-55A should be used.




Detectable Gas:

Detection range:

Voltage supply:

Current drawn:

Signal Sensitivity:

Zero Offset (20oC):

Response time (90%):


Expected lifetime:

Long Term Span Drift:

Long Term Zero Drift:

All Flammable Gases

0 – 50% LEL

2.5V +/- 0.2V

170mA +/- 10 mA

37-53mV / % CH4

0mV +/-  35mV

< 10seconds

+/- 1% LEL

< 3 years

<+/- 2% FSD/ month

<+/- 2mV / year

Operating Conditions:

Operating temperature:

Humidity range:


Temperature Drift (zero):


-10 +50 oC

0 – 95% RH

0.9 – 1.1 atm

<+/- 2% LEL

Effectively linear to 0-100% LEL


  •        Measures flammability directly
  •        Highly resistant to Catalyst poisons
  •        Complies with EN50194 Standard
  •        Effectively Linear output to 50%LEL
  •        Specific to flammable  gases
  •        Unaffected by Humidity
  •        Very Simple circuitry
  •        Very Low Long term drift