Ampcontrol Pty Ltd
– ABN 28 000 915 542
GASGUARD CH4 GAS SENSOR USER MANUAL
GSB076 Version 6
– March/2019
Uncontrolled Copy - Refer to Ampcontrol Website for Latest Version
Page 16 of 25
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5.3 Sensor Calibration
Before the start of calibration, the sensor should be powered up and left to stabilise for at least two
hours.
NOTE
Calibration can only be carried out once the installation is complete and
fault free.
Following the stabilisation period, sensor performance can be checked. If performance is within the
limits of error given in the product specification, no calibration is required.
5.3.1 Calibration Gas
Sensor zero calibration must only be carried out using
industrial grade clean air
that is within its
expiry date and carries a standards traceable specification.
Sensor span calibration must only be carried out using
methane
that is within its expiry date and
carries a standards traceable concentration.
To achieve the required concentration for calibration purposes, methane is mixed or ‘balanced’ with a
‘carrier’ gas. This carrier gas must be air for the Gasguard’s catalytic sensor to operate correctly.
Methane balanced with nitrogen must never be used to verify or calibrate the sensor since this will
inhibit the function of the catalytic sensor bead.
Calibration gas should ideally be 50% of full scale. However, sometimes, due to practical restraints and
safety reasons, the gas may need to be less than 50%. Concentrations of less than 25% of full scale
should not be used in order to avoid potential calibration inaccuracies.
5.3.2 Flow Rate
Calibration gas should be applied to the sensor at a rate of approximately 0.5 to 1.0 litres per minute. It
is not necessary to leave the gas flowing to the sensor for any longer than is needed for the output to
stabilise and the calibration adjustment to be made.
5.3.3 Safety
Because sensor calibration involves the use of gas, appropriate safety procedures must be observed in
regard to its safe handling and use.
Proper regard to site safety practices must be given, including the creation of safe work method
statements where necessary. Specific conditions relating to the site into which the sensor is located
may also need to be considered. It may be necessary to use equipment that is approved for use within
the area where the sensor is located.
