STATUS SCIENTIFIC CONTROLS
FGD3 Infrared Gas Detector Heads
TD06/024
Issue:
7
Change Note:
1904
Page 11
4
Relative Response Characteristics
This section is applicable to FGD3 gas detectors fitted with an infrared
Hydrocarbon
sensor.
Unless otherwise specified, the FGD3 infrared hydrocarbon gas detector is calibrated
to provide an output signal linearised for methane (CH
4
) during manufacture.
However, the gas detector will also respond to a range of hydrocarbon gases. The
characteristics shown on the following page demonstrate the relative response to
some of the common hydrocarbons.
If the expected target gas is other than methane then either:-
a) The characteristics can be used as a guide when setting up the alarm levels in the
associated control unit, e.g. where a general hydrocarbon response is required.
b) The FGD3 can be calibrated using a test gas for any of the gases shown in the
characteristic, using the span setting procedure as described in Section 5.2.2
Note:
the correct sensor type must be used to match the gas type.
