STATUS SCIENTIFIC CONTROLS
Installation, Commissioning & Routine Gas Testing
FGD10A-M Gas Detector
TD18/032
Issue:
10
Change Note:
1869
Page 79
11.
R
OUTINE
G
AS
T
ESTING
Refer to Figure 6 in section 8. showing the arrangement for applying the test
gas to the FGD10A-M.
1. Before application of the test gas, check that the FGD10A-M reads
zero with no known gas present in the atmosphere. If necessary,
carry out adjustment of the zero setting as described in section
9.1.2.
2. Apply the test gas and allow a sufficient time for the sample to
reach the gas detector. The response time will vary according to the
length of the sampling tube.
3.
Record the time taken
for the gas detector to provide a reading of
90% (T
90
) of its final value (e.g. to reach 27% when using a 30%
CH4 test gas). This reading should be retained for future reference
as it can provide an indication of the health of the sinter (flame
arrestor). This is situated in the base of sensor housing and it is
through this device that the gas passes in order to reach the sensor
itself. If necessary, carry out adjustment of the span setting as
described in section 9.1.3.
Carrying out the above procedure, and comparing the results with previous
readings, will confirm that the FGD10A-M is functioning correctly, both
physically and electrically.
There is therefore no requirement for any further
maintenance other than to clean the display window as required.
In the unlikely event that the response time is seen to be increasing, when
comparing periodic readings, it is advisable to change the unit so that it can
be checked.
The period between carrying out routine gas testing shall be in accordance
with the customer’s specification.
