STATUS SCIENTIFIC CONTROLS
Installation, Commissioning & Routine Gas Testing
FGD4 Gas Detector
TD19/001
Issue:
5
Change Note:
1869
Page 12
6.
I
NITIAL
G
AS
T
ESTING
FGD4 units are factory calibrated as detailed on the calibration certificate
supplied with the instrument. However, it is always advisable after installation
to confirm that the instrument reads zero with no gas present and responds
accurately when presented with an appropriate concentration of the target
gas.
The FGD4 sensor should be allowed to stabilise for the period specified on
the associated calibration certificate before attempting to check the zero
setting and gas response.
6.1.
Zero gas
With no gas present check that the associated control panel display reads
zero.
a) If the instrument reads zero then no adjustment is required and gas
response testing may now be carried out as described in Section 6.2.
b) If the instrument does not read zero then adjustment of the zero setting
is required as described in Section 8.1.1. - Sensor Zero.
c) If the analogue signal is connected to an associated control panel,
confirm that when the FGD4 display reads zero, the control panel
display also reads zero or, adjust as necessary in accordance with the
control panel manufacturers’ instructions.
* Note
– If there is the possibility of a background gas being present then
zeroing of the detector should be carried out using a test gas cylinder of air in
nitrogen.
