29
5.3
Test gases
The following test gases are used in conjunction with the test set
SPE HG/SPE OD
to check the zero point and display accuracy
in the
factory
. Test gas concentrations other than those listed
here can also be used - see section 7.3: Setting the test gas
concentration.
Gas
test gases
THT
-
zero point
-sensitivity
fresh air
e. g. 15 mg/m
3
in synthetic air
TBM
-
zero point
-sensitivity
fresh air
z. B. 10 mg/m
3
in synthetic air
Carbon monoxide CO
-
zero point
-sensitivity
fresh airt
z. B. 30 ppm in synthetic air
Hydrogen H
2
-
zero point
-sensitivity
fresh air
1 % vol. in synthetic air
Hydrogen sulphide H
2
S
-
zero point
-sensitivity
(0 – 100 ppm and 0 – 2000 ppm)
fresh airt
40 ppm in N
2
Ammonia NH
3
-
zero point
-sensitivity
fresh air
50 ppm in N
2
Oxygen O
2
-
zero point
-sensitivity
100 % vol. CH
4
or CO
2
fresh air
Hydrogen chloride HCI
-
zero point
-sensitivity
fresh air
5 ppm in synthetic air
5 Testing the instrument