57
7 Appendix
7.5
Sensors
Note:
Probes increase the stated response times.
7.5.1
Infrared sensors (IR)
7.5.1.1 Methane CH
4
, propane C
3
H
8
, butane C
4
H
10
, nonane C
9
H
20
Type:
Infrared sensor
Measuring range:
0 – 100 % LEL
Measuring error:
– CH
4
– C
3
H
8
– C
9
H
20
±1 % LEL (short-term stability)
±4 % LEL (long-term stability)
±1 % LEL (short-term stability)
±1 % LEL (long-term stability)
±5 % LEL
Response times:
– CH
4
– C
3
H
8
, C
4
H
10
– C
9
H
20
t
50
< 8 s
t
90
< 14 s
t
50
< 9 s
t
90
< 17 s
t
50
< 16 s
t
90
< 120 s
Temperature range:
-20 ºC – +40 ºC
Interference:
All hydrocarbons C
x
H
y
Lifetime:
– Warranted
– Expected
2 years
5 years
Test gases:
– Zero point
– Sensitivity
Fresh air
2.20 % vol. CH
4
1.00 % vol. C
3
H
8
1.00 % vol. C
4
H
10
0.22 % vol. C
9
H
20
(replacement test gas
0.3 % vol. C
3
H
8
)
