Honeywell Sensepoint XCD - Flammable Gas Cross Calibration

Sensepoint XCD Technical Manual
SPXCDHMANEN Issue 15
75
Cross Calibration Flammable Gas Detector
Note: Not a scope for performance approval
For greater accuracy, a catalytic gas detector should be calibrated using a certified gas/air mixture equal
to 50 % LEL of the actual target gas intended to be monitored.
However, it is not always practical to obtain every detectable type of hydrocarbon gas in a calibration-
ready, certified and verifiable form. Therefore, it is possible to carry out a ‘cross calibration’ using another
hydrocarbon gas/air mixture.
When the Sensepoint XCD Combustible LEL sensor is to be calibrated with a gas which is different to
the gas or vapour to be detected, the following cross calibration procedure may be followed:
Note: Table 10 lists a selection of hydrocarbon compounds and states a reference figure or ‘Star
Rating’ according to the reaction they produce in relation to other hydrocarbons. An eight-star (8*) gas
produces the highest output, while a one-star (1*) gas produces the lowest output.
No.
Gas
Star Rating
1
Acetone
4*
2
Ammonia
7*
3
Benzene
3*
4
Butanone
3*
5
Butane
4*
6
Butyl acetate
1*
7
Butyl acrylate
1*
8
Cyclohexane
3*
9
Cyclohexanone
<1*
10
Diethyl ether
4*
11
Ethane
6*
12
Ethanol
5*
13
Ethyl acetate
3*
14
Ethylene
5*
15
Heptane
3*
16
Hexane
3*
17
Hydrogen
6*
18
Methane
6*
19
Methanol
5*
20
MIBK
3*
21
Octane
3*
22
Pentane
3*
23
Propane
5*
24
Propan-2-ol
4*
25
Styrene
2*
26
Tetra hydrafuran
4*
27
Toluene
3*
28
Triethylamine
3*
29
Xylene
2*
Table 10 Star Rating of Gases
CAUTION
Where the user calibrates any sensor using a different gas, responsibility for identifying and
recording calibration rests with the user. Refer to the local regulations where appropriate.