Honeywell Sensepoint XCD RFD - 19 Cross Interference and Cross Calibration; Cross Calibration Flammable Gas Detector

Sensepoint XCD RFD Technical Manual SPXCDHMRFEN Issue 4_08-2016
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19 Cross Interference and Cross Calibration
19.1 Cross Calibration Flammable Gas Detector
For greater accuracy, a catalytic gas detector should be calibrated using a certied
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, certied and veriable 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:
Notes:
1. Table 14 lists a selection of hydrocarbon compounds and states a reference gure or
“Star Rating” according to the reaction they produce in relation to other hydrocarbons.
2. 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*
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.