Teledyne Max-5 - Combustion efficiency analyzer - Manual (Page 11)

calibrate the instrument with Methane, but make it read as if it were exposed to the gas of
interest. For example, if you calibrate with Methane and the MAX 5 reads 3%, but Propane
would read 4%, you calibrate with Methane and adjust the MAX 5 to read 4%.
TABLE 1
DETECTOR RESPONSE TO GASES
COMPOUND LEL*
RESPONSE FACTOR
Methane
5.0 1.00
Hydrogen 4.0 0.86
Carbon Monoxide 12.5 0.32
Ethane 3.0 1.20
Ethylene 2.7 1.26
Acetylene 2.5 1.39
Propane 2.2 1.42
Propylene 2.0 1.33
Butane 1.9 1.54
Hexane 1.1 1.50
Cyclohexane 1.3 1.44
Heptane 1.05 1.59
Benzene 1.3 1.50
Pentane 1.5 1.45
Toluene 1.2 1.48
Ethylene Oxide 3.8 0.76
Methyl Ethyl Ketone 1.8 0.96
Methyl Acrylate 2.8 0.59
*Taken from Fire Hazard Properties of Flammable Liquids, Gases and Volatile Solids, National
Fire Protection Agency.
To determine the concentration of a compound present at the sensor from the MAX 5 reading,
when calibrated with Methane, divide the MAX 5 reading (in percent Methane) by the factor.
For example, if Ethylene is flowing by the sensor, and a MAX 5 reading of 2.0% is obtained, the
concentration of Ethylene would be:
MAX 5 Reading = 2.0% = 1.59%
Factor
1.26
For Hydrogen:
2.0 = 2.32%
.86
For Carbon Monoxide:
2.0 = 6.25%