Measuring Range
1 to 2 ppm 2 to 50 ppm 50 to 100 ppm
Number of Pump Strokes
4 2 1
Correction Factor
1/2 1 2
Sampling Time 1.5 minutes per pump stroke
Detecting Limit 0.5 ppm (n=4)
Colour Change White → Brown
Reaction Principle C6H5CH3 + I2O5 + H2SO4 → I2
Coefficient of Variation 10% (for 2 to 100 ppm), 5% (for 10 to 50 ppm)
Shelf Life 3 Years
Corrections for temperature & humidity Unnecessary
Store the tubes at cool and dark place.
Possible coexisting substances and their interferences (NOTE)
Substance Interference Change colour by itself to
Acetylene, Ethylene, Hexane No No
Alcohols, Ketones, Esters No No
Aromatic hydrocarbons + Brown
Other substance measurable with this detector tube
Substance Correction Factor No. of pump strokes Measuring Range
Xylene 4,2,1 1,2,4 2 to 200 ppm
Calibration Scale
Ethyl Benzene Conc. (ppm)
Tube 122L Reading (n = 2)
Calibration Scale
Cumene Concentration (ppm)
Tube 122L Reading (n= 2)
Calibration Scale
Diethyl Benzene Conc. (ppm)
Tube 122L Reading (n=4)
Calibration gas generation Diffusion tube method
TLV-TWA TLV-STEL Explosive range
20 ppm - 1.4 to 6.7%

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