Gastec Detector Tubes

Gastec Passive Dositubes

Gastec Passive Dosi-Tubes are used to measure time weighted average (TWA) gas concentrations over several hours. The Dositubes do not require the use of a sampling pump as ambient air diffuses through the tube. Each tube is filled with a diffuser and chemical reagent in parallel that allows the gas to disperse at a constant flow. This provides longer discolouration and better demarcation. The tubes are normally attached to the worker’s collar or clothing in the breathing zone with the holder and collar clip.

  • Uses gas diffusion method
  • Tube holder clips onto workers collar for breathing zone measurements or can be used as an area monitor
  • Measures time weighted averages (TWA) for numerous gases (See Dositubes List)
  • Direct measurement can be made from the calibration lines printed on each tube

Easy operation:

Step 1: Record Start Time
Step 2: Break tube end
Step 3: Place in tube holder
Step 4: When measurement is finished, write down finishing time
Step 5: Find the TWA using the formula; TWA (ppm) = Dositube reading (ppm=hr) / Actual sampling time (hr)

Gas or Vapour to be MeasuredMeasuring Range (ppm)Gastec Tube No.
Acetaldehyde0.1-2091D
Acetaldehyde4-1,200151D
Acetaldehyde1.2-360152D
Acetic Acid0.5-10081D
Acetic Anhydride0.45-9081D
Acetone5-1500151D
Acetone1.4-420152D
Ammonia2.5-1,0003D
Ammonia (Low)0.1-103DL
Benzene2.4-600122DL
1,3-Butadiene1.3-200174D
Carbon Dioxide0.02-12%2D
Carbon Monoxide1.04-2,0001D
Carbon Monoxide (Low)0.4-4001DL
Chlorine0.08-1008D
Chlorine2.4-240132D
Cumene3.4-850122DL
trans-1,2-Dichloroethylene3.9-600174D
trans-1,2-Dichloroethylene6-600132D
Dimethylamine1.9-7503D
N,N-Dimethylethylamine4-1,6003D
Ethanol100-25,000112D
Ethyl Benzene2.8-700122DL
Ethylene1.56-240174D
Ethylene dichloride3.9-600174D
Formaldehyde0.1-2091D
Formic Acid0.55-11081D
Furfural0.3-6091D
Hydrazine1.6-6503D
Hydrogen Chloride1-10014D
Hydrogen Chloride 1.8-180132D
Hydrogen Cyanide1-20012D
Hydrogen Fluoride1-10017D
Hydrogen Fluoride 2.5-25014D
Hydrogen Peroxide0.5-4032D
Hydrogen Sulphide0.2-2004D
Isoprene2.6-400174D
Methylamine0.19-193DL
Methyl Ethyl Ketone (MEK)2-600152D
Methyl Ethyl Ketone (MEK)0.125-2591D
Methyl Ethyl Ketone (MEK)6.5-1,950151D
Methyl Isobutyl Ketone11.5-3,450151D
Methyl Isobutyl Ketone4-1,200152D
Ntric Acid0.8-8014D
Nitric Acid0.32-3217D
Nitrogen Dioxide0.1-309D
Nitrogen Dioxide (Low)0.01-3.09DL
Styrene26-6,500122DL
Sulphur Dioxide10-6005DH
Sulphur Dioxide0.2-1005D
Tetrachloroethylene3-150133D
Tetrachloroethylene 1.5-150132D
Toluene2-500122DL
Trichloroethylene3-300132D
Triethylamine5.3-2,1003D
Trimethylamine0.23-233DL
Vinyl Chloride1.56-240174D
Xylene3.4-850122DL

Part Numbers

IG710 TUBE HOLDER, 10/BOX
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