Gastec Passive Dosi-Tubes
Gastec Colour Dosimeter Tubes (Dosi-tubes) provide reliable, on-the-spot Time-Weighted Average (TWA) monitoring of worker exposure to gases and vapours. The system is simple-to-use and easy-to-read, with no need for a pump, chart, or laboratory analysis. The Dosi-tube system allows an operator to evaluate the level of exposure over a long time period such as a working shift.
The system consists of Gastec Dosi-tubes and a tube holder (part number 810-710). The pre-scored ends of the tube are simply snapped off and the tube inserted into a tube holder. Air diffuses passively through the tube and reacts with the detecting reagent within, giving a colour change result that is indicated on the printed scale. The tube holder can either be attached in a worker’s breathing zone or installed in work areas to act as an area monitor.
Using a simple equation, the Dosi-tube system produces an average concentration of exposure over a set period of time – commonly known as a Time Weighted Average (TWA). To calculate the ppm level simply read the printed calibrated scale on the tube for exposure measurement in parts-per-million-hours (ppm-hours), and divide the reading by the number of hours sampled.
Note: When measuring carbon dioxide, mount the tube holder on the worker’s waist rather than in their breathing zone. This will avoid overstating CO2 levels due to exhalation.
Note: When measuring carbon dioxide, mount the tube holder on the worker’s waist rather than in their breathing zone. This will avoid overstating CO2 levels due to exhalation.
| Description | Pack Size | Part Number |
| Dosi-Tube Holder | 3 | 710 |
| Tube Breaker | Each | 722 |
| Gas or Vapour to be Measured | Measuring Range (ppm) | Gastec Tube No. |
| Acetaldehyde (Dosi tube) | 1.2-360 | 152D |
| Acetaldehyde (Dosi tube) | 4-1,200 | 151D |
| Acetaldehyde (Dosi tube) | 0.1-20 | 91D |
| Acetic acid (Dosi tube) | 0.5-100 | 81D |
| Acetic anhydride (Dosi tube) | 0.3-60 | 81D |
| Acetone (Dosi tube) | 5-1,500 | 151D |
| Acetone (Dosi tube) | 1.4-420 | 152D |
| Ammonia (Dosi tube) | 0.1-10 | 3DL |
| Ammonia (Dosi tube) | 2.5-1,000 | 3D |
| Benzene (Dosi tube) | 2.4-600 | 122DL |
| 1,3-Butadiene (Dosi tube) | 1.3-200 | 174D |
| Carbon dioxide (Dosi tube) | 0.02-12% | 2D |
| Carbon monoxide (Dosi tube) | 1.04-2,000 | 1D |
| Carbon monoxide (Dosi tube) | 0.4-400 | 1DL |
| Chlorine (Dosi tube) | 0.08-100 | 8D |
| Cumene (Dosi tube) | 3.4-850 | 122DL |
| trans-1,2-Dichloroethylene (Dosi tube) | 3.9-600 | 174D |
| Dimethylamine (Dosi tube) | 1.9-750 | 3D |
| N,N-Dimethylethylamine (Dosi tube) | 4-1600 | 3D |
| Ethanol (Dosi tube) | 100-25,000 | 112D |
| Ethyl benzene (Dosi tube) | 2.8-700 | 122DL |
| Ethylene (Dosi tube) | 1.56-240 | 174D |
| Formaldehyde (Dosi tube) | 0.1-20 | 91D |
| Formic acid (Dosi tube) | 0.55-110 | 81D |
| Furfural (Dosi tube) | 0.3-60 | 91D |
| Hydrazine (Dosi tube) | 1.6-650 | 3D |
| Hydrogen Chloride (Dosi tube) | 1.8-180 | 132D |
| Hydrogen chloride (Dosi tube) | 1-100 | 14D |
| Hydrogen cyanide (Dosi tube) | 1-200 | 12D |
| Hydrogen fluoride (Dosi tube) | 1-100 | 17D |
| Hydrogen fluoride (Dosi tube) | 2.5-250 | 14D |
| Hydrogen peroxide (Dosi tube) | 0.5-40 | 32D |
| Hydrogen sulphide (Dosi tube) | 0.2-200 | 4D |
| Isoprene (Dosi tube) | 2.6-400 | 174D |
| Methy ethyl ketone (Dosi tube) | 2-600 | 152D |
| Methyl ethyl ketone (Dosi tube) | 0.125-25 | 91D |
| Methyl ethyl ketone (Dosi tube) | 6.5-1,950 | 151D |
| Methyl isobutyl ketone (Dosi tube) | 11.5-3,450 | 151D |
| Methyl isobutyl ketone (Dosi tube) | 4-1200 | 152D |
| Methylamine (Dosi tube) | 0.19-19 | 3DL |
| Nitric acid (Dosi tube) | 0.8-80 | 14D |
| NItric acid (Dosi tube) | 0.32-32 | 17D |
| Nitrogen dioxide (Dosi tube) | 0.01-3.0 | 9DL |
| Nitrogen dioxide (Dosi tube) | 0.1-30 | 9D |
| Styrene (Dosi tube) | 26-6,500 | 122DL |
| Sulphur dioxide (Dosi tube) | 10-600 | 5DH |
| Sulphur dioxide (Dosi tube) | 0.2-100 | 5D |
| Tetrachloroethylene (Dosi tube) | 1.5-150 | 132D |
| Tetrachloroethylene (Dosi tube) | 3-150 | 133D |
| Toluene (Dosi tube) | 2-500 | 122DL |
| Trichloroethylene (Dosi tube) | 3-300 | 132D |
| Triethylamine (Dosi tube) | 5.3-2,100 | 3D |
| Trimethylamine (Dosi tube) | 0.23-23 | 3DL |
| Vinyl Chloride (Dosi tube) | 1.56-240 | 174D |
| Xylene (Dosit tube) | 3.4-850 | 122DL |
