Gastec Passive Dosi-Tubes
For on-the-spot TWA monitoring.
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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 GST_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.
Dosi-Tube
| Chemical | Tube Name | Target Measuring Range | Sample Time (hours) | Part Number |
|---|---|---|---|---|
| Acetaldehyde CH3CHO | Formaldehyde | 0.1 ppm – 20 ppm | 1-10 | GST_91D * |
| Acetaldehyde CH3CHO | Acetone | 4 ppm – 1200 ppm | 1-10 | GST_151D * |
| Acetaldehyde CH3CHO | Methyl ethyl ketone | 1.2 ppm – 360 ppm | 1-10 | GST_152D * |
| Acetic acid CH3CO2H | Acetic acid | 0.5 ppm – 100 ppm | 1-10 | GST_81D |
| Acetic anhydride (CH3CO)2O | Acetic acid | 0.3 ppm – 60 ppm | 1-10 | GST_81D |
| Acetone CH3COCH3 | Acetone | 1 ppm – 1500 ppm | 1-10 | GST_151D * |
| Acetone CH3COCH3 | Methyl ethyl ketone | 1.4 ppm – 420 ppm | 1-10 | GST_152D * |
| Ammonia NH3 | Ammonia | 2.5 ppm – 1000 ppm | 0.5-10 | GST_3D |
| Ammonia NH3 | Ammonia | 0.1 ppm – 10 ppm | 1-10 | GST_3DL |
| Benzene C6H6 | Toluene | 2.4 ppm -600 ppm | 1-10 | GST_122DL |
| 1,3-Butadiene CH2:CHCH:CH2 | 1,3-Butadiene | 1.3 ppm – 200 ppm | 1-8 | GST_174D |
| Carbon dioxide CO2 | Carbon dioxide | 0.02 % – 12 % | 0.5-10 | GST_2D |
| Carbon monoxide CO | Carbon monoxide | 1.04 ppm – 2000 ppm | 0.5-48 | GST_1D |
| Carbon monoxide CO | Carbon monoxide | 0.4 ppm – 400 ppm | 0.5-24 | GST_1DL * |
| Chlorine Cl2 | Chlorine | 0.08 ppm – 100 ppm | 0.5-24 | GST_8D |
| Chlorine Cl2 | Trichloroethylene | 2.4 ppm – 240 ppm | 1-8 | GST_132D * |
| Cumene C6H5CH(CH3)2 | Toluene | 3.4 ppm – 850 ppm | 1-10 | GST_122DL |
| 1,2-Dichloroethylene ClCH:CHCl | 1,3-Butadiene | 3.9 ppm – 600 ppm | 1-8 | GST_174D |
| 1,2-Dichloroethylene ClCH:CHCl | Trichloroethylene | 6 ppm – 600 ppm | 1-8 | GST_132D * |
| Dimethylamine (CH3)2NH | Ammonia | 1.9 ppm – 750 ppm | 0.5-10 | GST_3D |
| N,N-Dimethylethylamine C2H5N(CH3)2 | Ammonia | 4 ppm – 1600 ppm | 0.5-10 | GST_3D |
| Ethanol C2H5OH | Ethanol | 100 ppm – 25000 ppm | 1-10 | GST_112D |
| Ethylene CH2:CH2 | 1,3-Butadiene | 1.5 ppm – 240 ppm | 1-8 | GST_174D |
| Formaldehyde HCHO | Formaldehyde | 0.1 ppm – 20 ppm | 1-10 | GST_91D * |
| Formic acid HCO2H | Acetic acid | 0.55 ppm – 110 ppm | 1-10 | GST_81D |
| Furfural C5H4O2 | Formaldehyde | 0.3 ppm – 60 ppm | 1-10 | GST_91D * |
| Hydrazine N2H4 | Ammonia | 1.6 ppm – 650 ppm | 0.5-10 | GST_3D |
| Hydrogen chloride HCl | Hydrogen chloride | 1-100 | 1-10 | GST_14D |
| Hydrogen chloride HCl | Trichloroethylene | 1.8-180 | 1-8 | GST_132D * |
| Hydrogen cyanide HCN | Hydrogen cyanide | 1 ppm – 200 ppm | 1-10 | GST_12D |
| Hydrogen fluoride HF | Hydrogen fluoride | 1 ppm – 100 ppm | 1-10 | GST_17D |
| Hydrogen fluoride HF | Hydrogen chloride | 2.5 ppm – 250 ppm | 1-10 | GST_14D |
| Hydrogen peroxide H2O2 | Hydrogen peroxide | 0.5 ppm – 40 ppm | 1-10 | GST_32D |
| Hydrogen sulphide H2S | Hydrogen sulphide | 0.2 ppm – 200 ppm | 1-48 | GST_4D |
| Isoprene CH2:C(CH3)CH:CH2 | 1,3-Butadiene | 2.6 ppm – 400 ppm | 1-8 | GST_174D |
| Methylamine CH3NH2 | Ammonia | 0.19 ppm – 19 ppm | 1-10 | GST_3DL |
| Methyl ethyl ketone CH3COC2H5 | Methyl ethyl ketone | 2 ppm – 600 ppm | 1-10 | GST_152D * |
| Methyl ethyl ketone CH3COC2H5 | Formaldehyde | 0.125 ppm – 25 ppm | 1-10 | GST_91D * |
| Methyl ethyl ketone CH3COC2H5 | Acetone | 6.5 ppm – 1950 ppm | 1-10 | GST_151D * |
| Methyl isobutyl ketone (CH3)2CHCH2COCH3 | Acetone | 11.5 ppm – 3450 ppm | 1-10 | GST_151D * |
| Methyl isobutyl ketone (CH3)2CHCH2COCH3 | Methyl ethyl ketone | 4 ppm – 1200 ppm | 1-10 | GST_152D * |
| Nitric acid HNO3 | Hydrogen chloride | 0.8 ppm – 80 ppm | 1-10 | GST_14D |
| Nitric acid HNO3 | Hydrogen chloride | 0.32 ppm – 32 ppm | 1-10 | GST_17D |
| Nitrogen dioxide NO2 | Nitrogen dioxide | 0.1 ppm – 30 ppm | 1-10 | GST_9D * |
| Nitrogen dioxide NO2 | Nitrogen dioxide | 0.01 ppm – 3.0 ppm | 1-24 | GST_9DL * |
| Styrene C6H5CH:CH2 | Toluene | 26 ppm – 6500 ppm | 1-10 | GST_122DL |
| Sulphur dioxide SO2 | Sulphur dioxide | 10 ppm – 600 ppm | 1-5 | GST_5DH |
| Sulphur dioxide SO2 | Sulphur dioxide | 0.2 ppm – 100 ppm | 1-10 | GST_5D |
| Tetrachloroethylene Cl2C:CCl2 | Tetrachloroethylene | 3 ppm – 150 ppm | 1-8 | GST_133D * |
| Tetrachloroethylene Cl2C:CCl2 | Trichloroethylene | 1.5 ppm – 150 ppm | 1-8 | GST_132D * |
| Toluene C6H5CH3 | Toluene | 2 ppm – 500 ppm | 1-10 | GST_122DL |
| Trichloroethylene Cl2C:CHCl | Trichloroethylene | 3 ppm – 300 ppm | 1-8 | GST_132D * |
| Triethylamine (C2H5)3N | Ammonia | 5.3 ppm – 2100 ppm | 0.5-10 | GST_3D |
| Trimethylamine (CH3)3N | Ammonia | 0.23 ppm – 23 ppm | 1-10 | GST_3DL |
| Vinyl chloride CH2:CHCl | 1,3-Butadiene | 1.56 ppm – 240 ppm | 1-8 | GST_174D |
| Xylene C6H4(CH3)2 | Toluene | 3.4 ppm – 850 ppm | 1-10 | GST_122DL |
* Refrigerated storage – tubes to be stored at ≤10°C
Dosi-Tube Holder
| Description | Pack Size | Part Number | |
|---|---|---|---|
| Dosi-Tube Holder | 3 | GST_710 |  |