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.
Description |
Pack Size |
Part Number |
Dosi-Tube Holder |
3 |
810-710 |
Tube Breaker |
Each |
810-722 |
Dosi-Tubes
Chemical |
Tube Name |
Target Measuring Range (ppm) |
Sample Time (hours) |
Shelf Life (years) |
Part Number |
Acetaldehyde
CH3CHO |
Formaldehyde |
0.1-20 |
1-10 |
1* |
810-91D |
Acetone |
4-1200 |
1-10 |
2* |
810-151D |
Methyl ethyl ketone |
1.2-360 |
1-10 |
2* |
810-152D |
Acetic acid
CH3CO2H |
Acetic acid |
0.5-100 |
1-10 |
3 |
810-81D |
Acetic anhydride
(CH3CO)2O |
Acetic acid |
0.3-60 |
1-10 |
3 |
810-81D |
Acetone
CH3COCH3 |
Acetone |
1-1500 |
1-10 |
2* |
810-151D |
Methyl ethyl ketone |
1.4-420 |
1-10 |
2* |
810-152D |
Ammonia
NH3 |
Ammonia |
2.5-1000 |
0.5-10 |
3 |
810-3D |
Ammonia |
0.1-10 |
1-10 |
2 |
810-3DL |
Benzene
C6H6 |
Toluene |
2.4-600 |
1-10 |
2 |
810-122DL |
1,3-Butadiene
CH2:CHCH:CH2 |
1,3-Butadiene |
1.3-200 |
1-8 |
2 |
810-174D |
Carbon dioxide
CO2 |
Carbon dioxide |
0.02-12% |
0.5-10 |
2 |
810-2D |
Carbon monoxide
CO |
Carbon monoxide |
1.04-2000 |
0.5-48 |
2 |
810-1D |
Carbon monoxide |
0.4-400 |
0.5-24 |
2* |
810-1DL |
Chlorine
Cl2 |
Chlorine |
0.08-100 |
0.5-24 |
2 |
810-8D |
Trichloroethylene |
2.4-240 |
1-8 |
1* |
810-132D |
Cumene
C6H5CH(CH3)2 |
Toluene |
3.4-850 |
1-10 |
2 |
810-122DL |
1,2-Dichloroethylene
ClCH:CHCl |
1,3-Butadiene |
3.9-600 |
1-8 |
2 |
810-174D |
Trichloroethylene |
6-600 |
1-8 |
1* |
810-132D |
Dimethylamine
(CH3)2NH |
Ammonia |
1.9-750 |
0.5-10 |
3 |
810-3D |
N,N-Dimethylethylamine
C2H5N(CH3)2 |
Ammonia |
4-1600 |
0.5-10 |
3 |
810-3D |
Ethanol
C2H5OH |
Ethanol |
100-25000 |
1-10 |
3 |
810-112D |
Ethyl benzene
C6H5C2H5 |
Toluene |
2.8-700 |
1-10 |
2 |
810-122DL |
Ethylene
CH2:CH2 |
1,3-Butadiene |
1.5-240 |
1-8 |
2 |
810-174D |
Formaldehyde
HCHO |
Formaldehyde |
0.1-20 |
1-10 |
1* |
810-91D |
Formic acid
HCO2H |
Acetic acid |
0.55-110 |
1-10 |
3 |
810-81D |
Furfural
C5H4O2 |
Formaldehyde |
0.3-60 |
1-10 |
1* |
810-91D |
Hydrazine
N2H4 |
Ammonia |
1.6-650 |
0.5-10 |
3 |
810-3D |
Hydrogen chloride
HCl |
Hydrogen chloride |
1-100 |
1-10 |
3 |
810-14D |
Trichloroethylene |
1.8-180 |
1-8 |
1* |
810-132D |
Hydrogen cyanide
HCN |
Hydrogen cyanide |
1-200 |
1-10 |
2 |
810-12D |
Hydrogen fluoride
HF |
Hydrogen fluoride |
2.5-250 |
1-10 |
3 |
810-14D |
Hydrogen chloride |
1-100 |
1-10 |
3 |
810-17D |
Hydrogen peroxide
H2O2 |
Hydrogen peroxide |
0.5-40 |
1-10 |
3 |
810-32D |
Hydrogen sulphide
H2S |
Hydrogen sulphide |
0.2-200 |
1-48 |
3 |
810-4D |
Isoprene
CH2:C(CH3)CH:CH2 |
1,3-Butadiene |
2.6-400 |
1-8 |
2 |
810-174D |
Methylamine
CH3NH2 |
Ammonia |
0.19-19 |
1-10 |
2 |
810-3DL |
Methyl ethyl ketone
CH3COC2H5 |
Methyl ethyl ketone |
2-600 |
1-10 |
2* |
810-152D |
Formaldehyde |
0.125-25 |
1-10 |
1* |
810-91D |
Acetone |
6.5-1950 |
1-10 |
2* |
810-151D |
Methyl isobutyl ketone
(CH3)2CHCH2COCH3 |
Acetone |
11.5-3450 |
1-10 |
2* |
810-151D |
Methyl ethyl ketone |
4-1200 |
1-10 |
2* |
810-152D |
Nitric acid
HNO3 |
Hydrogen chloride |
0.8-80 |
1-10 |
3 |
810-14D |
Hydrogen chloride |
0.32-32 |
1-10 |
3 |
810-17D |
Nitrogen dioxide
NO2 |
Nitrogen dioxide |
0.1-30 |
1-10 |
1* |
810-9D |
Nitrogen dioxide |
0.01-3.0 |
1-24 |
1* |
810-9DL |
Styrene
C6H5CH:CH2 |
Toluene |
26-6500 |
1-10 |
2 |
810-122DL |
Sulphur dioxide
SO2 |
Sulphur dioxide |
10-600 |
1-5 |
2 |
810-5DH |
Sulphur dioxide |
0.2-100 |
1-10 |
3 |
810-5D |
Tetrachloroethylene
Cl2C:CCl2 |
Tetrachloroethylene |
3-150 |
1-8 |
1* |
810-133D |
Trichloroethylene |
1.5-150 |
1-8 |
1* |
810-132D |
Toluene
C6H5CH3 |
Toluene |
2-500 |
1-10 |
2 |
810-122DL |
Trichloroethylene
Cl2C:CHCl |
Trichloroethylene |
3-300 |
1-8 |
1* |
810-132D |
Triethylamine
(C2H5)3N |
Ammonia |
5.3-2100 |
0.5-10 |
3 |
810-3D |
Trimethylamine
(CH3)3N |
Ammonia |
0.23-23 |
1-10 |
2 |
810-3DL |
Vinyl chloride
CH2:CHCl |
1,3-Butadiene |
1.56-240 |
1-8 |
2 |
810-174D |
Xylene
C6H4(CH3)2 |
Toluene |
3.4-850 |
1-10 |
2 |
810-122DL |
* Refrigerated storage - tubes to be stored at ≤10°C