Time-Weighted Average (TWA) Personal Gas and Vapour Exposure Measurement
GASTEC passive TWA dosimetric detector tubes collect gas and vapour exposure in a worker's breathing zone over a defined period using the principle of natural diffusion, without requiring an external sampling pump. On this page, primary chemicals measurable with the same physical tube are grouped under a single tube code; measuring ranges, shelf life, and package contents are presented based on GASTEC manufacturer documentation. You can quickly locate the relevant product by searching by tube code or chemical name.
GASTEC Passive TWA Dosimetric Detector Tube List – A–Z (By Tube Code)
91D Acetaldehyde / Formaldehyde / Furfural / Methyl Ethyl Ketone GASTEC Passive TWA Dosimetric Detector Tube - Acetaldehyde / Formaldehyde / Furfural / Methyl Ethyl Ketone
Typical Applications
Resin and wood products manufacturing, laboratory/pathology, disinfection, foundry binders, and aldehyde/ketone exposure evaluations.
Measurement Range
Acetaldehyde (CH₃CHO): 0.1–20 ppm
Formaldehyde (HCHO): 0.1–20 ppm
Furfural (C₅H₄O₂): 0.3–60 ppm
Methyl Ethyl Ketone (CH₃COC₂H₅): 0.125–25 ppm
Formaldehyde (HCHO): 0.1–20 ppm
Furfural (C₅H₄O₂): 0.3–60 ppm
Methyl Ethyl Ketone (CH₃COC₂H₅): 0.125–25 ppm
Shelf Life
12 months (refrigerated storage)
Quantity per Box
10 tubes/box (10 measurements)
151D Acetaldehyde / Acetone / Methyl Ethyl Ketone / Methyl Isobutyl Ketone GASTEC Passive TWA Dosimetric Detector Tube - Acetaldehyde / Acetone / Methyl Ethyl Ketone / Methyl Isobutyl Ketone
Typical Applications
Paints and coatings, solvent cleaning, laboratories, chemical manufacturing, and processes using ketones/aldehydes.
Measurement Range
Acetaldehyde (CH₃CHO): 4–1200 ppm
Acetone (CH₃COCH₃): 5–1500 ppm
Methyl Ethyl Ketone (CH₃COC₂H₅): 6.5–1950 ppm
Methyl Isobutyl Ketone (C₆H₁₂O): 11.5–3450 ppm
Acetone (CH₃COCH₃): 5–1500 ppm
Methyl Ethyl Ketone (CH₃COC₂H₅): 6.5–1950 ppm
Methyl Isobutyl Ketone (C₆H₁₂O): 11.5–3450 ppm
Shelf Life
24 months (refrigerated storage)
Quantity per Box
10 tubes/box (10 measurements)
152D Acetaldehyde / Acetone / Methyl Ethyl Ketone / Methyl Isobutyl Ketone GASTEC Passive TWA Dosimetric Detector Tube - Acetaldehyde / Acetone / Methyl Ethyl Ketone / Methyl Isobutyl Ketone
Typical Applications
Occupational hygiene applications evaluating paint, coating, adhesive, solvent cleaning, and ketone exposure.
Measurement Range
Acetaldehyde (CH₃CHO): 1.2–360 ppm
Acetone (CH₃COCH₃): 1.4–420 ppm
Methyl Ethyl Ketone (CH₃COC₂H₅): 2–600 ppm
Methyl Isobutyl Ketone (C₆H₁₂O): 4–1200 ppm
Acetone (CH₃COCH₃): 1.4–420 ppm
Methyl Ethyl Ketone (CH₃COC₂H₅): 2–600 ppm
Methyl Isobutyl Ketone (C₆H₁₂O): 4–1200 ppm
Shelf Life
24 months (refrigerated storage)
Quantity per Box
10 tubes/box (10 measurements)
81D Acetic Acid / Acetic Anhydride / Formic Acid GASTEC Passive TWA Dosimetric Detector Tube - Acetic Acid / Acetic Anhydride / Formic Acid
Typical Applications
Chemical and pharmaceutical manufacturing, processes involving acids/anhydrides, laboratories, and occupational exposure evaluations.
Measurement Range
Acetic Acid (CH₃CO₂H): 0.5–100 ppm
Acetic Anhydride ((CH₃CO)₂O): 0.3–60 ppm
Formic Acid (HCO₂H): 0.55–110 ppm
Acetic Anhydride ((CH₃CO)₂O): 0.3–60 ppm
Formic Acid (HCO₂H): 0.55–110 ppm
Shelf Life
36 months
Quantity per Box
10 tubes/box (10 measurements)
3D Ammonia / Amines / Hydrazine / Triethylamine GASTEC Passive TWA Dosimetric Detector Tube - Ammonia / Amines / Hydrazine / Triethylamine
Typical Applications
Fertiliser/chemical manufacturing, refrigeration facilities, processes involving amines, boiler water treatment chemicals, and occupational hygiene exposure assessments.
Measurement Range
Ammonia (NH₃): 2.5–1000 ppmDimethylamine ((CH₃)₂NH): 1.9–750 ppmN,N-Dimethylethylamine (C₂H₅N(CH₃)₂): 4–1600 ppmHydrazine (N₂H₄): 1.6–650 ppmTriethylamine ((C₂H₅)₃N): 5.3–2100 ppm
Shelf Life
36 months
Quantity per Box
10 tubes/box (10 measurements)
3DL Ammonia / Methylamine / Trimethylamine GASTEC Passive TWA Dosimetric Detector Tube - Ammonia / Methylamine / Trimethylamine
Typical Applications
Chemical, laboratory, and occupational hygiene applications monitoring low-level ammonia and methylamine exposure.
Measurement Range
Ammonia (NH₃): 0.1–10 ppmMethylamine (CH₃NH₂): 0.19–19 ppmTrimethylamine ((CH₃)₃N): 0.23–23 ppm
Shelf Life
24 months
Quantity per Box
10 tubes/box (10 measurements)
122DL Benzene / Toluene / Xylene / Styrene / Ethylbenzene / Cumene GASTEC Passive TWA Dosimetric Detector Tube - Benzene / Toluene / Xylene / Styrene / Ethylbenzene / Cumene
Typical Applications
Petrochemicals, paint/solvent processes, fuel, and aromatic hydrocarbon exposure evaluations.
Measurement Range
Benzene (C₆H₆): 2.4–600 ppmCumene (C₉H₁₂): 3.4–850 ppmEthylbenzene (C₈H₁₀): 2.8–700 ppmStyrene (C₈H₈): 26–6500 ppmToluene (C₇H₈): 2–500 ppmXylene (C₈H₁₀): 3.4–850 ppm
Shelf Life
24 months
Quantity per Box
10 tubes/box (10 measurements)
174D 1,3-Butadiene / Ethylene / Isoprene / Vinyl Chloride / trans-1,2-Dichloroethylene GASTEC Passive TWA Dosimetric Detector Tube - 1,3-Butadiene / Ethylene / Isoprene / Vinyl Chloride / trans-1,2-Dichloroethylene
Typical Applications
Petrochemicals, synthetic rubber/polymer production, solvent processes, and olefin exposure assessments.
Measurement Range
1,3-Butadiene (C₄H₆): 1.3–200 ppmtrans-1,2-Dichloroethylene (C₂H₂Cl₂): 3.8–600 ppmEthylene (C₂H₄): 1.5–240 ppmIsoprene (C₅H₈): 2.5–400 ppmVinyl Chloride (C₂H₃Cl): 1.5–240 ppm
Shelf Life
30 months
Quantity per Box
10 tubes/box (10 measurements)
2D Carbon Dioxide GASTEC Passive TWA Dosimeter Tube - Carbon Dioxide
Typical Applications
Indoor and process air, fermentation, food & beverage, greenhouses, and carbon dioxide exposure assessments.
Measurement Range
Carbon Dioxide (CO₂): 0.02–12 %
Shelf Life
30 months
Quantity per Box
10 tubes/box (10 measurements)
1D Carbon Monoxide GASTEC Passive TWA Dosimeter Tube - Carbon Monoxide
Typical Applications
Combustion processes, boiler/furnace areas, confined spaces, and carbon monoxide exposure assessments.
Measurement Range
Carbon Monoxide (CO): 1.04–2000 ppm
Shelf Life
24 months
Quantity per Box
10 tubes/box (10 measurements)
1DL Carbon Monoxide GASTEC Passive TWA Dosimeter Tube - Carbon Monoxide
Typical Applications
Occupational hygiene and confined space applications where low-level carbon monoxide exposure is assessed.
Measurement Range
Carbon Monoxide (CO): 0.4–400 ppm
Shelf Life
24 months (refrigerated storage)
Quantity per Box
10 tubes/box (10 measurements)
8D Chlorine GASTEC Passive TWA Dosimeter Tube - Chlorine
Typical Applications
Water treatment, disinfection, chemical plants, and chlorine exposure assessments.
Measurement Range
Chlorine (Cl₂): 0.08–100 ppm
Shelf Life
24 months
Quantity per Box
10 tubes/box (10 measurements)
132D Chlorine / 1,2-Dichloroethylene / HCl / Tetrachloroethylene / Trichloroethylene GASTEC Passive TWA Dosimeter Tube - Chlorine / 1,2-Dichloroethylene / Hydrogen Chloride / Tetrachloroethylene / Trichloroethylene
Typical Applications
Metal cleaning/degreasing using chlorinated solvents, acid processes, chemical manufacturing, and industrial hygiene applications.
Measurement Range
Chlorine (Cl₂): 2.4–240 ppm1,2-Dichloroethylene (C₂H₂Cl₂): 6–600 ppmHydrogen Chloride (HCl): 1.8–180 ppmTetrachloroethylene (C₂Cl₄): 1.5–150 ppmTrichloroethylene (C₂HCl₃): 3–300 ppm
Shelf Life
15 months (refrigerated storage)
Quantity per Box
10 tubes/box (10 measurements)
112D Ethanol GASTEC Passive TWA Dosimeter Tube - Ethanol
Typical Applications
Pharmaceuticals, cosmetics, printing, food & beverage, and solvent-based manufacturing/cleaning applications.
Measurement Range
Ethanol (C₂H₅OH): 100–25000 ppm
Shelf Life
36 months
Quantity per Box
10 tubes/box (10 measurements)
14D Hydrogen Chloride / Hydrogen Fluoride / Nitric Acid GASTEC Passive TWA Dosimeter Tube - Hydrogen Chloride / Hydrogen Fluoride / Nitric Acid
Typical Applications
Chemical processes using acids, metal surface treatments, laboratories, and acid vapour exposure assessments.
Measurement Range
Hydrogen Chloride (HCl): 1–100 ppm
Hydrogen Fluoride (HF): 2.5–250 ppm
Nitric Acid (HNO₃): 0.8–80 ppm
Hydrogen Fluoride (HF): 2.5–250 ppm
Nitric Acid (HNO₃): 0.8–80 ppm
Shelf Life
36 months
Quantity per Box
10 tubes/box (10 measurements)
17D Hydrogen Chloride / Hydrogen Fluoride / Nitric Acid GASTEC Passive TWA Dosimeter Tube - Hydrogen Chloride / Hydrogen Fluoride / Nitric Acid
Typical Applications
Metal finishing, chemicals, laboratories, and occupational hygiene applications where low-concentration acid exposure is assessed.
Measurement Range
Hydrogen Chloride (HCl): 0.4–40 ppm
Hydrogen Fluoride (HF): 1–100 ppm
Nitric Acid (HNO₃): 0.32–32 ppm
Hydrogen Fluoride (HF): 1–100 ppm
Nitric Acid (HNO₃): 0.32–32 ppm
Shelf Life
36 months
Quantity per Box
10 tubes/box (10 measurements)
12D Hydrogen Cyanide GASTEC Passive TWA Dosimeter Tube - Hydrogen Cyanide
Typical Applications
Chemical manufacturing, metal finishing/plating, and occupational hygiene applications where cyanide compounds may be present.
Measurement Range
Hydrogen Cyanide (HCN): 1–200 ppm
Shelf Life
24 months
Quantity per Box
10 tubes/box (10 measurements)
32D Hydrogen Peroxide GASTEC Passive TWA Dosimeter Tube - Hydrogen Peroxide
Typical Applications
Disinfection/sterilisation, aseptic processes, chemical manufacturing, and applications using hydrogen peroxide.
Measurement Range
Hydrogen Peroxide (H₂O₂): 0.5–40 ppm
Shelf Life
36 months
Quantity per Box
10 tubes/box (10 measurements)
4D Hydrogen Sulphide GASTEC Passive TWA Dosimeter Tube - Hydrogen Sulphide
Typical Applications
Wastewater and sewerage, oil and gas, pulp and paper, confined spaces, and hydrogen sulphide exposure assessments.
Measurement Range
Hydrogen Sulphide (H₂S): 0.2–200 ppm
Shelf Life
36 months
Quantity per Box
10 tubes/box (10 measurements)
9D Nitrogen Dioxide GASTEC Passive TWA Dosimeter Tube - Nitrogen Dioxide
Typical Applications
Combustion processes, welding, diesel exhaust, nitric acid processes, and nitrogen dioxide exposure assessments.
Measurement Range
Nitrogen Dioxide (NO₂): 0.1–30 ppm
Shelf Life
12 months (refrigerated storage)
Quantity per Box
10 tubes/box (10 measurements)
9DL Nitrogen Dioxide GASTEC Passive TWA Dosimeter Tube - Nitrogen Dioxide
Typical Applications
Occupational hygiene, laboratory, and combustion-source ambient measurements where low-level nitrogen dioxide exposure is assessed.
Measurement Range
Nitrogen Dioxide (NO₂): 0.01–3.0 ppm
Shelf Life
12 months (refrigerated storage)
Quantity per Box
10 tubes/box (10 measurements)
5DH Sulphur Dioxide GASTEC Passive TWA Dosimeter Tube - Sulphur Dioxide
Typical Applications
Chemicals, metal processing, sulphur-containing processes, combustion sources, and occupational hygiene exposure assessments.
Measurement Range
Sulphur Dioxide (SO₂): 10–600 ppm
Shelf Life
36 months
Quantity per Box
10 tubes/box (10 measurements)
5D Sulphur Dioxide GASTEC Passive TWA Dosimeter Tube - Sulphur Dioxide
Typical Applications
Industrial hygiene, combustion, and chemical process applications where low- and medium-level sulphur dioxide exposure is monitored.
Measurement Range
Sulphur Dioxide (SO₂): 0.2–100 ppm
Shelf Life
36 months
Quantity per Box
10 tubes/box (10 measurements)
133D Tetrachloroethylene GASTEC Passive TWA Dosimeter Tube - Tetrachloroethylene
Typical Applications
Dry cleaning, metal degreasing, processes using chlorinated solvents, and personal exposure assessments.
Measurement Range
Tetrachloroethylene (C₂Cl₄): 3–150 ppm
Shelf Life
15 months (refrigerated storage)
Quantity per Box
10 tubes/box (10 measurements)
GASTEC Passive TWA Dosimeter Tubes
Passive TWA dosimeter tubes are used in occupational hygiene and personal exposure assessments to collect gases or vapours in the worker's breathing zone over a specified period by natural diffusion. Requiring no external gas sampling pump, this method helps determine time-weighted average (TWA) concentrations over a shift or task duration.
Correct tube selection depends on the target chemical, expected concentration, measurement duration, and ambient conditions. Where the same GASTEC tube code can be used for multiple chemicals, the relevant substances are shown on this page under a single tube alongside each chemical's specific measuring range. Checking the current GASTEC product data sheet prior to procurement and application is recommended.