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What is a Gas Detector Tube?

Learn more about Gas Detector Tubes - their history and how to use.

Gas Detector Tubes: Glass tubes that have graduating scales printed on them. You can directly read the concentrations of the gas or vapor to be measured based on the color change of the scale. The color change is achieved because the tube contains a detaching reagent that is sensitive to the target substance. No color chart is needed. There are different variations of the Gas Detector Tube: Most common are the Short-term tubes which require a sampling pump for use. The Long-term tubes (TWA or DOSI) (time-weighted average) do not require a pump and Solution tubes are used in water. Airtec or Aerotest tubes are used with a compressed air kit.

The Detector Tube Method permits a simple, quick and economical analysis at working sites.


The first gas detector tube was invented in the USA in 1919 to measure concentrations of carbon monoxide (CO) in working places. It utilized a chemical reaction of CO with a special reagent filled in a thin glass tube. If air containing CO passed through the tube, the reagent would change its color in reaction to the CO. Its color intensity was proportional to the CO concentration in the air. Therefore, operators could get the concentration by comparing the color intensity with a previously prepared color chart.