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.

Gastec Dosi-Tubes
Dosi-Tube Holder
Dosi-Tube Holder and Tubes

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.

Passive Sampler Selection GuidePassive Sampler Selection Guide
Hazard SearchHazard Search
What is Air Sampling?What is Air Sampling?

Cookies user preferences
We use cookies to ensure you to get the best experience on our website. If you decline the use of cookies, this website may not function as expected.
Accept all
Decline all
Read more
Tools used to analyze the data to measure the effectiveness of a website and to understand how it works.
Google Analytics