TWA measuring system (time-weighted average) – also known as dosimeter tube or passive tubes gas detection – measures the time-weighted average concentrations of a gas in ambient air.
The dosimeter tube is inserted in its holder and wore close to the breathing zone (e.g. a shirt collar) to get an accurate measure of inhaled concentrations. This allows the monitoring of hazardous exposure during a working day.
Thanks to this system, wokers can easily get daily exposure concentrations and evaluate working areas. These simple and direct measures require no specific analyzis instruments or complex operation procedures.