An ASU (Air Sampling Unit) can be used to monitor hazardous gases in an air duct. The Crowcon Air Sampling Unit ASU is mounted outside the ventilation duct. Test air is fed through a tube into an intake chamber where the XGard gas sensor is mounted. The residual air is fed back into the ventilation duct via another pipe on the other side of the intake chamber.
The air flow rate must be between 5-20 m/s.
If the test air cannot be sampled from a ventilation duct, we recommend the
ESU (Environmental Sampling Unit) gas intake system with integrated intake fan.