Gas sensor cross sensitivity

What is gas sensor cross sensitivity?

Cross sensitivity is a phenomenon that occurs when a sensor shows readings for a gas that is not the target gas. This interfering gas causes a reaction in the sensor — therefore showing a change in readings — even if the target gas is not present. An example of this would be an H₂S sensor reacting to H₂ in the area.



What does Blackline do to alleviate cross sensitivity?

Blackline Safety uses sensors that are less likely to react to interfering gases — some of these sensors also have built in filters that help to keep interfering gases from reaching the sensor.

 

What will I see when sensors are cross sensitive?

When a sensor is cross sensitive, you will see readings change even if there is none of the target gas in the area. For example, you could be applying a single type of gas to the device for a bump test, and you may see the other sensors react.



What can I do when sensors get cross sensitive readings?

When sensors get cross sensitive readings, we recommend you allow the device to sit and stabilize. Depending on the gas it was exposed to, it can take as little as a few minutes or as long as several hours. Once the readings have stabilized, you can re-calibrate the device if desired.



What gas combinations produce noticeable cross sensitivity?

Almost all gases cause some cross sensitivity, but our devices are designed to filter out many of the most commonly occurring ones.

CO and H₂ is a combination that causes noticeable changes in readings. When H₂ is applied to the CO sensor, the CO sensor reading will increase substantially. The same occurs when ethylene and other alcohols are picked up by the CO sensor. It is important to note that while H₂ exposures will usually clear up after a few minutes, it can take hours for the sensor to stabilize after being exposed to ethylene and other kinds of alcohols.