What are 2 common sensors?

• A. NO2 & SO2
• B. O2 (Oxygen) & Lower Exposure Limit (LEL)
• C. CH4 & O3
• D. CO2 & NO2

Answer: (B)

Two common sensors you’ll see in many gas-detection setups are the oxygen sensor and the LEL sensor. An oxygen sensor keeps track of how much breathable oxygen is in the air, flagging environments that are deficient or enriched, which is crucial for anyone operating in confined or changing atmospheres. The LEL sensor, standing for Lower Explosive Limit, measures the concentration of flammable gases relative to the point at which they could ignite, helping avert potentially explosive atmospheres.

Together, these two address two fundamental safety concerns: ensuring there’s enough oxygen to breathe and preventing ignition hazards from flammable gases. While detectors can monitor other specific gases like NO2, SO2, CH4, O3, or CO2, the combination of O2 and LEL sensors represents a common, baseline pairing found in many portable safety devices.