What are two common sensors on the MultiRAE Pro?

• A. CO2 and H2S
• B. Oxygen (O2) and LEL
• C. Oxygen (O2) and CO2
• D. Methane and Hydrogen

Answer: (B)

The main idea here is that a portable multi-gas monitor is built around two essential safety measurements: oxygen level and the presence of flammable gases. An oxygen sensor checks the air you’re breathing, signaling oxygen-deficient or oxygen-enriched conditions that can be dangerous in confined spaces or industrial settings. The LEL sensor serves as a general warning for any flammable gas by measuring its concentration as a percentage of its lower explosive limit, so it can warn you before an ignition risk across many different fuels. Together, these two readings cover both breathing safety and fire/explosion hazards, which is why oxygen and LEL are the common pair on devices like the MultiRAE Pro. Other options involve gases that aren’t standard baseline sensors on these monitors (such as CO2 as a common built-in sensor) or pair specific gases rather than using a broad combustible-gas detector, so they don’t fit the typical, widely used configuration.