For calibration, which mixture is listed?

• A. MX4
• B. Pentane, CO, O2, H2S for calibration
• C. O2 19.5-23%
• D. CO 25PPM

Answer: (B)

Calibration of a four‑gas detector uses a single gas mixture that contains all the monitored species at known concentrations so every sensor can be set correctly in one step. The mixture that includes pentane as the hydrocarbon surrogate, along with CO, O2, and H2S, provides a calibration gas for the LEL/combustible sensor, the carbon monoxide sensor, the oxygen sensor, and the hydrogen sulfide sensor. This allows you to verify and adjust each sensor's response to its specific gas, using one gas mix. Using just a single gas like CO or a pure oxygen range doesn’t calibrate all sensors, and a brand name without listing components doesn’t specify the actual calibration contents.