When calibrating a Combustible Gas Indicator (CGI), which gases should be used?

The correct choice for calibrating a Combustible Gas Indicator (CGI) involves the use of Hexane and Pentane. These gases are chosen because they are both aliphatic hydrocarbons that fall within the typical range of gases that can be encountered in various applications requiring combustible gas measurements. Calibrating with Hexane and Pentane provides a reliable reference point for the CGI, ensuring that the measurements it takes reflect the concentrations of combustible gases accurately.

Hexane and Pentane are utilized because they are both relatively straightforward to detect and represent the behavior of hydrocarbons commonly found in various environments, making them suitable standards for calibration. This choice allows the CGI to be effective in identifying hazardous conditions when combustible gases are present.

The other options, while they may involve hydrocarbons, do not align as closely with the most common calibration practices that ensure accurate readings across a broader range of combustible situations typically faced.