What minimum percentage of commercial butane is typically composed of butane and butylene?

The correct choice reflects the standard composition of commercial butane, which is typically composed of a high percentage, often around 95%, of butane and butylene. This high concentration is necessary because commercial butane is used in various applications, such as heating, cooking, and as a fuel in automotive engines. The presence of butylene, an unsaturated hydrocarbon, contributes to the energy content and efficiency of the fuel.

Having a minimum of 95% in commercial butane ensures that the product remains effective and useful for its intended purposes, as lower percentages may lead to insufficient performance and energy release. Recognizing these composition standards is essential for fire investigation technicians, as it helps in identifying fuels involved in fires and understanding their characteristics and behaviors during combustion.