What is a dual-fuel appliance according to NFPA 54?

A dual-fuel appliance, according to NFPA 54, refers to an appliance that is specifically designed to operate on more than one type of fuel, such as gas and propane. This flexibility allows the appliance to function efficiently regardless of the fuel availability or preference, enhancing its utility in various settings.

The concept of dual-fuel appliances is significant in the context of ensuring that users can leverage different fuel sources based on what is available or more economical, contributing to energy efficiency and resilience in fuel supply. This is particularly relevant in areas where natural gas supply may be interrupted, and propane may serve as a reliable alternative.

The other options deviate from the definition of a dual-fuel appliance. An appliance that operates on electricity and gas pertains to hybrid systems rather than dual-fuel classifications, while switching between different brands of gas does not define dual-fuel functionality. Lastly, operating indoors and outdoors does not relate to the type of fuel but rather to the installation and use environment of the appliance.