What is the lower cord of an aerial ladder called?

The lower cord of an aerial ladder is referred to as the base rail. This component is significant because it serves as the foundational support structure upon which the ladder’s rungs and other components are secured. The base rail provides stability and serves to distribute the load as the ladder is extended and utilized during firefighting and rescue operations.

Understanding the components of an aerial ladder is critical for operators, as it ensures they can effectively assess the equipment's integrity and functionality. The base rail is integral in maintaining the overall strength and safety of the ladder during use. Recognizing its role helps in proper training and handling of aerial apparatus.