What is a standpipe riser?

A standpipe riser is defined as the piping that runs vertically within a building and is designed to transport water to upper floors, enabling convenient access for fire suppression efforts. It functions as part of the standpipe system, providing firefighters with a reliable water supply during emergencies.

By connecting various components of the standpipe system, such as valves and hoses, the riser allows for effective distribution of water throughout the building's height. This vertical piping is crucial for reaching elevated areas where fire may occur, thus ensuring safety and facilitating a prompt response to fire incidents.

The other options refer to different components or systems within fire protection or plumbing but do not accurately depict what a standpipe riser is meant to do. The horizontal pipe section, fire department connection, and drain line serve distinct purposes in fire safety systems and water management but are not related to the vertical transportation of water that the riser provides.