Which term refers to the above ground horizontal or vertical pipe between the water supply and the mains?

The term that refers to the above ground horizontal or vertical pipe between the water supply and the mains is "System riser." A system riser serves as a crucial component in fire protection systems, allowing water to move from the water supply to the mains of a fire sprinkler system. It is designed to carry water to various distribution points, facilitating both pressure maintenance and flow throughout the system.

In contrast, a sprig is generally a term used to describe a short vertical pipe or branch connection that extends from the main system to feed individual sprinkler heads, rather than the primary connection between the supply and mains. The waterflow alarm device is an apparatus designed to alert when water is flowing through the system—an essential safety feature, but not a type of pipe. A riser nipple is a short fitting used to connect pipes vertically; however, it does not encompass the larger function of connecting the water supply with the mains. Therefore, the system riser accurately describes the critical pipe configuration involved in fire sprinkler systems.