riser

Riser is a term used in several disciplines to denote a vertical element or a device that transports something upward between levels. The meaning varies by context, but the common thread is a component that rises or carries material, people, or equipment from one floor or level to another.

In stairs, the riser is the vertical face between two consecutive treads. It contrasts with the tread, the horizontal part you step on. Riser heights are often regulated by building codes; in the United States, typical single-step rises are around 7 inches (178 mm), though actual limits vary by jurisdiction. A staircase’s overall rise and run are determined by desired comfort, safety, and architectural design.

In buildings, a riser refers to a vertical pipe or duct that carries water, waste, or other services between floors. Water risers feed multiple levels, while soil and waste risers convey drainage to the main sewer. Riser shafts may also house venting lines or fire-stopping systems. Materials and configurations depend on local codes and the specific utility system.

In electrical and data installations, a riser can describe a vertical run of cables and conduits within a building. Riser spaces are designed to organize vertical distribution separate from horizontal runs. In computer hardware, a PCIe riser or riser card is a device that orients an expansion card differently, typically allowing a card to sit at a right angle to the motherboard to fit compact enclosures.

In offshore and industrial contexts, a riser is a pipe string that connects subsea facilities to a surface platform or vessel, enabling the flow of hydrocarbons, water, or other fluids. Riser systems must withstand marine conditions and are engineered with buoyancy, corrosion protection, and structural support in mind.