On a 6-inch riser, what size of drain is needed?

To determine the appropriate size of the drain for a 6-inch riser, it's important to consider the hydraulic calculations and drainage requirements stipulated by fire protection codes and standards.

Typically, a drain size is selected based on the riser diameter to ensure that it can effectively manage the flow of water from the system during maintenance or in case of an emergency. For a 6-inch riser, a 2-inch drain is generally adequate. This size allows for sufficient drainage capacity without restricting water flow, ensuring that any residual water can be effectively evacuated from the system.

Choosing a drain that is too small could lead to insufficient drainage, potentially allowing water to accumulate in the system, which can lead to maintenance issues or even system failure. Conversely, opting for a drain size that is excessively large might not necessarily enhance performance and could complicate the installation and maintenance processes.

In summary, a 2-inch drain size effectively balances the need for adequate drainage capacity relative to a 6-inch riser while adhering to standard practices in fire protection systems.