What is the minimum pipe size required to feed 1½" hose lines for horizontal runs up to 20'?

In fire protection systems, the sizing of pipes is crucial for ensuring that there is sufficient water flow to meet the demands of hose lines. For 1½-inch hose lines, the minimum pipe size required for horizontal runs up to 20 feet is 1 inch in diameter. This is based on guidelines that specify how to maintain adequate water pressure and flow velocity within the system.

Using a 1-inch diameter pipe allows enough water to flow adequately through the system without causing excessive friction loss over that length. Friction loss increases when the diameter of the pipe decreases, which can negatively impact the effectiveness of the system when the hose is in use.

Therefore, choosing a 1-inch diameter pipe for horizontal runs of up to 20 feet is optimal for practical application, ensuring that hose lines can be handled effectively and efficiently while maintaining compliance with fire code standards and ensuring firefighter safety.