Which of the following statements about looping mains in a distribution grid is true?

• A. They restrict flow to hydrants
• B. They ensure that water flows from two directions into hydrants
• C. They create sediment buildup in pipes
• D. They are only used in rural areas

Answer: (B)

Looping mains in a distribution grid is a design practice that enhances the reliability and efficiency of water delivery systems. The accurate statement regarding looping mains is that they ensure water flows from two directions into hydrants. This dual-direction flow provides several benefits, including improved pressure and flow rates at fire hydrants, which is crucial for fire protection efforts. Additionally, having water available from more than one direction can help maintain service even if one section of the loop is compromised.

This design also minimizes the occurrence of stagnant water, which can occur in dead-end pipes, and helps in distributing water more evenly throughout the network. The ability to draw from multiple sources in a looped system mitigates the risks tied to water quality and supply reliability, making it a preferred approach in most water distribution systems.