Private fire service mains supplying internal fire protection systems may extend horizontally no more than what cumulative distance?

The correct answer is based on the guidelines from NFPA 24 regarding the installation of private fire service mains and their permissible configurations. According to these standards, private fire service mains that are supplying internal fire protection systems should not extend horizontally beyond a cumulative distance of 10 feet.

This limitation is essential to ensure that the fire protection systems maintain adequate pressure and function effectively. If the horizontal distance were to exceed this limit, it could lead to issues such as reduced water supply pressure and increased friction loss in the system, which can compromise the performance of fire protection measures during an emergency. Therefore, adherence to the 10-foot limit plays a critical role in the reliable operation of fire service mains, enhancing safety and effectiveness in fire protection efforts.