What type of standpipe is designated for fire department use only?

The correct choice is Class I standpipe, which is specifically designated for fire department use. Class I standpipes are designed to provide a means for firefighters to connect their hoses and access water directly from the standpipe system during firefighting operations, especially in high-rise buildings or large structures.

The components of a Class I standpipe system typically include a 2.5-inch outlet which allows for larger diameter hoses to be connected, facilitating a high flow rate suitable for aggressive firefighting efforts. This system is not intended for use by the general public, unlike Class II standpipes, which are designed for use by trained building occupants, and Class III standpipes, which combine the features of both Class I and Class II, allowing both firefighters and building occupants access.

In summary, Class I standpipes are an essential resource for fire departments when fighting fires, providing the required flow and pressure needed to effectively extinguish fires in larger buildings.