What type of standpipe system is maintained under constant water pressure for fire fighting?

The wet standpipe system is designed to be maintained under constant water pressure, ensuring that water is readily available for firefighting operations. In this system, the pipes are filled with water at all times, which allows for immediate use in the event of a fire. This is essential for quick response, as firefighters can access the water supply directly and immediately through the hoses connected to the standpipe.

In contrast, dry standpipe systems do not contain water in the pipes until they are needed. These systems are often used in environments where freezing may be an issue, and they require fire department personnel to connect a water supply to the system before using it. Manual standpipe systems rely on a firefighter's action to operate, and while yard hydrants provide water access, they are generally not under constant pressure and serve a different purpose than standpipe systems directly connected to building fire protection systems.