Which type of standpipe system is filled with water only when needed?

A dry standpipe system is designed to be filled with water only when needed, making it particularly effective for situations in which the risk of freezing is a concern. In dry standpipe systems, the pipes are typically empty and are connected to a water supply that can be activated when necessary. This attribute allows fire departments to maintain the integrity of the system without worrying about the effects of weather conditions that could lead to freezing of the water inside the pipes.

Wet standpipe systems, on the other hand, are always filled with water and are used in areas where the climate allows for such a configuration without concern over freezing. Combined standpipe systems incorporate both wet and dry elements, providing flexibility based on the specific needs of different parts of a building. Automatic standpipe systems feature automatic water supply mechanisms but do not inherently classify as systems that remain dry until needed.

This distinction emphasizes the unique role of dry standpipe systems in fire protection strategies, particularly in environments where temperature fluctuations present a challenge.