What type of system is commonly used in areas where pipe freezing is a concern?

A dry pipe system is commonly used in areas where pipe freezing is a concern because it prevents water from being stored in the pipes until a fire is detected. In a dry pipe system, the pipes are filled with pressurized air or nitrogen, and water is only allowed to enter the system when a sprinkler head is activated. This design helps to mitigate the risk of freezing since there is no water standing in the pipes during cold temperatures.

In locations prone to freezing, using a system that contains water could lead to blockages or ruptures if temperatures drop sufficiently. Therefore, the dry pipe system's reliance on air pressure ensures that no water is vulnerable to freezing conditions within the piping network, allowing for a more reliable operation in colder climates.

Other systems like wet pipe systems maintain water in the pipes at all times, making them less suited for environments where freezing is a risk. Pre-action and deluge systems, while useful for specific applications, also do not offer the same degree of protection against freezing as a dry pipe system does.