What type of sprinkler system uses a dry pipe?

A dry pipe sprinkler system is specifically designed for areas where the risk of freezing is high, such as unheated warehouses or outdoor spaces. In this system, the pipes are filled with pressurized air or nitrogen, and the water is held back within the sprinkler head by a valve. When a fire activates one of the sprinkler heads, the air pressure drops, allowing the valve to open and water to flow into the pipes, ultimately discharging from the activated sprinkler head to suppress the fire.

This configuration is crucial because it prevents water from sitting in the pipes, thereby avoiding freezing and potential damage during cold temperatures. It provides an effective solution where traditional wet pipe systems would be inadequate due to the risk of frost damage.

Other systems mentioned, such as wet pipe systems, contain water at all times and would not be suitable for environments prone to freezing. Residential systems can incorporate both wet and dry pipe arrangements but are mostly associated with wet pipe systems. Combined systems integrate various types but still need a clear understanding of the specific roles of the dry pipe configuration.