In fire safety, what does the term 'dry pipe system' refer to?

The term 'dry pipe system' refers specifically to a fire protection system that is filled with pressurized air instead of water. In this system, the pipes remain empty until a fire is detected. When a fire occurs and the heat activates the sprinkler heads, the pressurized air is released, allowing water from the supply to flow into the pipes and through the sprinkler heads. This type of system is particularly useful in environments where the risk of freezing might damage a water-filled system.

Using pressurized air ensures that there is no water present in the pipes until needed, reducing the risk of freezing in colder climates. This makes it an appropriate choice for buildings that are not heated or are subject to low temperatures. Dry pipe systems are integral to fire protection because they can provide an automatic response to a fire while minimizing potential complications from freezing pipes.