Which sprinkler system consists of closed sprinklers attached to piping that contains air under pressure?

Which sprinkler system consists of closed sprinklers attached to piping that contains air under pressure?

• A. Wet Pipe System
• B. Deluge System
• C. Dry Pipe System
• D. Pre-Action System

Answer: (C)

In a dry pipe system, the piping is charged with pressurized air (or nitrogen) while the sprinkler heads themselves remain dry and closed. Water is kept in a separate supply line behind a dry valve, and when a sprinkler head is heated and opens, the valve releases water into the pressurized dry piping. The air is displaced by the water, and water reaches the activated head. This arrangement prevents water from sitting in the pipes in unheated spaces and allows longer runs. By contrast, wet pipe systems have piping filled with water, deluge systems have all heads connected to open piping with water to all heads, and pre-action systems require a detection or other trigger before water enters the piping.

In a dry pipe system, the piping is charged with pressurized air (or nitrogen) while the sprinkler heads themselves remain dry and closed. Water is kept in a separate supply line behind a dry valve, and when a sprinkler head is heated and opens, the valve releases water into the pressurized dry piping. The air is displaced by the water, and water reaches the activated head. This arrangement prevents water from sitting in the pipes in unheated spaces and allows longer runs. By contrast, wet pipe systems have piping filled with water, deluge systems have all heads connected to open piping with water to all heads, and pre-action systems require a detection or other trigger before water enters the piping.