In a deluge sprinkler system, all sprinklers are open; water is released to all heads when activated. In what occupancies is it typically used?

• A. Only designated sprinklers release water
• B. All sprinklers are open and water is released to all heads when activated
• C. Water is released only after foam concentrate is introduced
• D. It is typically used in single-family residences

Answer: (B)

Deluge systems are built so all sprinkler heads are open and water is released to every head as soon as the system is activated. This arrangement provides immediate, total coverage across a space, which is essential when a fire could grow rapidly or threaten large, open areas. Because of that, deluge systems are typically used in high-hazard occupancies with large open spaces where you want water to reach any part of the area without waiting for heat to trigger individual sprinklers—think aircraft hangars, chemical plants, large warehouses with flammable contents, power plants, tunnels, and similar facilities.

Other options don’t fit this use: requiring only designated sprinklers to release water describes other system types, foam concentrate involvement belongs to specific foam-water applications, and single-family residences are not a setting where a deluge system is practical or common.