How are density and area of coverage determined for sprinkler design?

• A. Density is water per unit area; Area of coverage is the approximate area protected by sprinkler discharge
• B. Density equals pipe diameter
• C. Area equals building footprint
• D. Density equals voltage

Answer: (C)

In sprinkler design, you’re balancing how much water must reach a fire per a given protected space and how large that protected space is for a single sprinkler. The key ideas are density and area of coverage. Density is the rate at which water must be applied over a design area, typically expressed as inches (or millimeters) per hour. Area of coverage is the approximate zone that a sprinkler discharge can protect, determined by the sprinkler type, its spray pattern, and how the heads are spaced. This area is the design area for a single sprinkler, not the total footprint of the building. So the statement that density is water per unit area and area of coverage is the approximate area protected by sprinkler discharge is the correct way to describe how these concepts are determined. The area protected per sprinkler isn’t the whole building footprint, and density isn’t tied to pipe diameter or voltage.