An additional sprinkler is required when which condition is present?

An additional sprinkler is required when which condition is present?

• A. The area is very large
• B. Obstructions are too close
• C. The ceiling is vaulted
• D. The walls are noncombustible

Answer: (B)

The key idea is that sprinkler discharge patterns must reach every part of the protected area with the required density. When an obstruction sits too close to a sprinkler head, the spray pattern is blocked or shadowed, leaving portions of the room inadequately covered. In that situation, adding another sprinkler ensures those blocked areas still receive sufficient water, maintaining proper protection. The other scenarios don’t automatically trigger an extra head. A very large area is handled by spacing rules and may require more heads where those rules dictate, but it’s not the obstruction condition itself. Vaulted ceilings can complicate coverage, but without an obstruction blocking the head’s spray, extra heads aren’t mandated simply by the ceiling shape. Noncombustible walls don’t create a need for more sprinklers since they don’t compromise the sprinkler’s ability to deliver water to the protected space.

The key idea is that sprinkler discharge patterns must reach every part of the protected area with the required density. When an obstruction sits too close to a sprinkler head, the spray pattern is blocked or shadowed, leaving portions of the room inadequately covered. In that situation, adding another sprinkler ensures those blocked areas still receive sufficient water, maintaining proper protection.

The other scenarios don’t automatically trigger an extra head. A very large area is handled by spacing rules and may require more heads where those rules dictate, but it’s not the obstruction condition itself. Vaulted ceilings can complicate coverage, but without an obstruction blocking the head’s spray, extra heads aren’t mandated simply by the ceiling shape. Noncombustible walls don’t create a need for more sprinklers since they don’t compromise the sprinkler’s ability to deliver water to the protected space.