Which space type is especially suitable for a projected beam smoke detector?

• A. Large atriums
• B. Small offices
• C. Bathrooms
• D. Kitchens

Answer: (A)

Large atriums are the space type best suited for a projected beam smoke detector. A projected beam system uses an emitter and receiver across a space to create a beam; when smoke enters the beam, it interrupts the light reaching the receiver and triggers an alarm. This setup is ideal for open, expansive areas with high ceilings because one detector can monitor a long span and cover large unobstructed air volumes, avoiding the need to install many individual spot detectors and reducing detection gaps.

In smaller, enclosed spaces like offices, or rooms with moisture and fumes such as bathrooms and kitchens, a beam detector is less practical. The short distance can make a single beam unnecessary, and humidity, steam, or cooking aerosols can cause nuisance alarms or incorrect readings, so spot or other specialty detectors are usually preferred in those environments.