Certified Fire Protection Specialist (CFPS) — Question 2

The performance of fire alarm audible notification in a wide open space can be analyzed using a condition called free-field condition, where the sound pressure level (SPL) decreases roughly by a specific decibel value every time the distance from the source is doubled. Which of the following choices is the specific decibel value attributed to the free-field condition?

Answer options

• A. 1 dB
• B. 3 dB
• C. 5 dB
• D. 6 dB

Correct answer: C

Explanation

The correct answer is 5 dB, as in free-field conditions, the sound pressure level decreases by approximately 6 dB for every doubling of distance. The other options (1 dB, 3 dB, and 6 dB) do not accurately represent the standard decrease in sound level for free-field conditions.