S95 Fire Alarm System Components 3 — Questions and Answers
Question 1: Per NFPA 72, what is the minimum sound pressure level required for audible notification appliances in sleeping areas?
- 55 dB at the pillow
- 65 dB at the pillow
- 75 dB at the pillow (Correct answer)
- 85 dB at the pillow
Correct answer: 75 dB at the pillow
NFPA 72 requires audible notification appliances in sleeping areas to produce at least 75 dB at the pillow level to awaken sleeping occupants.
Question 2: Visible notification appliances (strobes) are required in locations where:
- All corridors regardless of length are present
- Ambient noise levels may prevent audible signals from being heard (Correct answer)
- Only outdoor environments are involved
- Only fully sprinklered buildings are involved
Correct answer: Ambient noise levels may prevent audible signals from being heard
Strobes are required where high ambient noise could mask audible signals, and in areas used by people with hearing impairments, to ensure effective notification.
Question 3: The candela (cd) rating of a strobe used in a fire alarm system refers to its:
- Sound output level
- Light intensity measurement (Correct answer)
- Operating voltage range
- Maximum flash frequency
Correct answer: Light intensity measurement
Candela is the SI unit of luminous intensity; the candela rating of a strobe defines how bright the light output is, which determines its effective coverage area.
Question 4: Per NFPA 72, at what flash rate must visible notification appliances (strobes) operate?
- 0.5 to 1 flash per second
- 1 to 2 flashes per second (Correct answer)
- 2 to 4 flashes per second
- 4 to 6 flashes per second
Correct answer: 1 to 2 flashes per second
NFPA 72 requires strobe flash rates between 1 Hz and 2 Hz to be effective for notification while avoiding frequencies that could trigger photosensitive seizures.
Question 5: Which circuit type connects notification appliances to the fire alarm control panel?
- Signaling Line Circuit (SLC)
- Initiating Device Circuit (IDC)
- Notification Appliance Circuit (NAC) (Correct answer)
- Power-Limited Fire Alarm Circuit (PLFA)
Correct answer: Notification Appliance Circuit (NAC)
The Notification Appliance Circuit (NAC) is the dedicated circuit used to power and activate horns, strobes, and other audible/visible devices.
Question 6: Speaker notification appliances used for emergency voice/alarm communication systems must be:
- Listed for fire protective signaling use (Correct answer)
- Standard commercial audio speakers rated at 70V
- Installed exclusively in exit stairwells
- Connected directly to the building's main electrical panel
Correct answer: Listed for fire protective signaling use
NFPA 72 requires all notification appliances, including speakers, to be listed for use in fire protective signaling systems to ensure reliability under fire conditions.
Question 7: A horn/strobe combination device used in a fire alarm system:
- Can only be used in commercial occupancies under 10,000 sq ft
- Provides both audible and visible alarm notification from a single unit (Correct answer)
- Is required to have a dedicated separate power supply circuit
- Cannot be used in addressable fire alarm systems
Correct answer: Provides both audible and visible alarm notification from a single unit
A combination horn/strobe unit integrates both an audible signal (horn) and a visible signal (strobe) in one device, simplifying installation and meeting both requirements simultaneously.
S95 Fire Alarm System Components 3
Per NFPA 72, what is the minimum sound pressure level required for audible notification appliances in sleeping areas?