FIRE ALARM SYSTEM
The Basics
NFPA 72 National Fire Alarm Code® 2007
Not a Code unless adapted by AHJ
NFPA 101 Life Safety ...
FIRE ALARM SYSTEM
NFPA 101 Life Safety Code®2006




“The purpose of the code is to provide minimum
requirements, with r...
FIRE ALARM SYSTEM
NFPA 72




“The purpose of this code is to define the means
of signal initiation, transmission, notif...
Audible Signaling Terminology
dB
Frequency
dBA
Ambient Noise
Audible Signaling Terminology
dB= Measurement of loudness
Frequency= Pitch, Bass vs High pitch squeal
Narrow Band= A small...
Notification Terminology
Signaling
Arouse/Alert
Notification
Information
Notification-How?
Use the human
senses





Visual- Previously
discussed
Audible
Other
Audible System Goals
How loud must the fire alarm be for the
given noise information?


NFPA 72.4 Audible Characteristics
Public Mode Audible Req.
NFPA 72.4.2.1



15dB above average ambient sound
5dB above maximum sound level of 60
seconds.
Private Mode Audible Req.
Private mode-Staff is part of the overall
fire protection strategy






Minimize fire alar...
Sleeping Area Req.
NFPA 72.4.4.1



Public mode Requirements or
75dBA minimum
 Whichever is greater
Sound Attentuation
Sound is measured in dBA which is
logarithmic scale


Double distance= reduction of ½ of sound
pressur...
Design of Audible Signaling
Distance
(from device)
10’
20’
40’
80’

Sound level
(dBA)
95dB
89dB
83dB
77dB
Design of Audible Signaling
Using fewer appliances results in some
locations being very loud.
Using more appliances at a l...
Next Presentation
Audible Signaling





Noise Coefficients (NC)
Sound Transmission Coefficients (STC)
Locating device...
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Fire alarm system_ne-audible_signaling[1]

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Fire alarm system_ne-audible_signaling[1]

  1. 1. FIRE ALARM SYSTEM The Basics NFPA 72 National Fire Alarm Code® 2007 Not a Code unless adapted by AHJ NFPA 101 Life Safety Code® 2006 Not a Code unless adapted by AHJ
  2. 2. FIRE ALARM SYSTEM NFPA 101 Life Safety Code®2006   “The purpose of the code is to provide minimum requirements, with regard to function, for the design, operation and maintenance of buildings or structures for safety of life from fire” This is accomplished by:  1.) Protection of occupants not intimate with the Initial fire development  2.) Improvement of the survivability of occupants intimate with the initial fire development.
  3. 3. FIRE ALARM SYSTEM NFPA 72   “The purpose of this code is to define the means of signal initiation, transmission, notification, and annunciation; the levels of performance; and the reliability of the various types of fire alarm systems.” “The purpose of fire alarm systems shall be primarily to provide notification of fire alarm, supervisory, and trouble conditions; to alert the occupants; to summon aid; and to control fire safety functions.”
  4. 4. Audible Signaling Terminology dB Frequency dBA Ambient Noise
  5. 5. Audible Signaling Terminology dB= Measurement of loudness Frequency= Pitch, Bass vs High pitch squeal Narrow Band= A small range of frequenciesusually called an octave band dBA= Loudness measurement adjusted to how we hear and perceive the relative loudness of different frequencies Ambient Noise- The normal sounds during normal occupancy. Not temporary sounds.
  6. 6. Notification Terminology Signaling Arouse/Alert Notification Information
  7. 7. Notification-How? Use the human senses    Visual- Previously discussed Audible Other
  8. 8. Audible System Goals How loud must the fire alarm be for the given noise information?  NFPA 72.4 Audible Characteristics
  9. 9. Public Mode Audible Req. NFPA 72.4.2.1   15dB above average ambient sound 5dB above maximum sound level of 60 seconds.
  10. 10. Private Mode Audible Req. Private mode-Staff is part of the overall fire protection strategy      Minimize fire alarm Use voice Combine systems Text Messaging Eliminate audible tones and voice in some areas
  11. 11. Sleeping Area Req. NFPA 72.4.4.1   Public mode Requirements or 75dBA minimum  Whichever is greater
  12. 12. Sound Attentuation Sound is measured in dBA which is logarithmic scale  Double distance= reduction of ½ of sound pressure (or 6dB)
  13. 13. Design of Audible Signaling Distance (from device) 10’ 20’ 40’ 80’ Sound level (dBA) 95dB 89dB 83dB 77dB
  14. 14. Design of Audible Signaling Using fewer appliances results in some locations being very loud. Using more appliances at a lower level results in even distribution without loud spots.
  15. 15. Next Presentation Audible Signaling     Noise Coefficients (NC) Sound Transmission Coefficients (STC) Locating devices. Initiation Basics  Heat detectors

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