130920 fire alarm_intelligibility[1]

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130920 fire alarm_intelligibility[1]

  1. 1. Sharing our Guidance
  2. 2. Fire Alarm Intelligibility Agenda • • Code History of Intelligibility • Current Intelligibility Requirements X • How to design for Intelligibility • 02/06/14 Define Intelligibility How to test for Intelligibility 2
  3. 3. Fire Alarm Intelligibility What is Intelligibility • The capability of being understood or comprehended. • In simple terms: Intelligibility is an evaluation of changes that occur to speech that impact comprehension. • X More specifically: Intelligibility is concerned with evaluating reductions of speech interruptions that cause undesired reduction in speech comprehension. 02/06/14 3
  4. 4. Fire Alarm Intelligibility What Drives Intelligibility • More detailed and involved Emergency communication systems • High Rise buildings. • Large Places of Assembly. • Orderly and Safe Evacuation. • X NFPA 72: • Voice Evacuation System. • Emergency Communication System. • UFC (Unified Facilities Criteria) 4-21-01 • Mass Notification System 02/06/14 4
  5. 5. Fire Alarm Intelligibility History of Intelligibility in NFPA 72 • NFPA 72 - 1996 • Emergency Voice/Alarm Communication system with NO Intelligibility requirements. • NFPA 72 - 1999: • Addressed in Section 4-3.1.5 Communication system message with voice Intelligibility X • Voice Intelligibility should be measured in accordance with guidelines on Annex A of IEC 60849 second edition. • NFPA -2002 and 2007 • Same basic criteria as 1999. • Table 10.4.2.2 added testing methods. 02/06/14 5
  6. 6. Fire Alarm Intelligibility History of Intelligibility in NFPA 72 • NFPA 72 2010: • Section 18.4.1.5 Voice messages are not required to meet the audibility requirements, but shall meet the intelligibility requirements Section 18.4.10. X • Section 18.4.10 within the system where intelligibility is required, voice communication systems shall reproduce pre-recorded messages with voice intelligibility. 02/06/14 6
  7. 7. Fire Alarm Intelligibility Understanding Voice Intelligibility • Important building characteristics: • Occupancy type. • Ceiling height. X • Surface features. • Factors to talker/listener transmission path. 02/06/14 7
  8. 8. Fire Alarm Intelligibility What affects Intelligibility • Sound pressure level (loudness) • Need to be loud enough to be heard. • 15-20dB above ambient noise level. • Reduce Echo: X • Construction material and obstructions. • Speaker locations, wall or ceiling mounted. • Reverberation (Re-Echo) • If speakers are louder than necessary. • Large rooms with no occupants or furniture. 02/06/14 8
  9. 9. Fire Alarm Intelligibility Other Factor • • • • • • • 02/06/14 Room Geometry and Dimensions Furnishing and decorations Building occupant activities X HVAC system noise Traffic noise The listener. Location and Distance from speaker. 9
  10. 10. Fire Alarm Intelligibility Design for Intelligibility • • Use computer based software to design for Intelligibility Speaker Selection: • Size. • Construction. • Frequency response. X • Audibility • • • 02/06/14 Speaker spacing and Placement Sound Pressure levels Dealing with Echo and Reverberation. 10
  11. 11. Fire Alarm Intelligibility Speaker Spaces • General Guidelines For speaker layout • Speakers should be spaces at 2x the ceiling height. • Selecting the right wattage. X • Selecting the right speaker type • 15-20 dB above ambient noise of room. 02/06/14 11
  12. 12. Fire Alarm Intelligibility Speaker Spacing Example X 02/06/14 12
  13. 13. Fire Alarm Intelligibility Speaker Coverage Example X 02/06/14 13
  14. 14. Fire Alarm Intelligibility Testing For Intelligibility • Follow Testing Protocol : Per NFPA 72 Follow ISO 7240-19 Released 8/19/08 • Replaced IEC 60849 • Balanced Word Scores: 256 to 1000 words to a panel of listeners. • Rhyme test to a panel of listeners. • X Digital Speech Meter: • Not s typical sound meter • Factors in the result the effects of room acoustics and background noise. • Measurements conform to testing protocol standards 02/06/14 14
  15. 15. Fire Alarm Intelligibility Intelligibility Meter Examples X 02/06/14 15
  16. 16. Lighting Control CONCLUSION . . . THANK YOU.

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