1. NFPA 72 Mass Notification Regulations
November 10, 2011

2. Acentech Incorporated is a Registered Provider with The American Institute of Architects Continuing Education Systems. Credit earned on completion of this program will be reported to CES Records for AIA members. Certificates of Completion for non-AIA members are available on request. This program is registered with the AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation.
November 10, 2011

3. NFPA
Introduction:
Today we are going to discuss some of the changes to 2010 NFPA 72 document and its addition of Emergency Communication Systems.
We want to give an overview of the changes that designers need to know about.
Our primary focus will be to discuss how speech intelligibility has been added to the code and is now a required part of the NFPA 72 document.
It discusses the speech intelligibility requirements and how they will be needed in acoustically distinguishable spaces.
Two main points:
1. It’s now required
2. How do you accomplish it?

4. NATIONAL FIRE PROTECTION AGENCY - Organization was established in 1896
Background
NATIONAL FIRE PROTECTION AGENCY
- Organization was established in 1896
PUBLICATIONS
- NFPA 70 (aka NEC)
- NFPA 72
NFPA 72
- Document first published in 1993
- Was known as the “National Fire Alarm Code”
- Consolidated 6 individual standards documents, including EVACS
EVACS
- Emergency/Voice Alarm Communications Systems
- First published in EVACS had to be a dedicated voice communications system for use only in the event of a fire - Notification systems were horns or bells - Sound quality was not a design factor; “Intelligible” did not appear in NFPA 72 until 1999
EVOLUTION OF NFPA 72
- Reflected realizations that fire was not the only hazard to which building occupants need notifications
- Mass Notification Systems evolved due to ‘96 bombing of Khobar Towers in Saudi Arabia, September 11th attacks, and Columbine High School and Virginia Tech shootings.
Today NFPA is called “National Fire Alarm and Signaling Code”

5. Mass Notification Systems
NFPA 72, 2007
Mass Notification Systems
Provide “real-time information and instructions to people in a building, area, site, or installation using intelligible voice communications along with visible signals, text, and graphics, and possibly including tactile or other communication methods”
DoD UFC
2007 revision introduced Mass Notification Systems
- Annex - MNS developed by US Military through the Department of Defense - “Annex” = term provided for informational purposes only. “these are recommended”, but not considered mandatory requirements

6. Approved by ANSI in 2009 Chapter 24 NFPA 72, 2010
Emergency Communications Systems (ECS)
ECS = EVACS + MNS
ANSI = American National Standards Institute
EVACS = Emergency/Voice Alarm Communications Systems
MSN = Mass Notification Systems
ECS is intended to communicate information about emergencies (fire, natural disasters, accidents, etc).

7. NFPA 72, 2010
Chapter 24 establishes “Minimum required levels of performance, reliability, and quality of installation for ECS but does not establish the only methods by which these requirements are to be achieved.”
Ex: Controls, Ancillary Functions, Pathway Survivability, and…
Voice Evacuation Messages:
Sound System Requirements
Minimum Required Levels, Pathway Survivability (redundancy for cabling),
Sound System Rqmt’s:
- Speaker layout must be designed to ensure intelligibility and audibility
AHJ (or facility owner) may expect ECS to exceed these requirements

8. Intelligible Voice Messages
NFPA 72, 2010
Intelligible Voice Messages
“Emergency communications systems shall be capable of the reproduction of prerecorded, synthesized, or live messages with voice intelligibility”

9. Speech Intelligibility
Intelligible Voice Messages
“Intelligible”
Metrics:
Common Intelligibility Scale (CIS)
Speech Transmission Index (STI)
Speech Transmission Index for Public Address (STI-PA)
RApid Speech Transmission Index (RASTI)
Articulation Index (AI)
AlCons (Percent Articulation of Consonants)
Discuss definition of “Intelligible”
Intelligible vs Audible
Concept of intelligibility first introduced in NFPA 1999 appendix
Metrics…

10. Speech Intelligibility
Speech Transmission Index & Common Intelligibility Scale
Commonly used metrics
0.50 STI = 0.70 CIS
Example: STI
These methods are meant to be absolute measures of intelligibility.
Some are subject based (use human listeners); other methods use instrumentation.
0.5 STI = 0.70 CIS
.5 STI is subjectively defined as “fair”
is “good”
> .75 is “excellent

11. Speech Intelligibility
“The intelligibility of an emergency communication system is considered acceptable if at least 90 percent of the measurement locations within each ADS (acoustically distinguishable space) have a measured STI of not less than 0.45 (0.65 CIS) and an average STI of not less than 0.50 STI (0.70 CIS).”
-NFPA 2010 Annex D
Example: STI

12. Acoustically Distinguishable Spaces
“distinguished from other spaces due to acoustical, environmental or use characteristics, such as reverberation time and ambient sound pressure level”

13. Acoustically Distinguishable Spaces
MIT Sloan School of Management, Bruner/Cott Architects and Planners

14. Acoustically Distinguishable Spaces Logan Airport, Terminal A, HOK

15. Acoustically Distinguishable Spaces
Phillips Academy, Paresky Commons, Schwartz/Silver Architects

16. 3-Legged Approach Three aspects of Acoustics,
All 3 must be dealt with to achieve an effective Emergency Communication System
3 variables of speech intelligibility
1. Room acoustics
2. Noise control (HVAC)
3. Sound System

17. If one leg fails….

18. Room Acoustics

19. Room Acoustics

20. Room Acoustics

21. Room Acoustics

22. HVAC Noise Control

23. HVAC Noise Control

24. HVAC Noise Control

25. HVAC Noise Control

26. Sound Systems Loudspeakers
3 different spaces and 3 different loudspeaker types used.
Same sound quality achieved through the sound system by using the proper loudspeakers, signal processing, other tools
Miami International Airport: Terminal H Improvements, Rodriguez and Quiroga Architects; South Terminal Expansion, Borrelli + Partners

27. Sound Systems
3 different spaces and 3 different loudspeaker types used.
Same sound quality achieved through the sound system by using the proper loudspeakers, signal processing, other tools

28. Sound Systems
3 different spaces and 3 different loudspeaker types used.
Same sound quality achieved through the sound system by using the proper loudspeakers, signal processing, other tools

29. Sound Systems
3 different spaces and 3 different loudspeaker types used.
Same sound quality achieved through the sound system by using the proper loudspeakers, signal processing, other tools

30. Understanding the Tools
Sound Systems
Understanding the Tools

31. Loudspeakers Specifications Types Loudspeakers specifications:
Sound Systems
Loudspeakers
Specifications
Types
Horns
Full-range “Box” Enclosures
Loudspeakers specifications:
Directivity/pattern
Frequency response
Efficiency, Peak power, etc.
Loudspeaker Types:
Horns
Very good directivity control
Wide assortment of patterns available
Limited frequency response (not “Hi Fi”).
Full-range “Box” Enclosures
More “musical” than horn
Pattern control through full frequency range is typically limited.
Ex: A loudspeaker may be good at controlling high and/or mid-range frequencies but have very little control over low frequencies.

32. Sound Systems Types (cont.) Steerable Column Loudspeakers Line Arrays
Overall small width and depth, but very tall.
Better control over frequency range when taller loudspeakers are used
Custom tailor the loudspeaker’s coverage area.
Typically vertical direction only
Very helpful in reverberant acoustical environments
Expensive
Frequency response of loudspeaker can be limited
Line Arrays
Stack-able.
Full-range loudspeakers & subs
Typically, each has a wide horizontal & narrow vertical
Pattern becomes more narrow vertically as you add more speakers to the array
Most commonly used loudspeaker for touring acts
Commonly touted as the “best”, not always the case

33. Digital Signal Processing (DSP)
Sound Systems
Mixers
Digital Signal Processing (DSP)
Amplifiers

34. Sound Systems Equipment rack rooms will be needed
75 to 100 square feet minimum
Proper coordination with
- Mechanical for conditioning
- Electrical engineers for power

35. $ound $ystem + Bad Room Acoustics = Bad Sound

36. Speech Intelligibility Prediction

37. Speech Intelligibility Prediction
3D Computer Modeling
Used to verify various sound system and acoustic design elements.
Verify correct loudspeaker angles for proper coverage.
Predict sound pressure level (SPL)
Predict STI score

38. Speech Intelligibility Prediction
3D Computer Modeling
Used to verify various sound system and acoustic design elements.
Verify how loudspeaker should be positioned.
Predict sound pressure level (SPL)
Predict intelligibility

39. Speech Intelligibility Prediction
3D Computer Applications
EASE
Bose Modeler
CATT-Acoustic
Odeon

40. Speech Intelligibility Prediction
Results/Calculated metrics:
Direct SPL
STI (Speech Transmission Index)
Total SPL
D/R Ratio
RASTI
Privacy Index
Loudspeaker Overlap

41. Speech Intelligibility Prediction
Case Study:
Public council chamber
Dias positions
Presenter Positions
Lectern
Audience
Challenges
Rodriguez and Quiroga Architects, Homestead City Hall (unbuilt)

42. Speech Intelligibility Prediction

43. Speech Intelligibility Prediction
Constructed model in 3D
Applied acoustical properties to each surface
Inserted Loudspeakers

44. Speech Intelligibility Prediction
“Hot” = More direct sound from loudspeakers
“Cool” = Less sound
Loudspeakers provide even coverage to the public seating areas but…
Reflections from rear wall
Reflections from side wall
Identifying Potential Problem Areas

45. Speech Intelligibility Prediction
Creating Solutions

46. Speech Intelligibility Prediction

47. Intelligibility Measurement
Speech Intelligibility Measurement

48. Intelligibility Measurement
Standalone Tools
Software based tools
AHJ often hires a 3rd party to measure the intelligibility
Plymouth State Ice Arena, Sasaki Associates

49. In summary,
Discussed the changes to the NFPA 72 document and the new requirements relating to speech intelligibility.
In order to achieve speech intelligibility, there are three legs that include Room Acoustics, HVAC Noise Control, and Sound Systems
That there are tools available that can be used to predict SI
And that other tools are available to measure intelligibility in the field.

50. Questions? Thank you for your time.
November 10, 2011