NFPA 72 Mass Notification Regulations November 10, 2011

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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?

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 1985 - 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”

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 4-021-01 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

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).

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

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”

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…

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” .60 - .75 is “good” > .75 is “excellent

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

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

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

Acoustically Distinguishable Spaces Logan Airport, Terminal A, HOK

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

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

If one leg fails….

Room Acoustics

Room Acoustics

Room Acoustics

Room Acoustics

HVAC Noise Control

HVAC Noise Control

HVAC Noise Control

HVAC Noise Control

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

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

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

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

Understanding the Tools Sound Systems Understanding the Tools

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.

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

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

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

$ound $ystem + Bad Room Acoustics = Bad Sound

Speech Intelligibility Prediction

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

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

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

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

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

Speech Intelligibility Prediction

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

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

Speech Intelligibility Prediction Creating Solutions

Speech Intelligibility Prediction

Intelligibility Measurement Speech Intelligibility Measurement

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

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.

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