Directional Sound (DS) Psychoacoustic Basis & Implementation

1. Directional Sound (DS)Psychoacoustic Basis & Implementation Daniel J. O’Connor, P.E., FSFPE Vice President – Engineering Schirmer Engineering Corporation

2. Background • Professor Deborah Withington • Auditory neuroscience, University of Leeds • Expertise needed • Human behavior – Dr. G. Proulx, Dr. John Bryan • Acoustics – Robert Elfering, P.E./Shiner Associates • FP/LS design – Schirmer Engineering • Reviewed all published literature and human subject tests on DS • Reviewed key texts on sound & psychoacoustics

3. Basic Findings • Sound & psychoacoustic theory is well established • Significant work has been done that demonstrates the benefits of using DS • Implementation is relatively easy compared to other exit-assist technologies

4.  Ear Canal  Semicircular canals  Temporal bone  Round window  Malleus  Vestibule  Incus Vestibular nerve  Eardrum Cochlea  Stapes Eustachian tube 10 11 12 How Does It Work? • Human hearing can readily process sound information • Narrowband sounds can be ambiguous • Broadband sound greatly enhances localization cues

5. How Sound Localization Works

6. How Sound Localization Works

7. How Sound Localization Works

8. Broadband Sound Benefit • Broadband sound is complex & provides sound differences not found with narrowband frequencies • Loudness • Intensity • Spectrum • Redundant sound cues combined with head motion allows for easy localization • “Precedence Effect” – ear discerns and fixates on first sound and consequently no problem in highly reverberant spaces

9. Broadband Sound Benefit • Typical 3,000 Hz alarm dominates and DS need not be higher in overall sound pressure level • Clearly distinguished from standard notification devices (bells, horns) • Voice systems require additional considerations but can be integrated 3000 Hz

10. How Can DS Help an Evacuation • Not intended to replace, but rather be compatible with standard fire alarms • Focus is providing additional sound cues to assist occupants in locating the exit • “Attention capturing capability” overcomes issues of “learned irrelevance” of exit signs • Sound travels around corners avoids issues of line-of-sight methods (e.g. exit signs) • Sound independent of language • Provides cues in adverse conditions of smoke or other low visibility condition

11. Audience Demonstration

12. University of Strathclyde Trials Isle of Arran ferry crew quarters 4 trials – 3 exits available, 3% smoke, 9-17% exit time improvement 6 trials – 1 exit only, 3% smoke, 47-71% exit time improvement Influence on Human Behavior

13. Influence on Human Behavior • University of Strathclyde Trials • Caledonian Isles restaurant and lounge area • With DS trials 95% of subjects indicated sound guided them to an exit, 85% indicated DS was most helpful aid • With smoke trials • 85% prefer sound over LLL • 15% preferred both • No smoke trials • 73% preferred sound over LLL • 22% preferred LLL

14. Understanding Basic Egress Concepts • Exit access • Exit • Exit discharge • Refuge area, area of refuge, or area of rescue assistance • Horizontal exit • Exit passageway • Dead-end corridor • Common path-of-travel

15. What Defines Egress, Escape and Refuge Elements • International Code Council, Inc. • International Building Code • International Fire Code • International Existing Building Code • International Performance Code for Buildings and Facilities • National Fire Protection Association • NFPA 101, Life Safety Code • NFPA 5000, Building Construction & Safety Code • NFPA 1, Uniform Fire Code • Other NFPA documents

16. Federal Accessibility Laws • Americans with Disabilities Act Accessibility Guidelines (ADAAG) • Fair Housing Accessibility Guidelines (FHAG)

17. NFPA Definition Exit- That portion of a means of egress that is separated from all other spaces of a building or structure by construction or equipment as required to provide a protected way of travel to the exit discharge. ICC Definition Exit- That portion of a means of egress that is separated from other interior spaces of a building or structure by fire-resistance-rated construction and opening protectives as required to provide a protected path of egress travel between the exit access and the exit discharge. Exits include exterior doors at ground level, exit enclosures, exit passageways, exterior exit stairs, and horizontal exits. Key Definition - “Exit”

18. Types of “Exits” – Familiar Types • Doors leading directly to the outside at grade • Interior stairs enclosed by fire rated construction, which includes • Smokeproof towers • Pressurized stairways • Exterior stairs isolated from the building interior with fire rated or protective construction • Fire escapes

19. What are the Exits?

20. Possible Stair Exit Arrangements

21. What are the Exits?

22. Types of “Exits” – Others Types to Recognize • Passageways enclosed by fire rated construction (should not be confused with corridors) • Horizontal exits • Ramps enclosed by fire rated construction • Escalators enclosed by fire rated construction • Other special exits – may be result of code equivalency or a performance based design, or otherwise negoitiated concept

23. Horizontal Exit Fire

24. Exit Passageway

25. Areas of Refuge(most commonly required in nonsprinklered new construction)

26. Dead-End & Common Path-of -Travel

27. Locations not Suitable for Directional Sounders • Windows for Rescue • Stairway that is an Incomplete route • Exterior door that leads to a outdoor locked fenced area • Portable ladders, rope fire escapes and similar escape devices • NFPA and ICC documents state that access to an exit shall not pass through a high-hazard occupancy, a kitchen, a storeroom or a closet

28. Type 1 Installation– most basic, straightforward installation Locate at entry point to EXITS, Refuge Areas Set to fastest pulse pattern at EXIT Set to slow pulse at “area of refuge” Use “area of refuge” supplemental indicator May need additional sounders to address intervening doors Incorporate into Emergency Plans for facility Installation/Use Concepts – Type 1

29. Implementation

30. Installationat Doors

31. Open Floor Plan Example

32. Intervening Door

33. Type 2 Installation – enhanced installation, additional sound cues along egress path for occupants Locate at entry point to EXITS, Refuge Areas same as Type 1 installation, and door from a room/area having a common path-of-travel, the outlet end of a dead-corridor, At points of multiple route choice where a directional sound device is located leading in the direction of the nearest exit At points along a route where the sounder at the exit is not audible Use additional directional sounders where they will enhance the ability of occupants to locate exits and the direction thereto Use increasing speed in pulse patterns in moving from sounder locations most distant from the exit (slower pulse) to sounders nearer the exit (faster pulse). Maximum of 4 sounders along path (only 4 pulse settings) Incorporate into Emergency Plans for facility Installation/Use Concepts – Type 2

34. Type 2 Installation

35. Corridor Corners

36. Dead End Corridors

37. Don’t Use a Type 2 Installation • Do not use a Type 2 installation for open floor plans with multiple exits, where sounders will tend to conflict with each other • Do not use a Type 2 installation where occupant loads and exit capacities are not reasonably balanced with travel distances to routes

38. Example – When Not to Use Type 2

39. Retail – visual clutter, patrons not familiar with the variety of exits Directional sound can be a benefit Hospitals – highly trained staff, defend-in-place occupancy Directional sound –NOT appropriate Contrast of Occupancy Considerations

40. For More Information • http://www.systemsensor.com/exitpoint/ • NFPA Journal May/June 2005 • http://www.soundalert.com/

41. Thanks & Appreciation • Questions ?