Directional Sound Directional Sound (DS) Psychoacoustic Basis & Psychoacoustic Basis & Implementation Implementation Daniel J. O’Connor, P.E., FSFPE Vice President – Engineering Schirmer Engineering Corporation
Jan 18, 2016
Directional Sound Directional Sound (DS)Psychoacoustic Basis & ImplementationPsychoacoustic Basis & Implementation
Daniel J. O’Connor, P.E., FSFPEVice President – EngineeringSchirmer Engineering Corporation
222
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
333
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
444
How Does It Work?
Human hearing can readily process sound information
Narrowband sounds can be ambiguous
Broadband sound greatly enhances localization cues
Ear Canal Semicircular canals
Temporal bone Round window
Malleus Vestibule
Incus Vestibular nerve
Eardrum Cochlea
Stapes Eustachian tube
11
12
10
555
How Sound Localization Works
AIR PARTICLES MOVEDBY VIBRATING OBJ ECT
INTERAURAL TIME DIFFERENCE
666
How Sound Localization Works
0
-5
-10
LOU
DN
ESS D
IFFER
EN
CE IN
DEC
IBELS
100 500 1000 5000
-15
-20
-25
-30
-3510,000 20,000
FREQUENCY IN CYCLES PERSECOND
PURE TONE
INTERAURAL INTENSITY DIFFERENCES - LOUDNESS AS FUNCTION OF FREQUENCY
DIFFERENCE IN LOUDNESS-LEVELS AT THE TWO EARS WHEN PURE TONES OFVARIOUS FREQUENCIES COME DIRECTLY FROM THE SIDE. THE CURVEILLUSTRATES HOW SOUND-SHADOW OF THE HEAD CHANGES INTENSITY ATVARIOUS FREQUENCIES. (SOURCE: HEARING ITS PSYCHOLOGY ANDPHYSIOLOGY, AMERICAN INSTITUTE OF PHYSICS)
777
How Sound Localization Works
4
2
0
-2
-4
-6
-8
DEC
IBEL
S
NEAREAR
FAR EAR
DIFFERENCE
ANGLE IN DEGREES40200 60 80 100 120 140 160 180
THE CURVES SHOW THE VARYING LOUDNESS-LEVELS AS A SPEECH SOURCE ISROTATED AROUND THE HEAD. ALTHOUGH THE DIFFERENCE AT 42 AND 137DEGREES IS IDENTICAL, THE SOUND QUALITY DIFFERS BECAUSE THE HEADAND OUTER EAR DISTORTS THE SOUND DIFFERENTLY WHEN COMING FROMTHE FRONT OR BACK. (SOURCE: HEARING ITS PSYCHOLOGY AND PHYSIOLOGY,AMERICAN INSTITUTE OF PHYSICS)
INTERAURAL DIFFERENCE - FRONT-TO-BACK, HRTF EFFECT
42 137
888
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
999
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
Directional Sound vs. Fire Alarm Signal (3Khz)Directional Sound at 66dBA and Fire Alarm horn at 86dBA
Measured at 10' horizontally in a anechoic room
0102030405060708090
100110
0 5000 10000 15000 20000
Frequency (Hz)
dB
3000 Hz
101010
How Can DS Help an Evacuation
Not intended to replace, but rather be Not intended to replace, but rather be compatible with standard fire alarmscompatible with standard fire alarms
Focus is providing additional sound cues to Focus is providing additional sound cues to assist occupants in locating the assist occupants in locating the exitexit
““Attention capturing capabilityAttention capturing capability” overcomes ” overcomes issues of “issues of “learned irrelevance”learned irrelevance” of exit signs of exit signs
Sound travels around corners avoids issues Sound travels around corners avoids issues of line-of-sight methods (e.g. exit signs)of line-of-sight methods (e.g. exit signs)
Sound independent of languageSound independent of language
Provides cues in adverse conditions of Provides cues in adverse conditions of smoke or other low visibility conditionsmoke or other low visibility condition
111111
Audience Demonstration
121212
Influence on Human Behavior
University of University of Strathclyde TrialsStrathclyde Trials
Isle of Arran ferry Isle of Arran ferry crew quarterscrew quarters
4 trials – 3 exits 4 trials – 3 exits available, 3% available, 3% smoke, 9-17% exit smoke, 9-17% exit time improvementtime improvement
6 trials – 1 exit only, 6 trials – 1 exit only, 3% smoke, 47-71% 3% smoke, 47-71% exit time exit time improvementimprovement
131313
Influence on Human Behavior University of Strathclyde University of Strathclyde
TrialsTrials
Caledonian Isles restaurant Caledonian Isles restaurant and lounge areaand lounge area
With DS trials 95% of With DS trials 95% of subjects indicated sound subjects indicated sound guided them to an exit, 85% guided them to an exit, 85% indicated DS was most indicated DS was most helpful aidhelpful aid
With smoke trials With smoke trials 85% prefer sound over LLL 15% preferred both
No smoke trialsNo smoke trials 73% preferred sound over LLL 22% preferred LLL
141414
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
151515
What Defines Egress, Escape and Refuge Elements
National Fire Protection Association NFPA 101, Life Safety Code
NFPA 5000,
Building Construction & Safety Code
NFPA 1, Uniform Fire Code
Other NFPA documents
International Code Council, Inc. International Building Code International Fire Code International Existing Building Code International Performance Code for
Buildings and Facilities
161616
Federal Accessibility Laws
Americans with Disabilities Act Accessibility Guidelines (ADAAG)
Fair Housing Accessibility Guidelines (FHAG)
171717
Key Definition - “Exit”
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.
181818
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
191919
What are the Exits?
ENCLOSEDEXIT STAIR
EXIT ACCESSENDS AT EXITDOOR
up
dow
n
up dow
n
ENCLOSEDEXIT STAIR
XX
X
EXIT ACCESS STARTS ATANY POINT
X
X
X
EXIT ACCESSROUTES
202020
Possible Stair Exit Arrangementsu
p dow
n
FIRE DOOR
FIRE RATED ENCLOSEDSTAIRWAY
OPEN TO OUTSIDE
up do
wn
FIRE DOOR
FIRE RATED ENCLOSEDSTAIRWAY
FIRE DOOR
up do
wn
FIRE DOOR
MECHANICALVENTILATION
SHAFT
FIRE RATED ENCLOSEDSTAIRWAY
212121
What are the Exits?
EXTERIOR EXITSTAIRWAY
EXIT(FROM GRADE LEVEL)
INTERIOR EXITSTAIRWAY
EXIT DISCHARGE
222222
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
232323
Horizontal Exit
2 HOUR FIRE BARRIER DOORS ARE AUTOMATICOR SELF CLOSING FIRE DOORS
up
down
up
down
ENCLOSED EXITSTAIR
ENCLOSED EXITSTAIR
242424
Exit Passageway
FIRE RATING BASED ONNUMBER OF STORIES
up
down
up do
wn
FIRE RATED EXIT PASSAGEWAY(PENETRATIONS RESTRICTED)
CORRIDOR
FIRE RATED DOOR
252525
Areas of Refuge(most commonly required in nonsprinklered new construction)
up do
wn
30"x 48" WHEELCHAIR SPACE
AREA OF REFUGE IN AMEANS OF EGRESS
STAIRWAY
48" MINIMUM
48" MINIMUM
up
down
30"x 48" WHEELCHAIR SPACE
AREA OF REFUGEADJACENT TO MEANS OFEGRESS STAIRWAY
48
" M
INIM
UM
48
" M
INIM
UM
262626
Dead-End & Common Path-of -Travel
272727
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
282828
Installation/Use Concepts – Type 1
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
292929
ENCLOSEDEXIT STAIR
updow
n
ENCLOSEDEXIT STAIR
up
dow
n
AREA OFREFUGE
AREA OFREFUGE
SOUNDER SET TO“FAST” PULSE TOMARK EXIT STAIR
SOUNDER SET TO “FAST” PULSE PLUSREFUGE TONG TO MARK ENTRANCETO EXIT STAIR AND ADJOINING AREAOF REFUGE
SOUNDER SET TO “SLOW” PULSEPLUS REFUGE TONG TO MARK AREAOF REFUGE THAT IS NOT AN EXIT
KEY
EXIT SIGN SHADED QUADRANT REPRESENTSVISIBLE FACE
EXIT SIGN WITH DESIGNATION OF DIRECTIONALARROW
DIRECTIONAL SOUNDER
FULL HEIGHT WALLS
PARTIAL HEIGHT DIVIDERS
Implementation
303030
InstallationInstallationat Doorsat Doors
FLOOR
CEILING
CENTER LINEOF DEVICE
2 FT.
WHERE LIMITEDWALL SURFACESARE AVAILABLE, ACEILING MOUNTINSTALLATIONWITH DIRECTIONALSOUNDER NOMORE THAN 2 FEETDISTANCE OFFFACE OF DOOR
EXAMPLELOCATIONS FORDIRECTIONALSOUNDERS
SIDE VIEW
FLOOR
CEILING
FRONT VIEW
313131
Open Floor Plan Example
KEY
EXIT SIGN SHADED QUADRANT REPRESENTSVISIBLE FACE
EXIT SIGN WITH DESIGNATION OF DIRECTIONALARROW
DIRECTIONAL SOUNDER
FULL HEIGHT WALLS
PARTIAL HEIGHT DIVIDERS
up
down
up
down
COMMON PATH OF TRAVEL
DE
AD
-EN
DD
EA
D-E
ND
IN OPEN-PLAN FLOORS, TYPE 2SOUNDERS SHOULD NOT BE USED FOROTHER THAN DEAD-ENDS OR COMMONPATH OF TRAVEL CONDITIONS.MULTIPLE SOUNDERS IN THE COMMONEGRESS ROUTE OF AN OPEN FLOORPLAN WOULD RESULT IN CONFLICTINGDIRECTIONAL SOUND CUES. TYPE 1SOUNDERS MAY NEED TO HAVE THEPOWER SETTING INCREASED FORBETTER PENETRATION INTO THE OPENFLOOR SPACE.
323232
Intervening Door
FIRE RATING BASED ONNUMBER OF STORIES
up
down
up dow
n
CORRIDORSET DIRECTIONALSOUNDER TO “FAST”PULSE PATTERN
INTERVENING DOOR
ADDITIONAL SOUNDER SET TO “FAST” PULSE TO INCREASE THE DIRECTIONAL SOUND PENETRATIONINTO THE CORRIDOR ONCE THE THE INTERVENING DOOR CLOSES. THE SOUNDER SHOULD BE LOCATEDON THE CORRIDOR SIDE OF THE DOOR. ONCE THE EVACUEES PASS THROUGH THE DOOR THEY WILLBEGIN TO HEAR THE SOUNDER AT THE STAIRWELL AND PROCEED TOWARDS THE ACTUAL EXIT.
333333
Installation/Use Concepts – Type 2
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
343434
Type 2 Installation
ENCLOSED EXIT STAIR
up
down
‘FAST’ PULSE
KEY
DIRECTIONAL SOUNDER
FULL HEIGHT WALLS
‘MEDIUM 1’ PULSE
‘MEDIUM 2’ PULSE
‘SLOW’ PULSE
‘MEDIUM 2’ PULSE
SAME PULSE OK IF NOTSAME ROUTE TO EXIT
NOT MORE THAN FOURSOUNDERS ALONG SAMEROUTE TO EXIT
353535
Corridor Corners 2 FT.
DIRECTION OF TRAVEL TOTHE NEAREST EXIT
CENTER LINE OF CORRIDOR
PREFERRED INSTALLATIONZONE
ACCEPTABLEINSTALLATION ZONE
DIRECTION OF TRAVEL TOTHE NEAREST EXIT
363636
Dead End Corridors
373737
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
383838
Example – When Not to Use Type 2KEY
EXIT SIGN SHADED QUADRANTREPRESENTS VISIBLE FACE
EXIT SIGN WITH DESIGNATION OFDIRECTIONAL ARROW
DIRECTIONAL SOUNDER
FULL HEIGHT WALLS
CONSIDERATIONS FOR OCCUPANT LOAD BALANCE:ALTHOUGH ROUTE A IS THE SHORTEST TRAVELDISTANCE TO AN EXIT, TYPE 2 SOUNDERS ARE NOTRECOMMENDED TO BE LOCATED ALONG ROUTE ADUE TO THE LIMITED EXIT CAPACITY. WHEREOCCUPANT BALANCE ISSUES MAY BE PRESENT, ITIS RECOMMENDED THAT DIRECTIONAL SOUNDERSBE LIMITED TO A TYPE 1 INSTALLATION (EXITSONLY).
KEY DECISIONPOINT
KEY DECISIONPOINT
RO
UT
E A
EXIT EXIT
EXIT
AUDITORIUM(400 OCCUPANTS)
393939
Contrast of Occupancy Considerations
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
404040
For More Information
http://www.systemsensor.com/exitpoint/
NFPA Journal May/June 2005
http://www.soundalert.com/
414141
Thanks & Appreciation
Questions ?