4.1.3 (14) New
If emergency warning systems are provided, then they shall include both
audible and visual alarms complying with 4.28. Emergency warning systems
in medical care facilities may be modified to suit standard health care
alarm design practice.
Alarm systems required to be accessible by 4.1 shall comply with 4.28. At
a minimum, visual signal appliances shall be provided in buildings and
facilities in each of the following areas: restrooms and any other general
usage areas (e.g., meeting rooms), hallways, lobbies, and any other area
for common use.
Refers to those interior and exterior rooms, spaces, or elements that are
made available for the use of a restricted group of people (for example,
occupants of a homeless shelter, the occupants of an office building, or
the guests of such occupants).
(3)* Areas Used Only by Employees as Work Areas.
Areas that are used only as work areas shall be designed and constructed
so that individuals with disabilities can approach, enter, and exit the
areas. These guidelines do not require that any areas used only as work
areas be constructed to permit maneuvering within the work area or be
constructed or equipped (i.e., with racks or shelves) to be accessible.
For information on employee accommodation under title I of the ADA,
contact the Equal Employment Opportunity Commission (EEOC) ADA information
(800) 669-4000 (voice)
(800) 800-3302 (TTY)
4.28.3 Visual Alarms.
Visual alarm signal appliances shall be integrated into the building or
facility alarm system. If single station audible alarms are provided then
single station visual alarm signals shall also be provided. Visual alarm
signals shall have the following minimum photometric and location
The lamp shall be a xenon strobe type or equivalent.
The color shall be clear or nominal white (i.e., unfiltered or clear
filtered white light).
The maximum pulse duration shall be two-tenths of one second (0.2 sec)
with a maximum duty cycle of 40 percent. The pulse duration is defined as
the time between initial and final points of 10 percent of maximum signal.
The intensity shall be a minimum of 75 candela.
The flash rate shall be a minimum of 1 Hz and a maximum of 3 Hz.
The appliance shall be placed 80 in (2030 mm) above the highest floor
level within the space or 6 in (152 mm) below the ceiling, whichever is
In general, no place in any room or space required to have a visual signal
appliance shall be more than 50 ft (15 m) from the signal (in the
horizontal plane). In large rooms and spaces exceeding 100 ft (30 m)
across, without obstructions 6 ft (2 m) above the floor, such as
auditoriums, devices may be placed around the perimeter, spaced a maximum
100 ft (30 m) apart, in lieu of suspending appliances from the ceiling.
No place in common corridors or hallways in which visual alarm signalling
appliances are required shall be more than 50 ft (15 m) from the signal.
Strobe Lamp Coverage
2.2 Equivalent Facilitation.
Departures from particular technical and scoping requirements of this
guideline by the use of other designs and technologies are permitted where
the alternative designs and technologies used will provide substantially
equivalent or greater access to and usability of the facility.
Recommended spacing in corridors
Recommended placement in irregularly configured room
4.28.4 Auxiliary Alarms.
Units and sleeping accommodations shall have a visual alarm connected to
the building emergency alarm system or shall have a standard 110-volt
electrical receptacle into which such an alarm can be connected and a
means by which a signal from the building emergency alarm system can
trigger such an auxiliary alarm. When visual alarms are in place the
signal shall be visible in all areas of the unit or room. Instructions for
use of the auxiliary alarm or receptacle shall be provided.
9.3 Visual Alarms,
Notification Devices and Telephones.
In sleeping rooms required to comply with this section, auxiliary visual
alarms shall be provided and shall comply with 4.28.4. Visual notification
devices shall also be provided in units, sleeping rooms and suites to
alert room occupants of incoming telephone calls and a door knock or bell.
Notification devices shall not be connected to auxiliary visual alarm
signal appliances [...].
9.3.2 Equivalent Facilitation.
For purposes of this section, equivalent facilitation shall include the
installation of electrical outlets (including outlets connected to a
facility's central alarm system) and telephone wiring in sleeping rooms
and suites to enable persons with hearing impairments to utilize portable
visual alarms and communication devices provided by the operator of the
assistance is intended solely as informal guidance; it is not a
determination of the legal rights or responsibilities of entities subject
to the ADA.
landmark Americans with Disabilities Act (ADA), enacted on July 26, 1990,
provides comprehensive civil rights protections to individuals with
disabilities in the areas of employment (title I), State and local
government services (title II), public accommodations and commercial
facilities (title III), and telecommunications (title IV). Both the
Department of Justice and the Department of Transportation, in adopting
standards for new construction and alterations of places of public
accommodation and commercial facilities covered by title III and public
transportation facilities covered by title II of the ADA, have issued
implementing rules that incorporate the Americans with Disabilities Act
Accessibility Guidelines (ADAAG), developed by the Access Board.
The products shown in this guide are only
intended to serve as examples to illustrate the accessibility guidelines,
and are not intended as endorsements of the products. Other products may
be available. The Access Board does not evaluate or certify products for
compliance with the accessibility guidelines. Users are advised to obtain
and review product specifications for compliance with the accessibility
U N I T E D S T A T E S A C C E S S B O A R D
A FEDERAL AGENCY COMMITTED TO ACCESSIBLE DESIGN
TECHNICAL BULLETIN: VISUAL ALARMS
Why are visual
One American in
a hundred has a severe hearing loss; nearly one in ten has a significant
loss. In 1984, the Digest of Data on Persons with Disabilities reported
that: "(t)he severity of hearing problems was strongly associated with
age. persons 65 and older constituted 69 percent of the population with
the most severe hearing trouble...but only 8.7 percent of the population
without hearing trouble." Those who are deaf or hard-of-hearing--a growing
percentage of our population, due largely to the growth in the numbers of
older persons--depend upon visual cues to alert them to emergencies. A
visual alarm provides persons with hearing loss the same warning delivered
to hearing persons by an audible alarm.
Audible fire alarms have been a standard feature of building construction
since the life safety codes of the early 1900s. However, visible signals
did not appear even in accessibility codes until 1980. Early standards
required relatively dim flashing lights at exit signs--an alarm system
that was effective only along an exit route. As accessibility, life
safety, and building codes were revised, however, they began to
incorporate alarm technology that was developed for use in schools for
persons who are deaf and in factories where ambient noise levels made
audible alarms ineffective.
In passing the Americans with Disabilities Act in 1990, Congress
specifically directed the Access Board
to provide greater guidance regarding communications accessibility. Thus
the ADA Accessibility Guidelines (ADAAG) require that where
emergency warning systems are provided in new or altered construction,
they must include both audible and visible alarms that meet certain
What are visual
are flashing lights used as fire alarm signals. The terms visual alarm
signal, visible signal device, and visible signaling appliance are used
relatively interchangeably within the fire protection community; the
National Fire Protection Association (NFPA) calls them visual notification
appliances. There is no practical distinction between a visual signal and
a visible signal. Although visual signals may be used for other purposes,
the type described in this Bulletin is appropriate only for use as an
emergency alarm signal. An illustration shows a type of
commercially-available alarm fixture that incorporates a visual alarm.
There are two major
categories of fire alarms:
- self-contained units,
as exemplified by the single-station residential smoke detector
unit--battery-operated or hard-wired to building electrical power--which
produces an alarm signal at the fixture itself when activated by an
integral sensing device, and
integrated--often zoned--alarms whose local signals are remotely
initiated, either automatically from detectors or manually from
pull-stations spread throughout a facility.
ADAAG requires that when either type is installed, it must have a visual alarm
Where are visual
is subject to state and local ordinances that may both require and specify
standards for emergency alarm systems. These regulations--building codes,
life safety codes, accessibility codes, technical standards--are typically
based upon national model codes and standards. The requirement for
an emergency alarm system in new construction will be established by the
applicable State or local building, life safety, or fire protection
regulation. ADAAG does not mandate an emergency alarm system; its
scoping provision at 4.1.3(14) simply requires that when emergency
warning systems are provided, they shall include both audible and visual
alarms that comply with 4.28.
Thus the requirement for an alarm system in a facility will trigger the ADAAG technical specifications for alarms. ADAAG 4.1.3(14)
Accessible Buildings: New Construction requires that visual alarms be
installed if emergency warning systems are provided in a new facility. In
existing buildings, the upgrading or replacement of a fire alarm system
also requires compliance — see ADAAG 4.1.6(b) — with ADAAG technical provisions for alarms.
Because it is not always possible to fix the occupancy of a room or space
or anticipate its use by a person with a hearing impairment, visual alarms
are required in every common use room or space in facilities equipped with
an emergency alarm system. This is particularly important in those common
use spaces where a person may be alone. ADAAG 4.28.1 General
stipulates that alarm systems required to be accessible shall provide
visible signals in restrooms, in other general and common use areas, and
in hallways and lobbies. Common use areas also include meeting and
conference rooms, classrooms, cafeterias, filing and photocopy rooms,
employee break rooms, dressing, examination, and treatment rooms, and
similar spaces that are not used solely as employee work areas.
System designers and specifiers must be particularly attentive to signal
coverage issues. Where audible alarms are installed in corridors and
lobbies to serve adjacent common use rooms, individual visual alarm signal
appliances must be installed in those rooms, since the warning provided by
a visual signal, unlike that of a bell or other annunciation system, can
only be observed within the space in which it is installed. Dressing and
fitting rooms, for example, can be easily protected by an audible alarm
outside the room or space. However, the customer or patient who has a
hearing impairment will not be alerted unless the dressing room he/she is
using is protected with a visual alarm in (or above, if partitions do not
extend to full height) the space. In general, it is not sufficient to
install visual signals only at audible alarm locations.
Where are visual
alarms not required?
ADAAG does not require that areas used only by employees as work areas be fully
accessible. Thus, visual alarms are not required in individual employee
offices and work stations. However, providing a visual alarm in the work
area of an employee who is deaf or hard-of- hearing may be--like other
elements of workplace accessibility-- a reasonable accommodation under
title I of the ADA, which addresses employment issues. The potential for
such future employee accommodations should be considered when facility
wiring is planned to facilitate a later connection to the building alarm
system. Mechanical, electrical and telephone closets, janitor's closets,
and similar non-occupiable spaces that are not common use areas nor
assigned work areas are not required to have visual alarms. For
information on employee accommodation under title I of the ADA, contact
the Equal Employment Opportunity Commission (EEOC) ADA information line at
(800) 669-4000 (voice) or (800) 800-3302 (TTY).
provisions apply to visual alarms?
provisions of ADAAG 4.28 Alarms include minimum standards for the
design and installation of single-station and building-wide visual alarm
systems. They are based upon research sponsored by the Access Board and
other groups, principally Underwriters Laboratories (UL).
To be effective, a visual signal--or its reflection from adjacent walls
and ceiling--must be of an intensity that will raise the overall light
level sharply, but not so intense as to be unsafe for direct viewing at a
specified mounting height. Technical criteria for visual alarm signal
appliances are established in ADAAG 4.28.3 Visual Alarms (see
In research sponsored by the Access Board,
a high-intensity xenon strobe lamp was found to be the most effective in
alerting persons with hearing impairments. White light was judged to be
the most discernible; colored lamps (particularly red) were not effective
even at extreme intensities.
Ninety percent of the research subjects were alerted by a 75 candela (cd)
signal mounted fifty feet away on the wall directly behind them, where the
horizontal output of a strobe lamp is measured at 100% of its nominal
rating. For this reason, 75 cd is a minimum performance criterion--not a
lamp sizing or specifying standard--for all locations within the 50-foot
radius of the covered area. Because most strobes are not point sources,
light output falls off sharply to the sides; a lamp with a maximum output
of 75 cd when measured at 0 degrees will not provide the required increase
in illumination at a 45 degree angle. Lamp intensity is given in effective
candela, measured in use at the source.
Like a camera flash, the strobe produces a short burst of high-intensity
light. The repetition of this pulse at a regular interval is the flash
rate. Pulse duration--the interval of the flash between signal build-up
and decay--is limited so that the signal is not temporarily blinding.
Testing indicated that flash rate cycles between one and three Hertz
(flashes per second) successfully alerted subjects with hearing
impairments; a 3 Hz rate appeared to be somewhat more effective. Lamps
tested at 1/3 Hz were adjudged ineffective. ADAAG thus requires
flash rates within the 1 to 3 Hz range.
Rates that exceed 5 flashes per second may be disturbing to persons with
photosensitivity, particularly those with certain forms of epilepsy.
Information received during the development of these guidelines suggests
that multiple unsynchronized visual signals within a single space may
produce a composite flash rate that could trigger a photoconvulsive
response in such persons (for example, two strobes set at 3 Hz in a room
could generate a combined flash rate of 6 Hz). Installations that may
produce a composite rate in excess of 5 Hz should therefore be avoided by
decreasing the number of fixtures and raising the intensity of the lamps
they contain, by decreasing the flash rate of multiple lamps, or by
synchronizing the flash rates of multiple fixtures. This is particularly
important in schools, since children are more frequently affected by
photosensitivity than are adults.
Mounting provisions were developed from NFPA signal criteria and UL smoke
test findings. Strobes--whether projected from a wall or suspended from
the ceiling--must be a minimum of 6 inches below the ceiling plane to
avoid smoke obscuration in the event of a fire. To comply with provisions
covering protruding objects, alarm devices must be at least 80 inches
above the finished floor. To preclude installations that might be outside
the field of view in high-ceilinged spaces such as atriums and warehouses,
the guidelines require a strobe to be mounted at the lower of the two
heights. However, photometric calculations of lamp intensity for mounting
heights of 80 inches and of 96 inches show only nominal differences and
can be practically considered to be equivalent. A single visual signal
meeting ADAAG specifications could be expected to serve a large
room or length of corridor if optimally located on perimeter walls or
suspended below the ceiling so that the signal can spread throughout the
space, unobstructed by furnishings, equipment, or room geometry.
In multipurpose facilities where bleacher seating, athletic equipment,
backdrops, and other movable elements may at times be deployed or in
warehouses, libraries, convention centers and other building types where
devices would not be visible when installed at specified heights, optimal
signal placement may require considerable study and the development of
alternative intensity and placement calculations as an equivalent
Provisions governing the spacing of visual alarms in hallways and
corridors will generally require one fixture every 100 feet. In lengthy
corridors, such as in shopping malls and large buildings, it is
recommended that appliance spacing be maximized within the limits of the
technical provision to minimize the effect of a composite flash rate on
persons with photosensitivity. It is further recommended that the
placement of visual signals along a corridor alternate between opposing
walls to minimize the number of signals in a field of view.
affect the design of visual alarm systems?
through 4 describe general fixture placement and lamp coverage in
In general, it is recommended that visual alarm lamp intensity be
maximized so as to require the minimum number of fixtures. Large,
high-ceilinged spaces may best be served by suspended flash tubes of very
high intensity (lamps up to 1000 candela are available for such
applications). Smaller rooms, with an area that can be circumscribed by a
circle 50 feet in radius, can be covered by a single, centrally located
visual alarm meeting ADAAG intensity specifications. For very small
rooms, such as examination, toilet, and dressing rooms, a single strobe of
lesser intensity may well be sufficient as an equivalent facilitation.
equivalent facilitation be considered?
ADAAG technical provisions apply to normative conditions. Signal intensity and
placement in very small and very large rooms and in spaces with high
ceilings, irregular geometry, dark or non-reflective walls, or very high
ambient lighting levels may best be determined by specialized consultants
employing photometric calculation for system design rather than by a
literal application of ADAAG specifications. For these reasons, ADAAG 2.2 Equivalent Facilitation permits alternative designs that
achieve substantially equivalent or greater accessibility.
Lamp intensity (like sound) decreases in inverse relation to the square of
its distance from the viewer. Thus, by varying lamp intensity and spacing,
system designers can tailor an installation to the physical conditions of
the space being served. It is impossible to provide specific guidance for
the design of non-standard installations based upon the photometric
calculations necessary to demonstrate equivalent facilitation. Such
applications should generally be designed by experienced electrical
engineers or fire alarm consultants under performance specifications for
coverage and illumination levels derived from the technical provisions of ADAAG 4.28 and ambient conditions in the space. For example, a 75
cd strobe at 50 feet raises the ambient light by 0.03 at 0 degrees in the
horizontal plane. Equivalent design configurations should, therefore,
result in approximately the same increase at all positions within the
As there is no process for certifying alternative methods (except in
transportation facilities under DOT enforcement),
the responsibility for demonstrating equivalent facilitation in the event
of a challenge rests with the covered entity.
The American National Standard for Accessible and Usable Buildings and
Facilities (CABO/ANSI A117.1-1992), reflecting current NFPA 72 performance
recommendations for visual alarms, stipulates lamp, installation, and
spacing criteria at some variance with ADAAG technical
specifications for visual alarms and with this Bulletin. ANSI Table
188.8.131.52(a), Room Spacing Allocation, suggests that an alarm installation
of several low-intensity lamps within a room is the practical equivalent
of a single high-intensity lamp serving that space.
Given concerns for economy (lower-candela lamps are less expensive to
purchase and connect) and lamp standardization within a building
(lower-candela lamps are more available and simplify inventorying),
specifiers may be motivated to standardize on a minimum-candela fixture,
achieving coverage in large rooms by close spacing of low- intensity
Access Board strongly discourages this practice. Where a single lamp can
provide the necessary intensity and coverage, multiple lamps should not be
installed because of their potential effect on persons with
What types of
visual alarms are available?
suppliers to the fire protection industry manufacture visual appliances,
which are readily available to electrical contractors and others
responsible for the installation of building alarm systems. Visual alarms
incorporating smoke detectors and lamp-only signal appliances are supplied
through standard sources, although some lamp intensities and visual alarm
fixtures may not be commonly stocked. Strobe lamps are commercially
available in varying intensities up to 200 candela. Higher intensities can
be provided by specialized manufacture.
Although an integrated audible and visual signal is available at about the
same cost as an audible or visual signal alone, more visual signals than
audible signals will be necessary for most applications. Careful attention
to reflection from surfaces can increase light dispersion and coverage in
both new and renovated structures.
alarm requirements apply to sleeping rooms in transient lodging
ADAAG 9.3.1 requires that sleeping units covered by Section 9 Accessible
Transient Lodging have a visual alarm connected to the building alarm
system or provide a power outlet for a portable device that can be
triggered by the building emergency alarm system (such units can be
activated by a signal from the central alarm control system, transmitted
through the standard 110V building wiring to a receiver plugged into a
power outlet at a remote location). Portable units with a standard 110
volt electrical cord are available from specialized retailers of products
for persons who are deaf and hard-of- hearing. Because guest room sizes
are not large in such occupancies, the technical specification of 4.28.4
Auxiliary Alarms requires only that the signal--intended to alert persons
who are awake--be visible in all areas of the room or unit.
Visual alarms are not the technology of choice for awakening sleeping
persons, however. A UL study concluded that a flashing light more than
seven times brighter than that needed to alert office workers would be
required to arouse a person who was asleep (110 cd vs. 15 cd at 20 feet,
if mounted 24 inches or more from the ceiling; 177 cd if mounted less than
24 inches from the ceiling, where smoke obscuration might be a significant
factor). Alarm system designers are advised to consider the UL findings if
visual alarms are to be employed to warn sleeping persons of emergencies.
ADAAG does not establish standards for portable items or auxiliary
aids. However, devices that employ technologies other than visual
signaling may offer equivalent or superior warning for sleeping guests
who have hearing impairments. For example, a signal-activated vibrator was
found to be much more effective in alerting sleepers than were the visual
signals tested in the UL research. Such devices are commonly available and
may be connected to or activated by a building alarm system. Care must be
taken that notification devices intended to signal a door knock or bell
are separately wired.
Why is there an
exception in the scoping requirements of 4.1.3(14) for "standard health
care alarm design practice"?
In medical care
settings where a supervised emergency evacuation plan is in place, it is
usually not desirable to install alarms in patient rooms or wards. In such
occupancies, personnel responsible for ensuring the safe egress of
patients will respond to an intercom message or other signal that is not
intended to alert or alarm patients incapable of independent evacuation.
Additionally, visual alarms may not be appropriate for use in some
specialized medical facilities, such as operating rooms, where lighting
levels are high and the sudden discharge of a strobe flash might adversely
affect a surgical procedure. For such facilities, the requirements for
visual and audible alarms may be modified to suit industry-accepted
U N I T E D S T A T E S A C C E S S B O A R D
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