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BUILDING TRANSPORTATION SAFETY CODES BACKGROUNDER
Education Provided by
the National Elevator Industry, Inc.
Safety
Code for Elevators and Escalators, ASME A17.1/CSA B44
As
a companion to the Safety Code, ASME A17.7/CSA B44.7 was introduced and is known as the Performance-based
Safety Code (PBC). It provides Authorities Having Jurisdiction
(AHJ) with an objective and structured method for approving new technology
while ensuring continued elevator safety.
Building
transportation is required to comply with many other model codes and standards,
including building and fire codes, and material and fire testing standards. Organizations
producing these standards include the ASTM
International (ASTM), International Code
Council (ICC), National
Fire Protection Association (NFPA) and Canadian Standards Association
(CSA).
The
following are examples of some of the elevator and escalator/moving walk
requirements in some of the model codes and standards.
ELEVATORS
ACCESSIBILITY STANDARDS
There
are three accessibility standards enforced in the U.S. for individuals with
disabilities. The American National Standard for Accessible and Usable Buildings and Facilities (ICC/ANSI A117.1) specifies that buildings must be
accessible to and usable by people with physical disabilities. The model
building codes require compliance with this standard.
The
other standard is the Americans with Disabilities Act Accessibility Guidelines
for Buildings and Facilities (ADAAG). This
standard must be complied with under the regulations of the Americans with
Disabilities Act.
Examples of
elevator requirements in these standards include hall and car button location,
identifications and size, dimensions of elevator cars and doors to allow for
wheelchair access, audible signals at landings and in cars to identify car
direction and location, etc. ADAAG will eventually be replaced by the Americans
with Disabilities Act/Architectural Barriers Act Accessibility Guidelines
(ADA/ABA AG). In fact, compliance with ADA/ABA AG is already required in
transportation facilities, postal facilities, GSA and other federal facilities.
Door
Requirements
Elevator
doors must open and close automatically. They must be equipped with a reopening
device that must stop and reopen a car door and hoistway door automatically if
the door becomes obstructed by an object or person. Door reopening devices
shall remain effective for at least 20 seconds. After such an interval, doors
may close in accordance with the requirements of ASME A17.1/CSA B44.
CAR
Controls and Car Sizes
Car controls
must be located so they are accessible to persons in a wheelchair or of short
stature. They must be identified with raised characters and Braille for the
visually impaired. Car sizes and door size and location must allow for the
turning of a wheelchair.
ASME
A17.1/CSA B44 ELEVATOR REQUIREMENTS
Door
Requirements
Car doors
should be configured so that they are able to be moved by hand from inside the
car when the car is stopped within the unlocking zone and power to the door
operator is cut off. When the elevator is outside the unlocking zone, it is
unsafe for a passenger to try to exit the elevator entrance unassisted.
When a car is outside the
unlocking zone, the hoistway doors or car doors must be configured so that they
cannot be opened more than 4 inches from inside the car. When the car doors are
configured so they cannot be opened outside the unlocking zone, they must be
able to open from outside the car by elevator personnel without the use of a
special tool(s). Passenger elevator hoistway doors should also be equipped with
interlocks, a device that prevents the elevator from moving away from the
landing unless the hoistway door is locked in the closed position and the door can’t
open when the car is not at the landing.
Car Safeties
Every elevator car suspended by wire ropes must have a safety
device attached to the underside of the car frame to provide a safe stop for
the passengers in the event of an over-speeding descending car. The safety
devices should be designed to reduce the elevator speed in free-fall condition.
Additionally,
all electric traction elevators, except those whose empty car weight exceeds
the total weight of the suspension ropes and counterweight, must have a device
to prevent an ascending elevator from striking the hoistway overhead
structure.
Emergency Operation and
Signaling Devices
All elevators must be
provided with an emergency phone to signal a problem. Emergency phones replace
emergency alarm bells found in older elevators. This two-way communication ensures
that passengers in stalled cars can communicate with authorized personnel who
can take appropriate action. The two-way communication means must be readily
accessible to authorized personnel and/or emergency personnel. When the
location of the two-way communication means is not staffed 24 hours a day by
authorized personnel, the communication must automatically be directed within
30 seconds to an additional on- or-offsite location, staffed by authorized
personnel, who can take appropriate action.
Car Top Emergency Exit
An emergency exit with a
cover must be provided in the top of all elevator cars (except cars in
partially enclosed hoistways). The top emergency exit is used for evacuating
passengers from a stalled elevator when necessary.
The exit
cover must be attached to the car top by chain or hinges to assure it is not
removed or cannot fall off the top of the car. The exit cover can be opened
from the top of the car only to guarantee emergency personnel access.
Passengers cannot gain access to the car top until emergency personnel deem it
necessary.
Car
Illumination
At least two
lamps are required for both normal and auxiliary lighting in the event that if
one burns out, the car passengers will not be placed in total darkness.
Passenger
elevators also must have auxiliary lighting 48 inches above the car floor and
approximately 12 inches in front of the car-operating device. The intensity of
auxiliary lighting should not be less than 2 lx (unit of illumination).
Auxiliary lights should be automatically turned on in all elevators (in
service) after normal car lighting power fails. The power system must have the
capability to maintain the above light intensity for a period of at least 4
hours.
Firefighters’
Emergency Operations
The building
code requires a sign in elevator lobbies to advise building occupants not to
use elevators in a fire.
Phase I
Emergency Recall Operation
The elevator
will be automatically or manually recalled to a specific landing and removed
from normal service when firefighter service is activated by a smoke detector
in an elevator lobby, hoistway or machine room, or by a key switch. Once fire
personnel arrive and ensure the elevators have been recalled safely and are
safe to use again, they can be put back in operation in Phase II. When Phase I
is activated, passengers in the car will be alerted by a visual (illuminated
fire hat symbol) and audible signal.
Phase II
Emergency In-Car Operation
Firefighters
will have the maximum number of elevators available to use in emergencies.* All
elevators are required to have Phase II Operation.
*Editor’s
Note: Firefighters will take command during a fire, and will determine
whether and how many elevators they will use. It is standard operating
procedure for firefighters to use elevators not only to carry equipment for
firefighting or evacuation purposes, but also to disperse fire personnel to
non-fire involved floors and to evacuate those in the building that cannot use
stairs.
A
key-operated switch is provided in the operating panel in each car behind a
locked cover of the “Fire Operation” panel. The switch will be activated only
when Phase I Emergency Recall Operation is in effect and the car has
been returned to the recall level. When the “Fire Operation” switch is on, the
elevator will be in Phase II Emergency In-Car Operation, for use by
emergency personnel only. The elevator will be operable only by the person in
the car.
ASME
A17.1/CSA B44 ESCALATOR AND MOVING WALK REQUIREMENTS
Handrail Requirements
ASME A17.1/CSA B44 specifies that a handrail entry device must be provided at each newel, located at both
the lower and upper limits of the escalator, and assist passengers in boarding
and exiting the escalator. The handrail entry should be a manual device that
may cause the escalator to stop by removing power from the driving machine
motor and brake. It should operate in one of two ways:
(a) If
an object becomes caught between the handrail and the handrail guard; or
(b) If an object approaches
the area between the handrail and the handrail guard.
For those units that rely on
an opening of the balustrade* to prevent entrapment, all handrail entry devices
shall be running whenever the handrails are operating.
With moving walks, each
balustrade should have a handrail moving in the same direction and at
substantially the same speed as the treadway.
*Editors Note: The balustrades are the sides of the escalator, which
are usually made of stainless steel, aluminum, glass or plastic.
ASME A17.1/CSA B44 requires that hand guards be provided at the point where the handrail enters the
balustrade. Hand guards help prevent items from becoming entrapped in the
handrail opening in the newel. Usually made of rubber, a hand guard fits over
the outside of the handrail at a point where the handrail enters or leaves the
balustrade.
A handrail speed monitoring
device, which monitors handrail speed and is designed to shut down the
escalator if the handrail and step speeds are not synchronized, activates an
alarm whenever the speed of either handrail deviates from the step speed by 15
percent or more within a period of 2 to 6 seconds. The device also must shut
down the driving machine and brake’s electric power when the speed deviation is
in the specified range.
Comb Plate Requirements
(a) There
must be a comb plate (the portion of the landing adjacent to the step) at the
entrance and exit of every escalator/moving walk.
(b) The
comb teeth should set into the slots of the tread surfaces so that the points
of the teeth are always below the upper surface.
(c) Comb
plates must be adjustable vertically. Sections forming the comb teeth must be
readily replaceable.
(d)
The comb section, comb plate and landing plate assemblies must not make contact
with the step treads when a weight of 350 lbs. is applied to an area measuring
8 x 12 inches and the dimension is parallel to the direction of travel.
There
must be a visual contrast, achieved by color, pattern or texture, between the
comb and step.
The adjacent floor surfaces
at each landing must be continuous with the top of the landing plate with no
change in elevation of more than 6 mm (0.25 in.).
The entry and exit zone
should be kept clear of all obstacles. The width of the zone should not be less
than the width between the centerlines of the handrails. The length of the zone
should not be less than twice the distance between the centerlines of the
handrails. Space should be provided to accommodate all traffic in the safety
zone.
Brake Requirements
Escalator Driving-Machine
Brake
The brake
should be applied automatically if the electrical power supply is interrupted.
It must be capable of stopping the descending escalator with any load (of
maximum brake load).
Moving
Walk Driving-Machine Brake
Each
moving walk driving machine shall be provided with an electrically released and
mechanically or magnetically applied brake. If the brake is magnetically
applied, a ceramic permanent magnet shall be used. There shall be no
intentional time delay designed into the application of the brake.
The
brake shall be applied automatically if the electrical power supply is
interrupted. The brake shall be capable of stopping the down- or-horizontal-running
moving walk with any load up to the brake rated load. The brake shall hold the
stopped moving walk with any load up to the brake rated load.
Emergency
Stop Button Requirements
A red stop
button should be visible at the top and the bottom landings on the right side
facing the escalator. Remote stop buttons are prohibited.
Step
Skirt Requirements
Means must
be provided to shut down the electric power from the escalator driving-machine
motor and brake if an object becomes caught between the step and the skirt as
the step approaches the upper or lower comb plate. The device should be located
at a point at which the step assumes a flat step position.
The escalator Step/Skirt Performance Index*
must be included in one of the following, whichever is applicable:
(a) Escalators without skirt deflector devices
(designed to minimize the risk of side-step entrapments) will require an index
of 0.15 or less.
(b) Under
ASME A17.1a–2000 and earlier editions: Escalators with skirt deflector devices
must maintain an index of 0.4 or less.
(c) Under ASME
A17.1a–2002 and later editions: Escalators with skirt deflector devices must
maintain an index of 0.25 or less.
*Editor’s Note: The Step/Skirt Performance
Index was created to provide a reliable standard from which all escalators, new
and old, can be measured and evaluated for rider safety. This Index was
developed by NEII in conjunction with Arthur D. Little (ADL), and is now part
of the ASME. The Index measures the potential for possible entrapments between
the moving stair and the stationary sidewall on a basis of 0.0 to 1.0
Index.
The field test measurement
protocol starts with the inspection of an escalator, both stationary and
running, to note the step/skirt gap and any abnormalities (e.g., wide gaps;
damaged steps, treads or skirt panels; skirt panel misalignment; step/skirt
rubbing). Next, a test apparatus is positioned to gauge the coefficient of
friction and the loaded gap as the escalator runs. Finally, loaded gap values
are obtained at the upper and lower levels of the escalator while stopped.
Step Tread Requirements
Step treads must be
horizontal and provide a secure foothold.
Means must be provided to
shut down electric power from the driving-machine motor and brake in case of
reverse travel (while operating in the ascending direction). The device should
be of the manual-reset type.
A device
must be provided to detect a missing step and bring the escalator to a stop. The
device should stop the power of the driving-machine motor and brake before the
gap resulting from the missing step emerges from the comb. The device shall be
of the manual-reset type.
CONTACT: NEII Media Relations
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