Low energy doors are often thought of as "handicap accessible automatic
doorways". These doorways usually have signage showing the universal
symbols that are understood as wheelchair accessible openings. In most
installations, low energy door systems are either swinging or sliding
doors. They are predominantly activated by a "knowing act" on
the part of the doorway user. A button or push plate is used to activate
the door operating mechanism. A person wishing to enter the doorway must
push the button to start the door opening function. The low energy requirement
of these doorways pertains to the forces exerted by the moving door through
all aspects of the opening and closing cycle.
Some of the low energy door systems are strictly power assisted door openers.
In their most basic form, these doors use motor controls to push or pull
open a door. After reaching the fully opened position a basic timer will
keep the door open for a specific set time. This allows a person in a
wheel chair access without having to push or pull open the door in front
of their path of travel. When the timer has counted down, the door will
close, and cannot be reactivated to reopen without another push of the button.
Every low energy door system must operate slowly and with minimal force
upon impact or resistance. A properly adjusted low energy doorway will
stop, stall, or reverse when an obstruction is encountered during its
operations.
The more complex or sophisticated the low energy door control, the more
potential features will be available. Some possible options include a
power assisted feature that will sense the force exerted by a user and
activate the door motor control to take over the opening effort. A feature
called "Push and Go" is often available which performs this
type of function. There are also obstruction reactive elements that will
stop, reverse or recycle the opener that may be included in the motor
control command options.
According to specific industry wide safety standards, no optical sensor
or proximity sensor of any kind is required on any low energy door system
that is operated by a push of a button known as a "Knowing Act".
For this reason, these types of doorways are practical for low volume
traffic. They are safe when used appropriately and regularly tested for
proper force and speed when moving. These doors can be problematic when
installed in place of a more costly high energy, fully automated doorway.
Daily inspections of all low energy door systems is an industry wide requirement.
Most manufacturers provide signage and stickers that are positioned on
door frames instructing the manager of any facility that the observation
of these doorways is needed routinely. In an effort to improve the low
energy products, retrofitted sensors and threshold protective devices
used on fully automatic high energy door systems have been installed on
low energy doors. This has become an industry wide practice that is acceptable.
The sensors are often placed on these low energy openers to keep a "tailgating"
pedestrian from being hit by a closing door that has "timed out"
after the first user has passed through the doorway. When actual pedestrian
traffic counts exceeds the original expectations of the architect or designer,
it is a good idea to replace the low energy door system with a fully automatic
high energy doorway.
HIGH ENERGY DOOR SYSTEMS
High energy door system
s are available in many different configurations. Swingers, sliders, revolving,
bi-parting, and telescoping are the most prevalent types in usage today.
Their application and installation are dictated by design choices, weather
requirements and location parameters. These doorways differ from low energy
door systems in the way that the door operates and the force and speed
that the doors possess when moving.
In general, automatic door systems have an approach sensor, a threshold
protection sensor and an egress sensor. The complexity of the automated
door system dictates the level of sophistication of the entire door component
control and sensor package. As discussed in many of my previous automatic
door articles, specific requirements of different automatic door systems
govern the types and locations of door sensors and safety devices.
The one consistent requirement of every automatic door system is the need
to perform
daily safety inspections. Industry wide accepted standards have been adopted to help maintain the
safety of all users of all pedestrian doorways. In the most general sense,
no properly maintained and functioning automatic door should ever hit
a user of that doorway.
Industry standards stating the importance of daily safety checks and component
inspections are normally positioned on warning labels provided by the
product manufacture adjacent to the door control activation panels. The
proper methods of determining the correct functions and operations of
the doorway are listed along with test procedures and instructions to
seek professional service assistance if any of the safety devices fail
to work as described. There is usually a warning to discontinue the usage
of the doorway until all safety features function consistently and properly.
Because high energy doorways move at a much faster speed and force than
low energy doorways when opening and closing, it is very important to
know that all of the built in safety sensors are functioning properly
at all times when the doorway is in use.
HOW THE STANDARDS FOR HIGH & LOW ENERGY DOORS ARE DETERMINED
Most standards are compiled from suggestions and the informed input from
manufacturers, installers, architects, engineers, and door designers.
The general public has the ability to suggest additions to these standards
as well. When the standards are developed, written, and finally accepted,
there is often a delay in instituting the new ideas until the next revision
is printed and published.
Products that are produced during an interim period between standard revision
editions are considered compliant at the time of manufacturing. However,
they may not always comply with the revised standards shortly after their
production period. In most cases the previous standards are incorporated
into the newer editions. The basic parameters and ideas behind the earlier
version of the standards have been more refined or finely tuned, not generally
changed from the original concept.
With changes in technologies certain aspects of door controls, activation
devices, door sensors, and safety equipment have made prior standards
obsolete. An example of this is the current usage of overhead door sensing
devices to control door functions. Originally, on the early automatic
door systems, prior to the development of consistent and dependable sensors,
floor mats with electric or hydraulic contacts were the most common form
of door activation. Pressure sensitive mats are now in limited installations
and considered outdated in most applications.
There are generally provisions in the standards that refer to older equipment
that has been in service and still functioning adequately. But, the emphasis
on safety is always the primary basis for automatic door standards and
the reason that improved designs and newer technology products have taken over.
GENERAL OBSERVATIONS FROM A DOOR SERVICE PROVIDER & DOOR EXPERT WITNESS
As the retained expert witness for both plaintiff and defense in hundreds
of personal injury and wrongful death automatic door cases, I have seen
severe injuries and deaths occur as a result of every type and design
of malfunctioning door systems.
In older automatic door installations, failure of the sensor floor mats
often caused injuries. These older technology mats, and, in some cases,
original system components were generally installed in grocery stores.
They were most frequently associated with automatic swinging doors and
were considered a great convenience to shoppers that no longer had to
hold open the store doorways as they pushed their shopping cart in or
out of the store.
Some old door standards make reference to control mat usage in sliding
door installations. In actual practice, multiple scanning sensors were
typically installed in place of the pressure activated floor mats in those
systems. Pressure sensitive control mats would ultimately deteriorate
due to heavy shopping carts constantly running over them. Weather related
issues such as exposure to ultraviolet rays from the sun, or effects from
freezing rain, snow, and ice, would cause the mats to become brittle,
have contact problems, and fall apart. Pedestrians using these doorways
would become confused as the mats failed to consistently signal the door
operator. The doors would either fail to open, fail to remain open, or
react erratically when stepped upon.
With more modern technology and the usage of scanning sensors, the zones
of coverage and potential for increased safety of the pedestrian using
the automatic doorway is greatly improved. Some new automatic doorways
have integrated safety features that will deactivate the door operator.
This integrated safety feature can render the doorway harmless to any
user when these new state of the art sensors are malfunctioning or improperly
positioned.
Even so, the majority of doorways that are currently in use must be inspected
daily to insure that the sensors and motor controls are operating safely
prior to the start of business every day.
I have authored and published many articles about maintaining
automatic door systems. In those articles I have referred to numerous past cases where injuries
resulted from a variety of deferred conditions or a complete lack of inspection
and/or maintenance.
TYPICAL INCIDENTS THAT CAN HAPPEN WHEN AUTOMATIC DOORS MALFUNCTION
1. A woman entering a small convenience store was hit by an outward swinging
automatic door when another patron approached the interior side of the
doorway to leave the store.
In some installations, two-way traffic is possible with one door opening.
In other installations, a door to enter and a door to exit is provided.
Due to the fact that a single doorway was in place to allow both ingress
and egress, the door system had to have safety devices in place to guard
against this type of circumstance.
Upon my inspection, I determined that the overhead sensor on the exterior
of the doorway was not sending information to the door motor controller
which would have kept the door from opening outward when the patron on
the interior of the opening was attempting to exit the building. For this
reason, a two way door system that swings has often been replaced with
a sliding or bi fold doorway to eliminate the possibility of collision
or entrapment. The subject door I inspected was not compliant with the
industry standards for operation, and had not been tested or professionally
inspected for several years prior to the incident.
2. A woman was entering a department store when an automatic swinging door
struck her from behind, slicing her ankle. When struck by the jagged door
edge, her Achilles tendon was cut and she immediately fell to the ground
in the middle of the doorway.
After viewing the store video footage that captured the incident, reviewing
the service records provided, and from personally testing and inspecting
the doorway during an on-site visit, it was apparent that the door moved
far too quickly. The sensors were improperly adjusted and there had not
been any in-house inspection of the doorway as required.
3. A small boy and girl were walking ahead of their father through an automatic
sliding doorway at a local home center store. The children were about
to cross the threshold when the door suddenly closed upon one of them.
The second child saw the door move and grabbed his sister as the door
slammed upon her. The boy broke his hand, and the girl sustained a broken leg. The father
quickly scooped up the two children, and was also struck by the out of
control sliding door injuring his shoulder. The incident was captured
on a video recording that was "lost" during discovery.
CASE OUTCOME
In case #1 it was discovered during a deposition that the store owner had
not wanted to pay for professional service repairs. He enlisted the help
of his son to disable partial function of the outside door sensor. Altering
the function of the outside sensor allowed the approach portion of the
exterior sensor to function while stopping the sentinel portion. The sentinel
protection was designed to disable the door motor control when someone
is occupying the outswing path of the door. That tampering with the sensor
created the possibility of hitting pedestrians in the path of the door
swing. The store owner claimed that he could not afford to repair the
defective sensor, so he made do with what he had. His son was going to
school for electrical engineering at a local school, and he knew how to
make the door work without spending any money. By altering the function
of the doorway sensor system, the store owner was found responsible for
the injury. He was also found negligent in his store maintenance and daily
operations.
In case #2 the store ownership believed that the woman using the door was
responsible for her own injuries. According to the store manager, she
had slowed down as she was entering the store or had actually stopped
in the threshold while entering the store doorway. The store management
claimed in depositions that daily inspections were made by their security
guards. The security guards contradicted the management's position
stating that they turned on the power to the doorway, but never really
checked the function when they opened the store each morning.
Observation of the store during subsequent months proved that no daily
inspections were ever made by the store security or any other employees.
When the doorway was inspected, it was determined that the motor controller
had been damaged during a prior power surge, and the erratic operation
of the door was confirmed.
In case #3, the store intentionally disposed of the video taken during
the event. Any good attorney will issue a notice to preserve all evidence
including video recordings from the time of an incident. Upon inspection,
the doors operated as described by the father. It was determined that
two cross threshold sensors had been disabled. The two children were not
"seen" by the upper sensors as this older automatic sliding
door relied upon electric eye type of beams to guard the threshold during
operation. The store was penalized by the court for tampering with evidence,
and was sanctioned. The store was found responsible for negligent operations
and practices.
Automatic door systems are complex and can be potentially dangerous pieces
of equipment. In deferred condition, automatic doors can exhibit significant
forces that can lead to life threatening injuries. In the above three
examples, all of the injured parties recovered fully. Many injured in
automatic doorways are not so lucky. Every year there are many wrongful
deaths associated with malfunctioning automatic doors. But that does not
mean that a properly functioning and correctly adjusted automatic doorway
is not safe.
AUTOMATIC DOOR MANUFACTURERS – Are their products safe?
The manufacturers of most automatic door systems provide products that
are safe and time tested. Most of the products commercially available
have been thoroughly inspected, lab tested, and put in to production after
careful design and usage parameters have been met. In almost every case
where I have been retained as the door and hardware expert, the defects
found in the door systems have arisen from improper maintenance, a lack
of policies, plans and procedures that the store management fails to observe,
and an attempt to save the cost of hiring a professional competent service provider.
PEDESTRIANS - BE AWARE
As a pedestrian using these ubiquitous doorways, be aware of the doors
that you are passing through. Observe the operation of any doorway prior
to entering, and proceed with caution as you pass through the threshold.
Diligence on the part of any automatic door user will help to assure safe
passage. Be sure to report any defective operation to a store manager,
and avoid distractions when entering an automatic doorway of any kind.
Always pay attention as you walk through any doorway.
About the Expert
:
Mike Panish is the nation's leading expert witness and most frequently
retained automatic and manual door consultant. He has been involved in
over 650 cases representing both plaintiff and defense evenly. Mike has
a thorough working knowledge of door hardware and components. He has personally
serviced, installed, and maintained major brand door products for many
years. He is the author of many published articles that cover most aspects
of door components, door hardware and door injury claims. Visit his website at
www.constructionwitness.com for a list of relevant articles and to view all of his expert and consulting services.