You should never install, or have installed on your property,
a vehicular gate operator that does not carry the "MARK"
of an NRTL such as ETL or UL. You should also be aware that NRTL's
do not "approve" or "certify" products that
they test. Manufacturers that use this terminology are incorrect
in its usage. When a product is tested by an NRTL, and that product
is found to be in compliance with the safety standard, then that
product is said to be "LISTED" and the manufacturer receives
a "MARK" and an "Authorization to Label" from
the NRTL.
The standard to which vehicular gate operators are manufactured
and tested to is U.L 325 - Underwriters Laboratories Inc., Standard
for Safety: Door, Drapery, Gate, Louver, and Window Operators and
Systems. In addition to the 325 standard, vehicular gate operators
must also be tested to U.L. 991 - Tests for Safety-Related Controls
Employing Solid-State Devices.
The U.L. 325 Standard has undergone significant revisions over
the past several years. The main purpose of the revisions were
to create entrapment protection criteria for vehicular gate operators,
and to increase over-all safety of the product. The revised standard
was first published September 18, 1998, and went into effect March
1, 2000. The key issues of the September 18, 1998 revision are
as follows:
Created different "classes" of vehicular gate operators.
Requires a primary and a secondary entrapment protection device
(30A.1.1). Defined the different types of entrapment protection
devices than can be used for primary and secondary protection in
a given class of operator. Requires an audio alarm to sound upon
two sequential activations of an entrapment protection device not
interrupted by an open or close limit device (30A.1.1A). Requires
a renewed intended input in the line-of-sight of the operator once
the entrapment sensing system detects a second sequential obstruction
(30A.1.2b). Requires slide gates not to move greater than 1 ft/sec
(30A.1.19). Requires the gate operator to have an integral means
for manual operation (30A.1.20).
Gate Opener & Gate Operator Safety
Serious accidents (and some fatalities) have resulted from the
improper design, installation, and usage of vehicular gate operators
and vehicular gate operating systems. This web page is designed
so that you know what to expect from your vehicular gate system,
how to make it safe, and how to prevent accidents from happening.
We also discuss several issues that need to be addressed when designing
and installing a vehicular gate system. Vehicular gate systems
can be made safe, but achieving this safety is the joint responsibility
of the manufacturer, the system designer, the installer, and the
end user. Below are some critical issues that you need to be aware
of before designing or installing an automated vehicular gate operating
system for your property.
Inherent Entrapment Sensing
When selecting a gate operator, whether it is a slide or swing
gate design, it is imperative that the product has been designed
with an inherent entrapment sensing system that will sense an
entrapment and reverse the gate in either the opening or closing
gate cycle. This issue is CRITICAL. Several deaths have occurred
when persons became entrapped in opening slide gates and the
gate operator lacked an inherent systems to detect the entrapment.
Many gate operators are designed with no entrapment detection,
entrapment detection that is operable in the closing cycle only,
or entrapment detection that reverses the gate in the closing
cycle, but simply stops the gate in the opening cycle. These
type gate operators lack an adequate entrapment sensing system
and will require expensive additional add-on features to bring
the gate system up to safe operating standards. Pay special attention
to the opening cycle operation on slide gate operators. Operators
that sense an entrapment in the opening cycle, but then simply
stop the gate (rather than reversing) do not provide the necessary
safety to prevent serious accidents from happening.
Case History - California, 1996. Adult male, slide gate. An adult
mail reached through a slide gate to activate it. When the gate
started in the opening cycle, the man's jacket became entangled
in the gate and began to choke him and cut off his air supply.
The gate operator sensed this entrapment and then simply shut-off
(as it was designed to do). The man remained trapped with his air
supply cut-off. When a deputy sheriff arrived, the man had no pulse
or respiration. Using a knife, the deputy cut the mans jacket off
to free him and started CPR. The gentleman did survive this close
call. The point here is that had the operator been designed to
reverse the gate upon sensing the entrapment, the accident may
never have happened.
Manual (Emergency) Release Mechanism
Once an automated vehicular gate operator is installed on a gate
on your property, you must assume that at some point in time
the operator will fail to open because of a power outage. Gate
operators must have a provision to allow access from the outside
of the property in, and egress from the inside of the property
out, during these power failures. If you are a homeowner, there
is nothing more frustrating than not being able to exit your
property , or not being able to get into your property, because
your automatic gate won't open. For property managers, this can
become a nightmare with a long line a tenants in their vehicles
blocking lanes because the gate won't open. Let's take this one
step further. During fires or natural disasters (like an earthquake),
power to a property is often cut-off. Now the critical issue
becomes how do emergency vehicles enter the property, or how
do people exit the property, if there is no power? The answer
to the above dilemma is to use (in general access applications)
gate operators that employ a Fail-Safe release system. Simply
stated, during power outages, these operators fail in a safe
condition allowing the gate to be pushed open without the need
of any mechanical device, keys, or cranks. Many Fire Department
regulations require that fail-safe gate operators be installed
to allow emergency vehicle access during power outages. In Los
Angeles, California for example, the Fire Department requirement
for power operated gates specifically states: In the event of
a power failure, the gate/gates shall automatically open, or
the gate must be capable of being pushed open without additional
steps having to be performed. In Orange County (CA.), Fire Department
Requirements state: The design and operation of all electrically
operated gates shall be as follows: The gate control shall be
operable by an approved emergency override key switch which is
an integral part of the mechanism. In the event of a power failure,
the gate shall automatically transfer to a fail-safe mode allowing
the gate to be pushed open without the use of special knowledge
or any equipment."
Case History - California, 1994. The Northridge Earthquake. The
6.6 earthquake that struck Southern California on January 17, 1994
disrupted power, gas, and water services to thousands of residents
and commercial customers for days following the quake. To make
matters worse, many residents of apartment buildings and gated
communities found that they could not evacuate their vehicles from
secured parking areas. Without power, gate operators on the access
gates were all locked shut. In the hours after the quake, release
keys, handles, cranks, and other items intended to release the
gate in just such an emergency could not be found. And because
the quake was in the early morning hours, maintenance and management
personnel were not immediately available. One gate operator service
company described residents in a panic because they could not get
their vehicles out of the parking area. Other gates were simply
run down to get them open. However, gates that had operators designed
with a Fail-Safe release system where simply pushed open and residents
were able to exit the property. One property manager stated that
his gate operator was the only thing that performed as designed
during the emergency and that the fail-safe release feature was
invaluable.
Battery Back-Up Systems
Some operators now have the option of being equipped with a battery
back-up drive system that will open the gate upon sensing a power
outage. This back-up drive system is self contained in the gate
operator, but is also completely independent from the primary
(AC) drive system. These back-up drive systems are not designed
to maintain normal gate operation during a power failure, rather
they are designed to automatically open the gate so that the
traffic lane (driveway) is not blocked - a convenience factor
really. Battery back-up systems are especially useful in gated
communities and apartment applications. When a power failure
occurs, the gates automatically open thus allowing residents
to enter and exit the property without the need of waiting for
maintenance or management personnel to release the gate.
It should be noted that gate operators equipped with battery back-up
systems generally do not relieve you of the fail-safe release requirement
that some Fire Departments may have. When it comes to blocking
emergency vehicle access lanes (gates), Fire Marshall's will assume
the worse case - there is a power failure and the batteries in
the back-up system are dead. The question that is put to you is:
My truck is on the outside, now how do I get in?
Laboratory Listing
Be sure that the gate operator manufacturer has had the product
tested and that it is listed by a Nationally Recognized Test
Laboratory (NRTL). These products will have the UL, ETL, or one
of the other approved laboratory seals on their housing. The
two most recognized listings are U.L. (Underwriters Laboratories)
and ETL (Electrical Testing Laboratories). Many city building
codes require that the products installed be recognized by an
approved testing laboratory. This insures that the product has
been tested in accordance with established test procedures and
that the product conforms to certain safety standards. Failure
to comply with the local building code can be cause for the operator
to be red tagged requiring it to be removed and replaced with
a product that has been listed.
Operating Control Location
Proper location of the gate access device (keypad, push button,
card reader, telephone entry system, etc.) is one of the easiest
ways to prevent accidents from happening. Improperly placed controls
can cause tragic accidents. It is CRITICAL that all gate control
devices be located in such a way that a person using the device
cannot touch the gate or gate operator while using the device.
It is especially important that the control be located so that
persons using it cannot reach through a gate to activate the
unit. A general rule of thumb is to not install any gate operating
control device closer than 10 feet to the gate. Any gate control
that is closer than 10 feet to the gate should be disconnected
and removed from service immediately.
Case History - California, Adolescent female, slide gate. A young
girl was going to a friends house to baby-sit. She reached through
the gate to activate a switch on the inside of the gate. When the
gate started, she was pulled into the gate pocket. The child died
of asphyxiation. If the gate activation switch was not located
where it was accessible from the outside, the child would not have
had the opportunity to reach through the gate to activate it.
Pedestrian Gates
One of the hazards of automated vehicular gates is that everyone
seems to want to use the vehicular gate and traffic lane as a
pedestrian walk way. This creates two hazards. First, pedestrians
are in the traffic lane which in and of itself is a hazard. Secondly,
vehicular gate operators are not designed for use in pedestrian
traffic applications and should never be used as a means to control
pedestrian traffic. We recommend that whenever a vehicular gate
system is designed or installed, provisions should be made for
a pedestrian walk gate to keep pedestrian traffic out of the
traffic lanes and away from the gate system.
Case History - Adult male, slide gate. An adult male was on the
inside of his gated community and had walked to the vehicular gate
system where he was to be picked up by a friend. When his friend
arrived, he climbed the gate to exit the property and fell off
of the gate during his attempt. The gentleman has suffered severe
and permanent damage because of his fall - according to his lawyer.
There was no provision in the gate system to allow pedestrian entry
and exit.
Vehicular Safety
In addition to the issues addressed above, designers and installers
of vehicular gate systems must also make provisions for vehicular
traffic safety. The accepted method to provide a safe operating
environment for vehicular traffic is the use of a loop detection
system and the installation of strategically placed ground loops.
In addition to the loop system, speed bumps should also be considered
to slow traffic through the gate system. There is no need for
vehicles to be speeding through the system or for trying to beat
the gate. Many gates that have hit a vehicle are actually the
result of a speeding car trying to beat the gate system and striking
the gate. Speed bumps are a method to decrease and/or eliminate
this problem.
Summary
Be sure the gate operator is designed with an inherent entrapment
sensing system that is operable in both the open and close cycles
of gate travel, and that the system will reverse the gate travel
in either direction. Be sure the operator is equipped with a
manual release system that will allow the gate to be pushed open
during power outages. Fail-safe release systems are the preferred
method. Be sure that the gate system will allow emergency vehicle
access during both modes of operation - power available and power
not available. In the case of a power failure, the gate must
be able to be opened from the outside without any special tools
to allow these vehicles entry. Battery back-up systems in gate
operators can be useful - but a release method must still be
provided with the gate operator when the battery system fails.
Never install any gate activation device in such a manner that
the gate or gate operator can be touched while using the device.
Access control devices should be a minimum of 10 feet away from
the gate. Install a pedestrian access gate to keep pedestrians
out of the traffic lane. Be sure that the ground loops in the
loop detection system are properly placed and installed. Consider
installing speed bumps in the traffic lanes to prevent vehicles
from speeding through the lanes and hitting gates. |