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Gate Operators and the ANSI/UL 325 Standard
Introduction
UL 325 is a standard for safety that addresses the automatic operation of garage doors, vehicular gates,
louvers, and windows. In this Technical Data Sheet, we will provide you with some background information
about UL, UL standards, and the requirements in UL 325 that apply to vehicular gate operators. In addition to
this Technical Data Sheet, DASMA has produced a brochure that summarizes safety issues related to
automated vehicular gates. The brochure is available on the DASMA website on the following web page:
http://www.dasma.com/pdf/publications/brochures/GateSystemsSafetyBrochure.pdf
What is UL
Underwriters Laboratories, Inc., established in 1894, is self-described as “the leading third-party certification
organization in the United States and the largest in North America.” UL’s primary stated mission is “to
evaluate products in the interest of public safety.” Note that while UL declares it is the “leading” third-party
certification organization, it is not the only one. There are other testing laboratories and certification
organizations in the United States and in many other countries.
What is a UL Standard
UL standards are voluntary standards that establish minimum requirements for a product. The standards are
developed via an open, non-exclusionary process, and they continually evolve over time. “Voluntary” means
that the standard has not been initiated through any government or similar regulatory agency mandate.
“Minimum” means that the industry and those who developed the standard believe that the requirements
should be met by all participants and products governed by the standard and that more stringent provisions
may be adopted by some in the industry. Finally, an “open, non-exclusionary process” indicates that any
interested party can participate in the development of a UL standard. In addition, a number of UL standards
have undergone a review and voting process in order to obtain additional recognition as American National
Standards.
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The purpose of this process is to gain a wider acceptance of a specific standard. The process typically
includes interested individuals and organizations that may have direct or material interest in a particular
standard. UL 325 is one of the standards that have attained the ANSI (American National Standards
Institute) designation.
What is the UL 325 Standard
For products within the scope of the standard, UL 325:
1. Contains the basic qualifying factors that products must meet in order to be documented (listed) and
marked (labeled) as complying with the requirements of the UL 325 voluntary Listing and Labeling
program;
2. Provides methods for testing products, primarily related to safety performance;
3. Covers installation of products in accordance with the National Electrical Code, which is maintained
by the National Fire Protection Association (NFPA) and is in force nationwide. UL 325 is to be
harmonized with this Code;
4. Addresses safety concerning potential fire and electrical hazards, as well as the safety of the general
public.
How is UL 325 Used
UL 325 is used as a basis to test products at a nationally recognized testing laboratory. Gate operator
manufacturers that choose to participate in a listing and labeling program submit their products for testing. If
they are found to be in compliance with the UL 325 standard, they are “Listed” and receive a “Mark.” It is
very important to remember two facts:
• There are laboratories other than UL that are capable of listing and labeling products to the UL 325
standard, including Intertek Testing Services NA, Inc., Met Laboratories, Inc., and TUV Rheinland
of North America, Inc. A “UL label” is not a generic term. For example, many people use
“Kleenex” and “Band-Aid” as generic terms when, in fact, they are specific brand names. UL is a
brand name, and “UL label” should not be used generically.
• Products are not approved by UL or other laboratories. Approval implies acceptance of
responsibility for compliance with standards. This responsibility lies with the listing and labeling
applicant and not with the laboratory. The burden of proof regarding data always lies with the
manufacturer.
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Development of UL 325
The first edition of UL 325 was released in 1973. That edition was primarily focused on the electric
operation of garage doors and did not contain provisions for gates. DASMA members of the gate operator
industry initiated the inclusion of vehicular gate operator provisions within UL 325 in the early 1990's.
Overview of UL 325 and Gates
Highlights of UL 325 include the following:
• A glossary which defines each type of operator
• Different classes of gate operators
• Entrapment* protection criteria for types of operators
• Requirements for gate construction and installation (for detailed requirements regarding
construction, see ASTM F2200, Standard Specification for Automated Vehicular Gate
Construction)
• Instructional requirements and warning requirements
*In the document, entrapment is defined as “the condition when an object is caught or held in a
position that increases the risk of injury.”
The heart of the UL 325 provisons for gate operators and entrapment protection is section 32 and tables
32.1 and 32.2. These parts of the UL 325 standard outline the options for different means of protecting
against entrapment and state the minimum quantities of entrapment protection sensors for each type of
gate operator.
Section 32.1.1 states: "A vehicular gate operator or vehicular barrier (arm) operator shall:
a. Have provisions for or be supplied with, a minimum of two independent entrapment protection means as
specified in Table 32.1 for each entrapment zone.
b. Operate only after installation and enabling of the minimum number of acceptable entrapment protection
means, as specified in Table 32.2…"
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Table 32.1
Protection against entrapment
Table 32.1 effective August 1 2018
Gate operator category
Horizontal slide, vertical lift, and vertical pivot Swing and vehicular barrier (arm)
Entrapment protection typesa Entrapment protection typesa
A, B1, B2 or D A, B1, B2, C or D
Note - The same type of device shall not be utilized for both entrapment protection means. Use of a single device to cover both the
opening and closing directions is in accordance with the requirement.
a
Entrapment protection types:
Type A - Inherent entrapment protection system. See 32.1.6.
Type B1 - Non-contact sensor (photoelectric sensor or the equivalent). See 32.1.7 - 32.1.15.
Type B2 - Contact sensor (edge device or the equivalent). See 32.1.8 and 32.1.17 - 32.1.19.
Type C - Inherent force limiting, inherent adjustable clutch or inherent pressure relief device. See 32.1.21 and 32.2.1.1 (b) .
Type D - Actuating device requiring continuous pressure to maintain opening or closing motion of the gate. See 32.1.22 and
32.1.23.
This table is reprinted from the 7th edition of UL 325 and is reprinted with the permission of Underwriters Laboratories, Inc.
Table 32.2
Minimum quantity of entrapment protection means
Added Table 32.2 effective August 1, 2018
Opening Closing
Horizontal Slide Gate 2 2
Horizontal Swing Gate 2* 2*
Vertical Pivot Gate 2 2
Vertical Lift Gate 1 2
*For a horizontal swing gate operator, at least two independent entrapment
protection means are required in each direction of travel. Except, if there is
no entrapment zone in one direction of travel, only one means of entrapment
protection is required in that direction of travel; however, the other direction
must have two independent entrapment protection means.
This table is reprinted from the 7th edition of UL 325 and is reprinted with the permission of Underwriters Laboratories, Inc.
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Gate Definition and Types
UL 325 defines a gate as “a moving barrier such as a swinging, sliding, raising, lowering, rolling, or the like,
barrier that is a stand-alone passage barrier or is that portion of a wall or fence system that controls entrance
and/or egress by persons or vehicles and completes the perimeter of a defined area.” The main types of gate
operators/systems addressed in UL 325 are barrier, vertical pivot gate, horizontal slide gate, swing gate, and
vertical lift gate. It is important to note that all gate operators included in UL 325 are defined to be used with
vehicular gates and NOT PEDESTRIAN GATES. Property owners must provide a separate entrance for
pedestrian access because pedestrian gates provide a safe way for pedestrians to enter or exit a property and
help to keep people away from vehicles and automatic vehicular gate systems.
Gate Operator Classifications
Four distinct types of classifications have been established:
• Class I: "A vehicular gate operator (or system) intended for use in garages or parking areas associated
with a residence of one-to four single families."
• Class II: " Avehicular gate operator (or system) intended for use in a commercial location or
building such as a multi-family housing unit (five or more single family units), hotel, garages,
retail store, or other buildings accessible by or servicing the general public."
• Class III: "A vehicular gate operator (or system) intended for use in an industrial location or
building such as a factory or loading dock area or other locations not accessible by or intended to
service the general public."
• Class IV: "A vehicular gate operator (or system) intended for use in a guarded industrial location
or building such as an airport security area or other restricted access locations not servicing the
general public, in which unauthorized access is prevented via supervision by security personnel."
Provisions of Note Regarding Gate Operators
We have identified the following notable provisions included in UL 325 that are relevant to gate operators
and related entrapment protection devices.
1. For MOST installations, at least 2 independent means of protecting against entrapment are
required in each direction of travel. For ALL installations, at least 2 independent means of
protecting against entrapment are required in each direction WHERE THERE IS A RISK OF
ENTRAPMENT.
2. ALL external means of protecting against entrapment must be monitored.
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3. Slide gate operators for Classes I and II, and vertical lift-gate operators shall not exceed a speed
of 1 foot per second when the operator is pulling 75 pounds or more.
4. Manufacturers will be required to specify a brand and model number of external sensors
compatible for connection to an operator. This provision arose from concern over the gate
operator and external devices acting in tandem as a system, with a maximum allowable fault rate
of 6 failures in 1 million hours of use (which equates to 115 years of continuous operation).
5. After sensing an obstruction, reversing must begin within 2 seconds. This requirement is intended
to keep a person from being entrapped in a stationary position by the gate system. After the first
contact the gate must reverse and travel a minimum of 2 inches. If a second contact is detected by
a Type A device (inherent sensor), the gate must stop only and not reverse. If a second contact is
detected by Type B1 or B2 device (photoelectric sensor or edge sensor), the gate must stop but
may also reverse.
6. After any obstruction stop or reversal by either an A or B2 device, the timer-to-close is disabled
until reset. Both A and B2 devices sense direct gate contact with an obstruction, and the devices
must perform their intended function without interference from a timer-to-close action.
7. A Type A (inherent sensor) must stop the gate upon sensing a second sequential obstruction, must
activate an audio entrapmetn alearm, and must not operate until an intended hard wired input is
received. A person within the line of sight of the gate must see what has caused the second
sequential obstruction and must resolve this obstruction before operating the gate.
8. If a Type C device is chosen, swing gates must not exert more than 40 pounds of force at the
leading edge of the shortest recommended gate length, two seconds after initial start-up.
Installation Effects
The UL 325 gate operator provisions have an effect on gate and fence dealers:
1. Gate and fence dealers should look for an indication of the class of each operator, which will be
specified by the gate operator manufacturer.
2. Fence dealer sales personnel must match the site application with the class of operator. The gate
operator manufacturer should be contacted if there is any question about the site application.
3. Ensure that all potential entrapment zones are protected as required in Tables 32.1 and 32.2, which
must be described in the instruction manual for the gate operator. For most automatic gates,
external entrapment protection sensors will be required. The expertise of dealers is required to
apply the provisions of the standard to the wide variety of site specific conditions that are
encountered in the field.
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4. The gate operator manufacturer will provide extensive guidance and instructions which must be
followed at all times. Any questions should be directed to the gate operator manufacturer.
5. A minimum of two (2) warning signs must be displayed in the area of the gate. UL 325 includes
specific requirements on the format, content, and placement of these signs.
Factors Related to Automatic Gate Construction and Installation
• Vehicular gate operators can ONLY be used on vehicular gates and never pedestrian gates.
• A separate pedestrian gate must be provided for all sites where pedestrain access is likely.
• The design and construction of all automatic gates and the adjacent fence must conform to ASTM
F2200.
• Adequate clearance should be provided between a swinging gate and adjacent structures to reduce
risk of entrapment.
• A sliding gate should work smoothly with easy rolling/movement in both directions prior to the
installation of the operator.
• All gate activation controls should be as far away from the gate as possible and must be at least 6
feet from the gate to reduce the opportunity for “reach-through” injury.
• Warning signs and placards must be installed and be must visible in the area of the gate opening
from both sides of the gate.
• See DASMA TDS-370 and ASTM F2200, Standard Specification for Automated Vehicular Gate
Construction for information about gate construction.
Device-Specific Installation Instructions
There are also specific installation requirements for each type of external entrapment protection sensor.
These specific requirements emphasize the care and attention that each device must be given prior to and
during installation.
All external entrapment protection sensors must be monitored, and the operator must verify the presence
of every device at least once during each open and close cycle. According to the standard, "Upon
monitoring, should any device not be present, or a fault condition occur that precludes the sensing of an
obstruction, including an interruption of the wireless signal to the wireless device or an open or short
circuit in the wiring that connects the external entrapment device to the operator and the device’s supply
source, the operator shall function with constant pressure…for the direction of travel being protected, or
shall only be able to be moved manually…."
There shall be no modification made in the field to bypass, interfere with, or otherwise defeat the monitoring
function by adding, suppressing, or changing, either on the operator or on external entrapment protection
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device(s) by the connection of wires; terminals; switches; jumpers; or components supplied with the operator or
with the external entrapment protection device.
For gate operators utilizing non-contact sensor devices (Type B1), instructions should be consulted for
placement for each application and care should be exercised to reduce the risk of nuisance tripping. One
or more of these devices must be installed in all potential entrapment zones.
For gate operators utilizing contact sensor devices (Type B2), several requirements are spelled out in UL
325. One or more contact sensors shall be located in all potential entrapment zones.
A wired contact sensor shall be located, and its wiring arranged, so that communication between the
sensor and the gate operator is not subjected to mechanical damage. A wireless contact sensor shall be
located where the transmission of the signals is not obstructed or impeded by building structures, natural
landscaping, or similar obstructions, and shall function under the intended end use conditions.
For gate operators utilizing a continuous pressure activating device (Type D), controls must be placed so
that a user has full view of the gate area when the gate is moving. A placard must be placed adjacent to
the controls, and no other activation device shall be connected. Most importantly, an automatic closing
device shall not be employed.
Statements in Manufacturer’s Instructions Concerning Installation
Gate and fence dealers can expect to see detailed information regardign compliance with the UL 325
standard in gate operator instruction manuals. It is essential that dealers and installers follow all
instructions provided by the operator manufacturer.
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