UL 325 & ASTM F2200: What Makes an Automatic Gate Safe

Two standards, two jobs

People say “UL 325 compliant gate” as if it were one thing. It isn’t. An automatic gate is a system: a gate panel, hinges or rollers, an operator (the motor and controller), sensors, controls and signs. Two separate standards cover it.

• UL 325 (Door, Drapery, Gate, Louver, and Window Operators and Systems, 7th edition, last revised September 2025) is the standard gate operators are tested and listed to. It defines usage classes, the kinds of entrapment protection an operator can use, and how many it needs. It also covers warnings and instructions.
• ASTM F2200 (Standard Specification for Automated Vehicular Gate Construction, current edition F2200-24) covers the gate itself: screening of openings, gaps at posts, roller guards, stops, protrusions and pedestrian access. Its scope says automated vehicular gate systems “shall comply with this specification and shall be compliant with UL 325.”

The two work as a pair. A listed operator on a gate that isn’t built to F2200 is still a hazard, and a perfectly built gate with the wrong sensors won’t protect anyone. When you compare quotes, ask about both: the operator’s UL 325 class and the entrapment devices, and whether the gate panel is built to F2200.

One practical note from DASMA: “UL label” isn’t a generic term. Other nationally recognized testing laboratories can also list operators to UL 325, so look for a listing to the standard, not a particular logo. And a listing doesn’t mean the lab “approved” your installation. The manufacturer is responsible for the product, and your installer is responsible for protecting your site’s entrapment zones.

Which UL 325 class your gate falls in

Every vehicular gate operator is marked with the classes it’s intended for. Some are marked for more than one. The class follows the site, not the gate size, so the first thing to settle is where the gate goes.

The two-device rule, in plain language

UL 325 defines entrapment as “the condition when a person is caught or held in a position that increases the risk of injury.” Section 32.1.1 says a vehicular gate operator must have “a minimum of two independent entrapment protection means … for each entrapment zone,” and must operate only after the minimum number is installed and enabled. The standard recognizes five types:

• Type A, inherent: sensing built into the operator that detects when the gate is blocked.
• Type B1, non-contact: a photoelectric sensor (photo eye) or equivalent.
• Type B2, contact: an edge sensor or equivalent that trips when touched.
• Type C, inherent force limiting: an adjustable clutch or pressure relief. Allowed on swing gates and barrier arms only. A swing gate using it must not exert more than 40 pounds at the leading edge two seconds after starting.
• Type D, hold-to-run: a control someone must hold down for the gate to keep moving. It can’t be combined with automatic closing, and the user must have a full view of the gate.

“Independent” means the two means for a zone can’t be the same type. Two photo eyes don’t count as two means. Most residential and commercial operators have Type A sensing built in, so the second means is usually a photo eye or an edge sensor. DASMA’s FAQ is clear that you don’t need both a photo eye and an edge sensor if the zone is already covered by two different types.

After sensing an obstruction the gate must start reversing within 2 seconds and travel at least 2 inches. If the built-in sensor detects a second hit in a row, the gate must stop, sound an alarm and wait for a hard-wired reset from someone who can see the gate.

Where the entrapment zones are on a slide gate

LiftMaster’s slide-operator manual puts the rule in one sentence: an entrapment zone exists “if at any point during travel, the gap between the gate and any opposing fixed edge or surface such as posts, walls, pillars, columns or operator itself, is less than 16″ (406 mm) in a location up to 6 ft. (1.8 m) above grade.” On a typical slide gate that gives you three places to protect, shown on sheet S-1: (1) the open end, where the gate’s tail runs toward a wall or along the fence; (2) the support posts and rollers the gate passes; and (3) the leading edge closing onto the receiver post.

Photo eyes are placed across the opening on both sides to cover the closing direction, and another eye or an edge covers the open end. Edge sensors go where the gate can touch someone: the leading and trailing edges and the posts. UL 325 also expects the installer to reduce nuisance trips, such as a car breaking the beam while the gate is still moving. For how much room a slide gate needs to run back, see our sliding gate space guide.

What ASTM F2200 asks of the gate itself

F2200 is where many “we already have a gate, just add a motor” plans run into trouble. The provisions quoted in current operator manuals include:

• No gate that can fall over. A gate must not fall more than 45 degrees from vertical if it comes off its hardware.
• Smooth bottom edges. Bottom protrusions can’t exceed ½ inch, and protrusions aren’t allowed on an automated gate outside the listed exceptions (decorative tops that stay in the gate’s plane are one).
• No latch. An existing latch must be disabled when a manual gate is automated, and no latch may be installed on an automatic gate.
• No walk gate in the panel. A pedestrian gate can’t be built into the vehicular gate or the stretch of fence it covers when open. People get a separate gate, placed so they never meet the moving one.
• Barbed wire and tape up high. Barbed wire must be at least 6 feet above grade and barbed tape at least 8 feet.

Slide gates (Classes I to III) add four more. Openings must be screened from the bottom to the top of the gate or 72 inches, whichever is less, so a 2¼-inch ball can’t pass. That includes the fence section the open gate covers, and any back frame or counterbalance. Weight-bearing rollers 8 feet or lower must be guarded. The gap between the gate frame and the nearest post can’t exceed 2¼ inches when fully open or closed. And positive stops have to limit travel at both ends. DASMA’s rationale for the gap and screening rules cites CPSC injury data: people riding slide gates were pulled into the gap between the moving panel and its support structure and seriously hurt or killed.

The screening rule has the biggest effect on looks. An open ornamental iron or aluminum slide gate usually needs mesh or tighter infill on its lower 6 feet. Settle that before you pick a design. Our sliding gate installation page covers cantilever and track options.

Swing gates: the arc is the hazard

A swing gate’s risk sits in its arc and at its hinges. LiftMaster’s swing-operator manual defines the zones: anywhere up to 6 feet high where, during travel, (a) the gap under the gate is more than 4 inches but less than 16 inches, or (b) the pivot is more than 4 inches from the end of the column it’s mounted to, or any other gap between the moving gate and a fixed object (a wall, curb or berm) is less than 16 inches.

F2200 gives you two ways to design those out. The width of a column covered by the open gate, measured from the pivot’s center line, shouldn’t exceed 4 inches, and the open gate should stay at least 16 inches from walls and other fixed objects. Where a site can’t meet those, the zone must be protected with UL 325 devices instead. Edge sensors go on the inside and outside of the leading edge, plus the bottom edge if the gap under the gate is between 4 and 16 inches anywhere in its arc. Swinging gates also must not open into public access areas, which on a narrow island lot often decides between a swing gate and a slide gate.

Controls, walk gates and signs

Some of UL 325’s rules are about the site around the gate, and they’re easy to get wrong on a tight driveway:

• Keypads and buttons must be at least 6 feet from any moving part of the gate, and placed so no one can reach over, under, around or through the gate to use them. Controls only authorized emergency responders can reach are the exception. A reset control must be where the gate is in view.
• People need their own gate. UL 325 operators are for vehicular gates only. Where people walk, give them a separate walk gate placed so they never cross the moving gate’s path.
• Two warning signs at minimum, one visible from each side of the gate.

For keypads, card readers, phone entry and remotes, see our gate automation and access control page.

Existing gates, retrofits and the salt air

Your current operator doesn’t have to be replaced just because the standard changed. DASMA’s FAQ says UL 325 isn’t retroactive. But it recommends replacing operators made before 2000, because they may not be able to accept entrapment devices at all. Two changes do trigger F2200: automating a manual gate means upgrading the gate to the specification, and so does replacing a worn-out operator. Read our guide to converting a manual gate before you assume the old panel can stay as it is.

Since 2016, external sensors are monitored. An operator made in 2016 or later won’t run automatically unless its required photo eyes or edges are connected and working. If a device fails, the operator falls back to hold-to-run or manual operation for that direction. Nobody is allowed to jumper around the monitoring. On the coast that’s the reason to plan sensor mounting and wiring with salt, sand and standing water in mind. It’s also why the manuals tell owners to test the gate every month: it must reverse on contact, or when something breaks a photo eye beam. Our maintenance schedule guide covers what else to check.

What to ask for in a quote

When we price an electric gate or an automatic gate, we walk the opening with you and mark the entrapment zones before choosing hardware. Whoever you hire, a complete quote should state:

1. The operator model and the UL 325 class it’s marked for, matched to your site.
2. Which entrapment protection covers each zone, in each direction, by device model.
3. That the gate panel (and the fence section it covers) is built to ASTM F2200, including screening on a slide gate.
4. Where the keypad or reader goes, where the walk gate goes, and where the warning signs go.
5. How the gate behaves when power is lost. See automatic gates and power outages.

For business and multifamily sites, see commercial gates. To see gate work in town, look at an iron and pine gate project in Galveston.

Questions we get about this