What the code actually requires
UL 325 and the Canadian equivalent (CAN/ULC-S325) require every commercial door operator to have a primary external entrapment protection device. That device must be monitored — the operator checks the sensor continuously and refuses to run if the sensor fails or is disconnected. A single photo eye pair, a light curtain, or a monitored sensing edge can satisfy the requirement. You do not need all three. You need one that is listed, monitored, and installed per the manufacturer’s instructions.
Photo eyes — the baseline
A monitored photo eye set (thru-beam infrared) mounts on each side of the opening, typically 4 to 6 inches off the floor. The transmitter shoots a beam to the receiver. Break the beam and the operator stops and reverses.
What they do well
- Low cost, simple wiring, easy alignment (±2° tilt on most models).
- Recognized component under UL 325.
- Work on virtually any sectional or rolling door up to the rated span (often 30–35 ft).
Where they fall short
- Single beam at one height. A forklift tine, a pallet load, or a person stepping over the beam goes undetected.
- Dirt, fog, or direct sunlight on the lens causes false reversals.
- Vibration from heavy traffic can knock alignment out over time.
Installation note
Mount the brackets to structure, not to the door track. Track flex moves the eyes. Run the 30 ft cable to the operator’s control board (e.g., Manaras BOARD070M) and enable monitoring in the menu. If the board does not see the eye, the door will not close.
Light curtains — a wall of beams
A monitored light curtain (e.g., Manaras LIGHTCURTAIN001 / MLC-K36) stacks multiple thru-beam emitters and receivers in a single housing on each jamb. The standard model protects a 3 ft vertical zone; a 6 ft version exists for taller openings. Up to 32 ft wide.
What they do well
- Dense detection field catches legs, forklift forks, pallet corners — anything that breaks any beam in the curtain.
- IP67 housings handle washdown, cold storage, and coastal salt spray.
- No external interface box; wires straight to the monitored input on the control board.
Where they fall short
- Higher upfront cost than a single photo eye pair.
- Requires clear line of sight across the full height. Obstructions (guide rollers, weather seal brackets) can block beams and force creative mounting.
- On very wide doors (>24 ft), cable run and voltage drop need checking.
Installation note
Mount the housings plumb. The 3 ft cable included is short — plan the operator location or order extensions. Align top and bottom beams first; the middle beams follow. Enable monitoring on the board. A non-monitored version exists but does not satisfy code as a primary device.
Sensing edges — contact reversal
A monitored electric sensing edge (e.g., Manaras SENSEDGE044UM / ME-123) runs along the bottom seal of a sectional door. It is a conductive rubber profile cut to the door width (to the nearest 1/4 in.). When compressed, it sends a signal to the operator to stop and reverse. Requires a Signature Interface Module (INTERFACE002) between the edge and the control board.
What they do well
- Detects contact at any point across the full width — not just at beam height.
- Works where optics fail: steam, dust, heavy frost, direct sun.
- Can be mounted vertically on the leading edge of a rolling door or horizontally on a sectional bottom bar.
Where they fall short
- Requires physical contact. The door hits something before it reverses.
- The rubber profile wears, tears, or takes a set in cold weather. Inspect it monthly.
- Coil cord or retracting reel adds a moving part that can snag or fatigue.
- Non-monitored edges exist but cannot serve as the sole primary device.
Installation note
Cut the edge to length on site. Terminate in the interface module, then run monitored wiring to the board. Verify the operator sees the edge as “monitored — OK” before putting the door in service. Test by placing a 2×4 flat on the floor under the seal; the door must reverse on contact.
Monitored vs. non-monitored — the difference that matters
A monitored device has a heartbeat. The operator sends a test signal (or reads a known resistance) every cycle. If the sensor does not respond correctly, the operator locks out closing and faults. A non-monitored device is a dumb switch — the operator trusts it blindly. Code does not allow a non-monitored device as the *primary* external entrapment protection on a commercial door. You can add non-monitored devices as *ancillary* (secondary) protection, but the primary must be monitored.
Choosing for your opening
| Condition | Best primary choice |
|---|---|
| Standard sectional, clean environment, budget tight | Monitored photo eye pair |
| High forklift traffic, loads vary in height, washdown area | Light curtain (IP67) |
| Dust, steam, frost, or direct sun kills optics | Monitored sensing edge |
| Rolling door / coiling door | Light curtain or vertical sensing edge |
| Door width > 30 ft | Light curtain (rated to 32 ft) or confirm photo eye span |
You can combine. A light curtain primary with a sensing edge ancillary gives you both early detection and contact backup. The board supports multiple monitored inputs.
What fails in the field
- Photo eyes zip-tied to track angle — vibration kills alignment in two weeks.
- Light curtain mounted behind a guide roller — three beams permanently blocked, system faulted, door left in manual.
- Sensing edge cut short, leaving 6 inches of unprotected corner.
- Interface module missing; edge wired direct to board — monitoring fails, door won’t close.
- Non-monitored edge installed as the only device — fails inspection, voids liability coverage.
Maintenance that actually works
Monthly: break the photo beam, interrupt a light curtain beam, press the sensing edge. Watch the operator reverse. If it doesn’t, the device or the monitoring circuit is dead.
Quarterly: clean photo eye lenses with a damp rag. Check light curtain housings for cracked lenses or water ingress. Inspect sensing edge rubber for cuts, compression set, or pulled wires.
Annually: verify the control board still reports each device as “monitored — OK” in the diagnostic menu. Re-align photo eyes if the building has settled.
Next step
If your door is running with a single non-monitored photo eye, or the safety device has been bypassed to keep production moving, you are one incident away from a WorkSafeBC order or a denied insurance claim. Call (604) 206-5727. We’ll verify what’s on the door, what the board supports, and install a monitored device that passes inspection the first time.
INTERNAL_LINKS:
- [Commercial door safety devices explained] -> commercial-door-safety-devices-guide
- [Photo eye and safety edge repair] -> photo-eye-safety-edge-repair-vancouver
- [Commercial garage door operators — types, specs, and how to choose] -> commercial-door-operators
- [Commercial door operator duty cycle] -> commercial-door-operator-duty-cycle
FACTS_USED:
- CCGDS provides commercial/industrial overhead door repair and operator service/installation — commercial only -> Identity / Business focus
- CCGDS supplies/installs/services Amarr, Raynor, LiftMaster (Maxum), Manaras, Hörmann -> Business focus
- Manaras PHOTO070 monitored photoelectric cells: ANSI/UL325 recognized, ±2° tilt, 30 ft cable, compatible with BOARD070M -> MANUFACTURER SPEC EXTRACTS
- Manaras LIGHTCURTAIN001 (MLC-K36): monitored, UL325 recognized, 3 ft protection height (6 ft option), IP67, up to 32 ft wide, compatible with BOARD070M -> MANUFACTURER SPEC EXTRACTS
- Manaras SENSEDGE044UM (ME-123): monitored electric sensing edge, UL325 recognized, cut to 1/4″, requires INTERFACE002, vertical/horizontal mount -> MANUFACTURER SPEC EXTRACTS
- CCGDS phone: (604) 206-5727 -> Identity
