Maglock or Electric Strike? Fire Code, Egress and What NYC Allows

Two devices, two completely different sets of obligations. Most of the bad access control work we are called to correct in New York comes from treating them as interchangeable, and almost all of the dangerous work comes from putting a magnetic lock on a door where the code required a latch.

The two devices, physically

An electric strike replaces the keeper, the part in the frame that the latch bolt drops into. The door keeps its normal lock and its normal latch. When the strike is released, the keeper swings out of the way and the latch bolt slides past it. The door was latched before and it will latch again when it closes. The strike is not the lock; it is a controllable hole in the frame.

A magnetic lock is an electromagnet bolted to the frame head with a steel armature plate on the door, holding by direct magnetic attraction at 600 or 1,200 pounds of force. There is no latch. Nothing mechanical engages. The door is held closed only while current is flowing, and the moment power stops the door is free.

That last sentence is the entire code argument, in both directions.

Fail-safe and fail-secure

Fail-safe means power off equals unlocked. Fail-secure means power off equals locked. Electric strikes are made in both flavors and you specify which one you want. Magnetic locks are fail-safe by physics. There is no such thing as a fail-secure maglock.

The critical qualifier that gets lost: these terms describe the secure side of the door only. The egress side must always allow free mechanical exit, by lever or push bar, regardless of the power state and regardless of which device is fitted. If leaving a building ever requires a key, a code, a credential or electricity, the arrangement is wrong before you even get to the section numbers.

Where the law makes the choice for you

Fire-rated door assemblies must be fail-secure

Electric strikes and electrified locks on fire-rated assemblies have to be fail-secure and listed for use on those assemblies. The reason is structural, not electrical: a rated door contains smoke and fire by staying positively latched. A fail-safe device would unlatch the door on power loss, which is precisely when the fire is, and the assembly stops performing.

The corollary is the one worth writing on a wall: a magnetic lock cannot serve as the latching means on a fire-rated door, because a magnetic lock does not latch at all. A rated stair door held only by a maglock is not a code interpretation question. It is a rated assembly with no latch.

Field modification of a rated assembly is also tightly limited: broadly, undercutting of wood doors, mortise lock holes, viewer holes and small round holes. Cutting a frame to fit a strike that was not intended for it can void the label, and re-labeling means bringing in the listing agency.

Some doors must be fail-safe

Magnetic locks always. Delayed egress hardware. Elevator lobby locks. Stairwell re-entry locking. In each of those cases the code requires that loss of power results in an unlocked door, which is why on those doors the specification and the battery calculation look completely different.

Sensor release: what NYC Building Code §1010.1.9.8 actually requires

This is the section that governs the classic magnetic lock installation on a required egress door, and it is a list of conditions that all have to be satisfied at once. It applies in any occupancy except Group H. Every one of these is a separate line item on a real installation:

• A sensor on the egress side arranged to detect an approaching occupant and unlock the door. That is the overhead request-to-exit motion sensor.
• Loss of power to the sensor or to the locking system unlocks the door. Not one or the other. Either failure unlocks.
• A manual unlocking device mounted 40 to 48 inches above the floor and within 5 feet of the door, which causes direct interruption of power to the lock (independent of the controller, the software and everything else) and holds the door unlocked for a minimum of 30 seconds.
• That device must be signed PUSH TO EXIT. Signed, not implied.
• Fire alarm activation unlocks the doors, and they stay unlocked until the fire alarm system is manually reset.
• Sprinkler activation or automatic fire detection activation unlocks the doors, again until reset.
• Emergency lighting on the egress side.
• The locking system units listed to UL 294.

Read that list against the next maglock you walk past. The most commonly missing items, in our experience, are the direct-interrupt wiring on the push-to-exit button (it is very often wired as an input to the access controller instead, which is not a direct interruption of power and does not satisfy the section) and the 30-second hold, which is frequently set to a two-second pulse because that is the controller default.

There is a second code path worth knowing about: door hardware release, where the release switch lives inside the lever, the panic bar or a touch-sense bar and directly cuts power when someone operates the hardware. It requires fewer ancillary devices than the sensor path, which is often what makes it the cleaner design where the door will accept it. Where panic hardware is required, its operation has to release the lock.

Delayed egress: NYC Building Code §1010.1.9.7

Delayed egress is not a way to keep a door locked. It is a permitted 15-second pause, and it comes with prerequisites:

• The building must be equipped throughout with an automatic sprinkler system, or an approved automatic smoke or heat detection system. No sprinklers and no detection means no delayed egress, full stop.
• An irreversible release process starts when a force of not more than 15 pounds is applied for up to 3 seconds.
• Egress is delayed 15 seconds, or 30 seconds where specifically approved.
• The delay electronics must deactivate (permitting immediate free egress) on sprinkler activation, on fire detection activation, and on loss of power.
• Signage is required, and re-arming is manual.
• The egress path from any point must not pass through more than one delayed egress locking system.

New York additionally conditions delayed egress on special review and approval for spaces where extra safeguards are required. If a vendor proposes delayed egress on a retail back door in an unsprinklered building because of shrinkage, the answer is no, and the reason is not our preference.

Day two: NYC Fire Code §1027.3.1

Egress hardware and the physical components of the means of egress must be maintained in good working order at all times. That is a continuing obligation, not a commissioning test.

What it means in a building: the push-to-exit button that was tested at handover and later painted over is a violation. So is the sensor that has been taped over because it kept unlocking the door for people walking past. So is the exit device that has been chained after hours. That is both a violation and, in the scenario the rule exists for, the reason people do not get out. A door that needs securing overnight needs a compliant locking arrangement, not a chain.

Who signs off

Be clear about this before anybody buys hardware: special locking arrangements on required egress doors require the authority having jurisdiction to sign off. Depending on the occupancy and the scope, that can mean a DOB filing where the work constitutes an alteration, and fire department review for certain occupancies.

We design and install to the section the door has to meet, we provide the documentation, and we coordinate. We do not tell clients we can guarantee an approval, because the AHJ decides and no contractor gets to promise otherwise. Where a filing is required, it belongs to the design professional of record, and it needs to be in the project plan at the start rather than discovered at inspection.

The fire alarm interface, and where our scope ends

Every electrified lock in an egress path has to release on fire alarm activation, and that interface has to be tested. It is also the point where our work stops and someone else’s begins.

We do not work on fire alarm panels. Fire alarm work in New York City requires credentials we do not hold and would not pretend to. Where an access control system needs a release signal from the fire alarm system, we coordinate with the building’s licensed fire alarm contractor, they provide the interface from their panel, and we terminate it on our side.

On our side, though, there is a detail that gets missed constantly and matters enormously. Access control power supplies have a fire alarm control panel input that drops outputs on alarm, and on any competent supply the disconnect is individually selectable per output. That selectivity is the whole point:

• The magnetic locks on the stair doors and the elevator lobby doors must drop on alarm.
• The fail-secure strikes on the fire-rated doors must not. Releasing them would unlatch rated assemblies during a fire.

Get that mapping backwards and you have created a code violation and a security hole in the same afternoon. This is a per-output decision that belongs in a written schedule at design time, with each door listed by name against its behavior on alarm, and it should be verified physically at the annual test rather than assumed from the drawing.

The engineering comparison, once the code has had its say

Frame and door condition

A magnetic lock needs a rigid frame head. Mounted on a flexing aluminum storefront header, it will chatter, lose contact under wind load and eventually work its fasteners loose. An electric strike needs frame depth: aluminum storefront jambs are frequently only about 1.75 to 2 inches deep and may not accept a standard strike body at all, especially where there are sidelites. Hollow metal frames are often grout or plaster filled and need a die grinder and a cut-off wheel to prep. Wood frames need wood-specific bodies and usually anchoring back to a stud.

That is the honest answer to why maglocks exist on so many glass entrances in New York: not because they are better, but because there is nowhere to put a strike.

The deadlatch detail

On a cylindrical lock, the small secondary plunger beside the main latch bolt, the deadlatch finger, must land on the face of the strike, not fall into the pocket. If it drops into the cutout, the latch is no longer deadlocked and the door can be shimmed open with a card. It is a quarter-inch of geometry and it is the difference between a secured door and a decorative one. Mortise locks are harder again, because the latch centerline sits at a different height and an extended faceplate is usually needed to cover the shift.

Exit devices

Rim exit devices need a strike matched to the bolt style. Vertical rod devices are a known problem: electrifying only the top latch leaves the door held at a single point, and over a few thousand cycles the leaf warps. Narrow-stile deadbolts generally have to be swapped for a latch lock before they can be electrified at all.

Duty rating and cycle life

Specify continuous duty anywhere the door is held unlocked for scheduled periods: a lobby unlocked from 8 a.m. to 6 p.m., for instance. Intermittent-duty units in that role burn out, sometimes within a season. Strike hardware spans roughly $45 to $350, and the bottom of that band is often rated for something like ten cycles a day. On a busy residential lobby door that is a few weeks of normal use, which is why the cheapest strike is reliably the most expensive one.

Power, batteries and the 3 a.m. failure

This is where maglocks cost real money and nobody mentions it at quote stage: a magnetic lock draws current continuously, because it is energized whenever the door is locked. A fail-secure strike only draws during the unlock pulse. A building with eight maglocks has a dramatically larger standby battery requirement than the same building with eight strikes, and it will notice during a power outage.

Size supplies to the total inrush plus 25 percent: four strikes at 0.25 amps each is 1.0 amp, so specify at least 1.25 amps. And know the failure signature of an aging battery string: access power supplies disconnect their DC outputs when battery voltage falls to roughly 70 to 75 percent of nominal, which is why a building with tired batteries sees doors “randomly” dropping offline at night long before the batteries are actually flat.

Door position, and knowing what your doors are doing

Neither device tells you anything without a door position switch. Without one you cannot generate a door-forced-open alarm, cannot generate a door-held-open alarm, cannot verify the strike actually relatched, and cannot correlate a credential read against a door that opened. The most common finding on buildings that believe they have access control is that no door in the building has a position switch, and consequently nobody knew the service door had been propped for six months.

The buzz

An AC strike buzzes because the plunger oscillates at 60 hertz; a DC strike is silent. In older buildings the buzz is useful. It is how a visitor knows the door is open right now. In a renovated lobby it is a complaint. A DC strike fed AC will not release, and an AC strike fed DC overheats, so the substitution is not free either way. Decide deliberately and tell the residents before the work, not after.

Which door gets which

Three things we will not do

• Install a magnetic lock on a required egress door without the complete release package: sensor, direct-interrupt push-to-exit button with signage at the specified height and distance, alarm and sprinkler release, emergency lighting, listed equipment.
• Lock a required exit door in any way that requires special knowledge, a key, a code or a credential to leave.
• Specify delayed egress in a building that has neither sprinklers throughout nor approved detection.

Those are not house rules. They are the reason the sections exist, and the AHJ will reach the same conclusion at inspection, just later and more expensively.

One more item for the plan: signal wiring under 50 volts is exempt from the electrical permit requirement under NYC Admin Code §28-105.4.7, but one of that section’s four exceptions covers the point of connection to a control circuit that activates light, heat or power. The 120-volt feed for the access power supply is licensed electrical work, and it belongs in the scope by name.

If you are specifying doors now: access control installation, or read what MDL §50-a requires of an entrance door if this is a residential building.