Mag Lock Request on the Only Egress Door
A 12-unit residential building has one stairwell door serving as the only egress from the common corridor to the street. The owner's contractor asks you to fit a 600 lb electromagnetic lock released only by a card reader on the secure side, with no request-to-exit device and no link to the building fire alarm, because "the panel is old and the budget is gone." The nearest manual pull station is 18 m away in the lobby. Power would come from a 24 V supply plugged into a corridor receptacle. The contractor adds that residents already tailgate through the door, so "security is the priority." The building is occupied and the corridor is the sole path out for six apartments.
1. Assess the requested arrangement. Which elements make it non-compliant, and what is the underlying principle?
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- The door is the only means of egress for six apartments. Egress must remain available at all times without special knowledge, keys, or tools.
- A card-reader-only release requires a credential to leave the building - that alone is disqualifying on an egress door.
- No request-to-exit sensor or manual release removes the secondary release path that magnetic locks depend on.
- No fire alarm release means the lock holds during an evacuation, exactly when free egress matters most.
- The 24 V supply on a corridor receptacle gives no standby power; a power failure could leave the lock in whatever state the hardware defaults to, with no supervision.
- The 18 m distance to the nearest pull station does not compensate - release must be automatic and local to the door.
Underlying principle: life safety outranks property security. Access control may restrict entry; it may never restrict exit.
2. Give two compliant alternatives with the trade-offs, and state what you would say to the contractor.
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Option A - electric strike or electrified exit hardware with free mechanical egress.
- Leaving always operates the latch mechanically; the reader controls entry only.
- Lower cost, no release devices to maintain, no fire alarm interface needed for egress.
- Trade-off: weaker against tailgating and physical force than a mag lock.
Option B - magnetic lock with a full release package.
- Listed request-to-exit sensor plus a manual release at the door, released automatically by the fire alarm, powered from a supervised supply with battery standby.
- Trade-off: higher cost, more devices to test and document, and the fire alarm interface must actually work - the "old panel" objection is an integration task, not a reason to omit it.
Message to the contractor: the tailgating complaint is real but is solved with anti-passback, door position monitoring, or a vestibule - not by trapping occupants. I would put the refusal and the alternatives in writing so the decision is recorded.
3. You install Option B. What must be verified and documented before the door is put back into service?
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- Door releases on every release path: card, request-to-exit sensor, manual release, fire alarm activation, and loss of power.
- Measure and record the release time and confirm the lock drops with the door in the closed position.
- Confirm the supply supervises battery condition and reports trouble to the panel or local annunciator.
- Verify free egress with the door under normal use, not just from the reader side.
- Record results on a test sheet, update the as-built with device locations and the fire alarm interface point, and label the release devices.
- Brief building management in writing that the door now releases on fire alarm and that the release devices must not be obstructed.
Reasoning: a mag lock is only as good as its weakest release path. Each path is tested individually because a single failed release device is invisible until an emergency.