A 22-storey office tower in Manila ordered 38 card access control doors with 280 kg electromagnetic locks, all mounted on 4 mm aluminium-framed glass. Six of them failed the holding test on the first night: the armature plate flexed with the frame, and the effective force was closer to 90 kg. The locks were fine. The doors were not.
That order went out with a reader model, a card type and a lock part number on it. It had nothing about the door itself, which is where card access control doors are actually decided.
Start With the Door, Not the Reader
Most card access control doors fail at the frame, not at the reader. Before anyone quotes hardware, three facts about the door decide what will work:
- Frame material and thickness. Steel takes a maglock directly. Aluminium storefront and glass need a bracket, and the bracket has to be anchored into structure, not cladding.
- Leaf weight and swing. Heavy timber and steel doors need an electric strike or electromechanical lock; a maglock on a warped leaf will hold on the bench and fail on the door.
- Whether the door is on an escape route. That single question changes the lock type, the wiring and the fire approval.
Ask what the card access control doors are expected to do in a power cut and in a fire alarm. If the answer is vague, the specification is already wrong.
Four Layers You Are Actually Buying
Four layers sit behind most card access control doors, and they are usually quoted by four different suppliers:
- Reader. 125 kHz, 13.56 MHz, dual-band or biometric. Decides which cards work and how far the user stands.
- Controller. One per door or one per four doors, holding the user list, time zones and event log. Decides what happens after the reader reads.
- Lock. Maglock, electric strike, electromechanical lock or bolt. Decides whether the door physically opens.
- Exit and monitoring. Request-to-exit sensor, push button, door position switch, and the alarm relay that releases the lock.
A cheap reader on a good controller with the wrong lock is a callback. A good lock with no door position switch is a silent failure: the system believes the door is closed when it is not.
Fail-Safe or Fail-Secure
Fail-safe and fail-secure describe what card access control doors do when power drops. Fail-safe unlocks. Fail-secure stays locked.
The default in most commercial buildings is fail-safe on escape routes, because people have to get out without a key. Ask the fire consultant before you fix the fail state on card access control doors. It is a code question, not a preference. Fail-secure belongs on server rooms, cash offices and storage holding controlled goods, and even there the egress side usually needs a mechanical override.
A distribution centre in Nairobi specified fail-secure on all 120 doors because the security team wanted nothing open at night. The fire inspection failed 26 of them: those doors sat on escape routes. Retrofitting strikes, request-to-exit sensors and alarm relays cost more than the original lock package.
Cards and Fobs That Match the Reader
Cards and fobs are the cheapest part of card access control doors, and the most political. Three families cover most projects:
- 125 kHz read-only, EM4100 and compatible. Cheap, long range, no encryption, easy to clone.
- 13.56 MHz MIFARE Classic. Sector-based, widely used for printing and campus cards, also cloneable if keys leak.
- 13.56 MHz DESFire EV2 or EV3, and HID iCLASS. AES-based, used where the card carries payment or identity value.
Mixing families on one door needs a dual-band reader, and dual-band does not fix format. A reader that lists MIFARE and EM does not accept a DESFire card unless the controller and the encoding match. Check the exact chip family, not the frequency.
Power, Cable and Lock Force
Power is the quiet failure mode on card access control doors. A 12 V maglock draws 0.5 to 0.8 A at hold, and the inrush is higher. Twenty doors on one 5 A supply will work on the bench and drop out at 2 a.m.
Two numbers to put in the specification:
- Cable. 18 AWG is fine to about 30 m for a single lock circuit. Beyond that, voltage drop at 12 V eats the holding force.
- Lock force. The rated number assumes a clean, flat armature contact on rigid steel. On a flexing frame, expect 30 to 50 percent of the rating, and design the bracket before the lock.
Outdoor doors also need IP65 readers and a tamper contact, or the first rainy season becomes a service contract. Most callbacks on card access control doors trace back to supply and cable, not to the reader.
What to Put in the Specification
A specification for card access control doors should fit on one page, and it should survive a change of installer:
- Door schedule with frame material, leaf weight, and whether the door is on an escape route.
- Reader family and chip model, plus the encoding format and who encodes the cards.
- Lock type per door, with the fail state written out door by door.
- Controller model, door count per controller, and the event log retention.
- Power supply size, cable gauge, and the distance from the panel to each lock.
- Exit devices, alarm relay, and the sequence tested at handover.
At handover, test five things on every door: card read at the real angle, release on alarm, release on power loss where specified, door position reporting, and re-lock time. A door that passes four of five will fail in month three.
Send us the door schedule and the card type, and we will price the card access control doors as one package: reader, controller, lock and exit hardware matched to each opening. For the credential side, the RFID κάρτες για έλεγχο πρόσβασης guide compares 125 kHz and 13.56 MHz, and the Οδηγός για RFID κλειδιά-φοβ covers fob formats before you bulk order. For hardware, start from our access control RFID reader and the intelligent door access machine.