The hard part isn’t the tech, it’s the door and the gate
An electronic door lock (智能門鎖) verifies who you are and drives the bolt, so you no longer rely on a key; a smart lock adds connectivity, an app, voice, schedules, on top. The good news for a renovation is that these locks run on batteries, not mains, so fitting one needs no new wiring. The real Hong Kong difficulty is elsewhere: the pairing of an outer metal gate with an inner door, and the fire-escape rules that decide what you’re allowed to fit at all.
Gate and door: two different locks
Most Hong Kong entrances have an outer metal gate (a security barrier) and an inner door (which carries the fire-resisting and self-closing function). Their lock bodies are not interchangeable, a gate-frame lock and a solid-leaf lock are built differently. A few practical dimensions decide the fit:
| Detail | Typical |
|---|---|
| Clearance between door leaf and metal gate | 70–80 mm (so the handle and viewer clear) |
| Timber door-leaf thickness | ~45–60 mm |
| Internal lock-body depth | ~12 cm |
| Battery life, everyday use | ~10–12 months |
HOS and public-rental steel gates deserve a special warning: their tube frame differs from mainland security doors, so most standard mainland smart locks simply won’t fit. Specify a model marked for steel-gate installation and a fitter who has adapted them locally, otherwise the bolt jams and the gate won’t close.
The escape and fire-door rules (non-negotiable)
- A lock on an exit door must be openable from inside at any time without a key, a thumbturn or single action, never a double-cylinder deadlock needing a key on both sides.
- Any electrically driven lock must fail open, not shut, on power failure, with a mechanical key backup or an emergency power contact.
- A fire door is certified as a whole assembly. Drilling, slotting or over-cutting it removes the core and the intumescent (fire-expanding) material and can void the rating. Treat the existing leaf as a fire door, confirm its rating from the approved plans, reuse the existing lock hole, keep the closer and seals, and pick a lock with fire-test evidence for that door type.
- Altering the metal gate is a Minor Works item, it needs a registered contractor with notification. And both door and gate should open inward, toward your flat: a leaf swinging out onto the common corridor obstructs escape and can be treated as unauthorised.
Choosing how it unlocks
Most locks offer several methods, each with a trade-off: fingerprint (convenient, but unreliable on worn or damp prints, think older hands and children); PIN (use a virtual prefix/suffix so onlookers can’t read your code); proximity card (good for kids and elderly; a lost card can be deleted on the lock); app (usually Bluetooth, some Wi-Fi); face recognition (contactless); and the physical key, which almost every model keeps as the zero-battery fallback. For remote unlocking or automation you’ll need built-in Wi-Fi, a Zigbee gateway, or a Matter-over-Thread setup, plain Bluetooth only works up close.
How Primeworks handles this
We plan the entrance as a system, the gate, the fire-rated door, the clearance between them, and the escape function, before a lock is chosen, so what gets specified actually fits and stays compliant. Fitting the lock itself is a straightforward line in our scope; getting the door-and-gate detailing right is the part that protects you, and that’s designed in from the start.