Full lock replacement on the same footprint

The old lock case is removed and a smart lock with the same footprint takes its place. This is the dominant approach in East and Southeast Asia, where push-pull digital locks replace mortise sets on HDB, condo and apartment doors.

Door untouched: no · Keeps mechanical key: no · Difficulty: ●●●●

Applies to these lock types

Singapore HDB main-door mortise set and metal gate lock · Korean push-pull digital lock base (mortise) · Japanese mortise case and cylinder (MIWA / GOAL style) · Mortise lockset (ANSI/BHMA A156.13) · Australian deadlatch and deadlock

Measurements this architecture needs

  • Backset (Dornmaß)
  • Centre distance, spindle-to-cylinder (Entfernung / PZ)
  • Faceplate width × length
  • Lock case width × height × depth
  • Door thickness
  • Handing (DIN left / right)
  • Fire rating of the door leaf

Adapter interfaces to design

  • Lock case replacement matrix: backset × centre distance × faceplate length
  • Strike and frame pocket alignment shims
  • Fire-rated door compatibility: certification of the whole doorset, not just the lock
  • Gate-clearance slim profiles for doors opening onto a metal gate

Design targets

Targets marked "from standard" come from the cited document. Targets marked "practice" are our engineering guidance and must be verified for your design.

TargetValueBasis
Cycle life A156.13 Grade 2 = 800,000; Grade 3 = 800,000; Grade 1 = 1,000,000 from standard
Allegion's published table. Some vendor literature quotes 800,000 for Grade 1 bored locks under A156.2 — check which standard edition is being cited.
Fire rating 30 or 60 minutes per local code; in Singapore the doorset needs an SCDF-recognised Certificate of Conformity from standard

Known blockers

  • Fire-rated doors: an uncertified lock can void the door's rating and, in a claim, the insurance.
  • Old doors have non-standard pockets; every 'standard' has three local variants.
  • Gate clearance: a deep handle hits the gate handle on many Asian entrances.

Design checklist

  • Publish the exact footprint envelope you replace, not a marketing photo.
  • Offer a paper or cardboard template the installer can hold against the door.
  • For fire doors, state the certificate the replacement carries and who issues it.
  • Keep a mechanical key or a powered-off egress path.

Examples on the market

Sources

Engineer feedback