Practical Guide: DIN WC/Privacy Locks (Bathroom Locks) — Safe Privacy on Fire Doors

FDH Team
Oct 21
2 min read

DIN BATHROOM LOCK & KEEPER

What is a WC/Privacy lock?

A DIN WC/Privacy (bathroom) lock is a mortice sash lock with a thumbturn-thrown bolt (inside) and an emergency coin/slot release (outside). It gives privacy without needing a key.

Where you’ll use it: toilets, accessible WCs, changing rooms, shower rooms.

Key sizes at a glance

Centres: 72 mm (handle follower ↔ privacy turn)
Backset: 60 mm typical UK stock (DIN often 55 mm) — measured from forend/door edge to follower centre
Follower size: Handle 8 mm; privacy follower 5–8 mm (match your set)
Forend: 235 × 24 mm · Case height: 235 mm · Bolt throw: ≈ 20 mm

Compliance basics

Emergency release required on the corridor side (coin/slot). Test it after fitting.
Escape: Ensure single-action egress where relevant (no key needed from inside).
Accessibility: Lever handles only; easy-grip thumbturns; DIN 72 mm centres prevent hand clash.
Fire performance: Use the door maker’s approved lock + intumescent kit (behind forend and keep, around case if specified).

Fitting notes (field-proven)

Mark 72 mm centres; confirm follower sizes match furniture.
Check backset (60 mm typical) before morticing.
Mortice tight; don’t weaken the edge; pack the keep solidly.
Fit intumescent: behind forend, behind keep, and around case if required.
Through-bolt furniture where possible; trim the privacy spindle carefully (no bind).
Align the keep so latch + bolt both seat fully (no rattle).
From outside, use the coin/slot to confirm emergency release.
Record codes, batch, and rating for QA.

Maintenance checks

Handle returns latch smoothly; no stiffness.
Thumbturn throws bolt fully (≥ 20 mm); coin/slot release works.
Fixings tight; no spindle bind; roses seated.
Intumescent present & intact.
Keep alignment correct; no rub or partial engagement.

Common faults (fast fixes)

Turn stiff → spindle too long / follower mis-aligned.
Hand clashes with turn → wrong centres (not 72 mm).
Latch works but bolt doesn’t → wrong case or mis-packed keep.
Missing intumescent → rework to evidence.
Indicator bolt used instead of privacy set where emergency release is required → change to WC/Privacy lock.