Deadbolts, peepholes and fire rated doors. What you need to know about secondary locks

Posted by Mat Steele on 19th Feb 2026

Secondary Locks & the One-Penetration Principle

What you can — and can’t — add to an apartment fire door in Queensland.

Your Apartment Door Already Has a Primary Lock

Most apartment fire doors are supplied with a compliant primary locking device. This is commonly a fire-rated mortice lock or a fire-rated cylindrical lever set.

That primary lock forms part of the tested and certified doorset. It is not simply “hardware” — it is part of a system that has been fire-tested as a complete assembly.

The One-Penetration Principle

In many strata environments, only one additional secondary penetration is permitted beyond the original configuration.

Key point: The secondary lock hole or door viewer hole must typically not exceed 32 mm.

Once that secondary penetration exists, further drilling is generally not permitted without engineered approval and re-certification.

❌ Deadbolts Are Not Permitted on Apartment Fire Doors

A deadbolt can be thrown while the door is open.
This can defeat the door’s ability to self-latch correctly.
Fire doors must self-close and self-latch every time.
Most deadbolts use a 54 mm cross-bore.
54 mm exceeds the common 32 mm secondary penetration limit.

For these reasons, traditional residential deadbolts are generally not compliant for apartment fire doors.

✅ Recommended Mechanical Secondary Option: Fire-Rated Deadlatch (Not a Deadbolt)

If a secondary locking device is permitted, it must:

Maintain compliant latching behaviour
Stay within approved penetration size limits
Be installed in an approved location

That’s why compliant deadlatches are typically recommended in strata environments.

Lockwood Products

Lockwood 002 Deadlatch (Lever)

Fire-rated compliant deadlatch with lever — suitable where permitted on apartment fire doors.

View Product

Lockwood 002 Deadlatch (Knob)

Fire-rated compliant deadlatch with knob — another compliant option where permitted.

View Product

Prefer to upgrade to smart lock options?

See our article on compatible fire door smart locks:

Apartment Fire Doors in Queensland: What Locks & Smart Locks Are Actually Compliant

Door Viewers: Measure Before You Drill

Door viewers can be a useful security addition — but on an apartment fire door they can also consume your allowed secondary penetration.

If an approved fire-rated viewer is already installed, it generally counts as the secondary penetration.

Always confirm what already exists — and measure the hole size — before any new drilling is carried out.

Need Advice on Adding Extra Security?

If you’re unsure what type of secondary lock suits your door, we can help identify compatible options before you purchase.

Gold Coast residents can book one of our experienced locksmiths via tlslocks.com.au

Prefer phone advice first? Book a qualified locksmith support call via Gold Coast Smart Locks