The most complete override locking system on an anti-ligature lockset, our 5-way SOS (Staff Override System) lockset provides five override methods to ensure you gain access.  

​​In the most common barricade scenario, the staff key dominates the internal turn/pull, ending the barricade quickly and simply.  

There are four additional emergency override methods to overcome determined barricades. We hope you rarely use them, but they may just save a life. 

5-way SOS was previously called 'Twin-Tech'.


To find out more call us on 0330 058 0988 or email us at

Most complete override access

We know barricades happen. That’s why we designed our Staff Override System (SOS), with five override methods – ensuring you gain access, even if a service user tampers with the keyway or holds the turn/pull.

What are the override methods?

1. Key
The lock and the internal turn/pull operate independently, so the key always dominates. It’s a direct mechanical override, so there’s no geared cylinder to disengage the turn/pull or clutch mechanism involved.

2. Keyway
Concealed backup override directly turns the spindle, allowing entry if keyway is blocked with foreign objects, like chewing gum or paper.

3. Turn leverage
T-bar emergency tool provides superior leverage to rotate the turn/pull, even if the service user is stronger.

4. Spindle
Safety spindle shears under heavy resistance, ensuring entry if turn/pull is immobilised. So even in the most serious barricade attempts, where the service user attempts to jam the turn/pull with their bed or body, swift access is achieved without lockcase damage.

5. Pull advantage
T-bar provides significant power advantage to pull the door open – offering better grip than an anti-ligature handle and foiling attempts by a service user to hold the door shut.

Pulling power to override barricades

Using the emergency T-bar tool, staff have a x3 pull advantage over the internal handle – ending barricades quicker.

That's just another lifesaving detail.


Create your own lockset

You asked us to make lockset specification easier. 

So we created an interactive tool – enabling you to build your own 5-way SOS lockset with ease. 

Try out the lockset builder

Our 5-way SOS locksets has numerous options for handles, application types and backplates. Use our interactive lockset builder to specify your very own 5-way SOS lockset. 


South West Yorkshire Partnership NHS Foundation Trust 

As part of an ongoing refurbishment at the Priestley Unit and Priory 2 Ward in South West Yorkshire NHS FT, a mixture of old locks and handles needed replaced due safety concerns with clutched cylinders and the insufficient grip offered by some older handles.

They chose our 5-way SOS (Staff Override System) anti-barricade locksets and Pinch grip anti-ligature handles throughout.


Overcoming limitations of existing locksets 

1. Clutch cylinders

Clutch cylinders

When a service user holds the internal turn/pull to create a barricade, the catch is designed to slip at a higher torque. Operating on a spring and ball-bearing mechanism, the key then turns and unlocks the door.

Over time, however, doors move, expand or distort, limiting clutch effectiveness and making entry times longer in stressful situations.

Wear and tear can also cause the clutch to permanently slip – trapping service users inside and causing distress and fire safety issues.

2. Geared cylinders

Geared cylinders

When the key is put into a geared cylinder, it mechanically disengages the internal turn/pull, allowing the door to be opened.

However, service users can easily rotate the turn/pull past its maximum closed position, preventing the key fully engaging. Although the key can eventually be forced home, it can damage the cylinder and the key may snap, causing risk of injury and prolonging the barricade because of a blocked keyway.

Issues also arise in rehabilitation or step- down units, where service users may have their own key. This can be inserted into another service user’s lock, disengaging the turn/pull and locking them inside, resulting in anxiety, disruption and fire safety risks.

3. Square drive

Square drive override

Square drive mechanisms are sometimes used on anti-barricade locksets to unlock the door when the keyway is blocked. However, the small square drive key doesn’t always provide enough turn leverage – allowing a strong service user to prolong a barricade by tightly holding or wedging the turn/pull.

Because the square drive key simply pulls out, it provides no pull advantage or improved grip to open a door outwards.

Plus the insecure square mechanism can easily be rotated – with two spoons, for example – minimising security and creating privacy concerns. Circular shaped mechanisms can reduce this particular risk.

Glasgow office

Level 4, Skypark 3
14 Elliot Place
G3 8EP

t: 0330 058 0988

Blackpool office 

Unit 8 Bankfield House
250 Bristol Avenue



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Safehinge Primera is a trading name of Safehinge Limited (SC304496) and Primera Limited (03708136)