Thumbturn Cylinders

Aged Bronze 35/45T 5pin Euro Cylinder/Thumbturn, from our current range.

What is a thumbturn cylinder?

A thumbturn cylinder is a euro cylinder with a key operated from the outside as normal, but a simple turn knob, rather than a keyhole, on the inside. This means the door can be unlocked and opened quickly from within without needing to find a key, which is a genuinely important safety feature in an emergency, while the outside remains secured by key as usual.

Many building regulations and fire safety guidance recommend or require thumbturn cylinders on final exit doors, so that occupants can always escape quickly regardless of whether a key is to hand.

Where thumbturn cylinders are used

• Final exit doors – commonly required or recommended by fire safety guidance so occupants can escape without a key
• Family homes – useful for a household with children or anyone who might need to exit quickly in an emergency
• Rental properties – often specified by landlords to meet fire safety obligations

Choosing the right thumbturn cylinder

A few practical points are worth checking before you buy:

• Size – measured the same way as a standard euro cylinder, in two halves from the fixing screw
• Anti-snap rating – look for a certified anti-snap thumbturn cylinder for the best security
• Balance of security and safety – a thumbturn trades a small amount of external-only security for a significant safety benefit; this is generally the right trade-off on a habitable property's final exit

Related products

Browse our current range via search, or see the related Euro Cylinders guide.

Frequently asked questions

Is a thumbturn cylinder less secure than a standard cylinder?

It offers slightly less resistance from the inside than a keyed cylinder, since the thumbturn is intended to allow quick release without a key. The outside remains protected in the same way as a standard cylinder.

Do I need a thumbturn cylinder by law?

Building regulations and fire safety guidance often recommend or require them on final exit doors; it is worth checking current guidance for your specific property type.

Can I fit a thumbturn cylinder to an existing uPVC door?

Yes, in most cases a standard euro cylinder can be swapped for a correctly sized thumbturn version without further alteration to the door.

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