A Euro Cylinder lock, also known as a pin tumbler lock, is a popular locking system used in lock cases. It features a cylindrical profile with up to eleven pins, providing security for both domestic and commercial properties. Euro Cylinder locks are designed with a standardised profile, allowing them to fit a wide range of doors and locking systems in the UK and Europe. There are three main types:
Full Euro Cylinder Lock (also know as a double cylinder or key/key where as key is used for both sides)
Half Euro Cylinder Lock (or single cylinder, accessed with a key from one side)
Thumb Turn Euro Cylinder Lock (key on one side, turn/ knob on the other for easy exit).
Both sides of the cylinder require a key to operate the lock.
Ideal for entry doors, gates, or areas requiring controlled access on both sides.
Higher security (requires key for both sides). Suitable for secure locations.
Less convenient (requires a key to unlock both sides).
Half Cylinder (HC)
A single-sided cylinder where the mechanism is only accessible from one side, and the other side is blind.
Ideal for gates, cupboards, or garage doors where only one side requires access.
Simple and cost-effective. Suitable for areas with one-way access.
Limited functionality (can only be used from one side).
Thumbturn (TT)
One side of the cylinder has a thumbturn (inside) to easily open the door without a key, while the outside requires a key.
For doors where ease of exit from the inside is important, like in homes, offices, or HMOs.
Convenient (easy exit from inside with no key). Quick access in emergencies.
Lower security (can be opened from inside without a key).
According to UK fire safety regulations, in blocks of flats, all doors to individual flats must be able to be unlocked and opened from the inside without the need for a key. The same applies to Houses in Multiple Occupation (HMOs). For any bedrooms that are locked, the lock must allow the door to be opened from the inside without a key. This requirement is primarily for safety reasons. In the event of a fire or emergency, it’s crucial that residents can exit quickly. Having to search for a key could cause dangerous delays, potentially putting lives at risk.
Euro Cylinders and Thumbturn Locks
If a Euro Cylinder lock is installed in a flat or HMO, as is common, it should be a thumbturn lock. These locks require a key to operate from the outside, but from the inside, a simple knob or thumbturn allows the door to be opened easily without a key.
Fire Safety Regulations and Thumbturn Locks
If you’re a tenant and your door cannot be unlocked without a key from the inside, you should request that your landlord or property management replace the lock with one that complies with regulations. Failure to do so could mean that the landlord is in violation of the law. In an emergency, a delay in exiting the property due to an inaccessible door could lead to severe consequences. If you’re a landlord,
Each individual cylinder comes with its own unique key or key set. Ideal for private offices, flats, and individual security needs.
Keyed Alike
CYKKA
CYTTA
Each cylinder ordered (in the same transaction) uses the same key. Multiple locks can be opened with the same key. Useful for homes, offices, or businesses where shared access is needed. Keyed alike cylinders are made to order, which may extend shipping time. Contact us for details.
Keyed Alike Pairs
CYKKAP
CYTTAP
A pair of euro cylinders that are ready to ship at the time of purchase and allow a single key to operate both locks. Commonly used for residential front and back doors or French doors. Note: Only each pair is keyed alike.
Master Key
CYKKM
CYTTM
Each cylinder ordered (in the same transaction) has its own unique key, but all locks can also be opened by a master key. Used in hotels, office buildings, rental properties, and large facilities. Master key systems are made to order, which may extend shipping time. Contact us for details.
There are various standards and certifications given to Euro Cylinders but common examples include:
Certification/Standard
Description
BS EN 1303
European standard for cylinder locks, covering mechanical strength, corrosion resistance, and security against tampering (picking, drilling, bumping).
TS007 (UK Standard)
British standard specifically for door cylinder locks. Gives ratings (1 or 3 stars), focusing on resistance to physical attacks like bumping, drilling, picking, and snapping.
Sold Secure
Certification for locks that meet rigorous security tests for forced entry attempts and attacks. The Sold Secure Diamond rating offers the highest level of security. Secure is a broader organisation that tests and approves a wide range of security products
Kitemark (BSI)
UK certification mark given by the British Standards Institution, indicating compliance with standards like BS EN 1303 and TS007 for safety, durability, and security.
Secured by Design (SBD)
UK police-backed certification indicating the Euro Cylinder meets enhanced security standards to resist various attack methods. Secured by Design is a broader organisation that tests and approves a wide range of security products
BS8621
Specifies requirements for locks on fire doors that allow emergency egress without a key, ensuring safe exit during a fire. It applies to single-point locks used on FD30 or FD60 fire doors. These locks must maintain fire resistance while enabling quick and safe evacuation.
To determine the dimensions of your euro cylinder lock, measure from the center screw hole to the outer edges. This yields two measurements, which together represent the size of your door lock. The sum of these two measurements should match the overall length of the cylinder. For instance, a 40/40 configuration would total 80mm in length. The measurements for A and B should equal C if you measured your cylinder correctly. It is important to note there is no industry standard method in the way offset cylinder sizes are displayed. Some manufacturers would say a 45/35 is 45 Internal and 35 External while others would say the opposite where 45 would be the External and 35 is the Internal. To help with ordering from us online, SDH measures all our cylinders as INT/EXT so a 45/35 would be 45 Internal and 35 External.
Measurement Type
Standard Cylinder
Thumbturn Cylinder
Diagram
Overall Length (C)
Measure from one end of the cylinder to the other.
Same as standard cylinder—measure the total length (Excluding the Turn / Knob).
Internal Side (A)
Measure from the center fixing screw hole to the Internal side.
Measure from the screw hole to the thumbturn side (Excluding the Turn / Knob).
External Side (B)
Measure from the center fixing screw hole to the External face.
Most standard Euro cylinders with keys on both sides are reversible and can be installed in either direction, as they do not have a specific internal or external side. However, there are some exceptions. Euro cylinders with a thumb turn knob on one side do have a designated internal and external side. When measuring for a thumb turn cylinder, be sure to identify which of the two measurements corresponds to the internal side. Additionally, high-security cylinders may have a specific external side, as security features are typically concentrated on the external side. These cylinders will tend to have the text 'EXT' marked on the cylinder indicating the external side. If upgrading to a high-security cylinder (like a 3 star cylinder), check whether it has a defined external side before installation. SDH measures all our cylinders as INT/EXT so a 45/35 would be 45 Internal and 35 External.
Replacing a door cylinder is a relatively straightforward process. You can follow our detailed video below or follow our handy step by step guide which leads you through the process start to finish.
